Total phenol and antioxidant activity of some fruits and their under-utilized parts

Some fruits and their under utilized parts were evaluated for total phenolic contents (TPC), antioxidant (AOA) and free radical scavenging activities (FRSA). The leaves (73.8 mg/g) and fruits of Phoenix sylvestris, fruits of Ziziphus jujuba, Syzygium cumini and Zanthoxyllum acanthopodium and leaves of Protium serratum were found to have high amounts of TPC (69.4 mg/g to 128.6 mg/g GAE). The inflorescence and leaves of Phoenix sylvestris, fruits of Protium serratum, Syzygium cumini and Psidium guajava were found with reasonably good AOA (60.7% to 84.9%). Plants with promising AOA were further investigated for FRSA using DPPH free radical assay in terms of inhibitory concentration (IC50), efficiency concentration (EC50), anti radical power (ARP) and reducing power (RP). Promising fruit samples were further subjected to concentration-dependent FRSA using different methods and expressed in terms of IC50 values. Fruit extracts (20 μg/ml) of Phoenix sylvestris, Protium serratum and leaves of Zanthoxyllum acanthopodium effectively prevented DNA nicking studied on pBR322 DNA. The fruits of Passiflora edulis were found to be good source of caffeic acid, fruits of Phoenix sylvestris of chlorogenic acid, Phoenix sylvestris, Protium serratum and leaves of Zanthoxyllum acanthopodium were rich in gallic acid. The identification of specific polyphenols was further substantiated by MS/MS analysis.