Camellia Yokdonensis Leaves: Antioxidant, Potential Antidiabetic and In Vitro Anti-inflammatory Activities

Abstract

This study investigated the phenolic content, antioxidant activity, α-amylase and α-glucosidase inhibitory effects, and albumin denaturation inhibitory activity of extracts from the leaves of Camellia yokdonensis, a plant species native to Vietnam. The results revealed epigallocatechin gallate as the dominant phenolic compound (33.76–191.95 mg/g). The methanolic extract showed the most potent antioxidant activity (ABTS IC₅₀ = 135.01 ± 1.51 μg/mL, DPPH IC₅₀ = 25.96 ± 0.11 μg/mL). The aqueous ethanolic extract exhibited the strongest inhibitory activity against albumin denaturation (IC₅₀ = 320.20 ± 2.45 μg/mL). The aqueous methanolic extract possessed the highest α-glucosidase inhibition (IC₅₀ = 382.80 ± 14.82 μg/mL), while the ethanolic extract displayed the strongest α-amylase inhibition (IC₅₀ = 1105.96 ± 26.97 μg/mL). Pearson correlation analysis indicated positive correlations between total phenolic content and antioxidant activity, and albumin denaturation inhibition. These findings underscore C. yokdonensis leaves as a promising source of natural antioxidants and enzyme inhibitors for managing diabetes and inflammation.