Abstract: Peng Liqian, Zhang Erting, Liu Qing, Jiang Na, Li Huaping, Liang Bihua, Li Runxiang, Li Zhenjie, Zhu Huilan Institute of Dermatology, Guangzhou Medical University, Guangzhou 510095, China （Peng LQ, Zhang ET）; Guangzhou Institute of Dermatology, Guangzhou 510095, China （Liu Q, Jiang N, Li HP, Liang BH, Li RX, Li ZJ, Zhu HL） Corresponding author: Zhu Huilan, Email: zhlhuilan@126.com 【Abstract】 Objective To evaluate the scavenging effect of crude polysaccharides extracted from Lycium barbarum （LBP） on reactive oxygen species in ultraviolet radiation-induced HaCaT cells, and to explore its possible mechanism. Methods Cultured immortalized human keratinocyte HaCaT cells were divided into 6 groups: blank control group receiving no treatment, LBP group treated with crude LBP alone, ultraviolet A （UVA） group treated with UVA radiation alone, ultraviolet B （UVB） group treated with UVB radiation alone, UVA + LBP group treated with crude LBP for 24 hours followed by UVA radiation, and UVB + LBP group treated with crude LBP for 24 hours followed by UVB radiation. MTT colorimetry was performed to evaluate the cellular proliferative activity, UV spectrophotometric method to measure the UVA and UVB absorption of crude LBP, dichlorodihydrofluorescein diacetate （DCFH-DA） fluorescent probe assay to detect the level of ROS, enzymatic-biochemical method to estimate the activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px）, as well as to detect the leakage of lactate dehydrogenase （LDH）. Results Crude LBP at different concentrations of 0, 100, 200, 300, 400, 500, 600, 1 500, 2 000 mg/L had no obvious effects on the proliferative activity of HaCaT cells. Crude LBP had a high transmittance of ultraviolet rays at 280 - 400 nm. Compared with the blank control group, the UVA group and UVB group both showed significantly higher LDH leakage and ROS level, lower activities of SOD and GSH-Px （P < 0.001 or 0.05）. Pretreatment with crude LBP before the ultraviolet radiation could significantly increase the activities of SOD and GSH-Px, decrease the LDH leakage and ROS level in the UVA + LBP group and UVB + LBP group compared with the UVA group or UVB group （P < 0.05）. Conclusion Crude LBP have no effect of sunscreening agents, but can effectively scavenge ROS, decrease LDH leakage, inhibit ultraviolet radiation-induced photodamage in HaCaT cells, which may be associated with the enhancement of antioxidant enzyme activity.