In vitro antioxidant activity, cyclooxygenase-2, thioredoxin reductase inhibition and DNA protection properties of Teucrium sandrasicum L.

The aerial parts of Teucrium sandrasicum L. (Lamiaceae), an endemic species of the Turkish flora, are widely used in the daily diet. The plant is also valued as a traditional medicine and is used for diuretic, diaphoretic, tonic, antipyretic, antidiabetic, antispasmodic, and cholagogic purposes. This study investigated a methanolic extract of aerial parts of T. sandrasicum for its antioxidant and antiinflammatory effects, inhibition of thioredoxin reductase, and protection against DNA damage. The extract showed inhibitory activity against FeCl3/ascorbic acid induced phosphatidylcholine liposome oxidation (EC50 = 1.49 +/- 0.03 mg/mL), quenched stable DPPH (EC50 = 1.05 +/- 0.03 mg/mL), superoxide anion (EC50 = 1.20 +/- 0.06 mg/mL), and ABTS cation radicals (EC50 = 1.73 +/- 0.01 mg/mL). The extract also acted as a reductant, as determined by the FRAP value (2.66 +/- 0.21 mM/LFe2+), indicating its potential as an antioxidant. The T. sandrasicum species was determined to be a rich source of flavonoids (104.39 +/- 1.37 mg/g), which are likely to serve as antioxidant, anti-inflammatory, and cancer chemoprevention agents. The extract was strongly inhibitory against both cyclooxygenase-2 (COX-2) (EC50 = 1.18 +/- 0.03 mg/mL) and thioredoxin reductase (0.90 +/- 0.02 mg/mL), and it significantly and dose-dependently decreased the amount of nicked DNA, as well as increased the natural form of DNA. (C) 2015 Elsevier B.V. All rights reserved.