Amelioration of diabetes and its complications by Manilkara zapota (L) P. Royen fruit peel extract and its fractions in alloxan and STZ-NA induced diabetes in Wistar rats

Purpose

This study aims to evaluate the effects of Manilkara zapota (L) P. Royen fruit peel extract (EMZFP) and its fractions in ameliorating diabetes and its complications in alloxan and STZ-NA induced diabetes in Wistar rats.

Methods

Antidiabetic effects of EMZFP were assessed in alloxan (150 mg kg^-1) induced diabetes in differently grouped rats (n=6). Diabetic rats were treated with EMZFP 150, 300, and 600 mg kg^-1 while, glimepiride (0.09 mg kg^-1) was used as a reference standard. Treated animals were assessed for various biological parameters i.e. blood glucose, serum lipids, nephroprotective markers, cardiovascular risk indices, liver glycogen, neuropathy, body weight, and histopathology of kidneys. However, for evaluating antidiabetic effects of fractions (chloroform, acetone, ethyl acetate, and remaining ethanol fraction) of EMZFP, diabetes was induced by streptozotocin (60 mg kg^-1)-nicotinamide (120 mg kg^-1/ml) in differently grouped male rats (n=6). Diabetic rats were treated with EMZFP fractions 200 mg kg^-1 however; glibenclamide (10 mg kg^-1) was a reference standard and evaluated for blood glucose, serum lipids, cardiovascular risk indices, and diabetic neuropathy.

Results

EMZFP 300 and 600 mg kg^-1/day demonstrated significant antihyperglycemic effects with augmentation in glycogen content, perfection in serum lipid profile, cardiovascular risk indices, body weight enhancement, nephroprotective effects, beneficial in peripheral neuropathy, and histopathological evidence of reversal of glomerulosclerosis. EMZFP-Et and EMZFP-EA fractions depicted a significant improvement in blood glucose, serum lipid profile, cardiovascular risk indices, and peripheral neuropathy.

Conclusion

EMZFP and its Et and EA fractions ameliorated diabetes and its complications by improving glycemic control and associated biochemical alteration.

Highlights

• Manilkara Zapota (L.) P. Royen fruit peel 70% ethanolic extract exert antidiabetic effects• EMZFP significantly ameliorated diabetic biochemical parameters and its complications.• EMZFP-Et and EMZFP-EA fractions exert potential antihyperglycemic, hypolipidemic effects and significantly improved cardiovascular risk indices, and peripheral neuropathy.• Studied MZFP can be used as promising natural herbal source of antidiabetic principles.

Optimization of extraction conditions and evaluation of Manilkara zapota (L.) P. Royen fruit peel extract for in vitro α-glucosidase enzyme inhibition and free radical scavenging potential

Background

Most of the edible portions like peel and skin of some fruits is discarded while consuming it, though they are rich in several health beneficial phytochemicals or nutrients. Many reports from literature are about fruit pulp of (Sapota) Manilkara zapota (L) P. Royen having high radical scavenging and antioxidant potential, but the studies relating to peel extracts are scanty. Regardless of its commendable phytoconstituents which could have free radical scavenging potential, this fruit peel is as yet still needed to be assessed for in vitro antidiabetic prospects. Hence, the present study aims at evaluating in vitro free radical scavenging and α-glucosidase enzyme hindrance abilities of this fruit peel.

Results

With a maximum considerable % extractive yield (18.90%) in 70% ethanol, this study has demonstrated that 70% ethanolic extract of Manilkara Zapota (L.) P. Royen Fruit Peel (MZFP) has the highest in vitro free radical scavenging potential as compared to extracts of other solvents viz. n-hexane, chloroform, acetone, absolute ethanol, and water by DPPH and H2O2 assays. In order to optimize the extraction condition parameters, MZFP sample evaluated with three different concentrations of ethanol (40%, 70%, 100%), extraction times (6 h, 9 h, 12 h), and temperatures (40 °C, 50 °C, 60 °C) to get the highest radical scavenging potential. The MZFP when extracted with 70% ethanol, at 50 °C for 12 h, showed higher DPPH (IC50 = 0.34 and 88.42% inhibition at 1 mg/ml) and H2O2 (IC50 = 32.69 and 65.78% inhibition at 50 μg/ml) radical scavenging potential than absolute and 40% ethanolic extracts, when ascorbic acid was used as a reference standard. While further evaluation for in vitro α-glucosidase enzyme inhibition, 70% ethanolic MZFP extract demonstrated high inhibition activity (IC50 = 104.23 ± 1.75 μg/ml) than absolute ethanolic extract (IC50 = 111.65 ± 1.57 μg/ml) with a significant difference (p < 0.05), when acarbose was taken as reference inhibitor (IC50 = 86.93 ± 0.74 μg/ml).

Conclusions

Overall results indicated that MZFP 70% ethanolic extract exhibited promising in vitro radical scavenging and α-glucosidase enzyme inhibition potential. Thus, suggesting further studies with isolated phytochemicals from peel to explore its potentials for antidiabetic activity through in vitro α-glucosidase enzyme inhibition.