Evaluation of protective effects of wild bitter melon fruit and leaf extracts on UVB-irradiated human HaCaT keratinocytes

Hualien No.1 wild bitter melon (WBM; Linn. var. Ser.) leaf extract has been shown to possess antioxidant activity and could be potentially beneficial for mitigating reactive oxygen species (ROS)-mediated skin disorders. In this study, two crude extracts were respectively prepared from leaf (HL-1L) and fruit (HL-1F) of Hualien No.1 WBM to evaluating their potential to protect against the effects of ultraviolet (UV) B irradiation on human keratinocyte HaCaT cells. Our data showed that HL-1L and HL-1F significantly lowered levels of UVB-induced ROS generation by up to 58%. Both extracts also significantly suppressed UVB-activated mRNA and proteins of cyclooxygenase-2 (COX-2) and matrix metalloproteinase-1 (MMP-1). Our findings suggested that both leaf and fruit extracts of WBM could have the potential to protect keratinocytes from UVB damage.