좁은잎천선과로부터 항산화 및 티로시나아제 저해 활성성분 연구

Abstract

Ficus erecta var. sieboldii KING (Moraceae) is a deciduous tree distributed in the southern region of Korea. This plant has been used as a folk medicine for the treatment of arthritis. In our continuing efforts to find biologically active compounds from plants in Jeju Island, we became interested in the extract of F. erecta branch and leaves. Repeated column chromatography of ethyl acetate soluble fractions in the extract led to the isolation thirteen compounds such as β-sitosterol (1), p-hydroxybenzoic acid (2), ethyl linoleate (3), α-amyrin acetate (4), vanillic acid (5), syringic acid (6), methyl vanillate (7), methyl p-hydroxybenzoate (8), catechin (9), afzelechin (10), monoolein (11), oleic acid (12), lutein (13). All of these compounds were isolated for the first time from F. erecta. In addition, the extract and isolated compounds to anti-oxidative and anti-tyrosinase activity test were conducted. For the anti-oxidation activity test, the three compounds syringic acid (6), catechin (9), afzelechin (10) showed DPPH radical scavenging activity with RC50 of 8.22, 10.3, 39.4 μg/mL respectively (vitamin C, RC50 : 7.24 μg/mL). On the tyrosinase inhibition activity test, p-hydroxybenzoic acid (2) and methyl p-hydroxybenzoate (8) showed inhibition activites with IC50 135.4 μg/mL and 99.9 μg/mL respectively (arbutin, IC50 : 87.4 μg/mL). The inhibition kinetics, analyzed by Lineweaver-Burk plots, indicated p-hydroxybenzoic acid (2) and methyl p-hydroxybenzoate (8) to be competitive inhibitors of tyrosinase when L-tyrosine was used as a substrate. These structures were elucidated on the basis spectroscopic data from 1D and/or 2D NMR studies as well as by comparison of the data with the literature values.