ISOLATION, CHARACTERIZATION AND ANTI-DIABETIC POTENTIAL OF BETULINIC ACID AND BETA SITOSTEROL FROM THE EXTRACT OF LEAVES OF Blighia unijugata

Abstract

Diabetes is a disease with hyerglycemic index which is common and cuts across ages. The aim of this study is to characterize and establish the anti-diabetic potential of compounds isolated from B. unijugata, a medicinal plant used in folk medicine for the treatment of rheumatism, cardiovascular diseases, diabetis mellitus, inflammation and infections, among others. Results of acute toxicity indicated that the LD50 of the plant extracts is greater than 5000 mg/kg serving as a baseline for further pharmacological studies. Column chromatography of B. unijugata chloroform fraction followed by gel filtration chromatography using sephadex LH-20 lead to the isolation of two (2) compounds. The compounds were characterized using FTIR, ¹H NMR and ¹³C NMR and were found to be β-sitosterol (C₂₉H₅₀O, molecular weight 414.7) and betulinic acid (C₃₀H₄₈O₃, molecular weight 456.7). In vitro evaluation of anti-diabetic activities of the compounds showed relative inhibitory potency against α-glucosidase and α-amylase enzymes. The inhibitory concentration (IC₅₀) against α-glucosidase are 35.86 µg/cm³, 62.43 µg/cm³ and 77.1 µg/cm³, for acarbose (reference standard), β-sitosterol and betulinic acid respectively and it increased with increase in concentration. The IC₅₀ against α-amylase increased with reference standard, β-sitosterol and betulinic acid having IC₅₀ of 7.58 µg/cm³, 21.93 µg/cm³ and 34.15 µg/cm³ respectively.