Extraction of polyphenols in Himanthalia elongata and determination by high performance liquid chromatography with diode array detector prior to its potential use against oxidative stress

•This study demonstrates the potential use of polyphenols from Himanthalia elongata seaweed against cell damage caused by oxidative stress.•The paper shows a throughout optimization of the variables influencing the extraction of polyphenols and the resulting antioxidant activity.•Results obtained show a high antioxidant activity of the extract (76%) and the characterization of its polyphenols by HPLC-DAD.

Several studies have demonstrated the antioxidant capacity of seaweeds, which can be used for the development of biopharmaceuticals with extensive medical application. Antioxidant therapies appear to attenuate the organic deterioration originated by an excessive oxidative stress, which could prevent the harmful effects of various injuries such as ischemia-reperfusion (I/R) among others. Marine brown seaweeds play a significant role, as they are the only organisms on earth producing phlorotannins, which are polyphenols that exhibit important biological activity. To ensure obtaining an extract with the greatest antioxidant activity, some variables that affect the extraction of polyphenols are optimized, including seaweed amount, type of solvent, and time and temperature of extraction. Subsequently, the total phenolic content (TPC) and the antioxidant activity have been determined. The optimized condition was obtained for 6 g of seaweed, ethanol: water proportion of 60:40 and 2 h/60 °C, achieving 548.33 mg AG/100 g seaweed and 76% of antioxidant activity. The characterization of the extracted polyphenols was made by HPLC/DAD. 11 polyphenols were identified in the extract: Phloroglucinol, Gallic Acid, Catechin, Rutin, Gentisic Acid, Chlorogenic Acid, Caffeic Acid, Coumaric, Ferulic, Myricetin and Quercetin.