In vitro antioxidant properties of free and bound phenolic extract of Celosia argentea, Corchorus olitorius, Amaranthus hydridus and Jatropha tajorensis

Abstract

Polyphenols have attracted a lot of interest recently due to their antioxidant property. The present study is aimed at investigating the antioxidant properties of free and bound phenols of methanol leaf extracts of Celosia argentea, Corchorus olitorius, Amaranthus hydridus and Jatropha tajorensis. Total flavonoids and phenolic contents of the extracts was determined using spectrophotometric method while the antioxidant activity of crude extract, free and bound phenols (FP and BP) was determined using 2,2 diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The flavonoid contents ranged between 35.90±4.89 mg/100g in C. olitorius to 292.67±8.39 mg/100g in A. hydride while the phenolic contents ranged from 264.43±4.47 mg/100g in J. tajorensis to 431.98±4.90 mg/100g in C. argentea. The DPPH scavenging activity of the crude, free and bound phenolic extracts of the extratcs gave an IC50 of 383.52±1.05, 114.66±3.24 and 279.06±4.51 µg/mL for crude, FP and BP for J. tajorensis respectively, 331.29±1.33, 109.74±3.86 and 195.89±5.12 µg/mL for crude, FP and BP of C. argentea respectively, 379.46±3.11, 180.34±3.12 and 227.50±4.34 µg/mL for crude, FP and BP of C. olitorius respectively and 136.34±2.05, 135.47±1.88, 193.95±3.56 µg/mL for A. hydridus respectively which are significantly higher (p<0.05) with the standard (Ascorbic acid) with an IC50 of 12.66±3.33 µg/mL. From the result obtained, it is rational to attribute the wide usage of these vegetables in folkloric medicine to its high phenolic content. Hence, information from this study could be exploited in the global fight against degenerative diseases, whose etiology has been linked to oxidative stress.