THE EFFECT OF RADIATION PRESERVATION ON MACROMOLECULE CONTENT, ANTIMICROBIAL ACTIVITY AND RADICAL - SCAVENGING POTENTIAL OF PORTULACA OLERACEA L. LEAVES EXTRACT

Abstract

The Portulaca oleracea L. (P. oleracea) phytochemical composition (contains omega-3 fatty acids, quercetin, rutin, gallo tannins, proteins) is responsible for its biological effects, e.g. antioxidative, antibacterial, anti-inflammatory and antiradiation activity. The plant has a C4 metabolism and it is known for its tolerance to different stressors, such as salinity, no water, high - temperature conditions, and 9 kGy radiation. 
The purpose of the present investigation was focused on the inhibitory effects of P. oleracea leaves extracts against 5 - 10 kGy radiation - induced abiotic stress, and assess to total phenol, flavonoid, and tannins content; antibacterial potential (Staphylococcus aureus ATCC25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853) and antioxidant capacity. The free dried, powdered P. oleracea samples were 60Co irradiated, 50 % ethanol solvent (v/v) extracted and compared to 0 kGy extract. 10 kGy irradiated extract provide to be potentially effective against bacterial strains and possessed stable antioxidant activity, towards DPPH (p ˂ 0.002), ABTS•+ (p ˂ 0.05), FRAP (p ˂ 0.05) and NO (p ˂ 0.002). In addition, highly sensitive Electron Paramagnetic Resonance (EPR) was used to evaluate antiradical capacity. Single, symmetrical signal (g = 2.0023) was recorded in 10 kGy irradiated P. oleracea extract, comparable to the EPR signal in non-irradiated sample and depended directly on the antiradical potential. Moreover, in vitro P. oleracea inhibited the superoxide anion (•O2−), hydroxyl (•OH), alkyl radicals, and exhibited antioxidant properties against 10 kGy irradiation.