The inhibitory effects of anthocyanin-rich Thai berry extracts on carbohydrate digestion, glycation and adipogenesis

Abstract

Several studies have reported the benefits of anthocyanin-rich berries on improving human health. However, the effect of Thai berries on delaying carbohydrate digestion, antioxidant properties, glycation inhibition, and anti-adipogenesis have not been investigated. Therefore, the present study aimed to determine the potential of anthocyanin-rich Thai berry extracts from Antidesma bunius or Mamao (ABE), Lepisanthes rubiginosa or Mahuat (LRE) and Syzygium nervosum or Makiang (SNE) on the inhibition of carbohydrate digestive enzymes, the antioxidant activity, anti-glycation, and anti-adipogenic property. In this study, total phenolics, total anthocyanins, and cyanidin-3-glucoside (C3G) contents of the anthocyanin-rich Thai berry extracts were 237.90-300.91 mg GAE/ g extract, 32.45-66.86 mg C3G/ g extract, and 27.19-39.96 mg/ g extract, respectively. Besides, ABE and LRE also contained delphinidin-3-glucoside with values of 21.65 and 0.93 mg/ g extract, respectively. All extracts demonstrated inhibitory activity against intestinal maltase and sucrase with IC50 values of 0.79 -1.52 mg extract/ml and 1.34-1.65 mg extract/ ml, respectively. It was found that ABE exhibited better antioxidant properties than LRE and SNE. Therefore, ABE was further investigated on the antiglycation and antiadipogenic properties. It was found that ABE (0.25 mg/ml) significantly reduced the formation of fluorescence and non-fluorescence AGEs (NƐ-carboxymethyl lysine, NƐ-CML) in fructose and glucose-mediated protein glycation. ABE prevented protein oxidation by reducing the protein carbonyl content and inhibiting protein aggregation by decreasing the β-amyloid cross structure formation. Furthermore, ABE (16 µg/ml) prevented 3T3-L1 cell differentiation. It reduced the intracellular triglyceride accumulation by the inhibition of adipogenic transcription factor expression, C/EBPα. Pparγ receptor contributed to reducing the mRNA expression of acetyl-CoA carboxylase (ACC), fatty acid synthase (FASN), and lipoprotein lipase (LPL). These findings suggested that Thai berry extract in this study, especially ABE, can be useful as a promising natural compound for delaying carbohydrate digestion, decreasing the monosaccharide-induced protein glycation and oxidative protein damage, protein aggregation, and preventing adipogenesis.