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ABSTRACT: Azabicycloheptenoylditerpene 1-((2E,6E,10E)-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (artamodamide, 1), diphenylpentanoid (E)-1,5-bis(4-hydroxyphenyl)-pent-1-en-3-one (artamenone, 2) and N-methoxy-5-oxoaporphinoid (artamonteirine, 3) were isolated as new metabolites from Artabotrys modestus Diels ssp macranthus Verdc. and Artabotrys monteiroae Oliv. (Annonaceae), together with several known compounds. Structures of the isolated compounds were established based on analysis of their spectroscopic data. Some of the compounds exhibited antimicrobial activity (minimum inhibitory concentration values between 2.5 and 20 µg mL(-1)) and varying levels of mosquito larvicidal potency. These results further indicate the versatility of the family Annonaceae in accumulating bioactive natural products with diverse chemical structures and wide spectra of biological activities, and hence suggesting the need to conserve Annonaceae species that are potentially vulnerable to extinction.
Natural product research 09/2012; · 1.01 Impact Factor
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ABSTRACT: 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.
Phytochemistry 06/2011; 72(14-15):1826-32. · 3.35 Impact Factor
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ABSTRACT: The clerodane diterpenoids trans-kolavenolic acid, 18-oxocleroda-3,13(E)-dien-15-oic acid, ent-(18-hydroxycarbonyl)-cleroda-3,13(E)-dien-15-oate, 2-oxo-ent-cleroda-3,13(Z)-dien-15-oic acid and trans-2-oxo-ent-cleroda-13(Z)-en-15-oic acid, and the chlorobenzenoid O-(3-hydroxy-4-hydroxycarbonyl-5-pentylphenyl)-3-chloro-4-methoxy-6-pentyl-2-oxybenzoic acid were isolated from Tessmannia martiniana var pauloi and T. martiniana var matiniana. Structures were established based on interpretation of spectroscopic data. Some of the compounds exhibited significant antimosquito, antifungal and antibacterial activities.
Natural product communications 02/2010; 5(2):175-8. · 1.24 Impact Factor
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ABSTRACT: The new aristolactam alkaloid toussalactam {2-hydroxy-1,6-dimethoxy-5H-dibenzo[cdf]indol-4-one} and the known ones, namely aristolactam AII, aristolactam BII, piperolactam C and aristolactam FII; 1-(2-C-methyl-beta-D-ribofuranosyl)-uracil, 3,4,5-trimethoxyphenyl-beta-D-glucopyranoside, and three catechinoids were isolated from the cytotoxic Toussaintia orientalis Verdc stem and root bark extracts, and their structures established based on analysis of spectroscopic data. The aristolactams exhibited antimicrobial and antiinflammatory activity, aristolactam FII showing almost the same level of activity as the standard anti-inflammatory agent Indomethacin. The compounds also exhibited either mild or no antiproliferative and cytotoxic activities, except aristolactam FII that showed the same level of cytotoxicity as the standard drug Camptothecin. 1-(2-C-Methyl-beta-D-ribofuranosyl)-uracil, which is being reported for the first time as a natural product, was inactive in the antibacterial, antifungal, antiinflammatory, antiproliferative and cytotoxicity assays.
Natural product communications 02/2010; 5(2):253-8. · 1.24 Impact Factor
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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.
Journal of Insect Science 01/2010; 10:57. · 0.95 Impact Factor
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ABSTRACT: 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.
Phytochemistry 09/2009; 70(10):1233-8. · 3.35 Impact Factor
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ABSTRACT: 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.
Phytochemistry 09/2009; 70(17-18):2047-52. · 3.35 Impact Factor
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ABSTRACT: 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.
07/2009; 47(8):708-716.
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ABSTRACT: This paper reports the larvicidal activity of seventeen Tanzanian plant species against the malaria vector, Anopheles gambiae s.s. Giles larvae. Some of the plants are used traditionally as sources of insecticidal materials.
The crude extracts from the leaves, stem and root barks of the investigated plants were obtained by solvent extraction and then bio-assayed following WHO protocols showed LC50 values 10 to 400 ppm after 24 h exposure. The structures were determined on interpretation of spectroscopic data.
The most active extracts were those from the stem and root barks of Annona squamosa, Uvaria faulknerae, U. kirkii and Uvariodendron pycnophyllum, all of which had LC50 values between 10 and 100 ppm. Long-term exposure beyond 24 h also showed more susceptibility of the larvae to the extracts. Larvae deformities by forming tail-like structures were observed for the methanol extracts of Tessmannia martiniana var pauloi.
The results suggest that the investigated plant extracts are promising as larvicides against An. gambiae s.s. Giles mosquitoes and could be useful leads in the search for new and biodegradable plant derived larvicide products.
Journal of vector borne diseases 06/2009; 46(2):145-52. · 1.18 Impact Factor
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ABSTRACT: Studies on the larvicidal properties of extracts and fractions from Kotschya uguenensis Verdc. were done by long-term exposure of Anopheles gambiae s.s. larvae. The cumulative mean percentage mortalities and deformities at different concentrations for the extracts and fractions were recorded after every 24 h. Treatment of A. gambiae s.s. larvae with K. uguenensis extracts showed growth disruption by forming elongated guts and resulting in eventual death. Larvae treated with the methanol extracts from the stem and root barks, and fractions of the former extract attained complete mortality in 6–8 days at 50 and 100 ppm. More deformed larvae were observed from the methanol extract of the stem bark (40%) and methanol-soluble fraction (88%) than those treated with water-soluble fraction (22%) and methanol extract of the root bark (5%). The growth disruption may be associated with constituents in the plant that interfere with the normal endocrine system functions.
International Journal of Tropical Insect Science 11/2008; 28(04):220 - 224.
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ABSTRACT: Lantana viburnoides sp viburnoides var kisi is used in Tanzania ethnobotanically to repel mosquitoes as well as in traditional medicine for stomach ache relief. Bioassay-guided fractionation and subtraction bioassays of the dichloromethane extract of the root barks were carried out in order to identify the bioactive components for controlling Anopheles gambiae s.s. mosquito larvae.
Twenty late III or early IV instar larvae of An. gambiae s.s. were exposed to various concentrations of the plant extracts, fractions, blends and pure compounds, and were assayed in the laboratory by using the protocol of WHO 1996. Mean mortalities were compared using Dunnett's test (p < 0.05) and lethal concentration calculated by Lackfit Inversel of the SAS programme.
The crude extract (LC50 = 7.70 ppm in 72 h) and fractions exhibited different level of mosquito larvicidal activity with subtraction of some fractions resulting in activity enhancement. The active fractions contained furanonaphthaquinones regio-isomers (LC50 = 5.48-5.70 ppm in 72 h) and the lantadene triterpenoid camaric acid (LC50 = 6.19 ppm in 72 h) as active principles while the lupane triterpenoid betulinic acid (LC50 < 10 ppm in 72 h) was obtained from the least active fraction.
Crude extracts and some fractions had higher or comparable larvicidal activity to the pure compounds. These results demonstrate that L. viburnoides sp viburnoides var kisi extracts may serve as larvicides for managing various mosquito habitats even in their semi-purified form. The isolated compounds can be used as distinct markers in the active extracts or plant materials belonging to the genus Lantana.
Journal of vector borne diseases 09/2008; 45(3):240-4. · 1.18 Impact Factor
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ABSTRACT: The rosane diterpenoids hugorosenone [3beta-hydroxyrosa-1(10),15-dien-2-one], 18-hydroxyhugorosenone and 18-hydroxy-3-deoxyhugorosenone, and 12-hydroxy-13-methylpodocarpa-8,11,13-trien-3-one were isolated as antifungal constituents of H. castaneifolia Engl. root bark, together with the previously reported di-podocarpanoids hugonone A and hugonone B that were weakly active, and 1(10),15-rosadiene-2beta,3beta-diol (hugorosenol), 4alpha-methoxyhimachal-10-en-5beta-ol (hugonianene B) and 2-hydroxyhenpentacont-2-enal, and the known compounds tetracosyl-(E)-ferrulate and caryophyllene oxide, all of which were inactive. Hugorosenone also exhibited activity against Anopheles gambiae mosquito larvae. Structural determination was achieved based on spectroscopic data.
Phytochemistry 02/2008; 69(1):200-5. · 3.35 Impact Factor
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ABSTRACT: A new cytotoxic himachalene sesquiterpenoid 4alpha-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.
Natural Product Research 10/2007; 21(11):1027-31. · 1.01 Impact Factor
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ABSTRACT: 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.
Natural Product Research 10/2007; 21(11):1009-15. · 1.01 Impact Factor
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ABSTRACT: Ethnobotanical 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.
An 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.
In 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.
It 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.
Journal of Ethnobiology and Ethnomedicine 02/2007; 3:29. · 2.39 Impact Factor
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ABSTRACT: Candida 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.
Sixty-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).
Twenty- 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.
The extracts that showed strong anti-Candida activity are worth of further investigation in order to isolate and identify the active compounds.
BMC Complementary and Alternative Medicine 02/2006; 6:11. · 2.24 Impact Factor
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Phytochemistry 70(10):1233-1238. · 3.35 Impact Factor
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ABSTRACT: Background: Ethnobotanical 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. Methods: An 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. Results: In 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. Conclusion: It 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.
Journal of Ethnobiology and Ethnomedicine, 3:29.
