Bioactivities of organic riceberry broken rice and crude riceberry rice oil

Objectives: Riceberry broken rice (RBR) and crude riceberry rice oil (CRO) are inevitable by-products generated from organic rice process in Thailand for several tons per year with low value. The aims of this work were to determine gamma-oryzanol content, fatty acid content, antioxidant activity and tyrosinase-stimulating activities of the extract from RBR and CRO by-products. Materials and Methods: Different organic solvents were used to extract bioactives from RBR and ethanol was used for CRO. Extracts were analysed for gamma-oryzanol content by HPLC and fatty acid content by GC-MS. Their bioactivities were tested using DPPH, FRAP, ABTS assays and tyrosinase-stimulating activities. Results: Gamma-oryzanol content in ethanolic CRO (234 mg/100 g) extract was much higher than that in aqueous RBR extract (52.5 mg/100 g). The four isomers of gamma-oryzanol including 24-methylene campesteryl ferulate (51.3%) > campesteryl ferulate (26.0%) > cycloartanyl ferulate (13.1%) > β-sitosteryl ferulate (9.6%) were found in CRO as well as RBR however in lesser content. Seven fatty acids in the descending order 41% oleic acid > 30% linoleic acid > 19% hexadecanoic acid > 8% 10-octadecenoic acid > 1% 9-octadecenoic acid > 0.6% pentadecanoic acid > 0.4% stearic acid were found in CRO and similarly in RBR. Interestingly, aqueous RBR extract and ethanolic CRO exhibited 45% and 26% tyrosinase-stimulating activity, respectively. Moreover, RBR extract also exhibited antioxidant activities at 6.36 mg TEAC/g (DPPH), 1.33 mg FeSO 4 /g (FRAP), 5.82 mg TEAC/g (ABTS) with total phenolic compound of 9.94 mg GAE /g and total flavonoid content of 67.2 mg CE/g. Conclusion: These bioactive compounds and bioactivities in CRO and RBR have a potential to promote hair growth and hair melanogenesis and thus proved useful as cosmetic ingredients in hair product development.