Antioxidant activity and inhibitory efficacy of Citrus grandis peel extract against carbohydrate digestive enzymes in vitro

Abstract

Citrus peel extract has been observed with many beneficial-promoting effects. Pomelo (Citrus grandis (L) Osbeck) peel extracts (PPE) from the flavedo and albedo of two varieties namely Long Co Co and Thanh Kieu were investigated. In this study, the qualitative analysis indicated the presence of phytochemical groups including alkaloids, flavonoids, saponins, and tannin in the PPE from the flavedo and albedo. The PPE from the Thanh Kieu flavedo was found to possess the highest antioxidant activity at the EC₅₀ values of 60.89 ± 0.31 µg/mL, 60.69 ± 0.21 µg/mL, and 24.16±0.06 µg/mL for DPPH, ABTS, and FRAP assay. However, the Long Co Co albedo- PPE induced better inhibitory effect against α-amylase (EC 232-560-9) and α-glucosidase (EC 232-604-7) with respect to EC₅₀ values of 3.59 ± 0.02 mg/mL and 80.77 ± 0.34 µg/mL. This result suggested potential in the anti-hyperglycemic effect of pomelo peel extract from the flavedo and albedo that can serve as a nutraceutical in food and pharmaceutical industries.

Keywords:
antioxidant activity; albedo; flavedo; pomelo peel extract; α-amylase inhibition; α-glucosidase inhibition