AKTIVITAS PENGHAMBAT ENZIM TIROSINASE EKSTRAK ETANOL, FRAKSI N-HEKSAN, FRAKSI ETIL ASETAT DAUN PUCUK MERAH (SYZYGIUM MYRTIFOLIUM WALP.)

Abstract

As a organism, sunlight is an essential component of life, assisting in the synthesis of vitamin D, supporting bone health, and increase the immune system. However, continuous exposure to sunlight can lead to erythema, collagen damaged, and dark skin. The darkening of skin is caused by the activity of the enzyme tyrosinase, which converts L-tyrosine into melanin. Pucuk Merah leaves (Syzygium myrtifolium Walp.) contained flavonoids, tannins, saponins, and triterpenoids. Flavonoids are known to inhibit tyrosinase activity and act as Cu²⁺ metal chelators.This study aims to quantify the total flavonoid content and determine the IC₅₀ values of pucuk merah leaves. A total of 500 g of pucuk merah leaf was extracted using ultrasound-assisted extraction in 10 L of 70% ethanol for 40 minutes, followed by fractionation with n-hexane and ethyl acetate. Total flavonoid content was measured using quercetin as a standard at concentrations of (2,0 ; 4,0 ; 6,0 ; 8.0 ; 10.0) ppm. The absorbance was recorded at a wavelength of 418 nm, yielding a regression equation of y = 0,0451x + 0,1570 with a correlation coefficient (r) of 0,9977. The average total flavonoid contents for the ethanol extract and ethyl acetate fraction were 0,20% w/w ± 0,0042 and 0,31%w/w ± 0,0067. Enzyme inhibitory activity of the samples was performed at concentrations (1000; 500; 250; 125; 62.5; 31.25; 15.625) ppm using kojic acid standard as a positive control.The results showed that kojic acid was the highest in tyrosinase enzyme inhibition activity with an IC₅₀ value of 38,40 µg/mL in the strong category followed by ethanol extract IC₅₀ 181,25 µg/mL in the medium category and ethyl acetate fraction with an IC₅₀ value of 341,63 µg/mL in the medium category.