Phenolic composition and effects on allergic contact dermatitis of phenolic extracts Sapium sebiferum (L.) Roxb. leaves

Ethnopharmacological relevance The leaves of Sapium sebiferum (L.) Roxb. have long been used in Traditional Chinese Medicine (TCM) for the treatment of eczema, shingles, edema, swelling, ascites, scabs, and snakebites, among other maladies. The present study was an outreach research behind our previous study and aimed to analyze the chemical composition of phenolic extracts of Sapium sebiferum leaves and evaluate their effects on allergic contact dermatitis (ACD). Materials and methods The main compounds of Sapium sebiferum leaves were identified using UPLC-PDA method by comparing retention times and UV-vis spectra with those of reference standards. Their effects on ACD were examined using a dinitrofluorobenzene (DNFB) induced mice ACD model. Chemical parameters including reactive oxygen species (ROS), MDA and GSH/T-GSH ratio of ear tissue were also determined. Results Seven compounds including gallic acid, ellagic acid, hyperin, isoquercitrin, astragalin, quercetin and kaempferol were identified from Sapium sebiferum leaves, and their contents were also determined; ellagic acid, isoquercitrin and astragalin were in the majority. Phenolic extracts of Sapium sebiferum leaves exhibited dose-dependent inhibitory effects on edema induced by ACD at doses of 0.03, 0.1 and 0.3 mg/ear. The application of extracts also decreased ROS and MDA levels and increased GSH/T-GSH ratio of ear tissue. Conclusion The present study demonstrated that the bioactivity of Sapium sebiferum leaves may be due to the existence of the identified phenolic components, and several high polarity compounds were also active. The beneficial effect of Sapium sebiferum leaves on skin diseases is based on its antioxidant activity or effects on antioxidant defense system.