Phenolic Compounds Content and Tyrosinase Inhibitory Effect of Unripe Apple Extracts

This study consisted of a quantitative analysis of five phenolic ingredients in differently sized unripe apple extracts, and their tyrosinase inhibitory effects were examined. In the HPLC analysis of phenolic ingredients, small ($4{\pm}1\;g$ per one) unripe apple extracts were observed to have significantly higher quercetin content than larger ($8{\pm}1\;g$ per one) unripe apple and ripe apple extracts. The amount of catechin, epicatechin, p-coumaric acid and chlorogenic acid contents were similar in both the small and large unripe apple extracts. For the results of the tyrosinase assay, small unripe apple extracts provided a potent tyrosinase inhibitory effect, showing 89.2% at 1000 ppm. The tyrosinase inhibitory effects of large unripe apple and ripe apple extracts were weaker than those of the small unripe apple extract. These results suggest that the small unripe apple extract could be useful for de-pigmenting material, while quercetin could be responsible for the potent tyrosinase inhibitory properties of small unripe apple extracts.