Anti-diabetogenic and in vivo antioxidant activity of ethanol extract of Dryopteris dilatata in alloxan-induced male Wistar rats

Annona muricata L. peel extract inhibits carbohydrate metabolizing enzymes and reduces pancreatic β-cells, inflammation, and apoptosis via upregulation of PI3K/AKT genes

BACKGROUND AND OBJECTIVE

Annona muricata L. peel has been recognized for many ethnobotanical uses, including diabetes management. However, limited detailed scientific information about its mechanism of antidiabetic activity exists. The objective of this study was to evaluate the anti-diabetic properties of an aqueous extract of A. muricata peel (AEAMP) and its mechanism of action on alloxan-induced diabetic rats.

METHODS

In vitro antidiabetic assays, such as α-amylase and α-glucosidase were analyzed on AEAMP. Alloxan monohydrate (150 mg/kg b.w) was used to induce diabetes in the rats. 150 mg/kg b.w positive control group doses of 6.67, 13.53, and 27.06 mg/kg were administered to 3 groups for twenty-one days. The positive control group was administered 30 mg/kg of metformin. The negative and normal control groups were administered distilled water. The fasting blood glucose, serum insulin, lipid profile, inflammatory cytokines, antioxidant markers, carbohydrate metabolizing enzymes, and liver glycogen were analyzed as well as PI3K/AKT and apoptotic markers PCNA and Bcl2 by RT-PCR.

RESULTS

AEAMP inhibited α-amylase and α-glucosidase enzymes more effectively than acarbose. AEAMP reduced FBG levels, HOMA-IR, G6P, F-1,6-BP, MDA, TG, TC, AI, CRI, IL-6, TNF-α, and NF-κB in diabetic rats. Furthermore, in diabetic rats, AEAMP improved serum insulin levels, HOMA-β, hexokinase, CAT, GST, and HDL-c. Liver PI3K, liver PCNA and pancreas PCNA were not significantly different in untreated diabetic rats when compared to normal rats suggesting alloxan induction of diabetes did not downregulate the mRNA expression of these genes. AEAMP significantly up-regulated expression of AKT and Bcl2 in the liver and pancreatic tissue. It is interesting that luteolin and resorcinol were among the constituents of AEAMP.

CONCLUSIONS

AEAMP can improve β-cell dysfunction by upregulating liver AKT and pancreatic PI3K and AKT genes, inhibiting carbohydrate metabolizing enzymes and preventing apoptosis by upregulating liver and pancreatic Bcl2. However, the potential limitation of this study is the unavailability of equipment and techniques for collecting more data for the study.

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

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 hyperglycemia 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 and diabetic control (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.

CONCLUSION

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