Assessment of total phenolic and flavonoid contents of selected fruits and vegetables

This work was conceptualized with the goal to investigate different fruits and vegetables for their comparative investigation of total phenolic and total flavonoid contents. The total phenolic content of 9 fruits and 12 vegetables used in the current study was determined by Folin-Ciocalteau assay. In addition, total flavonoid content was identified through catechin and aluminum colorimetric analysis. The ratio among the phenolic and flavonoid contents of fruits and vegetables extracts were also analyzed. Our results showed that methanolic extract of Citrullus lanatus had higher contents of phenolics and flavonoids (215 +/- 1.24 mg GAE/100 g and 73 +/- 0.81 mg CE/100 g) than other fruits. Moreover, maturity process of fruits from unripened to fully ripened stage showed significant increase in the total phenolic and flavonoid contents. Fruits under study had shown flavonoids/phenolics ratio of 0.32, which indicates that these fruits contained about 32% of flavonoid contents. Among vegetables, the greatest value of phenolic contents was observed in Capsicum annuum (213 +/- 1.24 mg GAE/100 g), and total flavonoid content in Raphanus sativus (45 +/- 1.24 mg CE/100 g). Vegetables showed lower ratios of flavonoids/phenolics (0.11-0.2) indicating lesser total flavonoid content (11-20%) as compared with fruits. The obtained results indicate that fruits and vegetables could be attributed to a potential source of natural phenolics and flavonoids in the pharmaceutical and food industry. Moreover, the antioxidant activities of these selected fruits and vegetables should also be determined in order to explore their beneficial effects against the prevention and management of disorders caused by oxidative stress.