Background: Thai medicinal plant namely Eclipta prostrate Linn. (EP) and Sapindus rarak DC. (SR) are reported to improve hair growth and hair color. Theories of grey hair occurred from the gradual loss of pigmentation. Intrinsic factors are age, genetic, stress and extrinsic factor such as chemical that involved melanogenesis process and oxidative mechanism. Moreover, hydrogen peroxide (H2O2) is known as an oxidant which can destroy melanocytes cell. On the other hand, if the herb extracts can increase melanocytes cell and high antioxidant, they will protect melanocytes cell.
Objective: To investigate free radical protective activity from hydrogen peroxide, antioxidant and melanogenesis stimulating activities of Eclipta prostrate Linn. and Sapindus rarak DC.
Material and Method: The leaves of EP and the pericarps of SR were maceration in 95% ethanol (EPE95 and SRE95), 50% ethanol (EPE50 and SRE50), and were decoction with water (EPA and SRA). All extracts were tested antioxidant activity by DPPH radical scavenging assay and ABTS radical cation decolorization assay. The effect of extracts on melanocytes proliferation in mouse melanoma cell (B16F10) and in preventing cells from H2O2 by MTT assay were also investigated.
Results: The results showed that EPA had the highest DPPH radical ion inhibition with the EC50 value of 15.00 μg/ml. For ABTS assay, EPE50 and EPA showed the highest inhibitory effect on ABTs radical assay (EC50 = 54.24 and 30.28 μg/ml, respectively). For melanocytes proliferation assay, EPE95 showed the highest stimulating effect on melanocyte proliferation at the concentration of 50 μg/ml. Moreover, the SRA showed high activity on the effect of herbs in preventing cells from H2O2 at the concentration of 10 and 1 μg/ml.
Conclusion: These results can be concluded that SRA showed the effect of prevention of cell from H2O2 and EPE95 showed melanocytes proliferation stimulating effects and EPA showed high antioxidant activities. Thus, these extracts should be continuously developed as a hair product.

Keywords: Antioxidant, Hydrogen peroxide, Melanocyte proliferation, Grey hair, Eclipta prostrata Linn., Sapindus rarak
DC.