Anti‐adipogenic Effects of Anthocyanin‐enriched Riceberry Rice Extract (Oryza sativa L.) in 3T3‐L1 Preadipocytes

Abstract

Riceberry rice containing anthocyanins is a new pigmented variety of rice from Thailand with various biological activities such as antioxidant, anti‐inflammatory, anti‐hyperglycemia, and anti‐cancer. The present study aimed to investigate the effects of Riceberry rice extract (RBE) on adipogenic differentiation in mice 3T3‐L1 cells. RBE was obtained using water followed by freeze dryer lyophilization. Then, total phenolic compounds, total anthocyanin contents, and major anthocyanins in RBE were analyzed. The 3T3‐L1 preadipocytes were cultured in differentiation media and supplemented with RBE 1, 10, 20 and 50 μg/ml concentrations. After 8 days of incubation, cell viability, mature adipocyte number, triglyceride levels, and glucose uptake were determined. The mRNA expression of transcription factors and adipogenic genes including PPARγ, C/EBPα, FasN, ACC, aP2, AdipoQ, Leptin, Resistin, InsR, and Glut4 were also examined. The results revealed that RBE contained total phenolic compounds (63.33±2.4 mg gallic acid equivalent/g extract) and total anthocyanin (10.13±0.14 mg cyanidin‐3‐glucoside/g extract). The anthocyanins detected were cyanidin‐3‐glucoside and peonidin‐3‐glucoside. In 3T3‐L1 cells, RBE significantly reduced the number of mature adipocytes and triglyceride accumulation in a concentration‐dependent manner. In addition, the treatment of 3T3‐L1 cells with the various RBE concentrations did not cause cytotoxicity. Furthermore, the mRNA expression of major transcription factors, PPARγ and C/EBPα were significantly downregulated by RBE (20 and 50 μg/ml) in both early phase (day 3) and late phase (day 8) of adipogenesis. At 50 μg/ml RBE, there was a significant reduction in mRNA expression levels of all adipogenic genes. Interestingly, RBE (10, 20 and 50 μg/ml) significantly reduced glucose uptake into adipocytes via downregulated InsR and Glut4 mRNA expression. These findings suggest that RBE could potentially be used as an anti‐obesity agent by inhibiting adipogenesis and reducing glucose uptake in adipocytes.Support or Funding InformationDutsadi Phiphat Scholarship from Chulalongkorn University, LSU‐SVM CORP