Polyphenols of pseudostem of different banana cultivars and their antioxidant activities.

The present investigation is focused on potential use of banana pseudostem (BPS), which otherwise is disposed off as a waste or incinerated, as a source of polyphenols or antioxidants. The total phenolics (TP) and total flavonoids (TF) in various solvent extracts of pseudostem (PS) of different banana cultivars varied from 7.58 to 291 mg gallic acid equivalent (GAE/g of extract) and from 4 to 80 mg catechin equivalent (CE/g of extract), respectively. Acetone extract showed high antioxidant activity (AOA) in all of the in vitro models tested, whereas methanol extract exhibited high metal chelating activity. Among the banana cultivars, Nanjanagudu Rasabale (NR) showed the highest TP (291 mg GAE/g of extract), TF (80 mg CE/g of extract), and AOA. A detailed study on phenolic acids by reverse phase HPLC and ESI-MS revealed the presence of phenolic acids such as gentisic acid, (+)-catechin, protocatechuic acid, caffeic acid, ferulic acid, and cinnamic acid in cultivar NR. The differences in AOA of banana cultivars are in accordance with their phenolic and flavonoid concentrations.