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Papers by Alexander Nyarko

International Journal of Pharmacy and Pharmaceutical Sciences, 2016

Objective: The objectives of this study were to investigate the cytotoxic effects of extracts and... more Objective: The objectives of this study were to investigate the cytotoxic effects of extracts and fractions of Albizia zygia roots (AZR) on human T-lymphoblast-like leukemia (Jurkat), prostate cancer (LNCap) and breast cancer (MCF-7) cells and the apoptotic effect in Jurkat cells. Methods: Aqueous and hydroethanolic extracts were prepared and tested for cytotoxic effects on the cell lines using t he tetrazolium-based colorimetric assay. Apoptosis induction was determined by DNA fragmentation, cell morphological changes, flow cytometric and mitochondrial membrane potential assays. Results : Both aqueous and hydroethanolic extracts were more cytotoxic to Jurkat cells than the other cell lines, with selective index (SI) values of 104.4 and 86.6, respectively. The SI values of the extracts on LNCap cells were 9.0 and 35.4, respectively. Some of the fractions were non-cytotoxic. Nevertheless petroleum ether fraction was cytotoxic towards MCF-7 cells with SI value of 2.4. The hydroethanol...

Journal of Natural Science, Biology and Medicine, 2018

Background: Dissotis rotundifolia, commonly referred to as pink lady, has several medicinal uses ... more Background: Dissotis rotundifolia, commonly referred to as pink lady, has several medicinal uses including peptic ulcer. This study investigated the inhibitory effects of D. rotundifolia extract on H+/K+-ATPase and also assessed its antiradical activity. In silico study of some isolated compounds of this plant was also carried out to affirm the suspected binding properties of extract to H+/K+-ATPase enzyme. Materials and Methods: D. rotundifolia whole plant extract was obtained after extraction process and then assessed for its ability to scavenge free radicals in four in vitro test models. Its ability to inhibit the activity of H+/K+-ATPase enzyme was also evaluated. Molecular docking was carried out on phytoconstituents, namely, vitexin, isovitexin, orientin, and isoorientin reported to be present in the whole plant extract. Results: Data obtained indicated that D. rotundifolia extract (DRE) exhibits strong antioxidant activity. DRE also showed inhibitory effects on H+/K+-ATPase enzyme activity. Docking studies affirmed the in vitro binding effect of the extract to H+/K+-ATPase. Conclusion: These findings suggest that the plant extract possess antioxidant and antipeptic ulcer activity.

Journal of Ethnopharmacology, 2019

Ethnopharmacological relevance: Majority of people living in Ghana and many other developing coun... more Ethnopharmacological relevance: Majority of people living in Ghana and many other developing countries rely on traditional medicinal plants for their primary healthcare. These plants are used either alone or in combination to manage a wide range of ailments. However, most of these plants have not been investigated for their mutagenic effects. Aim of the study: This study, therefore aimed at evaluating the mutagenic activity of the most frequently used medicinal plants amongst Ghanaians living within the Accra metropolis, Ghana. Materials and methods: Validated questionnaires were administered to 53 herbalists and herbal medicines dealers in the Makola, Madina and Nima communities. Plants that were identified as being frequently used were investigated for their mutagenicity using the Ames test. Results: A total of 110 medicinal plants belonging to 53 families were identified as most frequently used plants in the study sites. These are used to treat various ailments including gastric ulcer, fever, malaria, male impotence, diabetes, typhoid, high blood pressure and candidiasis. Thirteen samples (52%) showed moderate to high mutagenicity in the TA 100 bacterial strain before and after metabolism with rat liver enzyme. Conclusions: The study showed that over half of the frequently used medicinal plants showed moderate to high mutagenicity before and after metabolism at the concentration of a 100 μg/mL. This may have implications for the safety of those who use them to manage diseases. These findings will suggest the need for an in-depth study of the mutagenic potentials of plants commonly used by indigenous people and more especially for those exhibiting high mutagenicity in this study.

BMC Infectious Diseases, 2019

Background: Distribution of Hepatitis C virus (HCV) genotypes varies significantly worldwide. Gen... more Background: Distribution of Hepatitis C virus (HCV) genotypes varies significantly worldwide. Genomic diversity between genotypes has implications for treatment, vaccine development and optimal design of HCV diagnostic assays. Molecular characterization of HCV in different geographical areas is therefore very essential for management and public health control of HCV infection. This study investigated the molecular epidemiology and characteristics of HCV genotypes in healthy individuals in Accra, Ghana. Methods: An experimental study was carried out on blood samples obtained from voluntary blood donors. Two hundred samples were initially screened for HCV antibodies and infection was confirmed by RNA detection through RT-PCR of the 5′-untranslated region (5'UTR). The core gene sequences were analysed for HCV genotype determination by genotype-specific PCR; and then by cloning and direct sequencing followed by phylogenetic analysis. The sequences were further analysed in detail by similarity plotting. Results: Molecular diagnosis confirmed the presence of HCV RNA in 2 out of 200 (1%) blood donors. Initial genotyping by genotype-specific PCR identified all two infections as subtypes 2a and 2b of genotype 2. Extensive evolutionary and genetic analyses indicated two epidemiological profiles. First, phylogenetic tree topologies clearly showed that, collectively, the core sequences of the Ghanaian HCV isolates belong to a single, distinct genetic group within HCV genotype 2 cluster, with high genetic similarity and rapid sequence variation in a single individual. Second, the sequences are mosaics comprising 2e and other genotype 2 subtype fragments. The analyses underscore a unique and complex HCV genotype 2 core sequence profile of the Ghanaian isolates.

BMC Public Health, 2019

Background: Malaria remains endemic in Ghana despite several interventions. Studies have demonstr... more Background: Malaria remains endemic in Ghana despite several interventions. Studies have demonstrated very high levels of asymptomatic malaria parasitaemia in both under-five and school-age children. Mass testing, treatment and tracking (MTTT) of malaria in communities is being proposed for implementation with the argument that it can reduce parasite load, amplify gains from the other control interventions and consequently lead to elimination. However, challenges associated with implementing MTTT such as feasibility, levels of coverage to be achieved for effectiveness, community perceptions and cost implications need to be clearly understood. This qualitative study was therefore conducted in an area with ongoing MTTT to assess community and health workers' perceptions about feasibility of scale-up and effectiveness to guide scale-up decisions. Methods: This qualitative study employed purposive sampling to select the study participants. Ten focus group discussions (FGDs) were conducted in seven communities; eight with community members (n = 80) and two with health workers (n = 14). In addition, two in-depth interviews (IDI) were conducted, one with a Physician Assistant and another with a Laboratory Technician at the health facility. All interviews were recorded, transcribed, translated and analyzed using QSR NVivo 12. Results: Both health workers and community members expressed positive perceptions about the feasibility of implementation and effectiveness of MTTT as an intervention that could reduce the burden of malaria in the community. MTTT implementation was perceived to have increased sensitisation about malaria, reduced the incidence of malaria, reduced household expenditure on malaria and alleviated the need to travel long distances for healthcare. Key challenges to implementation were doubts about the expertise of trained Community-Based Health Volunteers (CBHVs) to diagnose and treat malaria appropriately, side effects of Artemisinin-based Combination Therapies (ACTs) and misconceptions that CBHVs could infect children with epilepsy. Conclusion: The study demonstrated that MTTT was perceived to be effective in reducing malaria incidence and related hospital visits in participating communities. MTTT was deemed useful in breaking financial and geographical barriers to accessing healthcare. The interventions were feasible and acceptable to community members, despite observed challenges to implementation such as concerns about CBHVs' knowledge and skills and reduced revenue from internally generated funds (IGF) of the health facility.

Marine drugs, Jan 29, 2017

Leishmaniasis is a vector-borne neglected tropical disease caused by protozoan parasites of the L... more Leishmaniasis is a vector-borne neglected tropical disease caused by protozoan parasites of the Leishmania genus and transmitted by the female Phlebotomus and Lutzomyia sand flies. The currently prescribed therapies still rely on pentavalent antimonials, pentamidine, paromomycin, liposomal amphotericin B, and miltefosine. However, their low efficacy, long-course treatment regimen, high toxicity, adverse side effects, induction of parasite resistance and high cost require the need for better drugs given that antileishmanial vaccines may not be available in the near future. Although most drugs are still derived from terrestrial sources, the interest in marine organisms as a potential source of promising novel bioactive natural agents has increased in recent years. About 28,000 compounds of marine origin have been isolated with hundreds of new chemical entities. Recent trends in drug research from natural resources indicated the high interest of aquatic eukaryotic photosynthetic organi...

Planta Medica, 2016

Buruli ulcer (BU) is the third most prevalent mycobacteriosis, after tuberculosis and leprosy. Th... more Buruli ulcer (BU) is the third most prevalent mycobacteriosis, after tuberculosis and leprosy. The currently recommended combination of rifampicin-streptomycin suffers from side effects and poor compliance, which leads to reliance on local herbal remedies. The objective of this study was to investigate the antimycobacterial properties and toxicity of selected medicinal plants. Sixty-five extracts from 27 plant species were screened against Mycobacterium ulcerans and Mycobacterium smegmatis, using the Resazurin Microtiter Assay (REMA). The cytotoxicity of promising extracts was assayed on normal Chang liver cells by an MTT assay. Twenty five extracts showed activity with minimal inhibitory concentration (MIC) values ranging from 16 µg/mL to 250 µg/mL against M. smegmatis, while 17 showed activity against M. ulcerans with MIC values ranging from 125 µg/mL to 250 µg/mL. In most of the cases, plant extracts with antimycobacterial activity showed no cytotoxicity on normal human liver cells. Exception were Carica papaya, Cleistopholis patens, and Polyalthia suaveolens with 50% cell cytotoxic concentrations (CC 50) ranging from 3.8 to 223 µg/mL. These preliminary results support the use of some West African plants in the treatment of Buruli ulcer. Meanwhile, further studies are required to isolate and characterize the active ingredients in the extracts.

Journal of Parasitology Research, 2017

Schistosomiasis is a Neglected Tropical Diseases which can be prevented with mass deworming chemo... more Schistosomiasis is a Neglected Tropical Diseases which can be prevented with mass deworming chemotherapy. The reliance on a single drug, praziquantel, is a motivation for the search of novel antischistosomal compounds. This study investigated the anthelmintic activity of the stem bark and roots ofRauwolfia vomitoriaagainst two life stages ofSchistosoma mansoni. Both plant parts were found to be active against cercariae and adult worms. Within 2 h of exposure all cercariae were killed at a concentration range of 62.5–1000 µg/mL and 250–1000 µg/mL ofR. vomitoriastem bark and roots, respectively. The LC50values determined for the stem bark after 1 and 2 h of exposure were 207.4 and 61.18 µg/mL, respectively. All adult worms exposed to the concentrations range of 250–1000 µg/mL for both plant parts died within 120 h of incubation. The cytotoxic effects against HepG2 and Chang liver cell assessed using MTT assay method indicated that both plant extracts which were inhibitory to the proli...

Biomarker Research, 2016

There is an urgent need for new anti-malaria drugs with broad therapeutic potential and novel mod... more There is an urgent need for new anti-malaria drugs with broad therapeutic potential and novel mode of action, for effective treatment and to overcome emerging drug resistance. Plant-derived anti-malarials remain a significant source of bioactive molecules in this regard. The multicomponent formulation forms the basis of phytotherapy. Mechanistic reasons for the polypharmacological effects of plants constitute increased bioavailability, interference with cellular transport processes, activation of pro-drugs/deactivation of active compounds to inactive metabolites and action of synergistic partners at different points of the same signaling cascade. These effects are known as the multi-target concept. However, due to the intrinsic complexity of natural products-based drug discovery, there is need to rethink the approaches toward understanding their therapeutic effect. This review discusses the multi-target phytotherapeutic concept and its application in biomarker identification using the modified reverse pharmacology-systems biology approach. Considerations include the generation of a product library, high throughput screening (HTS) techniques for efficacy and interaction assessment, High Performance Liquid Chromatography (HPLC)-based anti-malarial profiling and animal pharmacology. This approach is an integrated interdisciplinary implementation of tailored technology platforms coupled to miniaturized biological assays, to track and characterize the multi-target bioactive components of botanicals as well as identify potential biomarkers. While preserving biodiversity, this will serve as a primary step towards the development of standardized phytomedicines, as well as facilitate lead discovery for chemical prioritization and downstream clinical development.

Biomarker Research, 2016

It is crucial to develop new antischistosomal drugs since there is no vaccine and the whole world... more It is crucial to develop new antischistosomal drugs since there is no vaccine and the whole world is relying on only a single drug for the treatment of schistosomiasis. One of the obstacles to the development of drugs is the absence of the high throughput objective screening methods to assess drug compounds efficacy. Thus for identification of new drug compounds candidates, fast and accurate in vitro assays are unavoidable and more research efforts in the field of drug discovery can target schistosomula. This review presents a substantial overview of the present state of in vitro drug sensitivity assays developed so far for the determination of anti-schistosomula activity of drug compounds, natural products and derivatives using newly transformed schistosomula (NTS). It highlights some of the challenges involved in in vitro compound screening using NTS and the way forward.

Evidence-Based Complementary and Alternative Medicine, 2016

Objective. This study investigated the elemental composition of unsweetened natural cocoa powder ... more Objective. This study investigated the elemental composition of unsweetened natural cocoa powder (UNCP), its effect on nitric oxide, and its hepatoprotective potential during simultaneous administration with high-dose artemether/lumefantrine (A/L).Method. Macro- and microelements in UNCP were analyzed with EDXRF spectroscopy. Thirty (30) male guinea-pigs were then divided into five groups. For groups 3 (low-dose), 4 (medium-dose), and 5 (high-dose), the animals received oral UNCP prophylactically for 14 days. Group 1 received distilled water (14 days) and group 2 A/L for the last 3 days (days 12 to 14). After euthanisation, biochemical and histopathological examinations were carried out in all groups.Results. Phytochemical analysis of UNCP showed the presence of saponins, flavonoids, tannins, and cardiac glycosides. Thirty-eight (38) macro- and microelements were found. UNCP produced significant decreases in ALT, ALP, GGT, and AST levels. A significant increase in total protein leve...

Food Science & Nutrition, 2016

Moringa oleifera (M. oleifera), a green leafy vegetable, is a good source of minerals and vitamin... more Moringa oleifera (M. oleifera), a green leafy vegetable, is a good source of minerals and vitamins which could be consumed as part of diet to improve human health and well-being. Drying M. oleifera leaves could make it readily available for use as a food fortificant. The objectives of the study were to determine micromineral and β-carotene content of dried M. oleifera leaves, and leafincorporated local dishes, and also assess school children's (4-12 yr) acceptability of dried M. oleifera leaf-incorporated local dishes and feasibility of introducing dried leaves into a school lunch menu. M. oleifera leaves were solar dried, milled into powder, and packaged into polythene bags. Moisture level in the dried leaves and pH were determined. Minerals in the leaf powder were determined by Atomic Absorption Spectrophotometry (AAS). Beta-carotene levels were determined by spectrophotometry. Acceptability tests of dishes fortified with M. oleifera leaf powder were conducted with score sheets (Smileys) on a 5-point hedonic scale of "Like Extremely" to "Dislike Extremely", and dishes ranked to determine preference. Dried M. oleifera leaves contained high levels of micronutrients: 0.36 ± 0.04 mg/100 g Copper (Cu); 5.80 ± 0.68 mg/100 g Manganese (Mn); 20.96 ± 1.37 mg/100 g Iron (Fe); 6.79 ± 1.82 mg/100 g Zn; and 21.42 ± 1.67 mg/100 g βcarotene. The dishes showed significant levels of these minerals compared to the nonfortified dishes (P < 0.05). M. oleifera leaf-fortified dishes were also highly acceptable to the children (highest mean score of 5.0 ± 0 of 5 and lowest of 3.50 ± 1.43 of 5). M. oleifera leaf powder contains high levels of the micronutrients βcarotene, Zn, Mn, and Fe, comparable to levels found in amaranth and spinach. M. oleifera leaf-fortified local dishes were well accepted by children in Ada-East district. M. oleifera leaf fortified dishes could be good sources of βcarotene and other minerals for children vulnerable to malnutrition in Ghana.

Molecules, 2016

Buruli ulcer (BU) is the third most prevalent mycobacteriosis, after tuberculosis and leprosy. Th... more Buruli ulcer (BU) is the third most prevalent mycobacteriosis, after tuberculosis and leprosy. The currently recommended combination of rifampicin-streptomycin suffers from side effects and poor compliance, which leads to reliance on local herbal remedies. The objective of this study was to investigate the antimycobacterial properties and toxicity of selected medicinal plants. Sixty-five extracts from 27 plant species were screened against Mycobacterium ulcerans and Mycobacterium smegmatis, using the Resazurin Microtiter Assay (REMA). The cytotoxicity of promising extracts was assayed on normal Chang liver cells by an MTT assay. Twenty five extracts showed activity with minimal inhibitory concentration (MIC) values ranging from 16 µg/mL to 250 µg/mL against M. smegmatis, while 17 showed activity against M. ulcerans with MIC values ranging from 125 µg/mL to 250 µg/mL. In most of the cases, plant extracts with antimycobacterial activity showed no cytotoxicity on normal human liver cells. Exception were Carica papaya, Cleistopholis patens, and Polyalthia suaveolens with 50% cell cytotoxic concentrations (CC 50) ranging from 3.8 to 223 µg/mL. These preliminary results support the use of some West African plants in the treatment of Buruli ulcer. Meanwhile, further studies are required to isolate and characterize the active ingredients in the extracts.

Data in Brief, 2016

This article contains data on in vitro antimycobacterial activity and cytotoxicity of hydroethano... more This article contains data on in vitro antimycobacterial activity and cytotoxicity of hydroethanolic crude extracts from five selected medicinal plant species traditionally used to treat tuberculosis in Ghanaian ethnomedicine, see "Medicinal plants used to treat TB in Ghana" [1]. The interpretation and discussion of these data and further extensive insights into drug discovery against tuberculosis from natural products of plant biodiversity can be found in "Antimycobacterial and cytotoxic activity of selected medicinal plant extracts" [2].

Journal of Ethnopharmacology, 2016

Ethnopharmacological relevance: Tuberculosis (TB) caused by Mycobacterium tuberculosis remains an... more Ethnopharmacological relevance: Tuberculosis (TB) caused by Mycobacterium tuberculosis remains an ongoing threat to human health. Several medicinal plants are used traditionally to treat tuberculosis in Ghana. The current study was designed to investigate the antimycobacterial activity and cytotoxicity of crude extracts from five selected medicinal plants. Material and methods: The microplate alamar blue assay (MABA) was used for antimycobacterial studies while the CellTiter 96 s AQ ueous Assay, which is composed of solutions of a novel tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt; MTS] and an electron coupling reagent (phenazine methosulfate) PMS, was used for cytotoxic studies. Correlation coefficients were used to compare the activity of crude extracts against nonpathogenic strains and the pathogenic Mycobacterium tuberculosis subsp.tuberculosis. Results: Results of the MIC determinations indicated that all the crude extracts were active on all the three tested mycobacterial strains. Minimum inhibitory concentration values as low as 156.3 mg/mL against M. tuberculosis; Strain H37Ra (ATCC s 25,177™) were recorded from the leaves of Solanum torvum Sw. (Solanaceae). Cytotoxicity of the extracts varied, and the leaves from S. torvum had the most promising selectivity index. Activity against M. tuberculosis; Strain H37Ra was the best predictor of activity against pathogenic Mycobacterium tuberculosis subsp.tuberculosis (correlation coefficient ¼0.8). Conclusion: The overall results of the present study provide supportive data on the use of some medicinal plants for tuberculosis treatment. The leaves of Solanum torvum are a potential source of anti-TB natural products and deserve further investigations to develop novel anti-TB agents against sensitive and drug resistant strains of M. tuberculosis.

BioMed Research International, 2015

Mycobacterium ulceransdisease has been a serious threat for people living in rural remote areas. ... more Mycobacterium ulceransdisease has been a serious threat for people living in rural remote areas. Due to poverty or availability of traditional medicine these populations rely on herbal remedies. Currently, data on the anti-Mycobacterium ulceransactivity of plants, so far considered community-based knowledge, have been scientifically confirmed, concomitantly with some medicinal plants used to treat infectious diseases in general. Products derived from plants usually responsible for the biological properties may potentially controlMycobacterium ulceransdisease; numerous studies have aimed to describe the chemical composition of these plant antimicrobials. Thus, the present work provides the first compilation of medicinal plants that demonstrated inhibitory potential onMycobacterium ulcerans. This work shows that the natural products represent potential alternatives to standard therapies for use as curative medicine forMycobacterium ulceransdisease.

International Journal of Mycobacteriology, 2015

Currently, one third of the world's population is latently infected with Mycobacterium tuberculos... more Currently, one third of the world's population is latently infected with Mycobacterium tuberculosis (MTB), while 8.9-9.9 million new and relapse cases of tuberculosis (TB) are reported yearly. The renewed research interests in natural products in the hope of discovering new and novel antitubercular leads have been driven partly by the increased incidence of multidrug-resistant strains of MTB and the adverse effects associated with the first-and second-line antitubercular drugs. Natural products have been, and will continue to be a rich source of new drugs against many diseases. The depth and breadth of therapeutic agents that have their origins in the secondary metabolites produced by living organisms cannot be compared with any other source of therapeutic agents. Discovery of new chemical molecules against active and latent TB from natural products requires an interdisciplinary approach, which is a major challenge facing scientists in this field. In order to overcome this challenge, cutting edge techniques in mycobacteriology and innovative natural product chemistry tools need to be developed and used in tandem. The present review provides a cross-linkage to the most recent literature in both fields and their potential to impact the early phase of drug discovery against TB if seamlessly combined.

Bioorganic & Medicinal Chemistry Letters, 2015

International Journal of Toxicology, 2014

Polyhexamethylene guanidine hydrochloride (PHMGH) is used worldwide as an antimicrobial agent wit... more Polyhexamethylene guanidine hydrochloride (PHMGH) is used worldwide as an antimicrobial agent with broad spectra of activity and also for treating pool water. This non-GLP preliminary study aims at investigating in a subchronic toxicity study possible effects at supra-optimal doses of this biocide. Both acute and subchronic toxicity studies were conducted. LD50 for PHMGH was estimated to be 600 mg/kg (ie LC50 2 ml of 7.5% solution) when administered as a single dose by gavage via a stomach tube in accordance with the expected route of administration. The acute studies showed that the median lethal dose (LD50) of 600 mg/kg was accompanied by signs of neurotoxicity. Haematological and biochemical parameters of subchronic toxicity studies were non-significant. Subchronic doses of 0.006 mg/kg, 0.012 mg/kg and 0.036 mg/kg were administered. 20% of the animals at a dose of 0.006 mg/kg and 0.036 mg/kg showed mild degrees of hydropic changes in proximal tubules while 10% of animals at all t...

Biochemical and Biophysical Research Communications, 2015

Despite remarkable advances in combination antiretroviral therapy (cART), human immunodeficiency ... more Despite remarkable advances in combination antiretroviral therapy (cART), human immunodeficiency virus type 1 (HIV-1) infection remains incurable due to the incomplete elimination of the replication-competent virus, which persists in latent reservoirs. Strategies for targeting HIV reservoirs for eradication that involves reactivation of latent proviruses while protecting uninfected cells by cART are urgently needed for cure of HIV infection. We screened medicinal plant extracts for compounds that could reactivate the latent HIV-1 provirus and identified a procyanidin trimer C1 derived from Theobroma cacao as a potent activator of the provirus in human T cells latently infected with HIV-1. This reactivation largely depends on the NF-κB and MAPK signaling pathways because either overexpression of a super-repressor form of IκBα or pretreatment with a MEK inhibitor U0126 diminished provirus reactivation by C1. A pan-PKC inhibitor significantly blocked the phorbol ester-induced but not the C1-induced HIV-1 reactivation. Although C1-induced viral gene expression persisted for as long as 48 h post-stimulation, NF-κB-dependent transcription peaked at 12 h post-stimulation and then quickly declined, suggesting Tat-mediated self-sustainment of HIV-1 expression. These results suggest that procyanidin C1 trimer is a potential compound for reactivation of latent HIV-1 reservoirs.

International Journal of Pharmacy and Pharmaceutical Sciences, 2016

Objective: The objectives of this study were to investigate the cytotoxic effects of extracts and... more Objective: The objectives of this study were to investigate the cytotoxic effects of extracts and fractions of Albizia zygia roots (AZR) on human T-lymphoblast-like leukemia (Jurkat), prostate cancer (LNCap) and breast cancer (MCF-7) cells and the apoptotic effect in Jurkat cells. Methods: Aqueous and hydroethanolic extracts were prepared and tested for cytotoxic effects on the cell lines using t he tetrazolium-based colorimetric assay. Apoptosis induction was determined by DNA fragmentation, cell morphological changes, flow cytometric and mitochondrial membrane potential assays. Results : Both aqueous and hydroethanolic extracts were more cytotoxic to Jurkat cells than the other cell lines, with selective index (SI) values of 104.4 and 86.6, respectively. The SI values of the extracts on LNCap cells were 9.0 and 35.4, respectively. Some of the fractions were non-cytotoxic. Nevertheless petroleum ether fraction was cytotoxic towards MCF-7 cells with SI value of 2.4. The hydroethanol...

Journal of Natural Science, Biology and Medicine, 2018

Background: Dissotis rotundifolia, commonly referred to as pink lady, has several medicinal uses ... more Background: Dissotis rotundifolia, commonly referred to as pink lady, has several medicinal uses including peptic ulcer. This study investigated the inhibitory effects of D. rotundifolia extract on H+/K+-ATPase and also assessed its antiradical activity. In silico study of some isolated compounds of this plant was also carried out to affirm the suspected binding properties of extract to H+/K+-ATPase enzyme. Materials and Methods: D. rotundifolia whole plant extract was obtained after extraction process and then assessed for its ability to scavenge free radicals in four in vitro test models. Its ability to inhibit the activity of H+/K+-ATPase enzyme was also evaluated. Molecular docking was carried out on phytoconstituents, namely, vitexin, isovitexin, orientin, and isoorientin reported to be present in the whole plant extract. Results: Data obtained indicated that D. rotundifolia extract (DRE) exhibits strong antioxidant activity. DRE also showed inhibitory effects on H+/K+-ATPase enzyme activity. Docking studies affirmed the in vitro binding effect of the extract to H+/K+-ATPase. Conclusion: These findings suggest that the plant extract possess antioxidant and antipeptic ulcer activity.

Journal of Ethnopharmacology, 2019

Ethnopharmacological relevance: Majority of people living in Ghana and many other developing coun... more Ethnopharmacological relevance: Majority of people living in Ghana and many other developing countries rely on traditional medicinal plants for their primary healthcare. These plants are used either alone or in combination to manage a wide range of ailments. However, most of these plants have not been investigated for their mutagenic effects. Aim of the study: This study, therefore aimed at evaluating the mutagenic activity of the most frequently used medicinal plants amongst Ghanaians living within the Accra metropolis, Ghana. Materials and methods: Validated questionnaires were administered to 53 herbalists and herbal medicines dealers in the Makola, Madina and Nima communities. Plants that were identified as being frequently used were investigated for their mutagenicity using the Ames test. Results: A total of 110 medicinal plants belonging to 53 families were identified as most frequently used plants in the study sites. These are used to treat various ailments including gastric ulcer, fever, malaria, male impotence, diabetes, typhoid, high blood pressure and candidiasis. Thirteen samples (52%) showed moderate to high mutagenicity in the TA 100 bacterial strain before and after metabolism with rat liver enzyme. Conclusions: The study showed that over half of the frequently used medicinal plants showed moderate to high mutagenicity before and after metabolism at the concentration of a 100 μg/mL. This may have implications for the safety of those who use them to manage diseases. These findings will suggest the need for an in-depth study of the mutagenic potentials of plants commonly used by indigenous people and more especially for those exhibiting high mutagenicity in this study.

BMC Infectious Diseases, 2019

Background: Distribution of Hepatitis C virus (HCV) genotypes varies significantly worldwide. Gen... more Background: Distribution of Hepatitis C virus (HCV) genotypes varies significantly worldwide. Genomic diversity between genotypes has implications for treatment, vaccine development and optimal design of HCV diagnostic assays. Molecular characterization of HCV in different geographical areas is therefore very essential for management and public health control of HCV infection. This study investigated the molecular epidemiology and characteristics of HCV genotypes in healthy individuals in Accra, Ghana. Methods: An experimental study was carried out on blood samples obtained from voluntary blood donors. Two hundred samples were initially screened for HCV antibodies and infection was confirmed by RNA detection through RT-PCR of the 5′-untranslated region (5'UTR). The core gene sequences were analysed for HCV genotype determination by genotype-specific PCR; and then by cloning and direct sequencing followed by phylogenetic analysis. The sequences were further analysed in detail by similarity plotting. Results: Molecular diagnosis confirmed the presence of HCV RNA in 2 out of 200 (1%) blood donors. Initial genotyping by genotype-specific PCR identified all two infections as subtypes 2a and 2b of genotype 2. Extensive evolutionary and genetic analyses indicated two epidemiological profiles. First, phylogenetic tree topologies clearly showed that, collectively, the core sequences of the Ghanaian HCV isolates belong to a single, distinct genetic group within HCV genotype 2 cluster, with high genetic similarity and rapid sequence variation in a single individual. Second, the sequences are mosaics comprising 2e and other genotype 2 subtype fragments. The analyses underscore a unique and complex HCV genotype 2 core sequence profile of the Ghanaian isolates.

BMC Public Health, 2019

Background: Malaria remains endemic in Ghana despite several interventions. Studies have demonstr... more Background: Malaria remains endemic in Ghana despite several interventions. Studies have demonstrated very high levels of asymptomatic malaria parasitaemia in both under-five and school-age children. Mass testing, treatment and tracking (MTTT) of malaria in communities is being proposed for implementation with the argument that it can reduce parasite load, amplify gains from the other control interventions and consequently lead to elimination. However, challenges associated with implementing MTTT such as feasibility, levels of coverage to be achieved for effectiveness, community perceptions and cost implications need to be clearly understood. This qualitative study was therefore conducted in an area with ongoing MTTT to assess community and health workers' perceptions about feasibility of scale-up and effectiveness to guide scale-up decisions. Methods: This qualitative study employed purposive sampling to select the study participants. Ten focus group discussions (FGDs) were conducted in seven communities; eight with community members (n = 80) and two with health workers (n = 14). In addition, two in-depth interviews (IDI) were conducted, one with a Physician Assistant and another with a Laboratory Technician at the health facility. All interviews were recorded, transcribed, translated and analyzed using QSR NVivo 12. Results: Both health workers and community members expressed positive perceptions about the feasibility of implementation and effectiveness of MTTT as an intervention that could reduce the burden of malaria in the community. MTTT implementation was perceived to have increased sensitisation about malaria, reduced the incidence of malaria, reduced household expenditure on malaria and alleviated the need to travel long distances for healthcare. Key challenges to implementation were doubts about the expertise of trained Community-Based Health Volunteers (CBHVs) to diagnose and treat malaria appropriately, side effects of Artemisinin-based Combination Therapies (ACTs) and misconceptions that CBHVs could infect children with epilepsy. Conclusion: The study demonstrated that MTTT was perceived to be effective in reducing malaria incidence and related hospital visits in participating communities. MTTT was deemed useful in breaking financial and geographical barriers to accessing healthcare. The interventions were feasible and acceptable to community members, despite observed challenges to implementation such as concerns about CBHVs' knowledge and skills and reduced revenue from internally generated funds (IGF) of the health facility.

Marine drugs, Jan 29, 2017

Leishmaniasis is a vector-borne neglected tropical disease caused by protozoan parasites of the L... more Leishmaniasis is a vector-borne neglected tropical disease caused by protozoan parasites of the Leishmania genus and transmitted by the female Phlebotomus and Lutzomyia sand flies. The currently prescribed therapies still rely on pentavalent antimonials, pentamidine, paromomycin, liposomal amphotericin B, and miltefosine. However, their low efficacy, long-course treatment regimen, high toxicity, adverse side effects, induction of parasite resistance and high cost require the need for better drugs given that antileishmanial vaccines may not be available in the near future. Although most drugs are still derived from terrestrial sources, the interest in marine organisms as a potential source of promising novel bioactive natural agents has increased in recent years. About 28,000 compounds of marine origin have been isolated with hundreds of new chemical entities. Recent trends in drug research from natural resources indicated the high interest of aquatic eukaryotic photosynthetic organi...

Planta Medica, 2016

Buruli ulcer (BU) is the third most prevalent mycobacteriosis, after tuberculosis and leprosy. Th... more Buruli ulcer (BU) is the third most prevalent mycobacteriosis, after tuberculosis and leprosy. The currently recommended combination of rifampicin-streptomycin suffers from side effects and poor compliance, which leads to reliance on local herbal remedies. The objective of this study was to investigate the antimycobacterial properties and toxicity of selected medicinal plants. Sixty-five extracts from 27 plant species were screened against Mycobacterium ulcerans and Mycobacterium smegmatis, using the Resazurin Microtiter Assay (REMA). The cytotoxicity of promising extracts was assayed on normal Chang liver cells by an MTT assay. Twenty five extracts showed activity with minimal inhibitory concentration (MIC) values ranging from 16 µg/mL to 250 µg/mL against M. smegmatis, while 17 showed activity against M. ulcerans with MIC values ranging from 125 µg/mL to 250 µg/mL. In most of the cases, plant extracts with antimycobacterial activity showed no cytotoxicity on normal human liver cells. Exception were Carica papaya, Cleistopholis patens, and Polyalthia suaveolens with 50% cell cytotoxic concentrations (CC 50) ranging from 3.8 to 223 µg/mL. These preliminary results support the use of some West African plants in the treatment of Buruli ulcer. Meanwhile, further studies are required to isolate and characterize the active ingredients in the extracts.

Journal of Parasitology Research, 2017

Schistosomiasis is a Neglected Tropical Diseases which can be prevented with mass deworming chemo... more Schistosomiasis is a Neglected Tropical Diseases which can be prevented with mass deworming chemotherapy. The reliance on a single drug, praziquantel, is a motivation for the search of novel antischistosomal compounds. This study investigated the anthelmintic activity of the stem bark and roots ofRauwolfia vomitoriaagainst two life stages ofSchistosoma mansoni. Both plant parts were found to be active against cercariae and adult worms. Within 2 h of exposure all cercariae were killed at a concentration range of 62.5–1000 µg/mL and 250–1000 µg/mL ofR. vomitoriastem bark and roots, respectively. The LC50values determined for the stem bark after 1 and 2 h of exposure were 207.4 and 61.18 µg/mL, respectively. All adult worms exposed to the concentrations range of 250–1000 µg/mL for both plant parts died within 120 h of incubation. The cytotoxic effects against HepG2 and Chang liver cell assessed using MTT assay method indicated that both plant extracts which were inhibitory to the proli...

Biomarker Research, 2016

There is an urgent need for new anti-malaria drugs with broad therapeutic potential and novel mod... more There is an urgent need for new anti-malaria drugs with broad therapeutic potential and novel mode of action, for effective treatment and to overcome emerging drug resistance. Plant-derived anti-malarials remain a significant source of bioactive molecules in this regard. The multicomponent formulation forms the basis of phytotherapy. Mechanistic reasons for the polypharmacological effects of plants constitute increased bioavailability, interference with cellular transport processes, activation of pro-drugs/deactivation of active compounds to inactive metabolites and action of synergistic partners at different points of the same signaling cascade. These effects are known as the multi-target concept. However, due to the intrinsic complexity of natural products-based drug discovery, there is need to rethink the approaches toward understanding their therapeutic effect. This review discusses the multi-target phytotherapeutic concept and its application in biomarker identification using the modified reverse pharmacology-systems biology approach. Considerations include the generation of a product library, high throughput screening (HTS) techniques for efficacy and interaction assessment, High Performance Liquid Chromatography (HPLC)-based anti-malarial profiling and animal pharmacology. This approach is an integrated interdisciplinary implementation of tailored technology platforms coupled to miniaturized biological assays, to track and characterize the multi-target bioactive components of botanicals as well as identify potential biomarkers. While preserving biodiversity, this will serve as a primary step towards the development of standardized phytomedicines, as well as facilitate lead discovery for chemical prioritization and downstream clinical development.

Biomarker Research, 2016

It is crucial to develop new antischistosomal drugs since there is no vaccine and the whole world... more It is crucial to develop new antischistosomal drugs since there is no vaccine and the whole world is relying on only a single drug for the treatment of schistosomiasis. One of the obstacles to the development of drugs is the absence of the high throughput objective screening methods to assess drug compounds efficacy. Thus for identification of new drug compounds candidates, fast and accurate in vitro assays are unavoidable and more research efforts in the field of drug discovery can target schistosomula. This review presents a substantial overview of the present state of in vitro drug sensitivity assays developed so far for the determination of anti-schistosomula activity of drug compounds, natural products and derivatives using newly transformed schistosomula (NTS). It highlights some of the challenges involved in in vitro compound screening using NTS and the way forward.

Evidence-Based Complementary and Alternative Medicine, 2016

Objective. This study investigated the elemental composition of unsweetened natural cocoa powder ... more Objective. This study investigated the elemental composition of unsweetened natural cocoa powder (UNCP), its effect on nitric oxide, and its hepatoprotective potential during simultaneous administration with high-dose artemether/lumefantrine (A/L).Method. Macro- and microelements in UNCP were analyzed with EDXRF spectroscopy. Thirty (30) male guinea-pigs were then divided into five groups. For groups 3 (low-dose), 4 (medium-dose), and 5 (high-dose), the animals received oral UNCP prophylactically for 14 days. Group 1 received distilled water (14 days) and group 2 A/L for the last 3 days (days 12 to 14). After euthanisation, biochemical and histopathological examinations were carried out in all groups.Results. Phytochemical analysis of UNCP showed the presence of saponins, flavonoids, tannins, and cardiac glycosides. Thirty-eight (38) macro- and microelements were found. UNCP produced significant decreases in ALT, ALP, GGT, and AST levels. A significant increase in total protein leve...

Food Science & Nutrition, 2016

Moringa oleifera (M. oleifera), a green leafy vegetable, is a good source of minerals and vitamin... more Moringa oleifera (M. oleifera), a green leafy vegetable, is a good source of minerals and vitamins which could be consumed as part of diet to improve human health and well-being. Drying M. oleifera leaves could make it readily available for use as a food fortificant. The objectives of the study were to determine micromineral and β-carotene content of dried M. oleifera leaves, and leafincorporated local dishes, and also assess school children's (4-12 yr) acceptability of dried M. oleifera leaf-incorporated local dishes and feasibility of introducing dried leaves into a school lunch menu. M. oleifera leaves were solar dried, milled into powder, and packaged into polythene bags. Moisture level in the dried leaves and pH were determined. Minerals in the leaf powder were determined by Atomic Absorption Spectrophotometry (AAS). Beta-carotene levels were determined by spectrophotometry. Acceptability tests of dishes fortified with M. oleifera leaf powder were conducted with score sheets (Smileys) on a 5-point hedonic scale of "Like Extremely" to "Dislike Extremely", and dishes ranked to determine preference. Dried M. oleifera leaves contained high levels of micronutrients: 0.36 ± 0.04 mg/100 g Copper (Cu); 5.80 ± 0.68 mg/100 g Manganese (Mn); 20.96 ± 1.37 mg/100 g Iron (Fe); 6.79 ± 1.82 mg/100 g Zn; and 21.42 ± 1.67 mg/100 g βcarotene. The dishes showed significant levels of these minerals compared to the nonfortified dishes (P < 0.05). M. oleifera leaf-fortified dishes were also highly acceptable to the children (highest mean score of 5.0 ± 0 of 5 and lowest of 3.50 ± 1.43 of 5). M. oleifera leaf powder contains high levels of the micronutrients βcarotene, Zn, Mn, and Fe, comparable to levels found in amaranth and spinach. M. oleifera leaf-fortified local dishes were well accepted by children in Ada-East district. M. oleifera leaf fortified dishes could be good sources of βcarotene and other minerals for children vulnerable to malnutrition in Ghana.

Molecules, 2016

Buruli ulcer (BU) is the third most prevalent mycobacteriosis, after tuberculosis and leprosy. Th... more Buruli ulcer (BU) is the third most prevalent mycobacteriosis, after tuberculosis and leprosy. The currently recommended combination of rifampicin-streptomycin suffers from side effects and poor compliance, which leads to reliance on local herbal remedies. The objective of this study was to investigate the antimycobacterial properties and toxicity of selected medicinal plants. Sixty-five extracts from 27 plant species were screened against Mycobacterium ulcerans and Mycobacterium smegmatis, using the Resazurin Microtiter Assay (REMA). The cytotoxicity of promising extracts was assayed on normal Chang liver cells by an MTT assay. Twenty five extracts showed activity with minimal inhibitory concentration (MIC) values ranging from 16 µg/mL to 250 µg/mL against M. smegmatis, while 17 showed activity against M. ulcerans with MIC values ranging from 125 µg/mL to 250 µg/mL. In most of the cases, plant extracts with antimycobacterial activity showed no cytotoxicity on normal human liver cells. Exception were Carica papaya, Cleistopholis patens, and Polyalthia suaveolens with 50% cell cytotoxic concentrations (CC 50) ranging from 3.8 to 223 µg/mL. These preliminary results support the use of some West African plants in the treatment of Buruli ulcer. Meanwhile, further studies are required to isolate and characterize the active ingredients in the extracts.

Data in Brief, 2016

This article contains data on in vitro antimycobacterial activity and cytotoxicity of hydroethano... more This article contains data on in vitro antimycobacterial activity and cytotoxicity of hydroethanolic crude extracts from five selected medicinal plant species traditionally used to treat tuberculosis in Ghanaian ethnomedicine, see "Medicinal plants used to treat TB in Ghana" [1]. The interpretation and discussion of these data and further extensive insights into drug discovery against tuberculosis from natural products of plant biodiversity can be found in "Antimycobacterial and cytotoxic activity of selected medicinal plant extracts" [2].

Journal of Ethnopharmacology, 2016

Ethnopharmacological relevance: Tuberculosis (TB) caused by Mycobacterium tuberculosis remains an... more Ethnopharmacological relevance: Tuberculosis (TB) caused by Mycobacterium tuberculosis remains an ongoing threat to human health. Several medicinal plants are used traditionally to treat tuberculosis in Ghana. The current study was designed to investigate the antimycobacterial activity and cytotoxicity of crude extracts from five selected medicinal plants. Material and methods: The microplate alamar blue assay (MABA) was used for antimycobacterial studies while the CellTiter 96 s AQ ueous Assay, which is composed of solutions of a novel tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt; MTS] and an electron coupling reagent (phenazine methosulfate) PMS, was used for cytotoxic studies. Correlation coefficients were used to compare the activity of crude extracts against nonpathogenic strains and the pathogenic Mycobacterium tuberculosis subsp.tuberculosis. Results: Results of the MIC determinations indicated that all the crude extracts were active on all the three tested mycobacterial strains. Minimum inhibitory concentration values as low as 156.3 mg/mL against M. tuberculosis; Strain H37Ra (ATCC s 25,177™) were recorded from the leaves of Solanum torvum Sw. (Solanaceae). Cytotoxicity of the extracts varied, and the leaves from S. torvum had the most promising selectivity index. Activity against M. tuberculosis; Strain H37Ra was the best predictor of activity against pathogenic Mycobacterium tuberculosis subsp.tuberculosis (correlation coefficient ¼0.8). Conclusion: The overall results of the present study provide supportive data on the use of some medicinal plants for tuberculosis treatment. The leaves of Solanum torvum are a potential source of anti-TB natural products and deserve further investigations to develop novel anti-TB agents against sensitive and drug resistant strains of M. tuberculosis.

BioMed Research International, 2015

Mycobacterium ulceransdisease has been a serious threat for people living in rural remote areas. ... more Mycobacterium ulceransdisease has been a serious threat for people living in rural remote areas. Due to poverty or availability of traditional medicine these populations rely on herbal remedies. Currently, data on the anti-Mycobacterium ulceransactivity of plants, so far considered community-based knowledge, have been scientifically confirmed, concomitantly with some medicinal plants used to treat infectious diseases in general. Products derived from plants usually responsible for the biological properties may potentially controlMycobacterium ulceransdisease; numerous studies have aimed to describe the chemical composition of these plant antimicrobials. Thus, the present work provides the first compilation of medicinal plants that demonstrated inhibitory potential onMycobacterium ulcerans. This work shows that the natural products represent potential alternatives to standard therapies for use as curative medicine forMycobacterium ulceransdisease.

International Journal of Mycobacteriology, 2015

Currently, one third of the world's population is latently infected with Mycobacterium tuberculos... more Currently, one third of the world's population is latently infected with Mycobacterium tuberculosis (MTB), while 8.9-9.9 million new and relapse cases of tuberculosis (TB) are reported yearly. The renewed research interests in natural products in the hope of discovering new and novel antitubercular leads have been driven partly by the increased incidence of multidrug-resistant strains of MTB and the adverse effects associated with the first-and second-line antitubercular drugs. Natural products have been, and will continue to be a rich source of new drugs against many diseases. The depth and breadth of therapeutic agents that have their origins in the secondary metabolites produced by living organisms cannot be compared with any other source of therapeutic agents. Discovery of new chemical molecules against active and latent TB from natural products requires an interdisciplinary approach, which is a major challenge facing scientists in this field. In order to overcome this challenge, cutting edge techniques in mycobacteriology and innovative natural product chemistry tools need to be developed and used in tandem. The present review provides a cross-linkage to the most recent literature in both fields and their potential to impact the early phase of drug discovery against TB if seamlessly combined.

Bioorganic & Medicinal Chemistry Letters, 2015

International Journal of Toxicology, 2014

Polyhexamethylene guanidine hydrochloride (PHMGH) is used worldwide as an antimicrobial agent wit... more Polyhexamethylene guanidine hydrochloride (PHMGH) is used worldwide as an antimicrobial agent with broad spectra of activity and also for treating pool water. This non-GLP preliminary study aims at investigating in a subchronic toxicity study possible effects at supra-optimal doses of this biocide. Both acute and subchronic toxicity studies were conducted. LD50 for PHMGH was estimated to be 600 mg/kg (ie LC50 2 ml of 7.5% solution) when administered as a single dose by gavage via a stomach tube in accordance with the expected route of administration. The acute studies showed that the median lethal dose (LD50) of 600 mg/kg was accompanied by signs of neurotoxicity. Haematological and biochemical parameters of subchronic toxicity studies were non-significant. Subchronic doses of 0.006 mg/kg, 0.012 mg/kg and 0.036 mg/kg were administered. 20% of the animals at a dose of 0.006 mg/kg and 0.036 mg/kg showed mild degrees of hydropic changes in proximal tubules while 10% of animals at all t...

Biochemical and Biophysical Research Communications, 2015

Despite remarkable advances in combination antiretroviral therapy (cART), human immunodeficiency ... more Despite remarkable advances in combination antiretroviral therapy (cART), human immunodeficiency virus type 1 (HIV-1) infection remains incurable due to the incomplete elimination of the replication-competent virus, which persists in latent reservoirs. Strategies for targeting HIV reservoirs for eradication that involves reactivation of latent proviruses while protecting uninfected cells by cART are urgently needed for cure of HIV infection. We screened medicinal plant extracts for compounds that could reactivate the latent HIV-1 provirus and identified a procyanidin trimer C1 derived from Theobroma cacao as a potent activator of the provirus in human T cells latently infected with HIV-1. This reactivation largely depends on the NF-κB and MAPK signaling pathways because either overexpression of a super-repressor form of IκBα or pretreatment with a MEK inhibitor U0126 diminished provirus reactivation by C1. A pan-PKC inhibitor significantly blocked the phorbol ester-induced but not the C1-induced HIV-1 reactivation. Although C1-induced viral gene expression persisted for as long as 48 h post-stimulation, NF-κB-dependent transcription peaked at 12 h post-stimulation and then quickly declined, suggesting Tat-mediated self-sustainment of HIV-1 expression. These results suggest that procyanidin C1 trimer is a potential compound for reactivation of latent HIV-1 reservoirs.