Antimelanogenesis and cellular antioxidant activities of rubber (Hevea brasiliensis) seed oil for cosmetics

The abundant rubber seed, the by-product of rubber tree (Hevea brasiliensis), is used for tree plantation, biodiesel production, coating, and animal feed. The reported major unsaturated fatty acid components of rubber seed oil are involved in the biological activities and may potentially be employed in the cosmetics. Nevertheless, the biological activity study of rubber seed oil for cosmetic application is limited. The aims of study were to extract the rubber seed oil, analyze the fatty acid components, and evaluate for the cytotoxicity by sulforhodamine B assay and biological activities, including melanogenesis assay and antioxidant activity, in cell culture. The extraction yield of rubber seed oil was 19.32 +/- 0.54%. The fatty acid components of rubber seed oil were palmitic (18.90 +/- 0.55%), stearic (10.91 +/- 0.25%), oleic (35.91 +/- 1.97%), and linoleic (33.31 +/- 1.56%) acids. The non-cytotoxic concentrations of rubber seed oil at 0.0001-0.1 mg/mL were shown the cell viability higher than 80% in B16-F10 melanoma cells and 3T3-L1 cells. The concentration of rubber seed oil that inhibited cell viability at 50% (IC50) was 0.29 mg/mL in B16-F10 melanoma cells. The melanogenesis assay of rubber seed oil at 0.1 mg/mL was shown the inhibitory effect on melanin content (46.24 +/- 2.64%), tyrosinase activity (53.85 +/- 5.04%) and tyrosinase-related protein-2 activity (66.01 +/- 1.84%). The antioxidant activity of rubber seed oil was demonstrated the cellular protective effect at 0.001 mg/mL with cell viability of 99.72 +/- 6.92%. The results of study have been supported the potential utilization of rubber seed oil as a functional raw material to be incorporated into the personal care and cosmetic preparations.