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Papers by Dr Mourice V N Mbunde

Research paper thumbnail of Anti-respiratory syncytial virus and anti-herpes simplex virus activity of six Tanzanian medicinal plants with extended studies of Erythrina abyssinica stem bark

Journal of Ethnopharmacology, 2022

ETHNOPHARMACOLOGICAL RELEVANCE Except for few highly pathogenic viruses, no antiviral drug has be... more ETHNOPHARMACOLOGICAL RELEVANCE Except for few highly pathogenic viruses, no antiviral drug has been approved for treatment of viral infections in humans. Plant extracts, selected based on their ethno-medical use, represent an important source of compounds for the development of novel candidate antiviral drugs. This especially concerns plants with ethnomedical records on their use in treatment of viral infections. AIM OF THE STUDY To identify and document medicinal plants used by traditional health practitioners (THPs) for treatment of respiratory infections and muco-cutaneous lesions in order to study their antiviral activity including identification of active components and elucidation of mode of antiviral activity. MATERIALS AND METHODS The ethno-medical survey was performed in the Kagera region of Tanzania. The THPs were asked for plants used for treatment of signs and symptoms of respiratory infections and watery mucocutaneous blisters in oral and genital regions. The plants identified were successively extracted with n-hexane, ethyl acetate and water, and the extracts assayed for anti-respiratory syncytial virus (RSV), anti-herpes simplex virus 2 (HSV-2), and anti-human parainfluenza virus 2 (HPIV-2) activity in cultured cells. Antiviral components were separated by ethanol precipitation and CL-6B chromatography, and the mode of antiviral activity elucidated by the time-of-addition assay and selection for the virus variants resistant to antiviral plant extract. RESULTS THPs identified fifteen plants used for treatment of respiratory infections and mucocutaneous blisters. The water extract, but not n-hexane or ethyl acetate extracts, of six of these plants including Erythrina abyssinica stem bark, inhibited infectivity of two glycosaminoglycan-binding viruses i.e., RSV and HSV-2 but not the sialic acid binding HPIV-2. An activity-guided separation revealed that antiviral component(s) of water extract of E. abyssinica could be precipitated with ethanol. This sample potently and selectively inhibited RSV and HSV-2 infectivity in cultured cells with IC50 values of 2.1 μg/ml (selectivity index >476) and 0.14 μg/ml (selectivity index >7143) respectively. The sample exhibited inhibitory effect on the virus attachment to and entry into the cells by directly targeting the viral particles. Indeed, 10 consecutive virus passages in HEp-2 cells in the presence of this extract selected for a resistant RSV variant lacking the attachment, viral membrane-associated, G protein due to a stop codon at amino acid residue 33 (Leu33stop). Fractionation of the E. abyssinica extract on a CL-6B column revealed that anti-RSV and HSV-2 activity correlated with carbohydrate content. The most pronounced antiviral activity was associated with a carbohydrate containing ingredient of molecular mass of <5 kDa, which may polymerize to antiviral composites of up to 410 kDa. CONCLUSIONS Altogether, the water extract of six medicinal plants showed anti-RSV and anti-HSV-2 activities. Extended studies of the stem bark of E. abbysinica identified antiviral components that potently and selectively inhibited infectivity of free RSV and HSV-2 particles, a feature of importance in topical treatment of these infections. This observation confirms ethno-medical information concerning the use of E. abyssinica extract for treatment of respiratory infections.

Research paper thumbnail of Ethnobotanical Survey and Toxicity Evaluation of Medicinal Plants used for Fungal Remedy in the Southern Highlands of Tanzania

Journal of Intercultural Ethnopharmacology, 2017

Research paper thumbnail of Anti-respiratory syncytial virus and anti-herpes simplex virus activity of six Tanzanian medicinal plants with extended studies of Erythrina abyssinica stem bark

Journal of Ethnopharmacology, 2022

Ethnopharmacological relevance Except for a few highly pathogenic viruses, no antiviral drug has ... more Ethnopharmacological relevance
Except for a few highly pathogenic viruses, no antiviral drug has been approved for the treatment of viral infections in humans. Plant extracts selected based on their ethnomedical use, represent an important source of compounds for the development of novel candidate antiviral drugs. This especially concerns plants with ethnomedical records on their use in the treatment of viral infections.

Aim of the study
To identify and document medicinal plants used by traditional health practitioners (THPs) for treatment of respiratory infections and mucocutaneous lesions in order to study their antiviral activity including identification of active components and elucidation of the mode of antiviral activity.

Materials and methods
The ethnomedical survey was performed in the Kagera region of Tanzania. The THPs were asked for plants used for the treatment of signs and symptoms of respiratory infections and watery mucocutaneous blisters in oral and genital regions. The plants identified were successively extracted with n-hexane, ethyl acetate, and water, and the extracts were assayed for the anti-respiratory syncytial virus (RSV), anti-herpes simplex virus 2 (HSV-2), and anti-human parainfluenza virus 2 (HPIV-2) activity in cultured cells. Antiviral components were separated by ethanol precipitation and CL-6B chromatography, and the mode of antiviral activity was elucidated by the time-of-addition assay and selection for the virus variants resistant to antiviral plant extract.

Results
THPs identified fifteen plants used for the treatment of respiratory infections and mucocutaneous blisters. The water extract, but not n-hexane or ethyl acetate extracts, of six of these plants including Erythrina abyssinica stem bark, inhibited infectivity of two glycosaminoglycan-binding viruses i.e., RSV and HSV-2 but not the sialic acid-binding HPIV-2. An activity-guided separation revealed that antiviral component(s) of water extract of E. abyssinica could be precipitated with ethanol. This sample potently and selectively inhibited RSV and HSV-2 infectivity in cultured cells with IC50 values of 2.1 μg/ml (selectivity index >476) and 0.14 μg/ml (selectivity index >7143) respectively. The sample exhibited an inhibitory effect on the virus attachment to and entry into the cells by directly targeting the viral particles. Indeed, 10 consecutive virus passages in HEp-2 cells in the presence of this extract were selected for a resistant RSV variant lacking the attachment, viral membrane-associated, G protein due to a stop codon at amino acid residue 33 (Leu33stop). Fractionation of the E. abyssinica extract on a CL-6B column revealed that anti-RSV and HSV-2 activity correlated with carbohydrate content. The most pronounced antiviral activity was associated with a carbohydrate-containing ingredient of molecular mass of <5 kDa, which may polymerize to antiviral composites of up to 410 kDa.

Conclusions
Altogether, the water extract of six medicinal plants showed anti-RSV and anti-HSV-2 activities. Extended studies of the stem bark of E. abyssinica identified antiviral components that potently and selectively inhibited infectivity of free RSV and HSV-2 particles, a feature of importance in topical treatment of these infections. This observation confirms ethnomedical information concerning the use of E. abyssinica extract for the treatment of respiratory infections and herpetic lesions.

Research paper thumbnail of In vitro study for antifungal compounds from Parinari curatellifolia (Chrysobalanaceae) and Terminalia sericea (Combretaceae)

Parinari curatellifolia (Chrysobalanaceae) and Terminalia sericea (Combretaceae) have been tradit... more Parinari curatellifolia (Chrysobalanaceae) and Terminalia sericea (Combretaceae) have been traditionally used in Southern Highlands of Tanzania for treatment of various infectious disorders. The present study aimed to evaluate antifungal activity of the isolated compounds from Parinari curatellifolia and Terminalia sericea plant species. The ethyl acetate extract of the root barks from Parinari curatellifolia and Terminalia sericea were fractionated using column chromatography. The structures of compounds were established using both 1D and 2D-NMR spectroscopic techniques while antifungal activities of the fractions and isolated compounds were evaluated using broth microdilution assay against Candida albicans, Cryptococcus neoformans and Aspergillus niger species. Two known compounds toddalolactone (1) and 10-hydroxy-13-methoxy-9methyl-15-oxo-20-norkaur-16-en-18-oic acid -lactone (2) from P. curatellifolia and two compounds Sericic acid (3) and sericoside (4) from T. sericea were is...

Research paper thumbnail of Antifungal activity of single and combined extracts of medicinal plants from Southern Highlands of Tanzania

This study investigated the antifungal activities of single and combined extracts of traditionall... more This study investigated the antifungal activities of single and combined extracts of traditionally used Tanzanian medicinal plants against the selected fungal pathogens. Plants samples were collected from Southern regions of Tanzania, dried, ground and extracted with petroleum ether, dichloromethane and ethanol. Broth micro dilution method was used to determine minimum inhibition concentration (MIC) while Fractional inhibitory concentrations (FIC) index was calculated from MICs of combined extracts to determine the effect of interactions. A total of sixteen medicinal plants were evaluated for antifungal activity against Candida albicans, Cryptococcus neoformans and Aspergillus niger. Strong antifungal activity was demonstrated by Bidens pilosa (MIC value 0.078-0.313 mg/ml), Mucuna stans (MIC value 0.117-0.313 mg/ml), Parinari curatellifolia (MIC value 0.039-0.469 mg/ml), Solanum incanum (MIC value 0.039-0.469 mg/ml), Strychnos spinosa (MIC value 0.313-0.469 mg/ml), Leonotis nepetifo...

Research paper thumbnail of Quantification of phenolics, flavonoids and antioxidant activity of Tamarindus indica from selected areas in Tanzania

Biofarmasi Journal of Natural Product Biochemistry

Mbunde M, Mdegela RH, Laswai HS, Mabiki FP. 2018. Quantification of phenolics, flavonoids and ant... more Mbunde M, Mdegela RH, Laswai HS, Mabiki FP. 2018. Quantification of phenolics, flavonoids and antioxidant activity of Tamarindus indica from selected areas in Tanzania. Biofarmasi J Nat Prod Biochem15: 22-28. The objective of this study was to establish the quantities and antioxidant activity in fruits and leaves of Tamarindus indica L. collected from three agro-ecological zones of Tanzania represented by Morogoro, Tanga and Dodoma regions. Samples were examined for their total phenolic and flavonoid contents as well as their antioxidant activity. The total phenolic content showed significant difference in all extracts of the fruits and leaves and ranged from 1994.4±530.77 to 17874.67±5234 mg GAE/100 g. Similarly, the total flavonoid content in tamarind leaf and fruit extracts ranged from 880±609.45 to 11483.11±2559.67 mg CE /100 g dry weight. There was a significant difference between the antioxidant activity in the leaf (54.39±0.13%) and fruit extracts (40.11±0.03%). Tamarind leaf...

Research paper thumbnail of Ethnobotanical survey and toxicity evaluation of medicinal plants used for fungal remedy in the Southern Highlands of Tanzania

Background/Aim: Some of the antifungal drugs used in the current treatments regime are responding... more Background/Aim: Some of the antifungal drugs used in the current treatments regime are responding to antimicrobial resistance. In rural areas of Southern Tanzania, indigenous people use antifungal drugs alone or together with medicinal plants to curb the effects of antibiotic resistance. This study documented ethnobotanical information of medicinal plants used for managing fungal infections in the Southern Highlands of Tanzania and further assess their safety. Materials and Methods: Ethnobotanical survey was conducted in Makete and Mufindi districts between July 2014 and December 2015 using semi-structured questionnaires followed by two focus group discussions to verify respondents' information. Cytotoxicity study was conducted on extracts of collected plants using brine shrimp lethality test and analyzed by MS Excel 2013 program. Results: During this survey about 46 plant species belonging to 28 families of angiosperms were reported to be traditionally useful in managing fungal and other health conditions. Among these, Terminalia sericea, Aloe nutii, Aloe lateritia, Zanthoxylum chalybeum, Zanthoxylum deremense, and Kigelia africana were frequently mentioned to be used for managing fungal infections. The preparation of these herbals was mostly by boiling plant parts especially the leaves and roots. Cytotoxicity study revealed that most of the plants tested were nontoxic with LC 50 > 100 which implies that most compounds from these plants are safe for therapeutic use. The dichloromethane extract of Croton macrostachyus recorded the highest with LC 50 value 12.94 μg/ml. The ethnobotanical survey correlated well with documented literature from elsewhere about the bioactivity of most plants. Conclusions: The ethnobotanical survey has revealed that traditional healers are rich of knowledge to build on for therapeutic studies. Most of the plants are safe for use; and thus can be considered for further studies on drug discovery.

Research paper thumbnail of Anti-respiratory syncytial virus and anti-herpes simplex virus activity of six Tanzanian medicinal plants with extended studies of Erythrina abyssinica stem bark

Journal of Ethnopharmacology, 2022

ETHNOPHARMACOLOGICAL RELEVANCE Except for few highly pathogenic viruses, no antiviral drug has be... more ETHNOPHARMACOLOGICAL RELEVANCE Except for few highly pathogenic viruses, no antiviral drug has been approved for treatment of viral infections in humans. Plant extracts, selected based on their ethno-medical use, represent an important source of compounds for the development of novel candidate antiviral drugs. This especially concerns plants with ethnomedical records on their use in treatment of viral infections. AIM OF THE STUDY To identify and document medicinal plants used by traditional health practitioners (THPs) for treatment of respiratory infections and muco-cutaneous lesions in order to study their antiviral activity including identification of active components and elucidation of mode of antiviral activity. MATERIALS AND METHODS The ethno-medical survey was performed in the Kagera region of Tanzania. The THPs were asked for plants used for treatment of signs and symptoms of respiratory infections and watery mucocutaneous blisters in oral and genital regions. The plants identified were successively extracted with n-hexane, ethyl acetate and water, and the extracts assayed for anti-respiratory syncytial virus (RSV), anti-herpes simplex virus 2 (HSV-2), and anti-human parainfluenza virus 2 (HPIV-2) activity in cultured cells. Antiviral components were separated by ethanol precipitation and CL-6B chromatography, and the mode of antiviral activity elucidated by the time-of-addition assay and selection for the virus variants resistant to antiviral plant extract. RESULTS THPs identified fifteen plants used for treatment of respiratory infections and mucocutaneous blisters. The water extract, but not n-hexane or ethyl acetate extracts, of six of these plants including Erythrina abyssinica stem bark, inhibited infectivity of two glycosaminoglycan-binding viruses i.e., RSV and HSV-2 but not the sialic acid binding HPIV-2. An activity-guided separation revealed that antiviral component(s) of water extract of E. abyssinica could be precipitated with ethanol. This sample potently and selectively inhibited RSV and HSV-2 infectivity in cultured cells with IC50 values of 2.1 μg/ml (selectivity index >476) and 0.14 μg/ml (selectivity index >7143) respectively. The sample exhibited inhibitory effect on the virus attachment to and entry into the cells by directly targeting the viral particles. Indeed, 10 consecutive virus passages in HEp-2 cells in the presence of this extract selected for a resistant RSV variant lacking the attachment, viral membrane-associated, G protein due to a stop codon at amino acid residue 33 (Leu33stop). Fractionation of the E. abyssinica extract on a CL-6B column revealed that anti-RSV and HSV-2 activity correlated with carbohydrate content. The most pronounced antiviral activity was associated with a carbohydrate containing ingredient of molecular mass of <5 kDa, which may polymerize to antiviral composites of up to 410 kDa. CONCLUSIONS Altogether, the water extract of six medicinal plants showed anti-RSV and anti-HSV-2 activities. Extended studies of the stem bark of E. abbysinica identified antiviral components that potently and selectively inhibited infectivity of free RSV and HSV-2 particles, a feature of importance in topical treatment of these infections. This observation confirms ethno-medical information concerning the use of E. abyssinica extract for treatment of respiratory infections.

Research paper thumbnail of Ethnobotanical Survey and Toxicity Evaluation of Medicinal Plants used for Fungal Remedy in the Southern Highlands of Tanzania

Journal of Intercultural Ethnopharmacology, 2017

Research paper thumbnail of Anti-respiratory syncytial virus and anti-herpes simplex virus activity of six Tanzanian medicinal plants with extended studies of Erythrina abyssinica stem bark

Journal of Ethnopharmacology, 2022

Ethnopharmacological relevance Except for a few highly pathogenic viruses, no antiviral drug has ... more Ethnopharmacological relevance
Except for a few highly pathogenic viruses, no antiviral drug has been approved for the treatment of viral infections in humans. Plant extracts selected based on their ethnomedical use, represent an important source of compounds for the development of novel candidate antiviral drugs. This especially concerns plants with ethnomedical records on their use in the treatment of viral infections.

Aim of the study
To identify and document medicinal plants used by traditional health practitioners (THPs) for treatment of respiratory infections and mucocutaneous lesions in order to study their antiviral activity including identification of active components and elucidation of the mode of antiviral activity.

Materials and methods
The ethnomedical survey was performed in the Kagera region of Tanzania. The THPs were asked for plants used for the treatment of signs and symptoms of respiratory infections and watery mucocutaneous blisters in oral and genital regions. The plants identified were successively extracted with n-hexane, ethyl acetate, and water, and the extracts were assayed for the anti-respiratory syncytial virus (RSV), anti-herpes simplex virus 2 (HSV-2), and anti-human parainfluenza virus 2 (HPIV-2) activity in cultured cells. Antiviral components were separated by ethanol precipitation and CL-6B chromatography, and the mode of antiviral activity was elucidated by the time-of-addition assay and selection for the virus variants resistant to antiviral plant extract.

Results
THPs identified fifteen plants used for the treatment of respiratory infections and mucocutaneous blisters. The water extract, but not n-hexane or ethyl acetate extracts, of six of these plants including Erythrina abyssinica stem bark, inhibited infectivity of two glycosaminoglycan-binding viruses i.e., RSV and HSV-2 but not the sialic acid-binding HPIV-2. An activity-guided separation revealed that antiviral component(s) of water extract of E. abyssinica could be precipitated with ethanol. This sample potently and selectively inhibited RSV and HSV-2 infectivity in cultured cells with IC50 values of 2.1 μg/ml (selectivity index >476) and 0.14 μg/ml (selectivity index >7143) respectively. The sample exhibited an inhibitory effect on the virus attachment to and entry into the cells by directly targeting the viral particles. Indeed, 10 consecutive virus passages in HEp-2 cells in the presence of this extract were selected for a resistant RSV variant lacking the attachment, viral membrane-associated, G protein due to a stop codon at amino acid residue 33 (Leu33stop). Fractionation of the E. abyssinica extract on a CL-6B column revealed that anti-RSV and HSV-2 activity correlated with carbohydrate content. The most pronounced antiviral activity was associated with a carbohydrate-containing ingredient of molecular mass of <5 kDa, which may polymerize to antiviral composites of up to 410 kDa.

Conclusions
Altogether, the water extract of six medicinal plants showed anti-RSV and anti-HSV-2 activities. Extended studies of the stem bark of E. abyssinica identified antiviral components that potently and selectively inhibited infectivity of free RSV and HSV-2 particles, a feature of importance in topical treatment of these infections. This observation confirms ethnomedical information concerning the use of E. abyssinica extract for the treatment of respiratory infections and herpetic lesions.

Research paper thumbnail of In vitro study for antifungal compounds from Parinari curatellifolia (Chrysobalanaceae) and Terminalia sericea (Combretaceae)

Parinari curatellifolia (Chrysobalanaceae) and Terminalia sericea (Combretaceae) have been tradit... more Parinari curatellifolia (Chrysobalanaceae) and Terminalia sericea (Combretaceae) have been traditionally used in Southern Highlands of Tanzania for treatment of various infectious disorders. The present study aimed to evaluate antifungal activity of the isolated compounds from Parinari curatellifolia and Terminalia sericea plant species. The ethyl acetate extract of the root barks from Parinari curatellifolia and Terminalia sericea were fractionated using column chromatography. The structures of compounds were established using both 1D and 2D-NMR spectroscopic techniques while antifungal activities of the fractions and isolated compounds were evaluated using broth microdilution assay against Candida albicans, Cryptococcus neoformans and Aspergillus niger species. Two known compounds toddalolactone (1) and 10-hydroxy-13-methoxy-9methyl-15-oxo-20-norkaur-16-en-18-oic acid -lactone (2) from P. curatellifolia and two compounds Sericic acid (3) and sericoside (4) from T. sericea were is...

Research paper thumbnail of Antifungal activity of single and combined extracts of medicinal plants from Southern Highlands of Tanzania

This study investigated the antifungal activities of single and combined extracts of traditionall... more This study investigated the antifungal activities of single and combined extracts of traditionally used Tanzanian medicinal plants against the selected fungal pathogens. Plants samples were collected from Southern regions of Tanzania, dried, ground and extracted with petroleum ether, dichloromethane and ethanol. Broth micro dilution method was used to determine minimum inhibition concentration (MIC) while Fractional inhibitory concentrations (FIC) index was calculated from MICs of combined extracts to determine the effect of interactions. A total of sixteen medicinal plants were evaluated for antifungal activity against Candida albicans, Cryptococcus neoformans and Aspergillus niger. Strong antifungal activity was demonstrated by Bidens pilosa (MIC value 0.078-0.313 mg/ml), Mucuna stans (MIC value 0.117-0.313 mg/ml), Parinari curatellifolia (MIC value 0.039-0.469 mg/ml), Solanum incanum (MIC value 0.039-0.469 mg/ml), Strychnos spinosa (MIC value 0.313-0.469 mg/ml), Leonotis nepetifo...

Research paper thumbnail of Quantification of phenolics, flavonoids and antioxidant activity of Tamarindus indica from selected areas in Tanzania

Biofarmasi Journal of Natural Product Biochemistry

Mbunde M, Mdegela RH, Laswai HS, Mabiki FP. 2018. Quantification of phenolics, flavonoids and ant... more Mbunde M, Mdegela RH, Laswai HS, Mabiki FP. 2018. Quantification of phenolics, flavonoids and antioxidant activity of Tamarindus indica from selected areas in Tanzania. Biofarmasi J Nat Prod Biochem15: 22-28. The objective of this study was to establish the quantities and antioxidant activity in fruits and leaves of Tamarindus indica L. collected from three agro-ecological zones of Tanzania represented by Morogoro, Tanga and Dodoma regions. Samples were examined for their total phenolic and flavonoid contents as well as their antioxidant activity. The total phenolic content showed significant difference in all extracts of the fruits and leaves and ranged from 1994.4±530.77 to 17874.67±5234 mg GAE/100 g. Similarly, the total flavonoid content in tamarind leaf and fruit extracts ranged from 880±609.45 to 11483.11±2559.67 mg CE /100 g dry weight. There was a significant difference between the antioxidant activity in the leaf (54.39±0.13%) and fruit extracts (40.11±0.03%). Tamarind leaf...

Research paper thumbnail of Ethnobotanical survey and toxicity evaluation of medicinal plants used for fungal remedy in the Southern Highlands of Tanzania

Background/Aim: Some of the antifungal drugs used in the current treatments regime are responding... more Background/Aim: Some of the antifungal drugs used in the current treatments regime are responding to antimicrobial resistance. In rural areas of Southern Tanzania, indigenous people use antifungal drugs alone or together with medicinal plants to curb the effects of antibiotic resistance. This study documented ethnobotanical information of medicinal plants used for managing fungal infections in the Southern Highlands of Tanzania and further assess their safety. Materials and Methods: Ethnobotanical survey was conducted in Makete and Mufindi districts between July 2014 and December 2015 using semi-structured questionnaires followed by two focus group discussions to verify respondents' information. Cytotoxicity study was conducted on extracts of collected plants using brine shrimp lethality test and analyzed by MS Excel 2013 program. Results: During this survey about 46 plant species belonging to 28 families of angiosperms were reported to be traditionally useful in managing fungal and other health conditions. Among these, Terminalia sericea, Aloe nutii, Aloe lateritia, Zanthoxylum chalybeum, Zanthoxylum deremense, and Kigelia africana were frequently mentioned to be used for managing fungal infections. The preparation of these herbals was mostly by boiling plant parts especially the leaves and roots. Cytotoxicity study revealed that most of the plants tested were nontoxic with LC 50 > 100 which implies that most compounds from these plants are safe for therapeutic use. The dichloromethane extract of Croton macrostachyus recorded the highest with LC 50 value 12.94 μg/ml. The ethnobotanical survey correlated well with documented literature from elsewhere about the bioactivity of most plants. Conclusions: The ethnobotanical survey has revealed that traditional healers are rich of knowledge to build on for therapeutic studies. Most of the plants are safe for use; and thus can be considered for further studies on drug discovery.