Polyphenolic profile and antioxidant properties of rhizome of commercial banana cultivars grown in India

In this present study, we probed the use of banana rhizome (BR), which is a bio-waste of banana plant as a source of polyphenols or antioxidants. Among the rhizome of eight commercial banana cultivars grown in India, cv. Nanjanagudu Rasabale (NR) displayed highest Total Phenolic Content (TPC), Total Flavonoid Content (TFC) and DPPH radical scavenging activity. Hence, cv. NR is used to study phenolic compounds and Antioxidant Activities (AOA) in detail. Acetone extract of BR showed high AOA in all the seven in vitro models tested, namely total reducing power, DPPH, superoxide, nitric oxide radical scavenging, β-carotene bleaching inhibition, anti-lipid peroxidation and hydrogen peroxide scavenging with an EC50 value of 6.5, 16, 27, 30, 33, 61 and 54 µg/mL respectively, whereas methanol extract exhibited high metal chelating activity (EC50 value 24 µg/mL). In addition, phenolic compounds viz., gentisic acid, (+) catechin, protocatechuic acid, caffeic acid, ferulic acid and cinnamic acid were identified by RPHPLC–DAD and ESI–MS. AOA of BR extracts correlated well with TPC and TFC, which indicates the important role of polyphenols into the overall AOA. This study reveals that BR can be used as potential source of natural antioxidants in food and pharmaceutical industries. The spectrum of rich bio-functional properties may be an impetus to increase the utilization of BR.

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