Subcritical Water Extraction of Phenolic Compounds from Vaccinium Dunalianum Wight Leaves and Their Antioxidant and Tyrosinase Inhibitory Activities in Vitro

Subcritical water extraction was used to extract bioactive phenolic compounds from Vaccinium dunalianum Wight leaves. The optimal extraction conditions were determined as an extraction temperature of 150 degrees C, an extraction time of 40 min, and a liquid-solid ratio of 35 : 1 mL/g. The total phenolic content reached 21.35 mg gallic acid /g, which was 16 % higher than that by hot water extraction. The subcritical water extraction extract exhibited strong scavenging activity of DPPH free radical and ABTS(+) free radical, as well as significant tyrosinase inhibitory activity. The study suggests that subcritical water extraction can alter the composition of the extracts, leading to the production of various phenolic compounds, effective antioxidants, and tyrosinase inhibitors from Vaccinium dulciana Wight leaves. These findings confirm the potential of Vaccinium dunalianum Wight as a natural antioxidant molecule source for the medicine and food industries, and for the therapy of skin pigmentation disorders.