Skin lightening effect of Dimocarpus longan arils extract and its active principle

The fruit of Dimocarpus longan (Sapindaceae) is a sweet fruit which is distribured in China and South Asia. It has been traditionally used as tonic and for the treatment of amnesia and insomnia [1]. Dried arils of D. longan were extracted by sonication with 50% ethanol. The extract was subjected to a bioactivity guided isolation process focusing on skin lightening activity. The extract of D. longan showed potent inhibitory activity on tyrosinase and melanin formation in melan-a cells. It also revealed higher skin lightening activity than hydroquinine, which was the positive control in in-vivo tests. An activity guided isolation of single compounds from the 50% ethanol extract using RP-HPLC was performed to identify the active principle in the extract. Final purification was performed with preparative-TLC (reversed phase). DART-TOF-MS revealed a protonated ion peak at m/z 127, and the structure was elucidated by ¹H-and ¹³C-NMR studies. From all the spectroscopic data, the compound was identified as 5-hydroxymethyl-2-furfural (5-HMF). 5-HMF showed significant skin lightening effects in vitro. From the results, it is possible that D. longan extract and 5-HMF may be developed as a functional skin lightening cosmetic.

References: 1. Jiyoung, R. et al. (2003) Arch. Pham. Res. 26(2):138–142.