C. A. Meyer Phenolic Acid Extract Alleviates Ultraviolet B-Irradiation-Induced Photoaging in a Hairless Mouse Skin Photodamage Model.

Here, we evaluated the skin-protective effects of topical applications of C. A. Meyer extract (PG2) and its phenolic acid- (PA-) based components against UVB-induced skin photoaging. PG2 or PA applied to skin of hairless mice after UVB-irradiation alleviated UVB-induced effects observed in untreated skin, such as increased transepidermal water loss (TEWL), increased epidermal thickness, and decreased stratum corneum water content without affecting body weight. Moreover, PG2 and PA treatments countered reduced mRNA-level expression of genes encoding filaggrin (FLG), transglutaminase-1 (TGM1), and hyaluronan synthases (HAS1, HAS2, and HAS3) caused by UVB exposure and reduced UVB-induced collagen fiber degradation by inhibiting the expression of matrix metalloproteinase genes encoding MMP-1, MMP-2, and MMP-9. Meanwhile, topical treatments reduced cyclooxygenase-2 (COX-2) mRNA-level expression in photodamaged skin, leading to the inhibition of interleukin-1 (IL-1) and interleukin-6 (IL-6) mRNA-level expression. Thus, ginseng phenolic acid-based preparations have potential value as topical treatments to protect skin against UVB-induced photoaging.