아그배나무(Malus sieboldii) 가지로부터 항산화 · 항염 및 항균 활성 성분 규명

Abstract

Anti-oxidative, anti-inflammatory and anti-bacterial activities were examined on the extract from Malus sieboldii branches. In addition, their active constituents were isolated and identified. This study was designed to evaluate the extract of M. sieboldii as the potential ingredient in functional cosmetics.

The extract was prepared from the branches of M. sieboldii with 70% aqueous ethanol. The ethanol extract was partitioned successively into n-hexane, ethyl acetate (EtOAc) n-butanol, and H2O. The extract and fractions were subjected to total phenolic contents, total flavonoid contents tests, DPPH and ABTS+ radical scavenging studies. The total phenolic contents for the EtOAc fraction were estimated as 45.3 mg (GAE/100 mg). In addition, the total flavonoid contents were measured as 98.0 mg (quercetin/100 mg) for the EtOAc fraction. And very strong DPPH and ABTS+ radical scavenging activities were observed for the EtOAc fraction. On the screening of anti-inflammatory activities, the EtOAc fraction showed the considerable inhibition on the production of nitric oxide for the RAW 264.7 cell without any cell toxicity. Also on the screening of anti-bacterial activities, the n-hexane fration showed the considerable inhibition for Propionibacterium acnes and Staphylococcus epidermidis. The identification of the active constituents were conducted with the EtOAc and n-hexane fractions. Repeated column chromatography on normal-phased silica gel and Sephadex LH-20 resulted in the isolation of twelve compounds, β-sitosterol (1), daucosterol (2), epi-catechin (3), 3-O-α -L-arabinofuranoyl-8-methoxyquercetin (4), phlorizin (5), 3-hydroxyphlorizin (6), avicularin (7), quercetin-4'-O-β-D-glucopyranoside (8), chrysin-7-O-β-D-glucopyranoside (9), ethyl linoleate (10), taraxerol (11), and lupeol (12). All of the compounds were isolated for the first time from this plant. The elucidation of the chemical structures of the compounds 1-12 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 3 (SC50 24.23 μM), 4 (SC50 54.71 μM), 6 (SC50 72.39 μM) and 7 (SC50 39.69 μM) showed good DPPH radical scavenging activities compared to ascorbic acid (SC50 54.22 μM) as a positive control. The compounds 3 (SC50 5.09 μM), 4 (SC50 7.02 μM), 6 (SC50 9.46 μM), 7 (SC50 6.84 μM) and 8 (SC50 11.19 μM) showed very good ABTS+ radical scavenging activities compared to ascorbic acid (SC50 13.36 μM) as a positive control. On the screening of anti-flammatory activities, the compounds 8 and 9 showed the considerable inhibition on the production of nitric oxide for the RAW 264.7 cell without any cell toxicity. And Compounds 8 and 9 dose-dependently inhibited the expressions of inflammatory mediators. Also the protein levels of inducible nitric oxide synthase(iNOS) and cyclooxygenase-2(COX-2) in LPS-stimulated RAW 264.7 cell were also quantified by western blotting method respectively.

Based on the above experimental results, it is suggested that the extract from Malus sieboldii branches could be potentially applicable in the cosmetical and/or pharmaceutical industries, especially as anti-oxidant, anti-inflammatory and anti-bacterial ingredients.