Potensi bakau Rhizophora apiculata sebagai inhibitor tirosinade dan antioksidan

Abstract

The purpose of this study was to screen the potency of crude extract, fractions from silica gel column chromatography, and fraction from preparative thin layer chromatography (TLC) of Rhizophora apiculata which has the best activity as tyrosinase inhibitors, and antioxidant. Stem, bark and roots of R. apiculata were extracted with n-hexane, ethylacetate and methanol. Each extracts were tested for tyrosinase inhibitors and antioxidant activities. Based on the tyrosinase inhibitors, methanol extracts of R. apiculata bark had the best potency as tyrosinase inhibitors (monophenolase: 78.79 μgmL-1; diphenolase: 1116.5 μgmL-1) and the best radical scavenging activity 1,1-diphenyl-picrylhidrazil (DPPH) and 2,2’- Azinobis(3-etilbenzatiazolin)-6-sulfonat acid (ABTS) with IC50: 3.81 μgmL-1 and 18.47 μgmL-1, respectively. Fractionation was performed on methanol extracts of R. apiculata bark using silica gel column chromatography and yielded 10 fractions (A to J). Fraction B from column chromatography had the best tyrosinase inhibitors with monophenolase (IC50: 1045.6 μgmL-1), diphenolase (IC50: 846.71 μgmL-1), and the best antioxidants activities with DPPH (IC50: 9.19 μgmL-1), ABTS (IC50: 7.73 μgmL-1). Fraction B was fractionated with preparative TLC resulted 9 fractions (B1 to B9). Fraction B1 had the best tyrosinase inhibitors with monophenolase (IC50: 1278 μgmL-1) and diphenolase (IC50: 1678.2 μgmL-1), dan the best antioxidants activity with DPPH (IC50: 5.75 μgmL-1), ABTS (IC50: 24.78 μgm/L). Fraction B1 further fractionated with preparative TLC resulted 2 fractions (B1.1 and B1.2). Fraction B1.1 had the best tyrosinase inhibitors with monophenolase (IC50: 1037.32 μgmL-1) and diphenolase (IC50: 1257.24 μgmL-1), and antioxidants activity with DPPH (IC50: 14.40 μgmL-1), ABTS (IC50: 40.67 μgmL-1). The result of phytochemical test and infrared spectroscopy on fraction B1.1 showed that the active compounds as tyrosinase inhibitors and antioxidant was an isoflavon compound.