272: Pyranoanthocyanins Surpass Efficacy of Anthocyanins in Reduction of Inflammation Under Hypoxic Conditions In Vitro

Introduction

Oxygen deficient environment (hypoxia) induces key inflammatory processes in degenerative and infectious diseases by activating inflammatory NF-kB transcription. Studies have shown that dietary bioactive compounds affect the inflammatory process by modulating gene expression through NF-kB stimulation. Anthocyanins are bioactive compounds in a subgroup of flavonoids with reported anti-inflammatory properties, and are responsible for the blue, purple and red colors of many plants. Pyranoanothocyanins are anthocyanin derived pigments with increased color stability, typically found in red wine, that offer potential as food colorants. However, limited information is available about their bioactivity. In this study, anti-inflammatory activity of anthocyanins and pyranoanthocyanins were compared in experimentally induced hypoxia in-vitro. 

Methods

Anthocyanins from highbush blueberries and black currant were extracted and semi-purified using solid phase extraction. Pyranoanthocyanins were prepared by mixing anthocyanins and 4-vinylphenol (3:1 molar ratio, pH 3.1) and incubated at 45°C for 4 days. Identities and purity were monitored by using UHPLC-PDA-ESI-MS/MS. Inflammation was examined in fibroblast cells (reporter cell lines 3T3 PMID:24039005) treated with anthocyanins or pyranoanthocyanins (0 – 100 nM) during differentiation of 3T-L1NFRE preadipocytes into adipocytes with or without cobalt chloride inducing hypoxic state. NF-kB dependent activation was quantified by measuring the expression of green fluorescence reporter protein (GFP) and normalized to protein concentration.

Results

Hypoxic conditions resulted in a significant reduction in cell number, cell size and showed higher NF-kB stimulation. Both anthocyanins and pyranoanthocyanins treatment decreased NF-kB stimulation however pyranoanthocyanins demonstrated greater ability (> 2X) to reduce NF-kB stimulation as compared to anthocyanins. This effect was observed at a minimal concentration of 9nM pyranoanthocyanins, highlighting their enhanced potential, likely due to its chemical structure featuring an additional hydroxylated ring which might enhance its anti-inflammatory activity. Our finding suggested pyranoanthocyanins may reduce hypoxic inflammation by suppressing NF-kB stimulation.

Significance

Results suggest higher anti-inflammatory activity of pyranoanthocyanins than their precursor anthocyanins. Therefore, there is potential for producing food colorants, offering the dual advantage of vibrant coloration and improved health benefits, paving the way for functional and wellness-focused food innovations.

Authors: Harmeen Prasher, Patrick Sellers, Ouliana Ziouzenkova, M. Monica Giusti