Grain–Oolong Tea Fermented Beverage Attenuates Adipogenesis-Related Phenotypes in 3T3-L1 Adipocytes

Obesity is a major global health concern, and functional fermented foods have attracted increasing attention for their potential metabolic benefits. Grain–oolong tea fermented beverage (GOFB), produced through a two-step spontaneous fermentation process, is rich in fermentation-derived bioactive compounds; however, its effects on adipogenesis remain unclear. In this study, we investigated the effects of GOFB on adipogenesis-related phenotypes in 3T3-L1 adipocytes. The results showed that GOFB exhibited antioxidant activity in vitro and significantly reduced intracellular reactive oxygen species and lipid peroxidation in MDI-induced adipocytes. GOFB treatment was associated with reduced cell proliferation, lipid accumulation, and triacylglycerol content in 3T3-L1 adipocytes. In addition, GOFB was associated with attenuated adipogenic responses, accompanied by reduced expression of genes related to RAS, ERK, c-Myc, cyclin D1, SREBP-1c, PPAR-γ, C/EBP-α, NCoR1, and FAS. Collectively, these findings suggest that GOFB is associated with attenuated adipogenic responses in 3T3-L1 adipocytes and support its potential application as a functional fermented beverage.