Clinical evaluation of the depigmenting effect of Glechoma Hederacea extract by topical treatment for 8 weeks on UV-induced pigmentation in Asian skin.

摘要

UV is a major environmental factor inducing and worsening the symptoms of hyperpigmentation disorders such as freckles, melasma and solar lentigines. During UV-induced skin inflammatory reactions, pro-inflammatory mediators initiate the production of various paracrine melanogenic factors (alpha-MSH, SCF, ET-1, bFGF and NO) in keratinocytes. These paracrine factors activate melanin synthase in melanocytes through the paracrine network between melanocytes and keratinocytes. Glechoma hederacea (GH) is a herbal plant used in oriental medicine to treat inflammation. Its anti-inflammatory effects, through inhibition of NO synthesis (NOS) as well as the pro-inflammatory cytokine TNF-alpha, have been reported. However, there has not yet been any report of a depigmenting effect. In this study of placebo-controlled, 8 week topical treatment with a 1% GH extract lotion on UV-induced pigmented spots in female Asian subjects, significant effects of anti-inflammation and depigmenting were proven. The depigmenting effect of GH seems to be related to inhibiting the secretion of pro-inflammatory cytokines and melanogenic paracrine factors from keratinocytes, rather than to direct inhibition of melanogenic activities in melanocytes.