Characterization and Anti-diabetic Activity of Dihydrophenantherene Isolated from Khaya senegalensis Stem Bark

Khaya senegalensis A. Juss (Meliaceae), is regarded as the most popular medicinal meliaceous plant. The present study was conducted to evaluate anti-diabetic potentials of column chromatography fractions (FI-FVII) from ethyl acetate extract of Khaya senegalensis stem bark and detect the bioactive compounds present in the fractions using spectroscopic techniques. Anti-diabetic potential of the fractions (FI-FVII) were tested at dose of 50 mg/kg on wistar albino rats. Fraction (VI) and metformin treated diabetic groups showed significant decrease in fasting blood glucose (FBS), ameliorate hepatic and renal damages by decreasing the level of AST, ALT, ALP, Urea and creatinine compared to untreated diabetic rats and stimulate insulin secretion by β cells. After alloxan administration, the levels of hepatic and renal tissues antioxidant enzymes such as glutathione peroxidase (Gpx), superoxide dismutase (SOD) and catalase (CAT) were decreased whereas the level of hepatic and renal tissues lipid peroxidation (LPO) was elevated. The levels of these antioxidant enzymes were also brought to normalcy by Fraction (VI). Histological studies supported the biochemical findings, and treatment with Fraction (VI) was found to be effective in restoring alloxan-induced pancreatic toxicity in rats. FTIR, GCMS and NMR analysis was conducted for the detection of bioactive compound(s) in Fraction (VI), and the result revealed the presence of methyl 6-ethenyl-7-hydroxy-7,8-dihydrophenanthrene-2-carboxylate. The study concludes that; the anti-diabetic property of Khaya senegalensis stem bark is mediated by the bioactive compound "methyl 6-ethenyl-7-hydroxy-7,8-dihydrophenanthrene-2-carboxylate" through its antioxidant properties and stimulation of damaged pancreas to produce more insulin.