Phenolic content and antioxidant activity of cactus (Opuntia ficus-indica L.) flowers are modified according to the extraction method

•The effect of solvent and extraction method on various phenolic extracts was studied.•The methanol and water are the best effective solvent for antioxidants extraction.•The Soxhlet method is the most suitable for antioxidant extraction from cactus flowers. The effect of different extracting solvents used by two methods on the total polyphenols and flavonoids contents of Opuntia ficus-indica flowers was studied. The antioxidant activity of these extracts was investigated by using DPPH radical scavenging, reducing power and β-carotene bleaching assays. The results showed that extracts exhibited different levels of polyphenols contents and antioxidant activity. Thus, solvents with different polarities had significant effect on antioxidant activity. The methanolic and aqueous extracts proved best in terms of high extraction of phenolic compounds and antioxidant activity. Moreover, it can be concluded that extracts obtained by Soxhlet method were the most interesting in terms of antioxidant activity and proved that polyphenols responsible for the antioxidant activity of O. ficus-indica flowers are thermostable. These results showed that O. ficus-indica flowers could be a potential natural source of antioxidants that can be used in food and nutraceutical applications.