Radical scavenger and Antioxidant activities of extracts and fractions from Bulgarian Ononis spinosa L. and GC-MS analysis of Ethanol extract

Extracts and fractions from Ononis spinosa roots were investigated for their radical scavenging activity using two different in vitro assays, 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) and 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The antioxidant potential measurements were expressed as Trolox equivalent antioxidant capacity (TEAC). The chloroform fraction possessed the highest radical scavenging activity (RSA) in both assays, DPPH (0.235 mmol g) and ABTS (0.264 mmol g). Total phenolic content was also determined using Folin–Ciocalteu reagent. The greatest total phenolic content was detected in the EtOAc and CHCl3 fractions from EtOH extract (108.7 mg/g GAE and 102.1 mg/g GAE, respectively). A correlation between radical scavenging capacities of samples with total phenolic compound content was not observed. GC-MS analysis of CHCl3 fraction showed that the triterpene 9, 19-cyclo-27-lanostan-25-on was the major constituent (13.17%), followed by s-sitosterol (9.61%), medicarpin (9.4%), maackiain (8.01%) and linolic acid (7.98%).