Phytochemical Analysis, Antimicrobial and Antioxidant Properties of Thymus zygis L. and Thymus willdenowii Boiss. Essential Oils

Essential oils (EOs) are chemical products produced by odoriferous glands from a variety of plants. These essential oils have many health benefits: antiseptic, anti-inflammatory and antimicrobial activities. So due to these medicinal properties, the present study was designed to analyze essential oils of Thymus zygis L. and Thymus willdenowii Boiss. for their chemical composition and biological activities. These two thyme species were collected from the region of Ifrane, Middle Atlas of Morocco. The EO was obtained by hydrodistillation, and the yields were 5.25% for T. zygis and 3.00% for T. willdenowii. The chemical composition of the EOs was analyzed by gas chromatography coupled with mass spectrometry (GC-MS), and the results showed that T. zygis EO is dominated by carvacrol (52.5%), o-cymene (23.14%), and thymol (9.68%), while the EO of T. willdenowii contains germacrene D (16.51%), carvacrol (16.19%), and geranyl acetate (8.35%) as major compounds. The antioxidant activity assessed by Diphenylpicrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays revealed that both EOs have excellent antioxidant activities; by DPPH it resulted in IC50 = 6.13 ± 0.11 for T. zygis and 6.78 ± 0.3 µg/mL for T. willdenowii, while the one by FRAP yielded EC50 = 2.46 ± 0.01 (T. zygis) and 5.17 ± 0.2 (T. willdenowii) µg/mL. The antimicrobial activity of the two essential oils was evaluated against six bacterial strains and five fungal strains by the disk diffusion method to determine the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC). The EOs revealed variable antimicrobial activities against the different tested microbial strains and showed strong antimicrobial activities, even against strains known as multi-resistant to antibiotics (Acinetobacter baumannii) at low concentrations (2 µL/mL). T. zygis EO showed the most powerful activity against all the studied bacteria, while that of T. willdenowii recorded moderate activity when tested against Shigella dysenteriae and Salmonella Typhi. With inhibition diameters that vary between 75 mm and 84 mm for concentrations of 2 µL/mL up to 12 µL/mL, S. aureus was shown to be the most sensitive to T. zygis EO. For the antifungal activity test, T. zygis EO showed the best inhibition diameters compared to T. willdenowii EO. These results showed that T. zygis EO has more powerful antioxidant and antimicrobial activities than T. willdenowii EO, therefore, we deduce that thyme EOs are excellent antioxidants, they have strong antimicrobial properties, and may in the future represent new sources of natural antiseptics that can be used in pharmaceutical and food industry.

The Comprehensive Toxicological Assessment of Total Chromium Impurities in Traditional Herbal Medicinal Product with Thymi herba (Thymus vulgaris L. and Thymus zygis L.) Available in Pharmacies in Poland: Short Communication

Scientific reports about elemental impurities in final pharmaceutical products are essential from a regulatory point of view; unfortunately, there is a lack of studies about this important toxicological topic. The aim of our short communication was determination of total Cr impurities in traditional herbal medicinal products (THMP) with Thymi herba (Thymus vulgaris L. and Thymus zygis L.) available in Polish pharmacies (n = 6, because only six manufacturers produce this kind of pharmaceutical products in Poland). The total content of Cr impurities was determined by atomic absorption spectrometry using electrothermal atomization (ETAAS). Applied comprehensive toxicological risk assessment was based on three main tiers: Tier 1, the comparison of raw results as total Cr impurities profile (metal per L of THMP) with ICH Q3D guideline standards; Tier 2, the estimation of total Cr exposure with a single dose; and Tier 3, the estimation of total Cr daily exposure. We confirmed that total Cr impurities were present in all analyzed THMP with thymi herba (the observed level was below 6.0 µg/L). Total Cr concentration in a single dose can be deceptively high in comparison to the raw results but is not a threat to patients (20.15–63.45 ng/single dose). Moreover, the estimation of total Cr daily exposure shows that all analyzed THMP are characterized by daily dose (40.30–181.41 ng/day) below PDE value (10,700 mg/day); hence, all products meet the standards of ICH Q3D elemental impurities guideline.

Impact of Herbicide Treatments on the Construction Materials in the Roman Wall of Lugo, Spain (UNESCO World Heritage Site)

Combined laboratory and field research examining the possible alterations caused by herbicide treatments applied to the construction materials (schist and some granite, bound with mortar) in the Roman wall of Lugo (NW Spain), declared a World Heritage site by UNESCO in 2000, was performed in three separate studies in the past 20 years. In the summers of 1998 and 1999, the herbicides glyphosate, sulphosate and glufosinate–ammonium, as well as physical treatments (infrared and burning) were separately applied to different areas of the wall. In the spring of 2016, the oxyfluorfen herbicide Goal Supreme® was applied to test areas. In the winter of 2018, three essential oils, Origanum vulgare L., Thymus zygis Loefl. ex L., and Thymus vulgaris L., were each applied to test areas. Mineralogical modifications in the materials (determined by X-ray diffraction analysis), as well as visible physical changes, such as colour changes, and the appearance of saline residues were evaluated after the treatments. In the 1998/9 trial, glyphosate and both physical treatments triggered changes in the vermiculite clay minerals in the schists, and the physical treatments also caused changes in the kaolinite. None of the treatments caused highly perceptible colour changes. The oxyfluorfen herbicide did not cause any mineralogical alterations in the construction materials, but it did generate an increase in chloride, nitrate and sulphate contents of the granite and a slight darkening of this material. In the most recent study, the only deleterious effect observed was a perceptible increase in lightness and reduction in the yellow component after the application of Thymus zygis Loefl. ex L. essential oil to granite.

Tribological behavior of stainless steel in sulfuric acid in the presence of Thymus zygis subsp. gracilis essential oil: experimental and quantum chemical studies

To reduce the use of synthetic compounds as wear-corrosion inhibitors, and substitute them with new ecological compounds, we are interested in evaluating the effect of the essential oils against the tribocorrosion. The present paper describes the effect of adding Thymus zygis subsp. gracilis (TZ) essential oil (3 g·L−1) on AISI 304L tribocorrosion behavior in 0.5 M H2SO4. As a result, the addition of this essential oil decreases the tribocorrosion rate [E (%) = 84.38], the value of friction coefficient, and the energy dissipated during sliding wear, in comparison to those recorded for dry environment and 0.5 M H2SO4. In addition, the essential oil improves the surface morphology of metal as shown by the scanning electron microscopy and energy dispersive X-ray and the three-dimensional optical profiler analysis. In addition, the modeling approaches of experimental results, involving the density functional theory, the electrostatic potential, and the Monte Carlo methods, show that thymol (42.5% of TZ oil) is the best corrosion and tribocorrosion inhibitor that adhered to the stainless steel surface and offers a greater coverage area to block the metal wear-corrosion. According to the obtained results, the TZ essential oil can be used in the food industry to prevent the wear of materials.

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

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.

Antioxidant, anti-inflammatory and anticoagulant activities of three Thymus species grown in southeastern Morocco

Background Thyme has been used for centuries in southeastern Morocco to treat a wide range of diseases such as inflammation disorders. The aim of the current study is to examine and to compare in vitro the anti-inflammatory, antioxidant, and anticoagulant activities of three thyme species grown in southeastern Morocco. Results Data showed that all studied species possess an important antioxidant activity: Thymus atlanticus (IC50 = 16.59 μg/mL), Thymus zygis (IC50 = 15.43 μg/mL), and Thymus satureioides (IC50 = 14.65 μg/mL). Concerning the anti-inflammatory activity, the highest effect was depicted in Thymus atlanticus followed by Thymus zygis and Thymus satureioides. With regard to the anticoagulant activity, the aqueous extract of these species prolongs activated partial thromboplastin time, prothrombin time, and thrombin time significantly (p < 0.05) in a dose-dependent manner. Conclusion Our results provide evidence that thymus extract exhibits marked antioxidant, anticoagulant, and anti-inflammatory effects, thus justifying the popular uses of these plants to treat some inflammatory and cardiovascular illnesses.

Zu den molekularbiologischen Grundlagen der antientzündlichen Wirkungen von Thymiankrautextrakt, Thymus vulgaris L. und Thymus zygis L., herba

ZUsammenfassungBereits früher publizierte Daten zeigten günstige Effekte von Thymian bei entzündlichen Prozessen. Um diese Erkenntnisse zu vertiefen, wurde in verschiedenen experimentellen Modellen ein Thymianextrakt auf die hier zugrundeliegenden molekularbiologischen Mechanismen in vitro untersucht. Nachgewiesen wurde eine Hemmung der LPS-induzierten Zytokin-Freisetzung von IL-1β, PGE2 sowie TNF-α in humanen Monozyten, eine Hemmung der LPS-induzierten Phosphorylierung und eine Aktivierung von IκBα sowie eine Inhibition der Transkriptionsaktivität von NF-κB und AP-1 in der Bronchialepithel-Zelllinie A549. Ein weiterer interessanter Befund war eine antagonistische Aktivität des untersuchten Thymianextraktes am TRPA1-Rezeptor, ein Rezeptor, der Hustenreize vermitteln kann. Die Anwendung des Thymianextraktes bei Erkältungs- bzw. Bronchitis-bedingtem Husten, bei dem entzündliche Prozesse auf bzw. in der Schleimhaut involviert sind, darf daher als plausibel gelten.