Plukenetia conophora seed oil ameliorates streptozotocin-induced hyperglycaemia and oxidative stress in rats

Abstract

Purpose

Plukenetia conophora (African walnut) is an edible seed, widely cultivated for its ethnomedicinal and nutritional purposes. Consumption of African walnuts has been linked with blood sugar lowering effect.

Objective

The effects of P. conophora seed oil treatment on hyperglycaemia and oxidative stress were investigated in plasma, liver and kidney of streptozotocin (STZ)-induced diabetic rats.

Materials and methods

Plukenetia conophora seed oil (PCO) was obtained by extraction of pulverized dried seed in n-hexane. Diabetes was induced by STZ injection (65 mg/kg, i.p). Rats were assigned into non-diabetic control (NC) and diabetic control (DC; treated with vehicle), PCO (200 mg/kg) and pioglitazone (10 mg/kg). Fasting blood sugar (FBS) was taken from overnight fasted animals on day 7 and 14, respectively. Plasma, liver and kidney samples were obtained on day 14 for the determination of oxidative stress parameters malondialdehyde (MDA), reduced glutathione (GSH), catalase and superoxide dismutase (SOD).

Results

PCO treatment significantly (p < 0.05) reduced STZ-induced hyperglycaemia by lowering the elevated FBS. PCO significantly reduced MDA level and attenuated STZ-induced depletion of GSH, catalase and SOD in the diabetic rats’ plasma, liver and kidneys.

Conclusions

These results suggest that consumption of Plukenetia conophora seed might offer protection against diabetes-induced hepatic and renal damage.

Keywords:

• Plukenetia conophora oil
• hepatotoxicity
• diabetes mellitus
• hyperglycaemia
• oxidative stress

Ethical approval

All experimental protocols followed standard guideline approved for animal experimentation by the University of Ibadan animal ethics committee following guidelines laid out in the ‘Principle of Laboratory Animal Care’ (NIH Publication No. 85-23).

Author contributions

AMA conceived the idea, AMA, VOB and BB performed the experiments. AMA and OGA performed statistical analysis and plot the graphs, AMA and OGA wrote the draft manuscript. All the authors involved have taken responsibility for the whole manuscript content and approved submission.

Disclosure statement

Authors declare no conflict of interest.

Data availability statement

All data generated from this study are available upon request from the corresponding author.

Additional information

Funding

There is no fund or grant whatsoever.