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dc.contributor.authorOLUBOMEHIN, O. O.-
dc.date.accessioned2018-08-10T11:25:34Z-
dc.date.available2018-08-10T11:25:34Z-
dc.date.issued2014-12-
dc.identifier.urihttp://80.240.30.238/handle/123456789/818-
dc.descriptionA Thesis in the Department of Pharmacognosy, Submitted to the Faculty of Pharmacy in partial fulfilment of the requirement for the Degree of DOCTOR OF PHILOSOPHY Of the UNIVERSITY OF IBADANen_US
dc.description.abstractDiabetes a major degenerative disease of global concern accounts for about 3.2 million deaths annually. Alpha-amylase inhibitors from plants are effective in managing postprandial hyperglycaemia which is significant in Type 2 diabetes. Search for natural anti-oxidants has increased recently because free radicals production has been linked to a number of diseases including diabetes. Anthocleista djalonensis and Anthocleista vogelii are used traditionally in Nigeria and parts of Africa to treat diabetes. This study was aimed at evaluating the α-amylase inhibition, anti-oxidant and anti-diabetic effects of extracts and compounds of both plants to verify their traditional use. The leaves, stem bark and roots of both plants were collected along Ijebu-Ode – Benin road and authenticated at the Herbarium of the Forestry Research Institute of Nigeria, Ibadan. The plant samples were macerated in 80% aqueous methanol for 72 h. Each crude extract, suspended in water: methanol (4:1) was partitioned into ethyl acetate. The crude extracts and ethyl acetate fractions of the leaves and stem bark of both plants were subjected to in vitro α-amylase inhibition assay with acarbose as positive control. The anti-oxidant activity was evaluated using 2, 2’-diphenyl-1-picrylhydrazyl with α-tocopherol as control, while anti-diabetic properties of the crude extracts were studied in vivo using 45 albino wistar rats (150-200 g) of both sexes. The rats were made diabetic with 80 mg/kg of alloxan and treated with the extracts (1 g/kg) for seven days; glibenclamide 2.5 mg/kg was used as reference. Blood glucose levels (BGL) were monitored daily. Bioassay-guided fractionation and chromatographic methods were used to isolate active compounds from the ethyl acetate fractions of both plants. Structures of the isolated compounds were elucidated using spectroscopic techniques: infra-red, mass spectrometry, nuclear magnetic resonance (one-dimensional and two-dimensional). Data were analysed statistically using ANOVA at p<0.001. Anthocleista djalonensis leaf and stem bark crude extracts gave highest α-amylase inhibition of 42.8% and 41% with their ethyl acetate fractions also producing the highest α-amylase inhibition of 50.0% and 36.6% at 1.0 mg/mL while acarbose gave 54.9%. The crude extract and ethyl acetate fraction of A. vogelii leaf gave 80.7% and 87.4% inhibitions at 1.0 mg/mL in the anti-oxidant assay while α-tocopherol gave 89.5%. Peak reduction in BGL was observed for A. djalonensis stem bark and leaf crude extracts at 72.6% and 45.7% on day-6 of treatment while the stem bark and leaf extracts of A. vogelii gave 68.9% and 60.4%, respectively on day-7. The root extracts of both plants also caused peak reduction in BGL at 48.5% on day-7 while glibenclamide had 57.4%. Bioassay-guided fractionation furnished djalonenol, a monoterpene diol with a significant α-amylase inhibition of 53.7% from fraction 11 of the stem bark of A. djalonensis and decussatin, a xanthone with significant inhibition of 78.0% from fraction 5 of the leaves and stem bark of A .vogelii. The presence of α-amylase inhibitors, djalonenol and decussatin from both plants makes them important in the treatment of type 2 diabetes and could be responsible for their anti-diabetic effect. Anthocleista vogelii could be a source of anti-oxidant compounds.en_US
dc.language.isoenen_US
dc.subjectAnthocleista speciesen_US
dc.subjectdecussatinen_US
dc.subjectdjalonenolen_US
dc.subjectanti-oxidant effecten_US
dc.subjectanti-diabetic activityen_US
dc.titleANTI-DIABETIC AND ANTI-OXIDANT EVALUATION OF ANTHOCLEISTA DJALONENSIS A. CHEV AND ANTHOCLEISTA VOGELII PLANCHen_US
dc.typeThesisen_US
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