This study reports for the first-time antioxidant activity and flavonoid composition of KP onion landrace whichis useful for future breeding programs and to obtain geographical indication (GI) tag for the benefit of farmers.The present study was aimed to determine antioxidant capacity and flavonoid composition of bulbs of redonion (Allium cepa L.) landrace ‘Krishnapuram’ (KP) from India using high-performance liquid chromatography(HPLC)-Electrospray Ionization (ESI)-multistage Ion Trap Mass Spectrometry (ITMS). Theantioxidant activity was assayed by Ferric Reducing Antioxidant Power (FRAP) and hypochlorous acid(HClO)-induced oxidative damage in human erythrocytes. The total phenolic (TPC) contents in KP onion bulbextract (with 80% methanol) found to be 1.10 ± 0.2 mg GAE/g FW and 38.88 ± 1.0 micro-M QE/g. The FRAPactivity measured for the bulb extract was 13.20 ± 0.1 micro-M QE/g. KP onion bulb extracts protected red bloodcells (RBC) effectively (23%) against the oxidative damage induced by HClO. HPLC-ESI-ITMS analysisshowed the presence of eight flavonols and five anthocyanins. Quercetin 3,40-O-diglucoside (384.71 ± 0.49mg/kg FW) and cyanidin 3-(600-malonylglucoside) (20.95 ± 0.60 mg/kg FW) were detected as major flavonoland anthocyanin, respectively. The study suggests that KP onion has a considerable antioxidant activity due tothe presence of high TPC. Moreover, quercetin glucosides are found to be more abundant than quercetin. Thedifferences in quercetin glycosides content among different red onions could be useful for breeding programmesin the future.
Volume 46, 2020
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