Photoprotective Effect of Pogonatherum paniceum Extract Against Ultraviolet-B-Induced Skin Aging in HaCaT Keratinocytes

UVB radiation causes premature skin aging through generation of reactive oxygen species in skin cells resulting in increasing matrix metalloproteinases to degrade collagen and elastin. Pogonatherum paniceum (Lam.) Hack., Poaceae, is a perennial grass found in many Asian countries. This plant exhibits various biological activities, including anti-oxidant and anti-inflammatory effects. However, its anti-photoaging effects induced by UVB in HaCaT keratinocyte cells have not been investigated. In this study, the photoprotective effects of P. paniceum extract and its underlying mechanism in prevention of skin aging-induced UVB in HaCaT cells were investigated. The results indicated that P. paniceum extract prevented and protected keratinocytes damage from UVB by attenuating intracellular ROS generation and enhancing antioxidant genes (Sod1 and Gpx1) expressions. Pogonatherum paniceum extract also inhibited expressions of matrix metalloproteinases (MMP1 and MMP9), and increased collagen type I (Col1) gene expression. Chlorogenic acid was identified as a major active ingredient of the analyzed plant material. Chlorogenic acid reduced UVB-induced cell death, superoxide dismutase activity, and reactive oxygen species generation in HaCaT cells. In addition, molecular docking results showed a high binding affinity between chlorogenic acid towards matrix metalloproteinases and antioxidant enzymes. This study suggests that the P. paniceum extract could protect cell damage from UVB and prevent premature skin aging through scavenging reactive oxygen species and reducing the activity of matrix metalloproteinases and increase endogenous antioxidant enzymes. Chlorogenic acid may be an active chemical of P. paniceum extract and a potential plant-derived polyphenol for photoaging therapy in the future.