Thymus zygis subsp. zygis an Endemic Portuguese Plant: Phytochemical Profiling, Antioxidant, Anti-Proliferative and Anti-Inflammatory Activities

Amélia M Silva; Carlos Martins-Gomes; Eliana B Souto; Judith Schäfer; João A Santos; Mirko Bunzel; Fernando M Nunes

doi:10.3390/antiox9060482

Thymus zygis subsp. zygis an Endemic Portuguese Plant: Phytochemical Profiling, Antioxidant, Anti-Proliferative and Anti-Inflammatory Activities

Antioxidants (Basel). 2020 Jun 3;9(6):482. doi: 10.3390/antiox9060482.

Authors

Amélia M Silva^{1

2}, Carlos Martins-Gomes^{2

3}, Eliana B Souto^{4

5}, Judith Schäfer⁶, João A Santos^{2

7}, Mirko Bunzel⁶, Fernando M Nunes^{3

8}

Affiliations

¹ Department of Biology and Environment, School of Life Sciences and Environment, University of Trás-os-Montes and Alto Douro (UTAD), 5001-801 Vila Real, Portugal.
² Centre for Research and Technology of Agro-Environmental and Biological Sciences (CITAB), UTAD, 5001-801 Vila Real, Portugal.
³ Food and Wine Chemistry Lab., Chemistry Research Centre-Vila Real (CQ-VR), UTAD, 5001-801 Vila Real, Portugal.
⁴ Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, 3000-548 Coimbra, Portugal.
⁵ CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
⁶ Department of Food Chemistry and Phytochemistry, Institute of Applied Biosciences, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Building 50.41, 76131 Karlsruhe, Germany.
⁷ Department of Physics, School of Sciences and Technology, UTAD, 5001-801 Vila Real, Portugal.
⁸ Department of Chemistry, School of Life Sciences and Environment, UTAD, 5001-801 Vila Real, Portugal.

Abstract

Thymus zygis subsp. zygis is an endemic Portuguese plant belonging to the Thymus zygis species. Although T. zygis is commonly used as a condiment and as a medicinal herb, a detailed description of the polyphenol composition of hydroethanolic (HE) and aqueous decoction (AD) extracts is not available. In this work, we describe for the first time a detailed phenolic composition of Thymus zygis subsp. zygis HE and AD extracts, together with their antioxidant, anti-proliferative and anti-inflammatory activities. Unlike other Thymus species, T. zygis subsp. zygis extracts contain higher amounts of luteolin-(?)-O-hexoside. However, the major phenolic compound is rosmarinic acid, and high amounts of salvianolic acids K and I were also detected. T. zygis subsp. zygis extracts exhibited significant scavenging activity of ABTS⁺, hydroxyl (^•OH), and nitric oxide (NO) radicals. Regarding the anti-proliferative/cytotoxic effect, tested against Caco-2 and HepG2 cells, the AD extract only slightly reduced cell viability at higher concentrations (IC₅₀ > 600 µg/mL, 48 h exposure), denoting very low toxicity, while the HE extract showed a high anti-proliferative effect, especially at 48 h exposure (IC₅₀ of 85.01 ± 15.10 μg/mL and 82.19 ± 2.46 μg/mL, for Caco-2 and HepG2, respectively). At non-cytotoxic concentrations, both extracts reduced the nitric oxide (NO) release by lipopolysaccharide (LPS)-stimulated RAW 264.7 cells (at 50 μg/mL, HE and AD extracts inhibited NO release in ~89% and 48%, respectively). In conclusion, the results highlight the non-toxic effect of aqueous extracts, both resembling the consumption of antioxidants in foodstuff or in functional food. Furthermore, the HE extract of T. zygis subsp. zygis is a source of promising molecules with antioxidant, anti-inflammatory and anticancer activities, highlighting its potential as a source of bioactive ingredients for nutraceutical and pharmaceutical industries.

Keywords: Thymus zygis subsp. zygis; anti-inflammatory activity; anti-proliferative activity; antioxidant; aqueous decoction; hydroethanolic extract; luteolin-O-hexoside; phenolic profiling; radical scavenging activity.

Abstract

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