Giulia Corona1,2, Maria Magdalena Coman2,3, Yuxuan Guo2, Sarah Hotchkiss4, Chris Gill5, Parveen Yaqoob2, Jeremy P E Spencer2, Ian Rowland2. 1. Health Sciences Research Centre, University of Roehampton, London, UK. 2. Department of Food and Nutritional Sciences, University of Reading, Reading, UK. 3. School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, (MC), Italy. 4. CyberColloids Ltd. Carrigaline Industrial Estate, Carrigaline, County Cork, Northern Ireland. 5. Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, Northern Ireland.
Abstract
SCOPE: Unlike other classes of polyphenols, there is a lack of knowledge regarding brown seaweed phlorotannins and their bioactivity. We investigated the impact of in vitro gastrointestinal digestion and colonic fermentation on the bioactivity of a seaweed phlorotannin extract from Ascophyllum nodosum and its high molecular weight (HMW) and low molecular weight (LMW) fractions. METHODS AND RESULTS: The highest phlorotannin and total polyphenol (TP) concentration was observed in the HMW fraction. Antioxidant capacity broadly followed phlorotannin and TP levels, with HMW having the highest activity. Both gastrointestinal digestion (GID) and colonic fermentation (CF) significantly affected phlorotannin and TP levels, and antioxidant capacity of the extract and fractions. Despite this, in HT-29 cells, all GID extracts significantly inhibit cell growth, whereas CF extracts effectively counteracted H2 O2 induced DNA damage. CONCLUSION: Although phlorotannins, TP levels and antioxidant power of the extracts were strongly reduced after in vitro digestion and fermentation, their anti-genotoxic activity and cell growth inhibitory effect in colon HT-29 cells was maintained and enhanced. HMW was the most effective fraction, indicating that the high molecular weight phlorotannins potentially exert a stronger beneficial effect in the colon.
SCOPE: Unlike other classes of polyphenols, there is a lack of knowledge regarding brown seaweed phlorotannins and their bioactivity. We investigated the impact of in vitro gastrointestinal digestion and colonic fermentation on the bioactivity of a seaweed phlorotannin extract from Ascophyllum nodosum and its high molecular weight (HMW) and low molecular weight (LMW) fractions. METHODS AND RESULTS: The highest phlorotannin and total polyphenol (TP) concentration was observed in the HMW fraction. Antioxidant capacity broadly followed phlorotannin and TP levels, with HMW having the highest activity. Both gastrointestinal digestion (GID) and colonic fermentation (CF) significantly affected phlorotannin and TP levels, and antioxidant capacity of the extract and fractions. Despite this, in HT-29 cells, all GID extracts significantly inhibit cell growth, whereas CF extracts effectively counteracted H2 O2 induced DNA damage. CONCLUSION: Although phlorotannins, TP levels and antioxidant power of the extracts were strongly reduced after in vitro digestion and fermentation, their anti-genotoxic activity and cell growth inhibitory effect in colon HT-29 cells was maintained and enhanced. HMW was the most effective fraction, indicating that the high molecular weight phlorotannins potentially exert a stronger beneficial effect in the colon.
Authors: João Cotas; Adriana Leandro; Pedro Monteiro; Diana Pacheco; Artur Figueirinha; Ana M M Gonçalves; Gabriela Jorge da Silva; Leonel Pereira Journal: Mar Drugs Date: 2020-07-24 Impact factor: 5.118