Abstract

The antidiabetic effects of methanol, N-hexane and ethyl acetate leaf fractions of Nauclea latifolia were investigated in diabetic model rats. 150 and 300mg/kg fractions of N. latifolia were administered orally to the experimental animals at two weeks interval, while their blood glucose levels were taken daily. At the end of the experiment, their lipid profiles were assayed using standard methods. The research data indicated significant decreases (P=0.05) of the blood glucose in all the fractions at a dose-dependent manner (ethyl acetate (150 mg/kg = 47.83%; 300 mg/kg = 64.17%), N-hexane (150 mg/kg = 58.45%; 300 mg/kg = 64.18%), methanol (150 mg/kg = 44.5%), except for the 300 mg/kg dose methanol fraction (0.82%) as compared to the increased level in the negative control (33.33%). In the lipid profile assay, there were also a dose dependent significant decrease (P=0.05) of serum Total Cholesterol (TC) and Low Density Lipoprotein (LDL) cholesterol in all the fraction groups (ethylacetate (150 mg/kg- TC = 69.88 ± 8.52 mg/dl, LDL-cholesterol = 8.23±7.76 mg/dl; 300 mg/kg-TC = 51.08±9.93 mg/dl, LDL-cholesterol = 6.44±7.66 mg/dl), N-hexane (150 mg/kg-TC = 73.16 ± 18.62mg/dl, LDL-cholesterol = 33.24±16.19 mg/dl; 300 mg/kg-TC = 69.78±8.41 mg/dl, LDL-cholesterol = 9.29±5.62 mg/dl and methanol (150 mg/kg;  TC = 116.86 ± 13.34 mg/dl, LDL-cholesterol = 50.68±14.13 mg; 300 mg/kg-TC = 108.66 ± 12.77 mg/dl, LDL-cholesterol = 42.09±9.93mg/dl) as compared to the high concentration of the negative control group (TC = 383.76 ± 79.68 mg/dl, LDL-cholesterol = 299.46 ± 79.23 mg/dl). Ethylacetate and N-hexane fractions showed significant reductions (P=0.05) of TC and LDL-cholesterol as compared to the positive control (TC=116.36±14.69 mg/dl, LDL-cholesterol = 32.06±13.23mg/dl) also at a dose-dependent manner; thus, portraying a more efficient hypolipidaemic activity than the standard drug. This antidiabetic research on N. latifolia suggest that ethylacetate fraction produces the best effect, followed by N-hexane and lastly by methanol fraction.

Key words: Nauclea latifolia, ethyl acetate, n-hexane, methanol, leaf fractions, glibenclamide, antidiabetic,  blood glucose, lipid profile.