Abstract
The rise in global coffee consumption has increased spent coffee grounds (SCG), a by-product rich in bioactive compounds. This study compared the anti-adipogenic and antioxidant activities of SCG extracts before (SCG) and after fermentation (FSCG) with Aspergillus oryzae. SCG showed higher antioxidant activity and total polyphenol content than FSCG. In vitro studies on 3T3-L1 adipocytes revealed that SCG significantly inhibited lipid accumulation and downregulated key adipogenic markers (PPARγ, C/EBPα, adiponectin) in a dose-dependent manner, while FSCG had limited effects. Thin-layer chromatography indicated fermentation decreased chlorogenic acid and increased caffeic acid, suggesting structural changes in bioactive compounds. The superior anti-adipogenic effect of SCG is likely due to chlorogenic acid, which degrades during fermentation. These findings highlight SCG's potential as a functional food ingredient with anti-obesity and antioxidant properties. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-025-01886-z.