Evaluation of some in vitro bioactivities of sunflower phenolic compounds

Phenolic compounds in crude extracts were obtained from defatted sunflower seed flour using sodium bisulfite and ethanol solutions as extracting agents. The antioxidant, antimicrobial, anti-proliferative, and DNA protective activities of the phenolic compounds in crude extract were analyzed. The phenolic compound contents were determined as chlorogenic acid (CGA) equivalent, presenting 11.57 and 15.44 g CGA eq/100g regarding the sodium bisulfite extract and ethanolic extract, respectively. The ORAC, DPPH, and ABTS methods were used to evaluate antioxidant activity. Both extracts presented antioxidant properties, considering that the ethanolic extract demonstrated higher values (EC₅₀ 0.36 g extract/g DPPH•). The antimicrobial action was analyzed as to the minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) of 4 kinds of bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis). The ethanolic extract was effective against all of these microorganisms, out of which E. coli was the most sensitive, with a MIC of 11.6 mg CGA/mL. The ethanolic extract presented DNA protective activity without cytotoxic activity concerning in vitro anti-proliferative assay. These findings can be considered as initial evidence of the potential use of phenolic compounds obtained from sunflower seed flour as natural additives in the food industry.