The evaluation of fermented broken rice, brewers' rice and rice bran extracts on anti-photoaging and anti-pigmentation potential using in vitro monoculture and co-culture models

Abstract

Agricultural by-products have drawn scientific interest as an economic resource for the production of high-value products. Thus, this study evaluated Aspergillus oryzae-fermented rice by-products : fermented broken rice (FBR), brewers’ rice (FBrR), and rice bran (FRB) extracts for anti-photoaging and anti-pigmentation potential using in vitro monoculture and indirect co-culture models. Fermented extracts were tested for their effect on collagenase-1 (MMP-1) levels, intracellular elastase activity and collagen synthesis in UVA- and UVB-exposed cells in the anti-photoaging study. While anti pigmentation study assessed their effects on melanin content and intracellular tyrosinase activity in human melanoma cells. The expression level of photoaging associated (MMP-1, SFE, COL1A1 and ELN) and melanogenic-related (TYR, TRP-1 and TRP-2) genes was also evaluated using qPCR analysis. The cytokines (TNF-a, IL-1ß and IL-6) levels in co-cultures were also measured using enzyme-linked immunosorbent assay (ELISA), including ET-1 growth factor in the anti-pigmentation co-cultures. Anti-photoaging studies revealed that fermented extracts were more effective at preventing the degradation of type-1 collagen and elastin via inhibition of MMP-1 and elastase than at promoting the production of both components. In UVA-and UVB-irradiated monoculture fibroblasts, fermented extracts exhibited significant elastase inhibitory activity via downregulation of SFE gene expression (p<0.05). In co-culture experiments, however, the anti-photoaging effect was variable, with the studied extracts inhibiting MMP-1 secretion and elastase activity significantly (p<0.05) despite varying MMP-1 and SFE gene expression in UVA-irradiated co-culture. While in UVB exposed co-culture, MMP-1 suppression was significant spanning from 22.28% to 66.86% via MMP-1 gene downregulation (p<0.05). Monoculture anti-pigmentation studies indicated FBR extracts significantly lowered intracellular tyrosinase activity and TYR gene expression in melanoma cells, whereas FRB (50 µg/mL) inhibited 17.17% of tyrosinase activity without affecting TYR gene expression (p<0.05). Conversely, the fermented extracts exhibited anti-pigmentation potential through significant inhibition of tyrosinase activity through downregulation of TYR, TRP-1 and TRP-2 gene expression in UVA and UVB-irradiated co-cultures (p<0.05). Overall findings showed anti-photoaging and anti-pigmentation mechanisms by FBR, FBrR and FRB varied between monocultures and co-cultures. It may be influenced by paracrine interactions in the co-culture system, where modulation of TNF-a, IL-1ß, IL-6 and ET-1 production by the studied extracts may also partially contribute to anti-photoaging and anti-pigmentation effects. In conclusion, FBR, FBrR and FRB may be attractive bioingredients that could be further explored for usage in cosmetic applications.