Anti-Tyrosinase, Anti-Inflammatory, and Cytotoxic Activity of Si Boo Gan Tang Rice and Rice Bran Extracts

Si Boo Gan Tang is a widely cultivated variety of rice in the Tak Bai district of Narathiwat province, located in the southern region of Thailand. This study aimed to evaluate the biological properties of Si Boo Gan Tang rice and rice bran extracts, focusing on their anti-tyrosinase activity, anti-inflammatory activity, and cytotoxicity. The anti-tyrosinase assay revealed that the aqueous extract of rice (RW) significantly inhibited tyrosinase activity by 41.47%. Similarly, the ethanolic extract of rice (RE) exhibited anti-tyrosinase activity at 35.34%. The aqueous (RBW) and ethanolic (RBE) extracts of rice bran showed anti-tyrosinase activity with percentages of 19.26% and 29.08%, respectively. The anti-inflammatory experiment, conducted using RAW 264.7 cells, demonstrated that all extracts (RW, RBW, RE, and RBE) from rice and rice bran exhibited anti-inflammatory properties by reducing the release of nitric oxide (NO) from lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The extracts had IC₅₀ values of over 400 μg/ml and CC₅₀ values over 400 μg/ml. Cytotoxicity was assessed using the MTT assay on HaCaT cells. The findings indicated that the IC₅₀ values for both aqueous and ethanolic extracts of rice and rice bran were greater than 800 μg/ml.