Anthocyanins reduce inflammation and improve glucose and lipid metabolism associated with inhibiting nuclear factor-kappaB activation and increasing PPAR-γ gene expression in metabolic syndrome subjects

Abstract

Anthocyanins exhibit antioxidant and anti-inflammatory activities via a multitude of biochemical mechanisms. However, the signaling pathways involved in the actions of anthocyanins against chronic inflammation are not fully understood.The effects of berry-rich anthocyanin supplements (320 mg/day) for four weeks were examined on features of metabolic syndrome components and the expression of PPAR-γ, Nrf2, and NF-κB dependent genes in MetS and healthy subjects. Total RNA was isolated from whole blood with the PAXgene proprietary blood collection system.Four weeks anthocyanin consumption significantly decreased fasting blood glucose (15.7% vs 3.2%), TG (18.2% vs -1.39%), cholesterol (33.5% vs 1.56%) and LDL (28.4% vs -15.6%) in the MetS compared to Control group (P-value < 0.05, 95% CI). There was a significant up regulation in the expression PPAR-γ gene associated with the lipid and glucose metabolism in MetS subjects which negatively correlated (P-value < 0.01) with the change in the FBG (r = -0.488), Cholesterol (r = -0.496), TG (r = -0.513) and LDL (r = -0.519). Moreover, anthocyanin supplementation decreases serum hs-CRP (-36.3% vs 6.25%) in MetS in compared to Control group (P-value < 0.05). Anthocyanin supplementation also down-regulated the expression of NF-κB dependent genes including TNF-α (-28% and -15%), IL-6 (-16.1% and -13.6%), IL-1A (-21.5% and -12.9%), PCAM-1 (-15% and -17.5%), and COX-2(-26% and -27%) in both MetS and Control group respectively (P-value < 0.05).The study results suggested that berry supplements improved selected features of metabolic syndrome and related cardiovascular risk factors. These benefits may be due to the inhibition of NF-κB dependent gene expression and enhancement of PPAR-γ.