• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.227-233
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• 2004

Chronic exposure to solar radiation, particularly ultraviolet (UV) light, causes a variety of adverse reactions on human skin, such as sunburn, photoaging and photocarcinogenesis. Free radicals and reactive oxygen species (ROS) caused by UV exposure or other environmental facts play critical roles in cellular damage. And, repeated-UV irradiation activated the expression of the matrix metalloproteinase (MMP) and induced skin irritation. Therefore, the development of effective and safe photoprotectants that can reduce and improve the skin damage has been required. The purpose of this study was to investigate the photo-protective effect of several chinese medical plants (Juniperus chinensis) on the UV -induced skin cell damages. We tested free radical and superoxide scavenging effect in vitro. Fluorometric assays of the proteolytic activities of MMP-1 (collagenase) were performed using fluorescent collagen substrates. UVA induced MMP-1 synthesis and activity were analyzed by enzyme-linked immunosorbent assay (ELISA) and gelatin-based zymography in skin fibroblasts. We also examined anti-inflammatory effects by the determination test of proinflammatory cytokine, interleukin 6 in HaCaT keratinocytes. Expression of prostaglandin E$_2$ (PGE$_2$) after UVB irradiation was measured by competitive enzyme immunoassay(EIA) using PGE$_2$ monoclonal antibody. In the human skin we tested anti-irritation effect on the SLS-induced damage skin after appling the extract containing emulsion. We found that Juniperus chinensis extract had potent radical scavenging effect by 98% at 100$\mu\textrm{g}$/mL. The extract of Juniperus chinensis showed strong inhibitory effect on MMP-1 activities by 97% at 100 $\mu\textrm{g}$/mL and suppressed the UVA induced expression of MMP-1 by 79% at 25$\mu\textrm{g}$/mL. This extract also showed strong inhibition on MMP-2 activity in UVA irradiated fibroblast by zymography. In the test of proinflammatory cytokines of human keratinocytes Juniperus chinensis extract decreased expression of interleukin 6 about 30%. The amount of PGE$_2$ by HaCaT keratinocytes was significantly increased at the doses of above 10 mJ/$\textrm{cm}^2$ of UVB (p < 0.05). At the concentrations of 3.2-25$\mu\textrm{g}$/mL of this extract, the production of PGE$_2$ by HaCaT keratinocytes (24 h after 10mJ/$\textrm{cm}^2$ UVB irradiation) was significantly inhibited in culture supernatants (p < 0.05). In SLS-induced skin irritation model in vivo, we found to reduce skin erythema and improve barrier recovery after appling Juniperus chinensis extract containing emulsion when compared to irritated non-treated and placebo-treated skin. Our results suggest that Juniperus chinensis extract can be effectively used for the prevention of UV and SLS-induced adverse skin reactions and applied as anti-aging and anti-irritation cosmetics.