Elastase activity inhibition by the most active fraction of star fruit (Averrhoa Carambola L.) leaves from three west java regions

Objective: Premature skin aging is caused by increased elastase proteolytic activity, which causes elastin breakdown and disorganization in connective tissue, reducing elasticity and flexibility, and wrinkling skin. Natural compounds in plants, especially polyphenols, inhibit elastase proteolytic activity and prevent premature skin aging. Star fruit (Averrhoa carambola L.) leaves contain many polyphenols with antioxidant, anti-inflammatory, hypoglycemic, and antimicrobial activities. However, no studies have shown that A. carambola leaves inhibit elastase proteolytic activity. Methods: This study tested the inhibition of elastase proteolytic activity by the water fractions (WF), ethyl acetate fractions, and n-hexane fractions of A. carambola leaves from the Depok, Sukabumi, and Subang regions of West Java. Each fraction was tested using a microplate reader, and the total phenolic and flavonoid content was determined for the most active fraction. Results: The WF of the A. carambola leaves from Depok was the most active fraction, with a half-maximal inhibitory concentration of 160.36 ng/mL. The total phenolic and flavonoid content in the WF was 115.68 mg gallic acid equivalent/g extract and 9.15 mg quercetin equivalent/g extract, respectively. Conclusion: The WF of A. carambola leaves is a natural material that may inhibit elastase proteolytic activity and prevents premature skin aging.