Anti-adipogenic effects of flavonoids and stilbenoids on adipocyte differentiation, lipid accumulation and adipogenic markers in a 3T3-L1 cell line.

Obesity is a major global health challenge characterized by excessive expansion of adipose tissue mass, driven in part by dysregulated adipogenic differentiation. Targeting adipogenesis has therefore emerged as a promising strategy to limit adipose tissue expansion and associated metabolic disorders. Naturally occurring polyphenols, particularly flavonoids and stilbenoids, exhibit anti-adipogenic properties through multiple mechanisms; however, the molecular determinants underlying their activity remain insufficiently defined. In this study, the anti-adipogenic potential of a panel of 16 structurally related flavonoids and 2 stilbenoids was evaluated using the 3T3-L1 pre-adipocyte differentiation model. Experimental conditions were carefully optimized to ensure biological robustness, including cell passage number, dimethyl sulfoxide (DMSO) concentration, and differentiation timing. Following cytotoxicity screening, adipogenic differentiation was assessed by Oil Red O staining and enzymatic quantification of intracellular triacylglycerides. Compounds showing significant inhibitory effects were further characterized by Western blot analysis of key adipogenic and lipid-handling proteins (C/EBPβ, PPARγ, FABP4, and ATGL), with transcriptional regulation evaluated by RT-qPCR for selected compounds. The results indicate that the tested compounds predominantly interfered with late stages of adipogenic differentiation, as C/EBPβ expression was largely preserved. Among the compounds evaluated, C10 (a synthetic 3-decyl-3',4',5,7-tetrahydroxyflavone) and piceatannol (C18) emerged as the most effective inhibitors of lipid accumulation. C10 markedly suppressed PPARγ isoforms, FABP4, and ATGL in a concentration-dependent manner, whereas piceatannol (C18) primarily reduced lipid accumulation through sustained FABP4 suppression with minimal effects on PPARγ. Overall, these findings highlight C10 and piceatannol (C18) as promising modulators of adipogenic differentiation and emphasize the importance of structure-activity relationships in shaping anti-adipogenic efficacy.