Study on imperatorin extracted from Angelica dahurica and its UV photocatalytic reaction with collagen

Abstract

Soxhlet extraction method was used to extract imperatorin from Angelica dahurica, and the extraction ratio under different extraction condition was optimized to attain the best condition. Then, XAD-16 macroporous resin was selected as the optimal resin to boost the extraction ratio of imperatorin. Afterwards, the higher purity of imperatorin (96.84±0.2%) was separated by preparative HPLC system. Next, the photocatalytic reaction between the above imperatorin and collagen which the highest levels in skin was investigated using UV-vis spectroscopy, amino acid analysis and HPLC analysis. The results showed that imperatorin reacted with collagen only under ultraviolet light which caused the denaturation of collagen, and three new products were generated. The ultraviolet products were isolated by preparative HPLC system and separately detected by high-resolution mass spectrum. The possible UV photocatalytic reaction mechanism between imperatorin and collagen is that ultraviolet light induces the increase of the activity of the imperatorin to react with the tyrosine in the collagen, resulted in the denaturation of collagen and reestablish of the normal epidermal tissue in skin.