Bashar Bello S. Dogarai

Anti-hyperglycemic activity of the leaves of Tetracera scandens Linn. Merr. (Dilleniaceae) in alloxan induced diabetic rats.

AIM OF THE STUDY The present study was aimed to investigate the anti-diabetic potential of the leaves of Tetracera scandens Linn. Merr. (Dilleniaceae) in vivo with regard to prove its efficacy by local herbalists in the treatment of diabetes frailties. MATERIALS AND METHODS Crude aqueous (AQ) and methanol (MEOH) extracts of the leaves of T. scandens L. were administered to both normal and alloxan induced diabetic male albino rats (Wistar strain). The blood glucose levels were measured at 0, 2, 4, 6 and 8h after oral administration of AQ and MEOH extracts. RESULTS Significant reduction in glucose was observed in fasting blood glucose levels in the treated diabetic rats without causing any hypoglycemic effect compared to normal rats. Both polar extracts of the leaves of T. scandens L. exhibited significant anti-hyperglycemic activity at different doses and intervals. The highest anti-hyperglycemic effect (62.5%) was observed by the AQ extract at 0.25 g/kg body weight (b.w.) and MEOH extract (36.5%) at 0.5 g/kg b.w. after 8h. The significant anti-hyperglycemic activity was found to be comparable with a known oral synthetic hypoglycemic drug, glibenclamide 0.25mg/kg b.w. CONCLUSION This study provides scientific evidence that the leaves of T. scandens L. have anti-diabetic efficacy and justifies its utility by local herbalists. However, more experiments at the clinical levels are required to confirm the utility of this plant by traditional practitioners in the management of diabetes mellitus.

Antifungal activity of Andrographis paniculata extracts and active principles against skin pathogenic fungal strains in vitro

Context: Andrographis paniculata Nees. (Acanthaceae) is an annual herbaceous plant widely cultivated in southern Asia, China, and Europe. It is used in the treatment of skin infections in India, China, and Malaysia by folk medicine practitioners. Objective: Antifungal activity of the whole plant extracts and isolation of active principles from A. paniculata were investigated. Materials and methods: Dichloromethane (DCM) and methanol (MEOH) extracts of A. paniculata whole plant were screened for their antifungal potential using broth microdilution method in vitro against seven pathogenic fungal species responsible for skin infections. Active principles were detected through bioguided assays and isolated using chromatography techniques. Structures of compounds were elucidated through spectroscopy techniques and comparisons were made with previously reported data for similar compounds. Results: DCM extract revealed lowest minimum inhibitory concentration (MIC) value (100 μg/mL) against Microsporum canis, Candida albicans, and Candida tropicalis, whereas MEOH extract revealed lowest MIC (150 µg/mL) against C. tropicalis and Aspergillus niger. DCM extract showed lowest minimum fungicidal concentration (MFC) value (250 µg/mL) against M. canis, C. albicans, C. tropicalis and A. niger, whereas MEOH extract showed lowest MFC (250 µg/mL) against Trichophyton mentagrophytes, Trichophyton rubrum, M. canis, C. albicans, C. tropicalis and A. niger. Bioassay guided isolation from DCM and MEOH extract afforded 3-O-β-d-glucosyl-14-deoxyandrographiside, 14-deoxyandrographolide, and 14-deoxy-11,12-didehydroandrographolide as antifungal compounds. The lowest MIC (50 µg/mL) and MFC (50 µg/mL) was exerted by 14-deoxyandrographolide on M. canis. Discussion and conclusion: This is first report on the isolation of antifungal substances through bioassay-guided assay from A. paniculata. Our finding justifies the use of A. paniculata in folk medicines for the treatment of fungal skin infections.