In-vitro evaluation of antioxidant and antiradical potential of successive extracts, semi-purified fractions and biosynthesized silver nanoparticles of Rumex vesicarius

The aim of the present study was to assess in vitro the antiradical and antioxidant activities of successive extracts and semi-purified fractions from Rumex vesicarius L. In the present work, three extracts (n-Hexane, ethyl acetate and methanol) and 22 column fractions of methanolic extract (as promising extract) were evaluated against 2,2-diphenyl- 1-picrylhydrazyl (DPPH•) and 2,2-azinobis (3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS) radical scavenging methods as antiradical and antioxidant activities compared with Butylated hydroxytoluene (BHT) as synthetic standard and silver nanoparticles of methanolic extract (Ag-NPs-Me), in addition to analysis of   chemical constituents of extract and fraction using Gas chromatography–mass spectrometry (GC-MS). The obtained results revealed that, both methods go parallel showing that the concentration of extract and incubation time are dependent and proportional with phenolic compounds concentration.  Absolute methanol extract recorded the highest antioxidant activity when compared with the other crude extracts with 79.3 and 78.8% against DPPH and ABTS respectively when compared with BHT as synthetic standard (89.4 and 89.9%) against DPPH and ABTS respectively. Calculation of the antiradical activity units showed the highest values of methanolic extract and its promising fraction (No. 12) after 300 seconds (5 minutes) comparing with antioxidant activity (30 min). Also, the antioxidant activity increased with synthetic Ag-NPs-Me when compared with methanolic extract by (IC50= 53.9 and 74.6 µg/ml respectively).  Thus, the GC-MS analysis of successive extracts of R. vesicarius L showed a highly complex profile, containing approximately 24 different components. One pure compound was identified from fraction No. 12. The identified compound was l-(+)- ascorbic acid 2, 6-dihexadecanoate. The data also revealed presence of closely similar antioxidant activities in methanolic extract or its pure compounds with BHT when mixed at different proportions. From the obtained results it could be concluded that R. vesicarius methanolic extracts and fractions can be extensively used in the production of potential antioxidant, antiradical and AgNPs-Me for biomedical application on the consumer’s health.