Protective Effect of the Ethyl Acetate Fraction of Sargassum muticum against Ultraviolet B–Irradiated Damage in Human Keratinocytes

Abstract

The aim of this study was to investigate the cytoprotective properties of the ethyl acetate fraction of Sargassum muticum (SME) against ultraviolet B (UVB)-induced cell damage in human keratinocytes (HaCaT cells). SME exhibited scavenging activity toward the 1,1-diphenyl-2-picrylhydrazyl radicals and hydrogen peroxide (H2O2) and UVB-induced intracellular reactive oxygen species (ROS). SME also scavenged the hydroxyl radicals generated by the Fenton reaction (FeSO4 + H2O2), which was detected using electron spin resonance spectrometry. In addition, SME decreased the level of lipid peroxidation that was increased by UVB radiation, and restored the level of protein expression and the activities of antioxidant enzymes that were decreased by UVB radiation. Furthermore, SME reduced UVB-induced apoptosis as shown by decreased DNA fragmentation and numbers of apoptotic bodies. These results suggest that SME protects human keratinocytes against UVB-induced oxidative stress by enhancing antioxidant activity in cells, thereby inhibiting apoptosis.

Erythrocytes and cell line-based assays to evaluate the cytoprotective activity of antioxidant components obtained from natural sources

“…The extracts had no protective effect on lipid peroxidation caused by H2O2. TBARS and AAPH assays evaluate different antioxidant mechanisms; for this reason, some compounds may show antioxidant capacity in both assays (Inayatullah et al, 2012), whereas others show ROS scavenging capacity in the AAPH assay but no anti-peroxidative effect on lipids in the TBARS assay (Piao et al, 2011). Our results indicate that the antioxidant effect of the extracts is mediated by radical scavenging, but not by protecting lipids from peroxidation.…”

“…Extracts of algae of Ulva and Sargassum spp. genres have been previously described as antioxidants (Shalaby, 2011;Piao et al, 2011). Furthermore, the ability of Ulva lactuca to adsorb heavy metals has attracted industrial interest (Areco et al, 2012).…”

The ethyl acetate fraction ofSargassum muticumattenuates ultraviolet B radiation-induced apoptotic cell death via regulation of MAPK- and caspase-dependent signaling pathways in human HaCaT keratinocytes

“…Extracts derived from S. muticum demonstrate antioxidant, antimicrobial, and anti-inflammatory properties (Kim et al, 2007;Yoon et al, 2010). Previous work by our group revealed that an ethyl acetate fraction of S. muticum (SME) defended human HaCaT keratinocytes against UVB exposure by enhancing cellular antioxidant systems (Piao et al, 2011). However, the molecular mechanism underlying the action of SME was not elucidated.…”

“…We previously showed that UVB exposure increases apoptosis in human HaCaT keratinocytes (Piao et al, 2011). Therefore, the UVB-absorbing capacity of SME was first examined using an UV/visible light spectrophotometry.…”

“…A voucher specimen (A06-0000080) has been deposited at the herbarium of Jeju Biodiversity Research Institute. The extraction process of S. muticum was previously reported (Piao et al, 2011); the dried S. muticum was extracted with 80% ethanol at room temperature for 24 h and was then evaporated under reflux. Next, the 80% ethanol extract was suspended in distilled water and successively fractionated with n-hexane, dichloromethane, ethyl acetate, and n-butanol.…”