The antioxidant, hemolytic and cholinesterase inhibition properties of Galium verum L. and Tragopogon pratensis subsp. pratensis

The antioxidant properties of Galium verum L. (Lady’s Bedstraw) and Tragopogon pratensis subsp. pratensis (Goat’s beard) methanol extracts, from localities in Serbia were evaluated, through determination of total phenolics and flavonoids content, as well as DPPH • (1,1-diphenyl-2-picrylhydrazyl) radical scavenging, ABTS •+ (2,2-azinobis-(3ethylbenzthiazoline-6-sulfonic acid) radical cation decolorization and ferricyanide methods. Methanol extracts of G. verum showed stronger free radical scavenging activity (IC50 values of 26.98 μg/mL for DPPH • decolorization assays and 125.14 mg Trolox/ g dry extract for ABTS •+ radical cation decolorization assays) and total reducing power (70.31 μg/mL) than methanol extracts of T. pratensis (SC50 values of 59.25 μg/mL for DPPH • decolorization assays and 6.31 mg Trolox/ g dry extract for ABTS •+ radical cation decolorization assays and 15.66 μg/mL of extract for total reducing power). Observed could be connected with a much higher content of phenolic and flavonoid constituents in G. verum extracts. Applying modified Ellman’s method, G.verum methanol extracts showed slight activation of humane serum cholinesterase (16.28 ± 0.09 %), while methanol extract of T. pratensis was proven as a weak inhibitor of the enzyme (4.65 ± 0.08 %). Also, methanol extracts of G. verum and T. pratensis were tested in vitro using standard Drabkin’s method to evaluate whether these extracts have hemolytic activity. Extracts of T. pratensis showed very strong hemolytic activity (after the first hour of incubation 50% of hemolysis induced concentration of 501.97 ± 32.65 μg/mL, the second hour 499.98 ± 38.45 μg/mL, 498.656 ± 39.85 μg/mL of the third and fourth 421.33 ± 34.98 μg/mL) while G. verum extracts had weak hemolytic activity.