Abstract:
Ethnopharmacological relevance: Dacryodes edulis L. is an evergreen tree indigenous to western and eastern Africa
which is utilized for nutritional and medicinal purposes. Folklorically, different parts of the tree are used in
treating and managing diabetes and its complications.
Aims: The antidiabetic effect of the butanol fraction of D. edulis ethanol extract (BFDE) was studied in fructosestreptozotocin
induced type 2 diabetic rats.
Methods: The ethanol extract was fractionated to yield the hexane, dichloromethane, ethyl acetate, butanol and
aqueous fractions. The in vitro antidiabetic activities of the fractions were determined by their ability to inhibit
α-glucosidase activity. BDFE was the most active and showed no cytotoxic effect while stimulating glucose
uptake in 3T3-L1 adipocytes. Thus, selected for in vivo study. Diabetic rats were grouped into 4. The negative
control group was administered water only, another group was treated with metformin (200 mg/kg bodyweight),
while the other groups were administered BDFE at 150 and 300 mg/kg bodyweight respectively. Two
other groups consisting of normal rats were given water and BFDE (300 mg/kg bodyweight) respectively, with
the former serving as normal control. After 6 weeks of intervention, the rats were humanely sacrificed using
appropriate anaesthesia.
Results: Treatment with the fraction significantly (p < 0.05) reduced the blood glucose level of the diabetic
rats, with concomitant increase in serum insulin secretion. It also caused significant (p < 0.05) elevation of
reduced glutathione level, superoxide dismutase, catalase, α-amylase, and ATPase activities, with concomitant
depletion in myeloperoxidase activity, NO and MDA levels of the serum and pancreas. The pancreatic morphology
and β-cell function were significantly improved in BFDE-treated rats, with restoration of the pancreatic
capillary networks. Treatment with BFDE significantly (p < 0.05) inhibited the activities of glycogen phosphorylase,
fructose 1,6 biphosphatase, glucose 6 phosphatase, and acetylcholinesterase, while suppressing the
expression of Nrf2. HPLC analysis revealed the presence of gallic acid, vanillic acid, vanillin, and (−)-epicatechin
in the fraction.
Conclusion: These results portray the antidiabetic and antioxidative properties of BFDE, which may be a synergistic
consequence of the identified phenolics.
