Pax Masimba | Muhimbili University of Health and Allied Sciences (MUHAS) (original) (raw)

Papers by Pax Masimba

In attempt to investigate some biological activities of Mammea usambarensis fruit, absolute ethan... more In attempt to investigate some biological activities of Mammea usambarensis fruit, absolute ethanolic crude extract, 80% DCM/PE fraction, 5% MeOH/DCM fraction and mammea B/AB were subjected to toxicity test in brine shrimps and mice, antimicrobial activity by disc diffusion and broth dilution method and antioxidant activity by DPPH scavenging activity. In the brine shrimps toxicity test, the crude extract, 80% DCM/PE fraction, 5% MeOH/DCM fraction and mammea B/AB were highly toxic with LC 50 values of 1.58, 1.14, 3.89 and 5.21 µg/ml, respectively. The crude extract was non-toxic to mice even at a dose above 2000 mg/kg body weight. The crude extract, 80% DCM/PE 5% MeOH/DCM fractions and mammea B/AB exhibited low activity with zone of inhibition of 8.3-16 mm for Salmonella kisarawe, 8.7-14 mm for Staphylococcus aureus and 8.3-10 mm for Klebsiella oxytoca. The minimum inhibitory concentrations ranged from 3.75 µg/µl-25 µg/µl. All samples tested had no activity against Candida albicans ...

International Journal of Herbal Medicine, 2020

This in vivo study aimed to compare hypoglycaemic activity of three commonly medicinal plants use... more This in vivo study aimed to compare hypoglycaemic activity of three commonly medicinal plants used traditionally for diabetes management in northern Tanzania Artemisia afra Willd. (Aerial parts), Moringaoleifera Lam. (Leaves) and Perseaamericana Mill. (Leaves).Evaluation for hypoglycaemic activity of 80% aqueous ethanol plant extracts was conducted at a dose of 200 mg/kg body weight, orally in glucose loaded normal white albino mice by using Oral Glucose Tolerance Test (OGTT) method. The statistical analysis of results was carried out by using Student t-test followed by one-way Analysis of variance (ANOVA) and Tukey’s multiple comparisons at probability value (p˂ 0.05).Phytochemical evaluation focused on the normal reactions of characterization based on precipitation and coloration with standard reagents. At a dose of 200 mg/kg bw.t, the three plants showed significant hypoglycaemic activity by lowering blood glucose level in glucose loaded normal white albino mice at a rate of 23%,...

The East and Central African Journal of Pharmaceutical Sciences, 2011

The 80% aqueous ethanol extract of Croton macrostachys A. Rich (Euphorbiaceae) roots and the six ... more The 80% aqueous ethanol extract of Croton macrostachys A. Rich (Euphorbiaceae) roots and the six isolated compounds were tested for oral glucose tolerance test, antibacterial activity and brine shrimp lethality test. The 80% aqueous ethanol extract significantly escalated postprandial blood glucose levels (P ≤ 0.05) in mice. The extract also exhibited a weak antibacterial activity against some Gram-positive and Gram-negative bacteria and a weak antifungal activity against Candida albicans. Among the six isolated compounds, one compound significantly elevated postprandial blood glucose (P≤0.05), while two compounds exhibited a weak antibacterial activity, but none exhibited antifungal activity. The crude extract and compounds were both cytotoxic to brine shrimps.

Journal of Pharmacognosy and Phytochemistry, 2015

Kotschya plant species have been shown to be potential larvicides against Culex quinquefasciatus ... more Kotschya plant species have been shown to be potential larvicides against Culex quinquefasciatus and Anopheles gambiae species. Isolation of compounds from larvicidal crude extracts of selected four Kotschya plant species namely K. uguenensis, K. strigosa, K. speciosa and K thymodora yielded cycloartenone (1) as the major compound. The presence of this compound in the four species was confirmed by detailed spectroscopic methods and the already published data. Quantitative analysis of cycloartenone (1) in the four species collected during wet and dry seasons was compared. Findings indicated higher yields during wet seasons ranging from 68 x 10-2 to 120 x 10-2 mg/ml than dry seasons which revealed amounts ranging from 0 to 150 x 10-2 mg/ml. However, the highest amount of cycloartenone (1) was present in the stem barks of K. uguenensis for the dry season whereas the 120 x 102 mg/ml was observed in the aerial parts of K. strigosa collected during wet season. Cycloartenone (1) is being i...

BMC Complementary and Alternative Medicine, 2017

Background: Malaria is an old life-threatening parasitic disease that is still affecting many peo... more Background: Malaria is an old life-threatening parasitic disease that is still affecting many people, mainly children living in sub-Saharan Africa. Availability of effective antimalarial drugs played a significant role in the treatment and control of malaria. However, recent information on the emergence of P. falciparum parasites resistant to one of the artemisinin-based combination therapies suggests the need for discovery of new drug molecules. Therefore, this study aimed to evaluate the antiplasmodial activity of extracts, fractions and isolated compound from medicinal plants traditionally used in the treatment of malaria in Tanzania. Methods: Dry powdered plant materials were extracted by cold macerations using different solvents. Norcaesalpin D was isolated by column chromatography from dichloromethane root extract of Caesalpinia bonducella and its structure was assigned based on the spectral data. Crude extracts, fractions and isolated compound were evaluated for antiplasmodial activity against chloroquine-sensitive P. falciparum (3D7), chloroquine-resistant P. falciparum (Dd2, K1) and artemisinin-resistant P. falciparum (IPC 5202 Battambang, IPC 4912 Mondolkiri) strains using the parasite lactate dehydrogenase assay. Results: The results indicated that extracts of Erythrina schliebenii, Holarrhena pubescens, Dissotis melleri and C. bonducella exhibited antiplasmodial activity against Dd2 parasites. Ethanolic root extract of E. schliebenii had an IC 50 of 1.87 μg/mL while methanolic and ethanolic root extracts of H. pubescens exhibited an IC 50 = 2.05 μg/mL and IC 50 = 2.43 μg/mL, respectively. Fractions from H. pubescens and C. bonducella roots were found to be highly active against K1, Dd2 and artemisinin-resistant parasites. Norcaesalpin D from C. bonducella root extract was active with IC 50 of 0.98, 1.85 and 2.13 μg/mL against 3D7, Dd2 and IPC 4912-Mondolkiri parasites, respectively. Conclusions: Antiplasmodial activity of norcaesalpin D and extracts of E. schliebenii, H. pubescens, D. melleri and C. bonducella reported in this study requires further attention for the discovery of antimalarial lead compounds for future drug development.

Ethnobotany Research and Applications, 2011

HIV/AIDS pandemic is currently the most socioeconomic challenge that faces Tanzania as it affects... more HIV/AIDS pandemic is currently the most socioeconomic challenge that faces Tanzania as it affects mostly the young and most economically productive population. People living with HIV/AIDS in Tanzania are susceptible to fungal and bacterial opportunistic infections, which are a major cause of mortality and morbidity in the country. Despite the government's intervention to provide ARVs to people living with HIV/AIDS, many of them especially those living in the rural areas can neither afford them due to poverty nor access them due to distance to health centers. Moreover, resistance of opportunistic microbial pathogens to conventional medicines and the serious side effects associated with antiretroviral drugs are also a major drawback to the management of HIV/AIDS in the country. Due to these factors, many people opt to use of traditional medicines. This paper highlights the use and conservation of herbal remedies to manage HIV/AIDS pandemic in Tanzania. Ethnobotanical surveys were carried out in Bukoba Rural District to explore the traditional ethno-medical knowledge, the use and conservation of medicinal plants in the management of HIV/AIDS opportunistic infections and to determine whether levels of harvesting are sustainable. The district is currently an epicenter of HIV/AIDS and although over 90% of the population in the district relies on traditional medicines to manage the disease, this traditional knowledge still remains largely unknown. Seventyfive plant species belonging to 66 genera and 40 families were found to be used to treat one or more HIV/AIDS related diseases in the district. Eight plant species were tested in-vitro for their antifungal activity against three major fungal pathogens, Candida albicans (C.P. Robin) Berkhout, Cryptococcus neoformans (San Felice) Vuill., and Aspergillus niger Tiegh. Three of them were further tested in-vivo for their anti-Candida activity. With decreasing natural stocks of medicinal plants, and based on the results, this study further provides concrete recommendations

Tanzania Journal of Health Research, 2009

Herbal medicines constitute a potentially important resource for new and safe drugs for the manag... more Herbal medicines constitute a potentially important resource for new and safe drugs for the management of microbial infections and other diseases. In this study, dichloromethane, ethylacetate and ethanol extracts of Canarum schwenfurth Engl., Dssots brazzae Cong., Iboza urtcfola (Bak) E.A.Bruce, Isoglosa lacteal Lindau, Strombosa Scheffler Engl., and Whtfielda elongate T. Anders were tested for antimicrobial activity and brine shrimp toxicity. The objective was to validate claims that they are used to treat bacterial infections, diarrhoea and heal wounds among the Haya tribe of northwestern Tanzania. At least one extract of each plant showed antibacterial activity. Dichloromethane extracts were the most active while ethanol extracts were the least active. Extracts of Whtfielda elongate and Isoglossa lacteal were the most and least active with MICs in the range 0.08-0.62 mg/ml and 15.6-62.5 mg/ml, respectively. The dichloromethane extract of Whtfielda elongate exhibited strong antifungal activity against Cryptococcus neoformans. Against brine shrimp larvae, the extracts from the six plants exhibited a low to very low toxicity with LC 50 values ranging from 15.35-374.0μg/ml. However, ethanol extracts of Dssots brazzae and Strombosa scheffler had LC 50 values of >1000μg/ml. The seemingly innocuous nature and relatively good antibacterial activity against skin infections and gastrointestinal pathogenic bacteria support the traditional uses of the plants and deserve more detailed studies.

Tanzania Journal of Health Research, 2010

Emergence of new and re-emergence of old infections continue to elude prospects of reducing morbi... more Emergence of new and re-emergence of old infections continue to elude prospects of reducing morbidity and mortality caused by microbial infections. Trends of resistance to currently in use antimicrobials and antimalarials threaten to increase mortality caused by these infections. This study explores the potential of marine invertebrates as a source for new antimicrobials and antimalarials. The lactate dehydrogenase method was used to assay marine sponges for activity against Plasmodium falciparum, while the disc diffusion method was used to assay the extracts for antibacterial and antifungal activity. Extracts of some marine sponges from the Zanzibar Island exhibited both antiplasmodial and antimicrobial activities. Among the 55 marine sponge extracts that were tested 23 (41.8%) inhibited Plasmodium falciparum W2 strain by more than 50% at both 250 and 50 μg/ml concentrations. Moderate polar extracts were more active against Plasmodium falciparum W2 strain than polar and non-polar extracts. None of the 12 extracts that were tested on Plasmodium falciparum strain D6 exhibited inhibitory activity reaching 50%. Among 18 marine sponge extracts that were tested for antimicrobial activity 12 (66.7%) showed activity against one or more of the bacteria and fungi used ranging from weak to strong on an arbitrary criterion. The ethyl acetate extracts of Agelas mauritania and Oceanopia sp. exhibited high activity against the fungi Candida albicans and Cryptococcus neoformans. The best antibacterial profile was exhibited by ethyl acetate extracts of Aplysinopsis sp., Halichondrida sp. 1 and Oceanopia sp. In conclusion, these results support the need for intensified efforts to search for active antimalarial and antimicrobial compounds from the Zanzibar marine sponges.

Tanzania Journal of Health Research, 2009

Warburga ugandenss Sprague (Canellaceae), is widely used by Traditional Health Practitioners in E... more Warburga ugandenss Sprague (Canellaceae), is widely used by Traditional Health Practitioners in Eastern and Southern Africa for treatment of diseases and conditions associated with HIV/AIDS infections. The most commonly prescribed parts of the plant are usually barks and roots. The aim of this study was to investigate whether leaves of this plant have biological activities comparable to those of barks and roots. Fresh leaves of W. ugandenss were freeze-dried to complete dryness while another portion of the leaves from the same collection were air-dried under shade. Ethanolic extracts from the two differently dried leaves were tested for antimicrobial activity and for brine shrimp toxicity test. Ethanolic extract from the freeze-dried leaves exhibited both antibacterial activity against standard strains of Staphylococcus aureus, Eschercha col, Vbro cholerae, Bacllus cereus and antifungal activity against Candda albcans and Cryptococcus neoformans. The extract from the air-dried leaves showed similar antibacterial activity against the mentioned organisms but had no antifungal activity. However, both extracts exhibited comparable cytotoxic activity (95% CI), against brine shrimp larvae with reference to cyclophosphamide, a standard anticancer drug. Fresh leaves of W. ugandenss have shown to exhibit anticandida activity, a factor which substantiates their application as a traditional herbal remedy to complement treatment of fungal infections in HIV/AIDS patients. Further studies to establish constituents responsible for the exhibited antifungal activity are highly desirable.

African Journal of Traditional, Complementary and Alternative Medicines, 2010

Aqueous ethanol (80%) extracts of six plants used traditionally for treatment of malaria, Vepris ... more Aqueous ethanol (80%) extracts of six plants used traditionally for treatment of malaria, Vepris glomerata (F.Hoffm.) Engl (Rutaceae), Maranthus floribunda (Bak.) F.White (Chrysobalanaceae), Strophanthus eminii Asch. & Pax ex Pax (Apocynaceae), Cassia abbreviata Oliv. (Leguminosae) and Caesalpinia bonducella L. Fleming (Fabaceae) were screened for antimalarial activity to establish validity of their claims. The extracts exhibited antimalarial activity in the 4-day Peter's suppressive antimalarial assay in mice inoculated with red blood cells parasitized with Plasmodium berghei. The extracts gave ID 50 values of 42.8, 111.0, 639.3 and 1560 mg/kg body wt for C. bonducella, C. abbreviata, T. furialis and S. eminii, respectively. The ID 50 values for V. glomerata and M. floribunda were above 2400 mg/kg body wt, above which point solubility was a problem. All the tested extracts were innocuous to the mice, up to 2400 mg/kg body wt, suggesting they may be safe for short-term use.

African Journal of Traditional, Complementary and Alternative Medicines, 2007

Evaluation of extracts of Diospyros fischeri Gurke (Ebenaceae), which is used traditionally for t... more Evaluation of extracts of Diospyros fischeri Gurke (Ebenaceae), which is used traditionally for the treatment of epilepsy shows that the aqueous extract of the tem bark has no effect against picrotoxin induced convulsions in mice. However, an 80% ethanol extract of the bark caused dose-dependent suppression of convulsions induced by 10 mg/kg body wt picrotoxin, , at doses between 100-3200 mg/kg body wt. Petroleum ether, 1:1 dichloromethane:methanol, and methanol extracts also suppressed picrotoxin-induced convulsions, but had a slightly lower inhibitory effect. The petroleum ether extract was the most active, but all were less active than the ethanol extract. Unlike phenobarbitone, which at 50 mg/kg body wt completely suppressed convulsions induced by 10 mg/kg body wt picrotoxin, none of the plant extracts completely suppressed convulsions in the mice. These results support the traditional uses of D.fischeri for the treatment of epilepsy. Given the seemingly innocuous nature of the extracts more work is suggested to ascertain their clinical application.

African Journal of Traditional, Complementary and Alternative Medicines, 2008

Plants which are used by traditional healers in Tanzania have been evaluated to obtain preliminar... more Plants which are used by traditional healers in Tanzania have been evaluated to obtain preliminary data of their toxicity using the brine shrimps test. The results indicate that 9 out of 44 plant species whose extracts were tested exhibited high toxicity with LC 50 values below 20µg/ml. These include Aloe lateritia Engl. (Aloaceae) [19.1µg/ml], Cassia abbreviata Oliv. (Caesalpiniaceae) [12.7µg/ml], Croton scheffleri Pax (Euphorbiaceae) [13.7µg/ml], Hymenodactyon parvifolium Brig (Rubiaceae) [13.4µg/ml], Kigelia Africana L. (Bignoniaceae) [7.2µg/ml], and Ocimum suave Oliv. (Labiatae) [16.7µg/ml]. Twelve plants gave LC 50 values between 21 and 50µg/ml, 11 plants gave LC 50 values between 50 and 100 µg/ml, and 18 plants gave LC 50 values greater than 100 µg/ml.

Journal of Advanced Pharmaceutical Technology & Research, 2016

Plants used in traditional medicine have been the source of a number of currently used antimalari... more Plants used in traditional medicine have been the source of a number of currently used antimalarial medicines and continue to be a promising resource for the discovery of new classes of antimalarial compounds. The aim of this study was to evaluate in vivo antimalarial activity of four plants; Erythrina schliebenii Harms, Holarrhena pubescens Buch-Ham, Phyllanthus nummulariifolius Poir, and Caesalpinia bonducella (L.) Flem used for treatment of malaria in Tanzania. In vivo antimalarial activity was assessed using the 4-day suppressive antimalarial assay. Mice were infected by injection via tail vein with 2 × 10 7 erythrocytes infected with Plasmodium berghei ANKA. Extracts were administered orally, once daily, for a total of four daily doses from the day of infection. Chloroquine (10 mg/kg/day) and solvent (5 mL/kg/day) were used as positive and negative controls, respectively. The extracts of C. bonducella, E. schliebenii, H. pubescens, and P. nummulariifolius exhibited dose-dependent suppression of parasite growth in vivo in mice, with the highest suppression being by C. bonducella extract. While each of the plant extracts has potential to yield useful antimalarial compounds, the dichloromethane root extract of C. bonducella seems to be the most promising for isolation of active antimalarial compound(s). In vivo antimalarial activity presented in this study supports traditional uses of C. bonducella roots, E. schliebenii stem barks, H. pubescens roots, and P. nummulariifolius for treatment of malaria.

The medicinal plants have been used traditionally for different purposes such as pest control and... more The medicinal plants have been used traditionally for different purposes such as pest control and treatment of human diseases. Despite these potentials, only few plants have been evaluated for their safety. This study aimed at investigating oral acute toxicity of Annona squamosa leaf extract and fractions using albino mice. The aqueous-ethanol, dichloromethane and petroleum ether fractions were prepared and tested for oral acute toxicity. Whereas some toxicity signs occurred for aqueous-ethanol extract at doses ≥1500 mg/kg bwt that of dichloromethane fraction were seen at 1000-5000 mg/kg and that of petroleum ether fraction were at 5000 mg/kg. All the tested materials at a dose above 300 mg/kg bwt had negative effects on the growth of the mice. The LD 50 were estimated to be >1000 mg/kg bwt for dichloromethane, >1500 mg/kg bwt for aqueous-ethanol extract and >3000 mg/kg bwt for petroleum ether fraction. All mice dissected had normal organs except one among six females treat...

Medicinal and Aromatic Plants of the World, 2017

Crude extracts of Dracaena steudneri bark (DSB), Sapium ellipticum bark (SEB) and Capparis erythr... more Crude extracts of Dracaena steudneri bark (DSB), Sapium ellipticum bark (SEB) and Capparis erythrocarpos root (CER) were investigated for their antifungal activity in immunocompromised mice infected with Candida albicans in an in vivo mice infection model. The results revealed a substantial dose dependency in all treatments given, with mice survival to the end of the experiment correlating well to the dose levels. At a dose of 400 mg/kg, C. erythrocarpos was the most effective with mice survival of 60% and organ burden clearance ranging from 64.0%-99.9% (P<0.0001) in all treatments. At the same dose, the least effective plant was S. ellipticum which had a mice survival of 20% and organ burden clearance ranging from 78.0%-96.6 (P>0.05). Mice survival for D. steudneri was 30% with organ burden clearance ranging from 89.0%-99.9% (P<0.05). All mice receiving no active treatment died before ten days post infection. In all treatment groups, there was a steady decline in mean weights of mice immediately after immunosuppression followed by gradual recovery in some cases which appeared to be dose dependent a few days post infection. Thus, extracts of D. steudneri and C. erythrocarpos portrayed the most significant potential as sources of antifungal drugs.

The medicinal plants have been used traditionally for different purposes such as pest control and... more The medicinal plants have been used traditionally for different purposes such as pest control and treatment of human diseases. Despite these potentials, only few plants have been evaluated for their safety. This study aimed at investigating oral acute toxicity of Annona squamosa leaf extract and fractions using albino mice. The aqueous-ethanol, dichloromethane and petroleum ether fractions were prepared and tested for oral acute toxicity. Whereas some toxicity signs occurred for aqueous-ethanol extract at doses ≥1500 mg/kg bwt that of dichloromethane fraction were seen at 1000-5000 mg/kg and that of petroleum ether fraction were at 5000 mg/kg. All the tested materials at a dose above 300 mg/kg bwt had negative effects on the growth of the mice. The LD50 were estimated to be >1000 mg/kg bwt for dichloromethane, >1500 mg/kg bwt for aqueous-ethanol extract and >3000 mg/kg bwt for petroleum ether fraction. All mice dissected had normal organs except one among six females treate...

HIV-1 resistance is one of the problems affecting success of antiretroviral therapy programmes wo... more HIV-1 resistance is one of the problems affecting success of antiretroviral therapy programmes worldwide. Many studies on efficacy of ART programmes, specifically on drug resistance, have been conducted in developed countries but not in developing countries due to lack of resources. So many tests have been optimized for HIV-1 subtype B which is prevalent in the developed countries but not for non-subtype B which is the main HIV-1 subtype in developing world. Some few studies have been conducted in Tanzania to evaluate the efficacy of the ART regimens and programmes. These studies have evaluated either the virological efficacy and genotypic resistance in patients receiving ART (to evaluate development of acquired resistance) or genotypic resistance in drug naive patients (to assess primary resistance). These few studies have been conducted in cities or urban areas with referral hospitals and have indeed shown some degree of resistance to ART and have provided some insights into degre...

In attempt to investigate some biological activities of Mammea usambarensis fruit, absolute ethan... more In attempt to investigate some biological activities of Mammea usambarensis fruit, absolute ethanolic crude extract, 80% DCM/PE fraction, 5% MeOH/DCM fraction and mammea B/AB were subjected to toxicity test in brine shrimps and mice, antimicrobial activity by disc diffusion and broth dilution method and antioxidant activity by DPPH scavenging activity. In the brine shrimps toxicity test, the crude extract, 80% DCM/PE fraction, 5% MeOH/DCM fraction and mammea B/AB were highly toxic with LC 50 values of 1.58, 1.14, 3.89 and 5.21 µg/ml, respectively. The crude extract was non-toxic to mice even at a dose above 2000 mg/kg body weight. The crude extract, 80% DCM/PE 5% MeOH/DCM fractions and mammea B/AB exhibited low activity with zone of inhibition of 8.3-16 mm for Salmonella kisarawe, 8.7-14 mm for Staphylococcus aureus and 8.3-10 mm for Klebsiella oxytoca. The minimum inhibitory concentrations ranged from 3.75 µg/µl-25 µg/µl. All samples tested had no activity against Candida albicans ...

International Journal of Herbal Medicine, 2020

This in vivo study aimed to compare hypoglycaemic activity of three commonly medicinal plants use... more This in vivo study aimed to compare hypoglycaemic activity of three commonly medicinal plants used traditionally for diabetes management in northern Tanzania Artemisia afra Willd. (Aerial parts), Moringaoleifera Lam. (Leaves) and Perseaamericana Mill. (Leaves).Evaluation for hypoglycaemic activity of 80% aqueous ethanol plant extracts was conducted at a dose of 200 mg/kg body weight, orally in glucose loaded normal white albino mice by using Oral Glucose Tolerance Test (OGTT) method. The statistical analysis of results was carried out by using Student t-test followed by one-way Analysis of variance (ANOVA) and Tukey’s multiple comparisons at probability value (p˂ 0.05).Phytochemical evaluation focused on the normal reactions of characterization based on precipitation and coloration with standard reagents. At a dose of 200 mg/kg bw.t, the three plants showed significant hypoglycaemic activity by lowering blood glucose level in glucose loaded normal white albino mice at a rate of 23%,...

The East and Central African Journal of Pharmaceutical Sciences, 2011

The 80% aqueous ethanol extract of Croton macrostachys A. Rich (Euphorbiaceae) roots and the six ... more The 80% aqueous ethanol extract of Croton macrostachys A. Rich (Euphorbiaceae) roots and the six isolated compounds were tested for oral glucose tolerance test, antibacterial activity and brine shrimp lethality test. The 80% aqueous ethanol extract significantly escalated postprandial blood glucose levels (P ≤ 0.05) in mice. The extract also exhibited a weak antibacterial activity against some Gram-positive and Gram-negative bacteria and a weak antifungal activity against Candida albicans. Among the six isolated compounds, one compound significantly elevated postprandial blood glucose (P≤0.05), while two compounds exhibited a weak antibacterial activity, but none exhibited antifungal activity. The crude extract and compounds were both cytotoxic to brine shrimps.

Journal of Pharmacognosy and Phytochemistry, 2015

Kotschya plant species have been shown to be potential larvicides against Culex quinquefasciatus ... more Kotschya plant species have been shown to be potential larvicides against Culex quinquefasciatus and Anopheles gambiae species. Isolation of compounds from larvicidal crude extracts of selected four Kotschya plant species namely K. uguenensis, K. strigosa, K. speciosa and K thymodora yielded cycloartenone (1) as the major compound. The presence of this compound in the four species was confirmed by detailed spectroscopic methods and the already published data. Quantitative analysis of cycloartenone (1) in the four species collected during wet and dry seasons was compared. Findings indicated higher yields during wet seasons ranging from 68 x 10-2 to 120 x 10-2 mg/ml than dry seasons which revealed amounts ranging from 0 to 150 x 10-2 mg/ml. However, the highest amount of cycloartenone (1) was present in the stem barks of K. uguenensis for the dry season whereas the 120 x 102 mg/ml was observed in the aerial parts of K. strigosa collected during wet season. Cycloartenone (1) is being i...

BMC Complementary and Alternative Medicine, 2017

Background: Malaria is an old life-threatening parasitic disease that is still affecting many peo... more Background: Malaria is an old life-threatening parasitic disease that is still affecting many people, mainly children living in sub-Saharan Africa. Availability of effective antimalarial drugs played a significant role in the treatment and control of malaria. However, recent information on the emergence of P. falciparum parasites resistant to one of the artemisinin-based combination therapies suggests the need for discovery of new drug molecules. Therefore, this study aimed to evaluate the antiplasmodial activity of extracts, fractions and isolated compound from medicinal plants traditionally used in the treatment of malaria in Tanzania. Methods: Dry powdered plant materials were extracted by cold macerations using different solvents. Norcaesalpin D was isolated by column chromatography from dichloromethane root extract of Caesalpinia bonducella and its structure was assigned based on the spectral data. Crude extracts, fractions and isolated compound were evaluated for antiplasmodial activity against chloroquine-sensitive P. falciparum (3D7), chloroquine-resistant P. falciparum (Dd2, K1) and artemisinin-resistant P. falciparum (IPC 5202 Battambang, IPC 4912 Mondolkiri) strains using the parasite lactate dehydrogenase assay. Results: The results indicated that extracts of Erythrina schliebenii, Holarrhena pubescens, Dissotis melleri and C. bonducella exhibited antiplasmodial activity against Dd2 parasites. Ethanolic root extract of E. schliebenii had an IC 50 of 1.87 μg/mL while methanolic and ethanolic root extracts of H. pubescens exhibited an IC 50 = 2.05 μg/mL and IC 50 = 2.43 μg/mL, respectively. Fractions from H. pubescens and C. bonducella roots were found to be highly active against K1, Dd2 and artemisinin-resistant parasites. Norcaesalpin D from C. bonducella root extract was active with IC 50 of 0.98, 1.85 and 2.13 μg/mL against 3D7, Dd2 and IPC 4912-Mondolkiri parasites, respectively. Conclusions: Antiplasmodial activity of norcaesalpin D and extracts of E. schliebenii, H. pubescens, D. melleri and C. bonducella reported in this study requires further attention for the discovery of antimalarial lead compounds for future drug development.

Ethnobotany Research and Applications, 2011

HIV/AIDS pandemic is currently the most socioeconomic challenge that faces Tanzania as it affects... more HIV/AIDS pandemic is currently the most socioeconomic challenge that faces Tanzania as it affects mostly the young and most economically productive population. People living with HIV/AIDS in Tanzania are susceptible to fungal and bacterial opportunistic infections, which are a major cause of mortality and morbidity in the country. Despite the government's intervention to provide ARVs to people living with HIV/AIDS, many of them especially those living in the rural areas can neither afford them due to poverty nor access them due to distance to health centers. Moreover, resistance of opportunistic microbial pathogens to conventional medicines and the serious side effects associated with antiretroviral drugs are also a major drawback to the management of HIV/AIDS in the country. Due to these factors, many people opt to use of traditional medicines. This paper highlights the use and conservation of herbal remedies to manage HIV/AIDS pandemic in Tanzania. Ethnobotanical surveys were carried out in Bukoba Rural District to explore the traditional ethno-medical knowledge, the use and conservation of medicinal plants in the management of HIV/AIDS opportunistic infections and to determine whether levels of harvesting are sustainable. The district is currently an epicenter of HIV/AIDS and although over 90% of the population in the district relies on traditional medicines to manage the disease, this traditional knowledge still remains largely unknown. Seventyfive plant species belonging to 66 genera and 40 families were found to be used to treat one or more HIV/AIDS related diseases in the district. Eight plant species were tested in-vitro for their antifungal activity against three major fungal pathogens, Candida albicans (C.P. Robin) Berkhout, Cryptococcus neoformans (San Felice) Vuill., and Aspergillus niger Tiegh. Three of them were further tested in-vivo for their anti-Candida activity. With decreasing natural stocks of medicinal plants, and based on the results, this study further provides concrete recommendations

Tanzania Journal of Health Research, 2009

Herbal medicines constitute a potentially important resource for new and safe drugs for the manag... more Herbal medicines constitute a potentially important resource for new and safe drugs for the management of microbial infections and other diseases. In this study, dichloromethane, ethylacetate and ethanol extracts of Canarum schwenfurth Engl., Dssots brazzae Cong., Iboza urtcfola (Bak) E.A.Bruce, Isoglosa lacteal Lindau, Strombosa Scheffler Engl., and Whtfielda elongate T. Anders were tested for antimicrobial activity and brine shrimp toxicity. The objective was to validate claims that they are used to treat bacterial infections, diarrhoea and heal wounds among the Haya tribe of northwestern Tanzania. At least one extract of each plant showed antibacterial activity. Dichloromethane extracts were the most active while ethanol extracts were the least active. Extracts of Whtfielda elongate and Isoglossa lacteal were the most and least active with MICs in the range 0.08-0.62 mg/ml and 15.6-62.5 mg/ml, respectively. The dichloromethane extract of Whtfielda elongate exhibited strong antifungal activity against Cryptococcus neoformans. Against brine shrimp larvae, the extracts from the six plants exhibited a low to very low toxicity with LC 50 values ranging from 15.35-374.0μg/ml. However, ethanol extracts of Dssots brazzae and Strombosa scheffler had LC 50 values of >1000μg/ml. The seemingly innocuous nature and relatively good antibacterial activity against skin infections and gastrointestinal pathogenic bacteria support the traditional uses of the plants and deserve more detailed studies.

Tanzania Journal of Health Research, 2010

Emergence of new and re-emergence of old infections continue to elude prospects of reducing morbi... more Emergence of new and re-emergence of old infections continue to elude prospects of reducing morbidity and mortality caused by microbial infections. Trends of resistance to currently in use antimicrobials and antimalarials threaten to increase mortality caused by these infections. This study explores the potential of marine invertebrates as a source for new antimicrobials and antimalarials. The lactate dehydrogenase method was used to assay marine sponges for activity against Plasmodium falciparum, while the disc diffusion method was used to assay the extracts for antibacterial and antifungal activity. Extracts of some marine sponges from the Zanzibar Island exhibited both antiplasmodial and antimicrobial activities. Among the 55 marine sponge extracts that were tested 23 (41.8%) inhibited Plasmodium falciparum W2 strain by more than 50% at both 250 and 50 μg/ml concentrations. Moderate polar extracts were more active against Plasmodium falciparum W2 strain than polar and non-polar extracts. None of the 12 extracts that were tested on Plasmodium falciparum strain D6 exhibited inhibitory activity reaching 50%. Among 18 marine sponge extracts that were tested for antimicrobial activity 12 (66.7%) showed activity against one or more of the bacteria and fungi used ranging from weak to strong on an arbitrary criterion. The ethyl acetate extracts of Agelas mauritania and Oceanopia sp. exhibited high activity against the fungi Candida albicans and Cryptococcus neoformans. The best antibacterial profile was exhibited by ethyl acetate extracts of Aplysinopsis sp., Halichondrida sp. 1 and Oceanopia sp. In conclusion, these results support the need for intensified efforts to search for active antimalarial and antimicrobial compounds from the Zanzibar marine sponges.

Tanzania Journal of Health Research, 2009

Warburga ugandenss Sprague (Canellaceae), is widely used by Traditional Health Practitioners in E... more Warburga ugandenss Sprague (Canellaceae), is widely used by Traditional Health Practitioners in Eastern and Southern Africa for treatment of diseases and conditions associated with HIV/AIDS infections. The most commonly prescribed parts of the plant are usually barks and roots. The aim of this study was to investigate whether leaves of this plant have biological activities comparable to those of barks and roots. Fresh leaves of W. ugandenss were freeze-dried to complete dryness while another portion of the leaves from the same collection were air-dried under shade. Ethanolic extracts from the two differently dried leaves were tested for antimicrobial activity and for brine shrimp toxicity test. Ethanolic extract from the freeze-dried leaves exhibited both antibacterial activity against standard strains of Staphylococcus aureus, Eschercha col, Vbro cholerae, Bacllus cereus and antifungal activity against Candda albcans and Cryptococcus neoformans. The extract from the air-dried leaves showed similar antibacterial activity against the mentioned organisms but had no antifungal activity. However, both extracts exhibited comparable cytotoxic activity (95% CI), against brine shrimp larvae with reference to cyclophosphamide, a standard anticancer drug. Fresh leaves of W. ugandenss have shown to exhibit anticandida activity, a factor which substantiates their application as a traditional herbal remedy to complement treatment of fungal infections in HIV/AIDS patients. Further studies to establish constituents responsible for the exhibited antifungal activity are highly desirable.

African Journal of Traditional, Complementary and Alternative Medicines, 2010

Aqueous ethanol (80%) extracts of six plants used traditionally for treatment of malaria, Vepris ... more Aqueous ethanol (80%) extracts of six plants used traditionally for treatment of malaria, Vepris glomerata (F.Hoffm.) Engl (Rutaceae), Maranthus floribunda (Bak.) F.White (Chrysobalanaceae), Strophanthus eminii Asch. & Pax ex Pax (Apocynaceae), Cassia abbreviata Oliv. (Leguminosae) and Caesalpinia bonducella L. Fleming (Fabaceae) were screened for antimalarial activity to establish validity of their claims. The extracts exhibited antimalarial activity in the 4-day Peter's suppressive antimalarial assay in mice inoculated with red blood cells parasitized with Plasmodium berghei. The extracts gave ID 50 values of 42.8, 111.0, 639.3 and 1560 mg/kg body wt for C. bonducella, C. abbreviata, T. furialis and S. eminii, respectively. The ID 50 values for V. glomerata and M. floribunda were above 2400 mg/kg body wt, above which point solubility was a problem. All the tested extracts were innocuous to the mice, up to 2400 mg/kg body wt, suggesting they may be safe for short-term use.

African Journal of Traditional, Complementary and Alternative Medicines, 2007

Evaluation of extracts of Diospyros fischeri Gurke (Ebenaceae), which is used traditionally for t... more Evaluation of extracts of Diospyros fischeri Gurke (Ebenaceae), which is used traditionally for the treatment of epilepsy shows that the aqueous extract of the tem bark has no effect against picrotoxin induced convulsions in mice. However, an 80% ethanol extract of the bark caused dose-dependent suppression of convulsions induced by 10 mg/kg body wt picrotoxin, , at doses between 100-3200 mg/kg body wt. Petroleum ether, 1:1 dichloromethane:methanol, and methanol extracts also suppressed picrotoxin-induced convulsions, but had a slightly lower inhibitory effect. The petroleum ether extract was the most active, but all were less active than the ethanol extract. Unlike phenobarbitone, which at 50 mg/kg body wt completely suppressed convulsions induced by 10 mg/kg body wt picrotoxin, none of the plant extracts completely suppressed convulsions in the mice. These results support the traditional uses of D.fischeri for the treatment of epilepsy. Given the seemingly innocuous nature of the extracts more work is suggested to ascertain their clinical application.

African Journal of Traditional, Complementary and Alternative Medicines, 2008

Plants which are used by traditional healers in Tanzania have been evaluated to obtain preliminar... more Plants which are used by traditional healers in Tanzania have been evaluated to obtain preliminary data of their toxicity using the brine shrimps test. The results indicate that 9 out of 44 plant species whose extracts were tested exhibited high toxicity with LC 50 values below 20µg/ml. These include Aloe lateritia Engl. (Aloaceae) [19.1µg/ml], Cassia abbreviata Oliv. (Caesalpiniaceae) [12.7µg/ml], Croton scheffleri Pax (Euphorbiaceae) [13.7µg/ml], Hymenodactyon parvifolium Brig (Rubiaceae) [13.4µg/ml], Kigelia Africana L. (Bignoniaceae) [7.2µg/ml], and Ocimum suave Oliv. (Labiatae) [16.7µg/ml]. Twelve plants gave LC 50 values between 21 and 50µg/ml, 11 plants gave LC 50 values between 50 and 100 µg/ml, and 18 plants gave LC 50 values greater than 100 µg/ml.

Journal of Advanced Pharmaceutical Technology & Research, 2016

Plants used in traditional medicine have been the source of a number of currently used antimalari... more Plants used in traditional medicine have been the source of a number of currently used antimalarial medicines and continue to be a promising resource for the discovery of new classes of antimalarial compounds. The aim of this study was to evaluate in vivo antimalarial activity of four plants; Erythrina schliebenii Harms, Holarrhena pubescens Buch-Ham, Phyllanthus nummulariifolius Poir, and Caesalpinia bonducella (L.) Flem used for treatment of malaria in Tanzania. In vivo antimalarial activity was assessed using the 4-day suppressive antimalarial assay. Mice were infected by injection via tail vein with 2 × 10 7 erythrocytes infected with Plasmodium berghei ANKA. Extracts were administered orally, once daily, for a total of four daily doses from the day of infection. Chloroquine (10 mg/kg/day) and solvent (5 mL/kg/day) were used as positive and negative controls, respectively. The extracts of C. bonducella, E. schliebenii, H. pubescens, and P. nummulariifolius exhibited dose-dependent suppression of parasite growth in vivo in mice, with the highest suppression being by C. bonducella extract. While each of the plant extracts has potential to yield useful antimalarial compounds, the dichloromethane root extract of C. bonducella seems to be the most promising for isolation of active antimalarial compound(s). In vivo antimalarial activity presented in this study supports traditional uses of C. bonducella roots, E. schliebenii stem barks, H. pubescens roots, and P. nummulariifolius for treatment of malaria.

The medicinal plants have been used traditionally for different purposes such as pest control and... more The medicinal plants have been used traditionally for different purposes such as pest control and treatment of human diseases. Despite these potentials, only few plants have been evaluated for their safety. This study aimed at investigating oral acute toxicity of Annona squamosa leaf extract and fractions using albino mice. The aqueous-ethanol, dichloromethane and petroleum ether fractions were prepared and tested for oral acute toxicity. Whereas some toxicity signs occurred for aqueous-ethanol extract at doses ≥1500 mg/kg bwt that of dichloromethane fraction were seen at 1000-5000 mg/kg and that of petroleum ether fraction were at 5000 mg/kg. All the tested materials at a dose above 300 mg/kg bwt had negative effects on the growth of the mice. The LD 50 were estimated to be >1000 mg/kg bwt for dichloromethane, >1500 mg/kg bwt for aqueous-ethanol extract and >3000 mg/kg bwt for petroleum ether fraction. All mice dissected had normal organs except one among six females treat...

Medicinal and Aromatic Plants of the World, 2017

Crude extracts of Dracaena steudneri bark (DSB), Sapium ellipticum bark (SEB) and Capparis erythr... more Crude extracts of Dracaena steudneri bark (DSB), Sapium ellipticum bark (SEB) and Capparis erythrocarpos root (CER) were investigated for their antifungal activity in immunocompromised mice infected with Candida albicans in an in vivo mice infection model. The results revealed a substantial dose dependency in all treatments given, with mice survival to the end of the experiment correlating well to the dose levels. At a dose of 400 mg/kg, C. erythrocarpos was the most effective with mice survival of 60% and organ burden clearance ranging from 64.0%-99.9% (P<0.0001) in all treatments. At the same dose, the least effective plant was S. ellipticum which had a mice survival of 20% and organ burden clearance ranging from 78.0%-96.6 (P>0.05). Mice survival for D. steudneri was 30% with organ burden clearance ranging from 89.0%-99.9% (P<0.05). All mice receiving no active treatment died before ten days post infection. In all treatment groups, there was a steady decline in mean weights of mice immediately after immunosuppression followed by gradual recovery in some cases which appeared to be dose dependent a few days post infection. Thus, extracts of D. steudneri and C. erythrocarpos portrayed the most significant potential as sources of antifungal drugs.

The medicinal plants have been used traditionally for different purposes such as pest control and... more The medicinal plants have been used traditionally for different purposes such as pest control and treatment of human diseases. Despite these potentials, only few plants have been evaluated for their safety. This study aimed at investigating oral acute toxicity of Annona squamosa leaf extract and fractions using albino mice. The aqueous-ethanol, dichloromethane and petroleum ether fractions were prepared and tested for oral acute toxicity. Whereas some toxicity signs occurred for aqueous-ethanol extract at doses ≥1500 mg/kg bwt that of dichloromethane fraction were seen at 1000-5000 mg/kg and that of petroleum ether fraction were at 5000 mg/kg. All the tested materials at a dose above 300 mg/kg bwt had negative effects on the growth of the mice. The LD50 were estimated to be >1000 mg/kg bwt for dichloromethane, >1500 mg/kg bwt for aqueous-ethanol extract and >3000 mg/kg bwt for petroleum ether fraction. All mice dissected had normal organs except one among six females treate...

HIV-1 resistance is one of the problems affecting success of antiretroviral therapy programmes wo... more HIV-1 resistance is one of the problems affecting success of antiretroviral therapy programmes worldwide. Many studies on efficacy of ART programmes, specifically on drug resistance, have been conducted in developed countries but not in developing countries due to lack of resources. So many tests have been optimized for HIV-1 subtype B which is prevalent in the developed countries but not for non-subtype B which is the main HIV-1 subtype in developing world. Some few studies have been conducted in Tanzania to evaluate the efficacy of the ART regimens and programmes. These studies have evaluated either the virological efficacy and genotypic resistance in patients receiving ART (to evaluate development of acquired resistance) or genotypic resistance in drug naive patients (to assess primary resistance). These few studies have been conducted in cities or urban areas with referral hospitals and have indeed shown some degree of resistance to ART and have provided some insights into degre...