Evaluation of different extraction methods (maceration and ultrasound) on antioxidant, anti-Alzheimer's and antimicrobial properties of Padina distromatic extract

Promising secondary metabolites of brown algae have been given particular importance, due to their various biological activities. In the present study, two extraction methods including maceration and ultrasound were performed to prepare extracts from brown algae including Padina distromatic, then, aimed to evaluate antioxidant, antimicrobial, and anti-Alzheimer’s activities of extracts. Padina algae extract prepared by ultrasound method had higher total phenol (43.25 mg GAE/g) and flavonoid content (24.59 mg QE/gDA). However, the maximum antioxidant activity was observed in algae extract prepared by maceration method. Padina algae extract prepared by ultrasound method had the highest inhibitory activity of acetylcholinesterase and the strongest inhibition of nitric oxide production was observed in this extract. Escherichia coli and Listeria innocua bacteria were more resistant to Padina algae extract than other microorganisms and the results of microbial test showed that Padina algae extract prepared by ultrasound method was more antimicrobial than maceration method. Collectively, the obtained results provide valuable evidence for antioxidant, anti-Alzheimer, and antimicrobial activity driven by Padina distromatic extracts which can highlight their possible approach in the therapeutic utilization.