The Potential of some Plant Extracts as Radical Scavengers and Dipeptidyl Peptidase-4 Inhibitors

Malik Et Al

doi:10.21123/bsj.2019.16.1(suppl.).0162

Abstract

Seeds, beans, leaves, fruit peel and seeds of five plants (Ferula assa-foetida, Coffea robusta, Olea europaea, Punica granatum and Vitis vinifera, respectively) were extracted with four solvents (distilled water, 80% methanol, 80% acetone and a mixed solvent that included methanol, ethanol, acetone and n-butanol at proportions 7:1:1:1). Such manipulation yielded 20 extracts, which were phytochemically analyzed for total polyphenols (TP) and flavonoids (TF). The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity (RSA) and DPP-4 (dipeptidyl peptidase-4) relative inhibition activity (RIA) were also assessed for each extract. The results revealed that mixed solvent extract of V. vinifera seeds showed the highest content of TP (194.8 ± 2.5 mg Gallic acid equivalent/g dry mass), while methanol extract of V. vinifera seeds recorded the highest content of TF (75.9 ± 0.3 mg catechin equivalent/g dry mass). The C. robusta bean aqueous extract was remarkable in scoring the highest DPPH RSA (87.2 ± 1.2%), while O. europaea leaf methanol extract had the highest DPP-4 RIA (86.4 ± 0.8%). In conclusion, the importance of natural products as radical scavengers and DPP-4 inhibitors is encouraged, and such biological effects were dependent on the plant species and the solvent of extraction. C. robusta beans are suggested to have a prominent RSA, while O. europaea leaves are recommended to be a target for investigations involved in the development of anti-T2DM therapies.

Highlights

Type 2 Diabetes mellitus (T2DM) is a global disease and recent estimates have revealed that around 10% of adults are diabetic, and 90% of whom are grouped under T2DM (1)
Discussion: the total polyphenols (TP) and Total flavonoids (TF) contents of investigated extracts showed a great variation, which was related to the plant parts and species and the solvent of extraction, most extracts displayed some richness in these two important phytochemicals, especially V. vinifera seed MX and ME extracts, which had the highest content of TP and TF, respectively
It might have been expected that the present 20 extract showed a good DPPH radical scavenging activity (RSA) that ranged between 30.5 ± 2.1% (P. granatum peel AQ extract) and 87.2 ± 1.2% (C. robusta bean AQ extract)

Summary

Introduction

Type 2 Diabetes mellitus (T2DM) is a global disease and recent estimates have revealed that around 10% of adults are diabetic, and 90% of whom are grouped under T2DM (1). It is a progressive chronic metabolic syndrome that is hallmarked by hyperglycemia due to a defect in insulin secretion, insulin action, or beta-cell impairment (2). The consequence is cell death (apoptosis) and diabetic complications, which include nephropathy, retinopathy and cardiovascular diseases (3). Oxidative damages mediated by highly reactive free radicals have been depicted to play an important role in these complications, and interplay between diabetes and oxidative stress has been suggested (4).

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Conclusion