Abstract: Angelicae Dahuricae is commonly used as whitening herb since ancient times,but it is disable as skin whitening product in recent years for coumarin in the root which has photosensitive toxicity.To find a better whitening active extractive with lower content of photosensitive toxicity,we compared the whitening activity of different extracts of this plant and measured their coumarin contents.Whitening activity of two extractions was determined by tyrosinase inhibition experiment and body whitening activity test,at the same time a high performance liquid chromatographic (HPLC) method was developed to determine the content of photosensitive coumarin.As a result,the water extraction showed a stronger inhibition on the activity of tyrosinase than the alcohol extraction did,and the body whitening activity of it was high.Photosensitive cumarin could barely be found in the water extraction but abundantly in the alcohol extraction.In conclusion,the water extraction of Angelicae Dahuricae was confirmed to be the active components responsible for whitening activity.

Key words: Angelicae Dahuricae, extraction, inhibitory effects on tyrosinase, skin whitening, photosensitive toxicity