Antioxidant and Anticholinesterase Potential of SixThymusSpecies

Abstract

The present study aimed to evaluate antioxidant and acetylcholinesterase (AChE) inhibitory activities of the ethanolic extracts of six selectedThymusspecies growing in Croatia (T. longicaulis,T. praecoxsubsp.polytrichus,T. pulegioides,T. serpyllumsubsp.serpyllum,T. striatus, andT. vulgaris). Antioxidant effectiveness was assessed using six different assays, in comparison with rosmarinic acid, luteolin, and reference antioxidants. All testedThymusextracts possessed DPPH (IC50= 3–6 μg/mL) and nitric oxide (IC50= 70–177 μg/mL) free radical scavenging activities, strong reducing properties (IC50= 11–15 μg/mL), ferrous ion chelating activity (IC50= 126–389 μg/mL), ability to inhibit lipid peroxidation (IC50= 34–80 μg/mL), and high total antioxidant capacities (238–294 mg AAE/g). AChE inhibitory activity was examined using Ellman's colorimetric method and all tested extracts showed anti-AChE activity in a dose dependent manner. The values of 10–28%, 23–39%, and 64–86% were obtained for tested concentrations of 0.25, 0.5, and 1 mg/mL, respectively. Additionally, the contents of total hydroxycinnamic derivatives, flavonoids, and tannins in dried plant samples were determined spectrophotometrically. Our results highlightedThymusspecies as a rich source of natural antioxidants and AChE inhibitors that could be useful in preventing and treating Alzheimer’s disease and other neurodegenerative disorders.