Ginsenoside, as an active ingredient in traditional Chinese medicine, has been widely used for skin whitening for several years. Recent research has found that Panax notoginseng has a higher content of ginsenosides compared with the Panax ginseng. Those ginsenosides have promising potential to be developed as skin whitening agents.

We selected five dammarane ginsenosides isolated from P. notoginseng and their mixtures to investigate the skin lightning activity. Zebrafish embryo model was used for initial screening of the whitening activity. Subsequently, the whitening effect of components was examined and compared via testing the inhibition of melanin and activity of tyrosinase in B16 cells treated with these components. Molecular docking was also applied to investigate the interactions between ginsenosides and tyrosinase. Finally, the most effective saponins were selected for dosage form optimization and the whitening effect of saponin-loaded ethosomes was further demonstrated on the C57BL/6 mouse model.

Experimental results showed that the protopanaxtriol saponins (PTS) were the most potent saponins with a decent safety profile, and the molecule docking results demonstrated that PTS had strong inhibitory ability to tyrosinase. PTS was successfully encapsulated into ethosomes with an encapsulation efficiency of 93%. The PTS ethosome gel could effectively inhibit the melanin production caused by UVB tanning on the back skin of mice.

The PTS ethosome gel provides an effective and safe formulation of PTS to whiten the UVB-tanned skin in vivo and could be used as a potential skin whitening agent in the future.