Megumi Nishikawa
Septem Soken Co., Ltd.
Akihiro Aioi
SPTM R&D Australia、School of Med, University of Queensland

[Abstract]
Interleukin (IL)-6 is a well-known participant in cutaneous local reactions such as inflammation, pigmentation and photo-aging. Interestingly, previous studies demonstrated that IL-6 involves in central nerve system as well as local reaction. To discover compounds which down-regulate IL-6 production, we have examined the suppressive effect of over 200 plant extracts on IL-6 production from RAW264.7 macrophage-like cells stimulated with lipopolysaccharide (LPS). Consequently, the extract from Arnica montana native to Europe suppressed significantly IL-6 expression in both protein and mRNA levels, with does-relation manner. Furthermore, suppressive effects of Arnica on IL-1a and prostaglandin (PG) E2 production were detected in ELISA. Also Arnica down-regulated mRNA expressions of endothelin-1 (ET-1) and iNOS, a type of nitric oxide (NO) synthase. Conversely, Arnica did not increase lactate dehydrogenase (LDH) as a cytotoxicity index, within the concentration used in the experiment. After these in vitro experiments, we performed preliminary in vivo trial. In this in vivo experiment, Arnica decreased area of erythema induced by UV irradiation. Taken together, these results suggest that Arnica is useful as a cosmetic ingredient for UV protection because Arnica suppressed the mediators to be produced and released from keratinocytes by UV irradiation.