Evaluation of the extract of traditional Chinese medicine formula Si Ben Cao for skin whitening

Abstract

Objective: To evaluate the safety, potential benefits and possible mechanisms of the extract of Si Ben Cao (SBC), a traditional Chinese medicine formula composed of four herbs, for skin whitening. Methods: The reflux method was performed to prepare the extract of SBC. MTT assay was used to evaluate the cytotoxic of SBC extract in vitro. Skin irritation test and skin allergy test on rats were performed to evaluate the safety of SBC extract in vivo. Intercellular melanin production was analyzed to assess the function of SBC extract for whitening. Afterwards, we analyzed the activity of intracellular tyrosinase, Ultraviolet (UV) absorption, and anti-oxidant activity, which were related to melanin production. Results: The aqueous extract and ethanol extract of SBC were prepared separately. MTT assay results showed aqueous extract of SBC at a concentration of 100 μg/mL had no inhibitory effect on the proliferation of B16F10 cells even after treatment for 96 h, indicating that aqueous extract of SBC was not cytotoxic. Thus, we conducted subsequent experiments using aqueous extract of SBC. The results on rats showed SBC extract was safe to apply on the skin without causing irritation and allergies. Analysis of melanin content showed SBC extract had inhibitory effect on cellular melanin generation and secretion. Moreover, we found that SBC extract was able to reduce cellular tyrosinase activity, as well as absorb UV light and scavenge DPPH radicals for anti-oxidants. Conclusion: Our data clearly demonstrated that SBC extract is safe and effective for skincare, and it is suitable for use with the purpose of skin whitening and health benefits.