title: The novel antihyperglycaemic action of Hunteria umbellata seed fractions mediated via intestinal glucose uptake inhibition.
abstract: The present study evaluated the antihyperglycaemic effect and mechanism of action of fractions of the aqueous seed extract of Hunteria umbellata (K. Schum.) Hallier f. (HU) in normal and alloxan-induced hyperglycaemic rats. HU was partitioned in chloroform, acetyl acetate and butan-1-ol to give chloroform fraction (HU c), ethyl acetate fraction (HU e), butanol fraction (HU b) and the "residue" (HU m), respectively. 200 mg/kg of each of these fraction dissolved in 5% Tween 20 in distilled water was investigated for its acute oral hypoglycaemic effects in normal rats over 6 hours while its repeated dose antihyperglycaemic effect was evaluated in alloxan-induced hyperglycaemic rats over 5 days. In addition, 50 mg/kg of the crude alkaloid fraction (HU Af) extracted from HU was evaluated for its possible antihyperglycaemic activity in alloxaninduced hyperglycaemic rats using oral glucose tolerance test (OGTT) over 6 hours. Using the solvent system, distilled water-butanol-ammonium hydroxide (2:15:1, v/v/v), HU b was chromatographed and stained with Dragendorff's reagent for confirmatory qualitative analysis for alkaloids. Results showed that oral pre-treatment with 200 mg/kg of HU e, HU b and HU m resulted in a significant (p<0.05, p<0.001) time dependent hypoglycaemic effect, with the butan-1-ol fraction HU causing the most significant (p<0.001) hypoglycaemic effect. In the alloxan-induced hyperglycaemic rats, repeated oral treatment with 200 mg/kg of same HU fractions for 5 days resulted in significant (p<0.05) decreases in the fasting blood glucose concentrations with the most significant (p<0.01) antihyperglycaemic effect also recorded for HU b. Similarly, oral pretreatment with 50 mg/kg of HU Af significantly (p<0.05, p<0.01 and p<0.001) attenuated an increase in the post-absorptive glucose concentration at 1(st) - 6(th) h in the alloxan-induced hyperglycaemic OGTT model. In addition, alkaloid was present in most of the separated spots on the TLC plate. In conclusion, results of this study showed that HU contains a relative high amount of alkaloids which could have accounted for the antihyperglycaemic action of HU that was mediated via intestinal glucose uptake inhibition.
authors: Department of Pharmacology, Faculty of Basic Medical Sciences, Lagos State University College of Medicine, Ikeja, Lagos State, Nigeria. adeneye2001@yahoo.com
authors: A A
authors: AA
authors: Adeneye
authors: O O
authors: OO
authors: Adeyemi
authors: E O
authors: EO
authors: Agbaje
authors: M O
authors: MO
authors: Sofidiya
mesh_terms: D000818:Animals; D029062:Apocynaceae; D001786:Blood Glucose / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D005951:Glucose Tolerance Test; D007004:Hypoglycemic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects*; D008297:Male; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D012639:Seeds
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D010936:Plant Extracts; D005947:Glucose
keywords: Alkaloid fraction; Hunteria umbellata aqueous seed extract; Intestinal glucose uptake inhibition; Normal and alloxan-induced hyperglycaemic rats
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