Protective Effects of a Mixture of Propolis and Petasites japonicus Against UVB-Induced Photoaging Through Suppression of Oxidative Stress and MAPK/AP-1 Signaling.

Ultraviolet B (UVB)-induced photoaging is associated with oxidative stress, inflammation, and extracellular matrix (ECM) degradation. This study investigated the protective effects of a mixture of propolis and Petasites japonicus (PPJM) against UVB-induced photoaging in SKH-1 hairless mice. HPLC analysis identified bakkenolide B, chrysin, and pinocembrin as the representative marker compounds of PPJM. Mice were orally administered PPJM (50, 100, or 200 mg/kg) daily for 6 weeks during repeated UVB irradiation (90 mJ/cm2, three times per week). PPJM significantly restored the glutathione, superoxide dismutase, and catalase levels that had been reduced by UVB exposure. PPJM also decreased dorsal skin tissue IL-1β and TNF-α levels while increasing hyaluronan levels. Histological analysis showed that PPJM attenuated UVB-induced epidermal thickening and collagen degradation. In addition, PPJM suppressed the expression of COX-2 and MMPs while increasing collagen type I and elastin expression. PPJM administration was also associated with reduced phosphorylation of p38 and JNK and with lower expression of c-Jun and FosB. These findings suggest that PPJM protects against UVB-induced photoaging in this preclinical model, in association with reduced oxidative stress and MAPK/AP-1-related ECM degradation.