Evaluation of Total Phenolic Content in Relation to Antioxidant Activity of Brown Algae Cystoseira barbata from Black Sea

Abstract

Seaweeds are widely used in the life science as source of compounds with diverse structural forms and biological activities, therefore, potential source of new antioxidant activity. The algae of the Black Sea have not been adequately explored for their potential as a source of bioactive substances. In this context, Brown algae Cystoseira barbata isolated from Black Sea coastal waters of Romania, were evaluated for their bioactivity potential. The results from Cystoseira barbata were obtained: for total phenolic content obtained in ethanolic extracts (TPC): 385.6 ± 1.85 mg GAE/100 g f.w. Phenolic Acids quantified by HPLC-DAD from hydroethanolic extract of Cystoseira barbata from Black Sea was 80.14% from total phenolic content identified. We showed that Cystoseira barbata from the Romanian shore of the Black Sea contains vanillic acid in highest quantity (99.5±0.08 mg/100 g f.w.), followed by benzoic acid (65.7±0.06 mg/100 g f.w.) and feluric acid (54.5±0.01 mg/100 g f.w.). The smallest quantities were for gallic acid (3.5±0.03 mg/100 g f.w.), pyrogallol acid (4.2±0.05 mg/100 g f.w.) and 4-amino-benzoic acid (5.2±0.09 mg/100 g f.w.). Cystoseira barbata has a total content of large phenols and also has strong antioxidant and antimicrobial activity. Antioxidant activity (ACL) was studied using DPPH radical scavenging activity and reducing power. The extracts containing high levels of total phenolic content were also potent DPPH radical scavengers. The IC50 (ìg/mL) for Cystoseira barbata in methanolic extract was 942.92± 2.56 ìg/mL. High absorbance obtained from reducing power assay indicates high reducing power, measured values of absorbance varied from 0.0901 at 0.9223.