Although ginseng leaves contain a larger amount of ginsenosides than the roots, studies on the protective effect of oral administration of ginseng leaves against photoaging are lacking. Processed ginseng leaves (PGL) prepared by acid reaction to increase effective ginsenoside content showed higher levels of Rg3 (29.35 mg/g) and Rk1 (35.16 mg/g) than ginseng leaves (Rg3 (2.14 mg/g) and Rk1 (ND)), and ginsenosides Rg3 and Rk1 were evaluated as active ingredients that protected human keratinocytes against UVB-induced cell damage by increasing cell proliferation and decreasing matrix metalloproteinase (MMP)-2 and 9 secretion. Herein, the effect of oral PGL administration (50, 100, or 200 mg/kg, daily) against photoaging in HR-1 hairless mice was assessed by measuring wrinkle depth, epidermal thickness, and trans-epidermal water loss for 16 weeks. The PGL treatment group showed reduced skin wrinkles, inhibited MMP-2 and MMP-9 expression, and decreased IL-6 and cyclooxygenase-2 levels. These data suggest that oral PGL administration inhibits photoaging by inhibiting the expression of MMPs, which degrade collagen, and inhibiting cytokines, which induce inflammatory responses. These results reveal that ginseng leaves processed by acid reaction may serve as potential functional materials with anti-photoaging activities.
Keywords: Panax ginseng C.A. Mayer; acid reaction; ginseng leaf; skin photoaging; ultraviolet irradiation.