Protective Effect of Crude Anthocyanin Extract from Mulberry on Ultraviolet-Irradiated Human Skin Fibroblasts

Exposure to ultraviolet (UV) radiation may cause skin photoaging, including pigmentation and wrinkling. The latter is relevant to degradation of collagen. UV radiation promotes the generation of reactive oxygen species (ROS) in skin fibroblasts, and therefore induce signal pathways to accelerate the degradation of collagen. Antioxidants protect cells from UV-induced oxidative stress. Mulberry (Morus alba) fruit is rich in anthocyanin with great antioxidative properties. The present study aimed at investigating the protective effect of mulberry juice and anthocyanin crude extract from mulberry on UV-induced photoaging in human skin using fibroblasts as the model. Mulberry fruit were bought from Hualien, Taiwan, homogenized, centrifuged to recover the juice, and lyophilized to obtain mulberry juice powder (MJP). Anthocyanin crude extract from mulberry juice (AEMJ) was separated from MJP by solid phase extraction (SPE). MJP and AEMJ were re-dissolved to determine the anthocyanin content, anti-tyrosinase and antioxidant activities. The anthocyanin content of AEMJ is about 15-fold that of MJP. The DPPH scavenging activity of AEMJ is 2506 μmol TE/gDW, while that of MJP is 119 μmol TE/gDW only. The anti-tyrosinase activity of 500