Antioxidant activity of four endemic Stachys taxa.

Methanol extracts of aerial flowering parts of four endemic Stachys taxa: S. anisochila VIS. et PANCIC, S. beckeana DORFLER & HAYEK, S. plumosa GRISEB. and S. alpina L. ssp. dinarica MURB. were investigated on their antioxidant activity. The extracts were studied for total antioxidant activity (TAA), along with 1,1-diphenyl 2-picryl hydrazyl (DPPH) and OH radical scavenging activity, and lipid peroxidation (LP). High correlations between total phenolics content, TAA and scavenging DPPH radical indicate that polyphenols are the main antioxidants. All Stachys extracts, with the exception of S. plumosa, exhibited high anti-DPPH activity (IC50<50 microg/ml). In concentration range from 6.25 to 50 microg/ml, all extracts scavenged OH radical above 40%, with maximal inhibitions for S. anisochila, S. alpina ssp. dinarica and S. beckeana extracts of 50.22%, 50.94% and 64.97%, respectively. Only S. plumosa extract achieved maximal activity of 60.67% at 100 microg/ml. As for LP, IC50 values for S. beckeana and S. alpina ssp. dinarica extracts were 25.07 and 49.00 microg/ml, respectively, while S. anisochila and S. plumosa extracts did not reach 50% of LP inhibition.