5a-Reductase Inhibition and Melanogenesis Induction of the Selected Thai Plant Extracts

Abstract

Five selected Thai plant extracts, including Lotus seeds, Black Sesame seeds, White Kwao Krua tubers, rice bran and Asiatic Pennywort leaves were extracted by different solvents (ethyl acetate, ethanol and water). The mixture of the rice bran extract and the White Kwao Krua extract at 1:1 weight ratio, the water and chloroform fractions of the decolorized Asiatic Pennywort extract and the rice bran extract loaded in b-cyclodextrin were prepared. The samples were investigated for 5a-reductase inhibition in DU-145 prostate carcinoma and melanogenesis in B16F10 melanoma cells. The rice bran extract not loaded and loaded in b-cyclodextrin exhibited the high linoleic acid contents of 21.13±1.22 and 21.47±0.91% w/w, respectively. The highest inhibitory effect of 5a-reductase type 1 was observed in 0.5 mg/mL of the rice bran extract at 87.43±7.15% of the control, which was higher than the standard dutasteride of about 1.60 times, followed respectively by the mixture of the rice bran extract and the White Kwao Krua extract, and the Lotus seed extract. The rice bran extract loaded in b-cyclodextrin at 1 mg/mL and the White Kwao Krua n-hexane fraction at 1 mg/mL demonstrated the highest melanogenesis induction and tyrosinase activity of 1.25 and 1.82 folds of the control, and 0.52 and 0.55 folds of the standard theophylline, respectively. This study has demonstrated the potential of the rice bran extracts on 5a-reductase inhibition and melanogenesis induction when loaded in b-cyclodextrin, which can be further developed as the anti-hair loss and hair darkening products.