Cyanidin is the most abundant
anthocyanin found in red-purple plants and possesses anti-
obesity properties. However, its mechanism of action in adipocytes remains unknown. The objective of this study was to elucidate how
cyanidin inhibits adipocyte formation in 3T3-L1 preadipocytes. Cells were cultured in adipogenic differentiation medium supplemented with
cyanidin and examined for adipogenesis, cell viability, and adipocyte gene expression using
Oil Red O staining, MTT assay, and RT-qPCR. Real-time Ca2+ imaging analysis was performed in living cells to elucidate
cyanidin's mechanism of action. The results demonstrated that
cyanidin (1-50 μM) supplementation to the adipogenic medium inhibited adipogenesis by downregulating adipogenic marker gene expression (PPARγ, C/EBPα,
adiponectin, and aP2) without affecting cell viability after 4 days of treatment. Stimulation of cells with
cyanidin (30-100 μM) increased intracellular Ca2+ in a concentration dependent manner with peak
calcium increases at 50 μM. Pretreatment of cells with the
phospholipase C (PLC) inhibitor
U73122,
inositol triphosphate (
IP3) receptor blocker 2-APB, and depletion of endoplasmic reticulum Ca2+ stores by
thapsigargin abolished the Ca2+ increases by
cyanidin. These findings suggested that
cyanidin inhibits adipocyte formation by activating the PLC-IP3 pathway and intracellular Ca2+ signaling. Our study is the first report describing the mechanism underlying the anti-
obesity effect of
cyanidin.