297 Vitamin D like activity of peony flower extract and effect on skin barrier function

Abstract

In 2012, the International Osteoporosis Foundation has reported that one of three subjects is lack of vitamin D in developing and developed countries and it is a serious problem in the world. The problem is caused by modern lifestyle which people try to avoid UV rays, because vitamin D is made by UV rays in skin. It has been reported that vitamin D is related to bone formation for a long time and nowadays it is getting clear that vitamin D is also related to skin barrier function, therefore it has a possibility that chronic dry and rough skin is caused by lack of vitamin D. In this study, we measured blood vitamin D levels of the subjects and divided them into lack and sufficiency of vitamin D groups with the standard value of 20ng/mL, then prepared dry and rough skin in each group by closed patch of sodium dodecyl sulfate solution. As a result, we found that especially lack of vitamin D group (n=3) tended to be easier to prepare dry and rough skin and more difficult to recover than sufficiency of vitamin D group (n=3). Next, we screened for natural component which has vitamin D like activity binding to vitamin D receptor and activating vitamin D receptor transcriptional activity by reporter assay and finally discovered that peony flower extract has vitamin D like activity with about 5-fold (p<0.01) efficiency compared to control. We also found that peony flower extract increased expressions of claudin and occludin proteins which are components of tight junction to regulate skin barrier function with about 1.5-fold (p<0.01) efficiency compared to control in keratinocytes. When we performed continuous applying test of peony flower extract for the above-mentioned subjects, we found that peony flower extract had remarkable improvement effect on dry and rough skin of lack of vitamin D group by a skin barrier function recovery. In this way, these results suggest that vitamin D is related to dry and rough skin closely and peony flower extract improves chronic dry and rough skin by a skin barrier function recovery effect with vitamin D like activity.