Identification and characterization of phenolic antioxidant compounds from brown Irish seaweed Himanthalia elongata using LC-DAD-ESI-MS/MS

摘要

This study investigated Himanthalia elongata Irish seaweed as a natural resource for antioxidant compounds. The phenolic compounds from the seaweed were extracted using 60% (v/v) aqueous methanol and the crude methanolic extract was purified with liquid-liquid partition (LW) followed by column chromatography (CC). Among the purified fractions/sub-fractions, LIP-CC-ethyl acetate sub-fraction exhibited the highest DPPH (2,2-diphenyl1-picrylhydrazyl) scavenging (EC50, 2.4 mg/g) and lipid peroxidation (LPO) scavenging capacity (97.7%). Rapid characterization of the same sub-fraction by LC-DAD-ESI-MS/MS identified a total of 8 phenolic compounds namely hydroxybenzaldehyde (meta/para), phloroglucinol, kaempferol, cirsimaritin, gallic acid 4-O-glucoside, carnosic acid and gallic acid. The purified sub-fractions showed higher antioxidant capacity (P < 0.05) than the reference ascorbic acid, suggesting its possible application in foods, pharmaceuticals and cosmetics for health promotion. Contributions of the study include identification of compounds (except gallic acid) that have not previously been reported in H. elongata, identifying it as a rich source of phenolic antioxidant compounds.