Study on the antioxidant and human neutrophil elastase inhibitory activities of mushroom Ramaria formosa extracts

Abstract

: In searching for novel agents for skin anti-aging from natural resources, we found that the extract of the fruiting bodies of Ramaria formosa ( R. formosa ) had significant antioxidant and human neutrophil elastase (HNE) inhibitory activities. R. formosa extract exhibited a considerable DPPH radical scavenging activity with an antioxidant content of 117.0 mg/mL (ascorbic acid equivalents) at the concentration of 500 µ g/mL. The capacity of R. formosa extract to scav-enge peroxy radicals measured by ORAC assay also showed dose-dependent antioxidant effect with ORAC Roo (trolox equivalents, 1 µ M) values of 0.8, 5.2, and 7.8 at the concentrations of 1, 10, and 20 µ g/mL. The cellular antioxidant capacity of R. formosa extract was investigated by assaying the cellular fluorescence intensity using dichlorodihydro-fluorescein (DCF). The cellular oxidative stress induced by AAPH, Cu 2+ or H 2 O 2 in HepG2 cells was significantly attenuated by more than 30% at 20 µ g/mL of R. formosa extract. HNE activity was reduced by treatment with R. formosa extract in a dose-dependent manner, and the ED 50 value for the ethanol extract of R. formosa was 42.9 µ g/mL. R. formosa extract did not exhibited antimicrobial activity against four microorganisms including Bacillus subtilis ( B. subtilis ), Escherichia coli ( E. coli ), Candida albicans ( C. albicans ), Aspergillus oryzae ( A. oryzae ). Furthermore, the extract did not affect the inflammatory cytokine production of interleukin-10 and interferon- γ in NK92 cells. From the above results, we found that R. formosa extract has considerable antioxidant and elastase inhibitory effects, and does not stimulate immune cells. These findings suggest that R. formosa extract may be used as a bioactive component in cosmetic composition.