Phlorotannins from Brown Algae: inhibition of advanced glycation end products formation in high glucose induced Caenorhabditis elegans

Advanced Glycation End products (AGE) generated in a non enzymatic protein glycation process are frequently associated with diabetes, aging and other chronic diseases. Here, we explored the protective effect of phlorotannins from brown algae Padina pavonica, Sargassum polycystum and Turbinaria ornata against AGEs formation. Phlorotannins were extracted from brown algae with methanol and its purity was analyzed by TLC and RP-HPLC-DAD. Twenty five grams of P. pavonica, S. polycystum, T. ornata yielded 27.6 +/- 0.8 mu g/ml, 37.7 mu g/ml and 37.1 +/- 0.74 mu g/ml of phloroglucinol equivalent of phlorotannins, respectively. Antioxidant potentials were examined through DPPH assay and their IC50 values were P. pavonica (30.12 +/- 0.99 mu g), S. polycystum (40.9 +/- 1.2 mu g) and T. ornata (22.9 +/- 1.3 mu g), which was comparatively lesser than the control ascorbic acid (46 +/- 0.2 mu g). Further, anti-AGE activity was examined in vitro by BSA-glucose assay with the extracted phlorotannins of brown algae (P. pavonica, 15.16 +/- 0.26 mu g/ml; S. polycystum, 35.245 +/- 2.3 mu g/ml; T. ornata, 22.7 +/- 0.3 mu g/ml), which revealed the required concentration to inhibit 50% of albumin glycation (IC50) were lower for extracts than controls (phloroglucinol, 222.33 +/- 4.9 mu g/ml; thiamine, 263 mu g/ml). Furthermore, brown algal extracts containing phlorotannins (100 mu l) exhibited protective effects against AGE formation in vivo in C. elegans with induced hyperglycemia.