Cosam C. Joseph

Use of Traditional Medicines in the Management of HIV/AIDS Opportunistic Infections in Tanzania: A Case in the Bukoba Rural District.

BackgroundEthnobotanical surveys were carried out to document herbal remedies used in the management of HIV/AIDS opportunistic infections in Bukoba Rural district, Tanzania. 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 knowledge is impressionistic and not well documented. The HIV/AIDS opportunistic conditions considered during the study were Tuberculosis (TB), Herpes zoster (Shingles), Herpes simplex (Genital herpes), Oral candidiasis and Cryptococcal meningitis. Other symptomatic but undefined conditions considered were skin rashes and chronic diarrhea.MethodsAn open-ended semi-structured questionnaire was used in collecting field information. Descriptive statistics were used to analyze the ethnobotanical data collected. Factor of informant consensus (Fic) was used to analyze the ethnobotanical importance of the plants.ResultsIn the present study, 75 plant species belonging to 66 genera and 41 families were found to be used to treat one or more HIV/AIDS related infections in the district. The study revealed that TB and oral candidiasis were the most common manifestations of HIV/AIDS opportunistic infections affecting most of the population in the area. It unveils the first detailed account of ethnomedical documentation of plants focusing the management of HIV/AIDS related infections in the district.ConclusionIt is concluded that the ethnopharmacological information reported forms a basis for further research to identify and isolate bioactive constituents that can be developed to drugs for the management of the HIV/AIDS opportunistic infections.

Screening of Tanzanian medicinal plants for anti-Candida activity

BackgroundCandida albicans has become resistant to the already limited, toxic and expensive anti-Candida agents available in the market. These factors necessitate the search for new anti-fungal agents.MethodsSixty-three plant extracts, from 56 Tanzanian plant species obtained through the literature and interviews with traditional healers, were evaluated for anti-Candida activity. Aqueous methanolic extracts were screened for anti-Candida activity by bioautography agar overlay method, using a standard strain of Candida albicans (ATCC 90028).ResultsTwenty- seven (48%) out of the 56 plants were found to be active. Extracts of the root barks of Albizia anthelmintica and Balanites aegyptiaca, and roots of Plectranthus barbatus showed strong activity.ConclusionThe extracts that showed strong anti-Candida activity are worth of further investigation in order to isolate and identify the active compounds.

Anti-mosquito and antimicrobial nor-halimanoids, isocoumarins and an anilinoid from Tessmannia densiflora.

The nor-halimane diterpenoid tessmannic acid and its methyl, 2-methylisopropyl and 1-methylbutyl esters, the unusual isocoumarins 8-hydroxy-6-methoxy-3-pentylisocoumarin and 7-chloro-8-hydroxy-6-methoxy-3-pentylisocoumarin, and 5-pentyl-3-methoxy-N-butylaniline were isolated from the stem and root bark extracts of Tessmannia densiflora Harms (Caesalpiniaceae) that showed mosquito larvicidal activity. The structures were determined on interpretation of spectroscopic data. Tessmannic acid and its methyl ester exhibited antibacterial and antifungal activity. The compounds also caused high larvae and adult Anopheles gambiae mosquitoe mortality effects, and stronger mosquito repellency than that shown by the standard repellent DEET, hence indicating Tessmannia species to be potential sources of bioactive natural products.

Screening of traditionally used Tanzanian medicinal plants for antifungal activity

Fungal infections represent a significant cause of morbidity and mortality especially in immunocompromised patients in the world today. Dichloromethane (DM) and aqueous (W) extracts of nine plants used traditionally for the treatment of fungal infections in Bukoba rural district in Tanzania were screened for antifungal activity against Candida albicans, Cryptococcus neoformans, and Aspergillus niger using agar well and disk diffusion methods. Dichloromethane extracts of Capparis erythrocarpos [CE] Isert (Capparaceae), Cussonia arborea [CA] Hochst. Ex A. Rich (Araliaceae), Dracaena steudneri [DS] Engl. (Dracaenaceae), Lannea schimperi [LS] (A. Rich) Engl. (Anacardiaceae), Rauvolfia vomitoria [RV] Afz (Apocynaceae), and Sapium ellipticum [SE] (Krauss) Pax (Euphorbiaceae) showed activity against all three fungi. Extracts of Rumex usambarensis [RU] (Dammer) Dammer (Polygonaceae) and Zehneria scabra [ZS] (L.f.) Sond. (Cucurbitaceae) had an activity limited to only one or two of the test organisms. Rhoicissus tridentata [RT] (L.f.) Wild & Drum (Vitaceae) was the only plant without activity. Fractions of the active extracts CE, CA, DS, LS, and SE exhibited higher antifungal activity against one or more of the three fungi. Four compounds isolated from S. ellipticum also exhibited antifungal activity against one or more of the three fungi. The minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs), determined using the microplate assay method, ranged between 0.4 and 50.0 μg/mL for crude extracts, 1.6 and 50.0 μg/mL for semi-purified fractions, and 0.12 and 1.0 μg/mL for pure compounds, as compared to 0.016–1.5 μg/mL for fluconazole. We confirm the potential of traditionally used plants as a source of new drugs for treatment of fungal infections.

A novel antiplasmodial 3′,5′-diformylchalcone and other constituents of Friesodielsia obovata

Phytochemical investigation of the stem and root barks of Friesodielsia obovata Benth (Annonaceae) afforded new 3′,5′-diformyl-2′,4′,6′-trihydroxychalcone and N-formyl-7-hydroxyglaucine together with five known compounds, 3′,5′-dimethyl-2′,4′,6′-trihydroxychalcone, (−)-crotepoxide, demethoxymatteucinol, lawinal, and benzyl benzoate. 3′,5′-diformyl-2′,4′,6′-trihydroxychalcone indicated significant antiplasmodial, cytotoxicity, and larvicidal activities.

Constituents of the Essential Oil of Suregada Zanzibariensis Leaves are Repellent to the Mosquito, Anopheles Gambiae s.s.

Abstract In traditional African communities, repellent volatiles from certain plants generated by direct burning or by thermal expulsion have played an important role in protecting households against vectors of malaria and other diseases. Previous research on volatile constituents of plants has shown that some are good sources of potent mosquito repellents. In this bioprospecting initiative, the essential oil of leaves of the tree, Suregada zanzibariensis Verdc. (Angiospermae: Euphobiaceae) was tested against the mosquito, Anopheles gambiae s.s. Giles (Diptera: Culicidae) and found to be repellent. Gas chromatography (GC), GC-linked mass spectrometry (GC-MS) and, where possible, GC-co-injections with authentic compounds, led to the identification of about 34 compounds in the essential oil. About 56% of the constituents were terpenoid ketones, mostly methyl ketones. Phenylacetaldehyde (14.4%), artemisia ketone (10.1%), (1S)-(-)-verbenone (12.1%) and geranyl acetone (9.4%) were the main constituents. Apart from phenylacetaldehyde, repellent activities of the other main constituents were higher than that of the essential oil. The blends of the main constituents in proportions found in the essential oil were more repellent to An. gambiae s.s. than was the parent oil (p < 0.05), and the presence of artemisia ketone in the blend caused a significant increase in the repellency of the resulting blend. These results suggested that blends of some terpenoid ketones can serve as effective An. gambiae s.s. mosquito repellents.

Toussaintines A-E: antimicrobial indolidinoids, a cinnamoylhydrobenzofuranoid and a cinnamoylcyclohexenoid from Toussaintia orientalis leaves.

Toussaintine A (N-cinnamoyl-5,6-dehydro-4-hydroxyindolidin-2,7-dione), toussaintine B (N-cinnamoyl-5,6-dehydro-4,7-dihydroxyindolidin-2-one), toussaintine C (N-cinnamoyl-5,6-dehydro-4-hydroxyindolidin-7-one), toussaintine D (N-cinnamoyl-2-amino-4-hydroxy-7-oxo-2,3,8,9-tetrahydrobenzofuran) and toussaintine E (N-cinnamoyl-1-acetoxymethyl-2-amino-1-hydroxycyclox-5-en-4-one) were isolated as antibacterial and antifungal constituents of the leaves of Toussaintia orientalis Verdc. (Annonaceae) and their structures established from analysis of spectroscopic data. The compounds belong to a series of variously cyclized aminocinnamoyl tetraketide derivatives, showing the importance of rarely occurring Annonaceae species as sources of structurally diverse natural products.

In Vitro Antibacterial and Antifungal Activities of Extracts and Compounds from Uvaria scheffleri

Petroleum ether, dichloromethane, and ethanolic extracts of the stem bark and leaves of Uvaria scheffleri Diels (Annonaceae) exhibited antifungal activity against Aspergillus niger (wild strain), Aspergillus fumigatus (wild strain), and a Penicillium species (wild strain). The ethanol extract of the stem bark was also active against Candida albicans (Strain H6392). The dichloromethane extract of the leaves showed the highest antifungal activity and in addition it showed antibacterial activity against Staphylococcus aureus (NCTC 6571). Fractionation of the dichloromethane extract of the leaves yielded nine known compounds. They included a 1 : 1 mixture of stigmasterol (1) and β-sitosterol (2), which showed antifungal activity against Candida albicans. Others were 3-farnesylindole (3), 2′,6′-dihydroxy-3′,4′-dimethoxy-chalcone (4), 2′-hydroxy-3′,4′,6′-trimethoxychalcone (5), 5-hydroxy-7,8-dimethoxyflavanone (6), 5,7,8-trimethoxyflavanone (7), and a 3 : 2 mixture of 2′,6′-dihydroxy-4′-methoxychalcone (8) and 5,7-dihydroxyflavone (9). Compound 7 and the mixture of compounds 8 and 9 showed antibacterial activity against Escherichia coli (NCTC 10418, MIC 125 µg/ml) and Staphylococcus aureus (MIC 125 µg/ml), respectively. The mixture of compounds 8 and 9 was also active against Candida albicans (MIC 31.25 µg/ml), Aspergillus niger, Aspergillus fumigatus, and the Penicillium species (MIC 1000 µg/ml). We conclude that Uvaria scheffleri extracts contain compounds with antifungal and antibacterial activity. The activities observed in this study are weak. Based on previous studies, it is being speculated that, possibly, the most active compounds were lost during fractionation. Further work to isolate more antifungal and antibacterial compounds is suggested.

Cytotoxic, anti-proliferative and antimicrobial furanoditerpenoids from Stuhlmania moavi

The furanoditerpenoids voucapane, voucapane-6alpha,7alpha-diol, voucapane-18,19-diol and 18-hydroxyvoucapan-19-al were isolated from the cytotoxic stem and root bark extracts of Stuhlmaniamoavi Verdc. (Ceasalpiniaceae) and their structures established based on analysis of spectroscopic data. The compounds exhibited anti-proliferative, cytotoxic, antibacterial and antifungal activities, 18-hydroxyvoucapan-19-al showing the highest anti-proliferative and cytotoxic properties. Voucapane-18,19-diol was only mildly active but the activity was enhanced for its 18,19-di-(4-methyl)-benzenesulphonate. Some of these results thus corroborate the traditional medicinal uses of the crude extracts for the treatment of skin infections.

A new cytotoxic and larvicidal himachalenoid, rosanoids and other constituents of Hugonia busseana

A new cytotoxic himachalene sesquiterpenoid 4α-methoxy-5,9-oxahimachal-9-ene (hugonianene A) which exhibited moderate activity against Anopheles gambiae mosquito larvae after 24 h at a concentration of 0.237 mg mL−1, and at 48 h and 72 h contact time causing complete larval mortality up to a concentration as low as 0.01369 mg mL−1, was isolated as the major constituent of the cytotoxic root bark extract of Hugonia busseana. Hugonianene A was obtained together with the hitherto unreported rosane diterpenoid 18-hydroxyrosane, the known rosane diterpenoid hugorosediol, an inseparable mixture of 12-methoxy-13-methylpodocarpa-8,11,13-trien-3,7-dione and 12-methoxy-13-methylpodocarpa-1,8,11,13-tetraen-3,7-dione, and the di-podocarpanoid hugonone B that was previously obtained from H. castaneifolia.