뽕잎피나무(Tilia taquetii) 가지로부터 항산화 및 미백활성 성분 분리

Abstract

In this study, anti-oxidative and anti-tyrosinase activities were examined on the extract from Tilia taquetii branches and their active constituents were identified. This study was designed to evaluate its extract and isolated compounds as the potential ingredient in functional cosmetics.

The extract was prepared from the branches of T. taquetii with 70% aqueous ethanol. The ethanol extract was partitioned successively into n-hexane, ethyl acetate (EtOAc) and n-butanol. The extract and fractions were subjected to DPPH radical scavenging and tyrosinase inhibition tests. In these studies, very strong DPPH radical scavenging activities were observed for the extracts. However, they showed very weak tyrosinase inhibition activities. The identification of the active constituents were conducted with the EtOAc-soluble fraction. Repeated column chromatography on normal-phase silica gel and Sephadex LH-20 resulted in the isolation of eight compounds, orobol 4'-O-β-glucopyranoside (1), 3'-O-methylorobol (2), cleomiscosin A (3), cleomiscosin B (4), 3,4-dihydroxybenzoic acid (5), β-sitosterol (6), epi-catechin (7) and oleic acid (8). Among these, the compound 1 is new, and the other compounds were isolated for the first time from T. taquetii. The elucidation of the chemical structure of the compounds 1-8 were accomplished using spectroscopic data including 1D and 2D NMR spectra, and by the comparison of their data to the literature values. The isolated compounds were also subjected to the above biological tests. The compounds 7 (SC50 17.7 μg/mL) and 2 (SC50 78.5 μg/mL) showed good DPPH radical scavenging activities compared to ascorbic acid (SC50 7.7 μg/mL) as a positive control. In addition, DPPH and hydroxy radical scavenging activities were examined using ESR spectrometer, strong activities were observed in the compounds 5 and 7. For the tyrosinase inhibition test, the compounds 3 (IC50 12.9 μg/mL) showed good activities compared to arbutin (IC50 104.6 μg/mL) as a positive control.

Based on the above experimental results, it is suggested that the extract from Tilia taquetii branches could be potentially applicable in cosmetic formulation as the functional, especially whitening ingredient.