Polyphenolic Compounds with Anti-Ages Activity from Three Clusiaceae Plants.

Aim: This study focused on finding molecules with inhibitory effects on Advanced Glycation End-products (AGEs) formation from Tanzanian some Clusiaceae plant species Study Design: Field study and Laboratory experimental tests. Place and Duration of Study: Institute of Traditional Medicine, Muhimbili University of Health and Allied Sciences, P.O. Box 65001, Dar es Salaam, Tanzania and PRES LUNAM, Université d’Angers, EA 921 SONAS, 16 Bd Daviers, 49045 Angers, France, between June 2011 and July 2013. Methodology: Three Clusiaceae plant species (Garcinia semseii, G. volkensii and Allanblackia ulugurensis) were collected and dried in the field with the assistance of a botanist. Extraction and concentration of plant samples to obtain crude extracts were done in the laboratory following standard procedures. The isolation of the phenolic compounds was carried out by using normal phase column chromatography as well as High performance liquid chromatography (HPLC). The isolated compounds were tested for anti- AGE activity using the in vitro automated assay. Results: Two polyphenolic compounds exhibiting phloroglucinol moieties [e.g. polyprenylated benzophenones, such as guttiferone F, 2 (18 mg)] or biflavonoids [such as morelloflavone, 1 (22mg)] were isolated and identified from A. ulugurensis and G. volkensis respectively. The results further indicated that compound 1 is an excellent inhibitor of AGE formation exhibiting an IC50 values of 78 and 64 μM at wavelength of 370/440 (vesperlysines-like AGEs) and 335/385 (pentosidine-like AGEs) respectively. Conclusion: Plants belonging to the Clusiaceae family commonly used in Tanzanian traditional medicine need to be considered as a potential source of molecules exhibiting pharmacological activities such as anti-AGE activity. Morelloflavone (1) and other biflavonoids prove to be very good anti-AGE compounds using our automated screening assay. Hence, our automated in vitro assay allows a fast, effective and quite inexpensive screening of natural compounds and can therefore be applied to high throughput screening projects.

Anti-Mycobacterial and Toxicity Activities of Some Priority Medicinal Plants from Lake Victoria Basin, Tanzania.

Aims: This study has evaluated ethanol extracts from five medicinal plants selected through ethnobotanical study from Lake Victoria basin, Tanzania for their in vitro antimycobacterial activity against two Mycobacterium species and cytotoxicity against brine shrimp larvae. Study Design: Laboratory experimental tests. Place and Duration of Study: Institute of Traditional Medicine, Muhimbili University of Health and Allied Sciences, P.O. Box 65001, Dar es Salaam, Tanzania, between July 2010 and July 2011. Methodology: Five medicinal plants were selected from the priority list obtained from Lake Victoria basin, Tanzanian side. Collection, processing and drying of plant samples were done in the field with the assistance of a botanist while extraction and concentration of plant samples to obtain crude extracts were done in the laboratory following standard procedures. The plants included in this study are Antidesma membranaceum, Crassocephalum manii, Entada abyssinica, Croton dichogamus and Rubia cordifolia. The two fold microdilution method was used to determine the MIC values of extracts against two Mycobacterium marker strains (Mycobacterium indicus pranii and Mycobacterium madagascariense). The cytotoxicity of plant extract was evaluated against brine shrimp larvae. Furthermore, the extracts were screened phytochemicaly to establish the group of compounds responsible for the activity. Results: Among the tested extracts, the stem bark of A. membranaceum and C. manii showed moderate to mild activity against M. indicus pranii (MIC = 0.3125 mg/ml) and M. madagascariense (MIC = 0.625 mg/ml) respectively. Furthermore, A. membranaceum exhibited significant toxicity activity with LC50 value of 36.134 μg/ml against brine shrimp larvae. Other plants were moderately active when tested in vitro against the above organisms. Phytochemical screening of extracts indicated the presence of different classes of compounds. Conclusion: This study has shown the potential of the priority medicinal plant extracts to be the source of possible lead compounds and anti‐TB drug candidates needed for the management of Tuberculosis. Isolation of active principles from active fractions will be further undertaken.