Thymus Capitatus Research Articles

Antimicrobial Activity and Medicinal Plants in the North and East of Syria: A Review Study

Herbal plants contain a medicinal source with antimicrobial properties that offer a safer and more cost-effective method to treat human pathogens. Scientists in the field are performing research on plants to discover their potential antimicrobial compounds. This study aimed to conduct a review of the antimicrobial and antioxidant properties and investigate particular herbal plants with medicinal activities in the north and east of Syria. Considering that some herbal plants, including Cuminum cyminum, Mentha piperita, Allium cepa, Majorana hortensis, Eucalyptus camaldulensis, Thymus capitatus, Achillea millefolium, Malva parviflor, and Capparis spinose, have antifungal, antimicrobial, and antioxidant activities, the products obtained from these plants may be used to control the growth of pathogenic microorganisms. In addition, this study focused on the chemical compounds, including p-cymene, kaempferol, quercetin, capsaicin, 1,8-cineole, flavonoids, gallic acid, and alkaloids, which play a role in inhibiting microbial growth. Based on the results obtained from this review study, using these herbal plants can control human infectious, pathogenic, cancerous, and antioxidant diseases.

How can ecosystem engineer plants boost productivity in east Mediterranean drylands

BackgroundWater availability is the key limiting factor for plant productivity in drylands covering ca. 40% of Earth’s land surface. For such ecosystems to retain productivity and biodiversity under climatic change, it would be valuable to identify/promote keystone plant species that (i) have developed strategies to more efficiently utilize moisture resources not easily accessible and (ii) improve moisture conditions for neighboring plants. The very deep-rooted Ziziphus lotus, considered an ecosystem engineer, is one such example. However, it is not known which biotic traits: (a) canopy interception of moisture/rainfall, (b) hydraulic redistribution of deep ground moisture by roots, or non-biotic factors: (c) soil’s volume, and (d) organic matter content, Z. lotus activates/modulates to play such a role. We, thus, selected dryland ecosystems where the plant dominates and measured for potential effects on the less deep-rooted Thymbra capitata. For assessing impacts on ecosystem productivity, we measured the spatial aggregation of ca. 3600 T. capitata plants. As a proxy for soil moisture availability and its spatial variability, we conducted a 7-year-long study using thymes’ nighttime rehydration. Sampling extended up to 15 m away from Z. lotus.ResultsThe density of T. capitata plants growing up to 5 m around Z. lotus vs. thymes growing 10–15 m away was found significantly increased (2.5–4.5 times), while their stem/leaf moisture was ca. 10% higher at predawn compared to nightfall during the dry season. This suggests that ecosystem productivity is driven by a greater soil moisture availability around Z. lotus permitting more thyme daytime transpiration, in contrast to thymes growing further away. The phenomenon appeared only under dry topsoil (during the dry season; becoming stronger during dry years). Morning dew/rainfall interception from the canopy or soil depth/organic matter did not show significant effects, leaving only the hydraulic lift properties of Z. lotus as the most likely driver for soil moisture availability.ConclusionsThe deep-rooting properties and hydraulic lift potential of Z. lotus may be the key in permitting it to boost ecosystem productivity. Such hydraulic plant traits require more attention as they may prove valuable in combating desertification and restoring ecosystems in arid/semiarid regions threatened by climate change.

Lignin Nanoparticles with Entrapped Thymus spp. Essential Oils for the Control of Wood-Rot Fungi.

After decades of utilization of fossil-based and environmentally hazardous compounds for wood preservation against fungal attack, there is a strong need to substitute those compounds with bio-based bioactive solutions, such as essential oils. In this work, lignin nanoparticles containing four essential oils from thyme species (Thymus capitatus, Coridothymus capitatus, T. vulgaris, and T. vulgaris Demeter) were applied as biocides in in vitro experiments to test their anti-fungal effect against two white-rot fungi (Trametes versicolor and Pleurotus ostreatus) and two brown-rot fungi (Poria monticola and Gloeophyllum trabeum). Entrapment of essential oils provided a delayed release over a time frame of 7 days from the lignin carrier matrix and resulted in lower minimum inhibitory concentrations of the essential oils against the brown-rot fungi (0.30-0.60 mg/mL), while for the white-rot fungi, identical concentrations were determined compared with free essential oils (0.05-0.30 mg/mL). Fourier Transform infrared (FTIR) spectroscopy was used to assess the fungal cell wall changes in the presence of essential oils in the growth medium. The results regarding brown-rot fungi present a promising approach for a more effective and sustainable utilization of essential oils against this class of wood-rot fungi. In the case of white-rot fungi, lignin nanoparticles, as essential oils delivery vehicles, still need optimization in their efficacy.

Synergistic action of Thymus capitatus or Syzygium aromaticum essential oils and antibiotics combinations against multi-resistant Salmonella strains

Synergistic action of Thymus capitatus or Syzygium aromaticum essential oils and antibiotics combinations against multi-resistant Salmonella strains

Influence of dietary supplementation of antibiotic and thyme on zootechnical parameters and caecal microflora of growing rabbit

The objective of this study was to compare the influence of antibiotic and thyme dietary supplements on zootechnical parameters and caecal microflora of growing rabbits. One hundred and ninety eight weaned rabbits (forty days old), white New Zealand (of both sexes) were divided into three groups to submit to the following dietary treatments: Control diet, diet A (control diet + 100 ppm zinc bacitracin), and diet T (control diet + 7% Thymus capitatus leaves) for twenty-one days. The remaining nine days they received only the control diet. The results showed that both the live body weight and feed conversion ratio were positively affected by the antibiotic diet (P<0.05). However, the rabbits' growth performance was not influenced by dietary thyme supplements. The antimicrobial effect of thyme observed against C. perfringens in caecum is not determined even after 20 days of treatment. In conclusion, zootechnical parameters and mortality were not positively affected by dietary thyme supplements comparing it with the antibiotic diet, but these phytobiotics showed the antibacterial effect against E. coli and C. perfringens in caecum of rabbit.

Screening of medicinal plant extracts as novel DNA gyrase inhibitors

Bioactivities of a number of medicinal plants; Alkanna tinctoria (L.) Tausch, Alnus glutinosa (L.) Gaertn., Calamintha nepeta Willk. and C. nepeta, Centaurea iberica Trevir. ex Spreng., Citrus paradisi Macfad., C. paradisi, Citrus sinensis (L.) Osbeck, Colutea cilicica Boiss. & Balansa, Cotinus coggygria Scop., Cuscuta arvensis Beyr. ex Engelm., Equisetum palustre L., Lapsana communis L., Laurus nobilis L., Olea europea L., Plantago major L., Rhus coriaria L, Salvia verticillata L., Sambucus ebulus L., Sedum acre L, Thymus capitatus (L.) Hoffmanns. & Link, T. capitatus, Thymbra spicata L., T. spicata (n: 20), which are used for the prevention and treatment of diverse diseases, were investigated. The antimicrobial activities of extracts were evaluated using broth microdilution assay. The cytotoxicities of extracts were investigated on HeLa cell line by MTT assay. Statistical analysis was performed using GraphPad Prism (5.0). The effects of the extracts, which have the highest antimicrobial activity, on the Escherichia coli and Staphylococcus aureus DNA gyrase gene expression were determined by using quantitative reverse transcription polymerase chain reaction (qRT-PCR). The MICs (µg/ml) of extracts were determined as 32-64, 2-128, 8-128,1-128, 4-128 against Gram-positive, Gram-negative bacteria, yeasts, dermatophytes, and Mycobacterium spp., respectively. No cytotoxicity has been observed in plant extracts tested. DNA gyrase activity was determined for T. capitatus-SFE (128 µg/mL) and L. nobilis-Hx (128 µg/mL) extracts according to the inhibition of DNA gyrase gene expression. Overall, T. capitatus-SFE and L. nobilis-Hx are good candidates for further antimicrobial studies.

Vaginal Sheets with Thymbra capitata Essential Oil for the Treatment of Bacterial Vaginosis: Design, Characterization and In Vitro Evaluation of Efficacy and Safety.

We aimed to incorporate Thymbra capitata essential oil (TCEO), a potent antimicrobial natural product against bacterial vaginosis (BV)-related bacteria, in a suitable drug delivery system. We used vaginal sheets as dosage form to promote immediate relief of the typical abundant vaginal discharge with unpleasant odour. Excipients were selected to promote the healthy vaginal environment reestablishment and bioadhesion of formulations, while the TCEO acts directly on BV pathogens. We characterized vaginal sheets with TCEO in regard to technological characterization, predictable in vivo performance, in vitro efficacy and safety. Vaginal sheet D.O (acid lactic buffer, gelatine, glycerine, chitosan coated with TCEO 1% w/w) presented a higher buffer capacity and ability to absorb vaginal fluid simulant (VFS) among all vaginal sheets with EO, showing one of the most promising bioadhesive profiles, an excellent flexibility and structure that allow it to be easily rolled for application. Vaginal sheet D.O with 0.32 µL/mL TCEO was able to significantly reduce the bacterial load of all in vitro tested Gardnerella species. Although vaginal sheet D.O presented toxicity at some concentrations, this product was developed for a short time period of treatment, so this toxicity can probably be limited or even reversed when the treatment ends.

Phytochemical Analysis, In vitro Assessment of Antioxidant Properties and Cytotoxic Potential of Thymus capitatus Essential Oil

Essential oils (EOs) of medicinal plants became a matter of interest in scientific research because of their potential of utilization for several therapeutic purposes, The EO of Thymus capitatus has been traditionally used in treatment of several conditions related to skin, muscles, and respiratory system, to reduce fever, and to stimulate menstrual flow in addition to its anti-bacterial properties. To chemically analyze the components of the EO of Thymus capitatus and to evaluate its anti-cancerous and anti-oxidant activity on breast cancer cells (T47D), colorectal adenocarcinoma cells (CACO2), and normal human fibroblasts (MRC5). The EOs were extracted by hydro-distillation. Gas chromatography and mass spectrometry were used to analyze the extracts. Cell viability was assessed using three different assays; MTT, trypan blue and neutral red assays. Antioxidant activity was assessed using DPPH scavenging assay. Cell apoptosis was assessed using DNA fragmentation tests and Annexin V-propidium iodide assay. Morphological analysis of cells was assessed using light microscopy and DAPI staining. Twenty-two different compounds were identified in the essential oil of T. capitatus leaves including Thymol (44.34%) and Carvacrol (38.89%) in addition to 20 minor components. The oil extract exhibited a significant inhibitory action on the three cell lines. The viability assays showed significantly higher (p<0.05) IC50 in the fibroblast cell line than the other two cell lines. The selectivity index was higher in T47D cell line compared to CACO II cell line. For apoptosis assessment, DNA fragmentation in T47D cells was significantly correlated with the extract concentration. The membrane polarity was disrupted in an increasing manner (15.60±1.13, 35.73±1.69 and 46.53±2.51) as the extract concentration (20.22, 40.45, and 80.9µg/ml, respectively) increased. On the cellular level, morphological changes including cell shrinkage, chromatin condensation and nuclear fragmentation in addition to marginalization of chromatin, vacuolization of cytoplasm and formation of micronuclei was clearly visible. The extract showed high anti-oxidant activity with an IC50 of 6.4µg/ml. Anti-oxidant activity was dose-dependent; double IC50 (80.9µg/ml) exhibited the highest antioxidant activity whereas the lowest antioxidant activity was observed for the ½ IC50 (20.225µg/ml). The oil extract exerted an inhibitory action lipid peroxidation. Thymus capitatus EO is a potential anti-oxidant and anti-neoplastic agent against breast and colon carcinomas due to its high selectivity for cancer cells compared to normal cell lines.

Determination of Antioxidant Capacity and HPLC Analysis of Gallic Acid Plus Rutin in Some Lamiaceae Plants Growing in the East of Libya

Lamiaceae family comprise a wide range of medicinal and aromatic plant species with strong antioxidant properties and multiple pharmaceutical applications in folk medicine. <i>Mentha piperita</i> L., <i>Ocimum basilicum</i>, <i>Origanum vulgare</i> L, <i>Rosmarinus officinalis</i> L, <i>Salvia officinalis</i> L. and <i>Thymus capitatus, </i>are edible plants in Libya, belonging to this family. The current work aims to evaluate gallic acid and rutin contents of the methanolic extract of the mentioned plants using RP- High performance liquid chromatography (HPLC) and assess their antioxidant properties by applying the DPPH radical scavenging assay. The content of gallic acid were found to be considerable in all plants studied, most remarkably in <i>Rosmarinus officinalis</i> L. and <i>Thymus capitatus</i> with area under the peak (56.14% and 54.62% respectively), while lower contents were detected in <i>Ocimum basilicum</i> (34.44%), <i>Origanum vulgare</i> L. (28.98%),<i> Mentha piperita</i> L.(26.09%), and<i> Salvia officinalis</i> L. (24.34%). On the other hand, it was noted that rutin is found in less quantities compared to previous results. The extracts of <i>Organium vulgare </i>and<i> Thymus capitatus </i>had a significant antioxidant potential compared to standard vitamin C with 0.34 ± 0.03 and 0.46 ± 0.02 mg/mL respectively, while a lower scavenging capacity were recoded for <i>Mentha piperita</i> L. (0.59 mg/mL ± 0.01), <i>Salvia officinalis</i> L. (0.60 mg/mL ± 0.01), <i>Rosmarinus officinalis</i> L (0.65 mg/mL ± 0.07), and <i>Ocimum basilicum </i>(0.99 mg/mL ± 0.02). In conclusion, the reported results point out the significance of this family as a source of antioxidant agents with high promising capability to affect the redox state.

Phytotoxic Effects of Essential Oils from Six Lamiaceae Species

Essential oils produced by plants, and their components, could be sources of new natural herbicidal compounds. Thirteen oils extracted from six wild Lamiaceae species (namely Clinopodium suaveolens (Sm.) Kuntze, Satureja montana L. subsp. montana, Thymbra capitata (L.) Cav., Salvia fruticosa Mill. subsp. thomasii (Lacaita) Brullo, Guglielmo, Pavone &amp; Terrasi, Satureja cuneifolia Ten., and Thymus spinulosus Ten.) from South Italy were tested in vitro for the phytotoxic activity to cress and branched broomrape seeds, tomato radicles, and lambsquarters leaf disks. Moreover, the possible correlation between oil composition and biological activity was evaluated. One of the oils from T. capitata inhibited cress germination by 96.4% at the lowest tested concentration (100 ppm) and reduced both chlorophyll and carotenoid content in lambsquarters leaf disks by around 50%. Some oils, particularly those from T. spinulosus, inhibited tomato radicle elongation by 85% at 1000 ppm. Many oils inhibited broomrape seed germination up to 100% when tested in solution at 1000 ppm or released as vapors. Among the oil components, α-terpinene, p-cymene, β-cis-ocimene, cis-sabinene hydrate, carvacrol methyl ether, and thymol were mostly correlated to the inhibition of cress seeds germination and tomato radicle elongation. The presence of thymol and p-cymene was also correlated to the inhibition of broomrape seed germination. Some of the tested essential oils or their components could have potential as pre-emergence herbicides and could be useful in the development of new weed control strategies.

Assessment of The Effect of Thymbra capitata Ethanolic Extract on Galleria mellonella Hemolymph Antioxidant Enzymes

Conehead thyme (Thymbra capitata) is widely distributed in the countries of the Mediterranean region and used due to its medical properties. The antibacterial, antifungal, and strong antioxidant properties of T. capitata are known. The model organism Galleria mellonella is mostly preferred for immunological studies and for the study of human pathogens. The aim of the study was to determine the effect of the ethanolic extract of T. capitata on the antioxidant defense of the hemolymph in G. mellonella larva. Solutions prepared with Phosphate-Buffered Saline (PBS) from the dry matter obtained from ethanolic extract at doses between 2 mg mL-1 and 20 mg mL-1 were injected into G. mellonella larvae. According to our findings, T. capitata extract had no effect on malondialdehyde (MDA) levels. However, it was determined that all doses between 10 to 20 mg mL-1 significantly reduced superoxide dismutase (SOD) and catalase (CAT) activities compared to the control groups. According to the results of our study, high doses of T. capitata extract had negative effects on G. mellonella antioxidant defense.

Phylogenetic Analysis of Libyan Thyme (Thymus Capitatus) Inferred from The Morphological Traits

The genetic diversity of wild thyme (Thymus capitatus) which growing in southern parts of Al-Jabal Al-Akhdar region, Libya was studied by using cluster analysis of morphological traits (flower measurements). This study was aimed to establish the phylogenetic relationships based on floral parameters among accessions of thyme (T.capitatus). The five populations (accessions) of Libyan thyme were assigned into two clusters (clades) at the critical distance value of 22%. The 1stcluster contained three populations that were included white-flowered, dotted white-flowered and violet-flowered accession, then the 1st cluster was divided into two sub-clusters by the critical distance value of 5%, the first sub-cluster contained two populations (white-flowered, dotted white-flowered accession). While, the second sub-cluster contained one population (violet-flowered accession). The 2nd cluster contained two populations which were purple-flowered and mosaic-flowered accessions. In conclusion, The flower measurements can be a preliminary tool to classify Libyan thyme (T.capitatus), and floral parameters can be used in the classification of Libyan thyme accessions (populations).

New Biological and Chemical Evidences of Two Lamiaceae Species (Thymbra capitata and Thymus sipyleus subsp. rosulans): In Vitro, In Silico and Ex Vivo Approaches.

In this study, the methanolic and infusion extracts of two species, Thymbra capitata and Thymus sipyleus subsp. rosulans, were tested for their chemical composition and biological abilities (antioxidant, enzyme inhibitory and anti-inflammatory effects). The extracts yielded total phenolic and flavonoid contents in the range of 83.43-127.52 mg GAE/g and 9.41-46.34 mg RE/g, respectively. HPLC analysis revealed rosmarinic acid to be a major component of the studied extracts (15.85-26.43%). The best ABTS radical scavenging ability was observed in the methanol extract of T. capitata with 379.11 mg TE/g, followed by in the methanol extract of T. sipylus (360.93 mg TE/g). In the CUPRAC assay, the highest reducing ability was also found in the methanol extract of T. capitata with 802.22 mg TE/g. The phosphomolybdenum ability ranged from 2.39 to 3.61 mmol TE/g. In terms of tyrosinase inhibitory effects, the tested methanol extracts (83.18-89.66 mg KAE/g) were higher than the tested water extracts (18.74-19.11 mg KAE/g). Regarding the BChE inhibitory effects, the methanol extracts were active on the enzyme while the water extracts showed no inhibitory effect on it. Overall, the methanolic extracts showed better enzyme inhibition compared to the infusion extracts. Molecular docking also showed the selected exhibited potential binding affinities with all enzymes, with a preference for cholinesterases. Additionally, the extracts were effective in attenuating the LPS-induced increase in COX-2 and IL-6 gene expression in isolated colon, thus indicating promising anti-inflammatory effects. The preliminary results of this study suggest that these species are good natural sources of antioxidants and also provide some scope as enzyme inhibitors, most likely due to their bioactive contents such as phenolic acids, and thus can be exploited for different applications related to health promotion and disease prevention.

Cytotoxic activity of Thymus capitatus collected from Hail region in Saudi Arabia with mechanistic study via induction of caspase-dependent apoptosis and S-phase arrest

Thymus capitatus is a plant grows in Mediterranean area and some Arab countries such as Saudi Arabia. It possesses numerous medicinal values. Its common name is Zaatar and it belongs to family Lamiaceae Thymus capitatus leaves and stem were collected from Hail region, Saudi Arabia. Then both leaves and stem were extracted with ethanol. This study was performed to evaluate cytotoxic activity of Thymus capitatus leaves and stem ethanolic extract in details. Doxorubicin was used as a standard and the relevant half maximal inhibitory concentration (IC50) values were computed for each cell line by 3-(4,5- diemthylthiazole-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. In addition, further mechanistic study was carried out by using Apoptosis assay to explore cytotoxic activity of plant extract. Both leaves and stems extracts were screened against HepG2, A-549, HCT-116 and MCF-7 cancer cell lines. It was found that leaves’ extract shows high and moderate cytotoxic activity against both A-549 and HepG2 cancer cell lines, respectively (with IC50 = 13.6 and 21.5 μg/ml, respectively), while stem’s extract exerted moderate cytotoxic activity against A-549 cancer cell lines (with IC50 = 21.38 μg/ml). Further mechanistic study was carried out on A-549 cells by using apoptosis assay. It showed that leaves’ extract resulted in arrest of S-phase and caused apoptosis through activation of caspase-3, p53 and Bax, in addition to down regulation of Bcl-2.

BIO-CONTROL AND ULTRASTRUCTURE OF POST-HARVEST PATHOGENIC FUNGI OF APPLE FRUITS

Post-harvest pathogenic fungi of fruits cause huge losses. Apples fruits are important for consumers. The antifungal activity of aqueous and ethanolic extracts of eleven medicinal plants at fives concentrations (0, 1, 3, 5, 10%; w/v) were tested against Alternaria alplateternata. Inhibition of fungal growth, along with the lower D50 values of the ethanolic extract of the tested plants compared to those of the aqueous extract exhibited more efficient antifungal activity. The ultrastructure of the fungal hyphae without treatment (control) showed normal hyphae enclosed by a wall composed of three layers in which the middle layer is more electron- denser than the outer and inner layers. An intact plasma membrane was also observed. In addition, an electron-dense material was observed at the tip of the hyphae. The cytoplasm contained several organelles. On the other hand, the treated hyphae with the ethanolic extracts of the mixture of E. citriodora and T. capitatus exhibited many changes as noted in both T.S and L.S such as the increase of the electron density of the outer layer of the hyphal wall more than the control, also numerous big lipid bodies were almost occupied the cytoplasm. Eucalyptus citridora and Thymus capitatus had a potential as antifungal agent for biocontrol of post-harvest pathogenic fungi of tested apple fruits.

Essential Oil Stabilisation by Response Surface Methodology (RSM): Nanoemulsion Formulation, Physicochemical, Microbiological, and Sensory Investigations.

This manuscript aimed to optimise the encapsulation of Thymus capitatus essential oil into nanoemulsion. Response Surface Methodology results were best fitted into polynomial models with regression coefficient values of more than 0.95. The optimal nanoemulsion showed nanometer-sized droplets (380 nm), a polydispersity index less than 0.5, and a suitable Zeta potential (-10.3 mV). Stability results showed that nanoemulsions stored at 4 °C were stable with the lowest d3,2, PolyDispersity Index (PDI), and pH (day 11). Significant ameliorations in the capacity to neutralise DPPH radical after the encapsulation of the antimicrobial efficacy of thyme essential oil were recorded. S. typhimurium growth inhibition generated by nanoencapsulated thyme essential oil was 17 times higher than by bulk essential oil. The sensory analysis highlighted that the encapsulation of thyme essential oil improved enriched milk's sensory appreciation. Indeed, 20% of the total population attributed a score of 4 and 5 on the scale used for milk enriched with nanoemulsion. In comparison, only 11% attributed the same score to milk enriched with bulk essential oil. The novel nanometric delivery system presents significant interest for agroalimentary industries.

EVALUATION OF THE ANTIBACTERIAL ACTIVITY OF ESSENTIAL OILS AGAINST E. COLI ISOLATED FROM RABBITS

The antibacterial activity of essential oils extracted from Origanum compactum, Thymus capitatus, Foeniculum vulgare, and Rosmarinus officinalis was assessed with the well diffusion method and a microbroth dilution assay against E. coli isolated from the carcasses of rabbits. The chemical composition of these essential oils was also determined by gas chromatography coupled with mass spectrometry (GC/MS). The results of this study indicate that essential oils with high phenol content exert a strong antibacterial activity against E. coli. Essential oils of Origanum compactum and Thymus capitatus containing high amounts of the monoterpenoid phenols thymol and carvacrol (68.99% and 95.25% carvacrol composition, respectively) were particularly effective against E. coli with low values of MIC = 0.3125% v/v and MBC = 0.625% v/v to report. The essential oil of Foeniculum vulgare also possessed moderate antibacterial activity (MIC = 50 % v/v) with a non-bactericidal effect, while the essential oil of Rosmarinus officinalis was ineffective at the concentrations tested.

Oviposition deterrence and repellent activities of selected essential oils against Tuta absoluta Meyrick (Lepidoptera: Gelechiidae): laboratory and greenhouse investigations

Tuta absoluta, an invasive pinworm characterized by high reproductive potential and adaptation to different agroecological conditions, cause serious damage to tomato crops. Chemical control with synthetic insecticides is widely used to control this pest, although pesticides exhibit side effects on non-target organisms and negatively impact the environment, with the occurrence of resistance to some active substances in the target pest. The use of essential oils (EOs) from aromatic or officinal plants could represent an environmentally safe control method, alternative to synthetic insecticide application. In this work we investigated the effect of EOs from Spanish oregano, laurel, basil, garlic, peppermint, cypress, and eucalyptus EOs on T. absoluta oviposition deterrence and larval repellency. Results showed a remarkable oviposition deterrence using laurel, Spanish oregano, basil, and garlic EOs in both laboratory and greenhouse experiments. In no-choice repellence tests carried 1, 2, 6, and 22 h after treatment application, peppermint and Spanish oregano EOs showed the most lasting effects while cypress and eucalyptus EOs were not effective after 6 and 22 h, respectively. In choice tests, at either 5 or 22 h after treatment application, low preference for the test over control by larvae was observed in all treatments, except for basil EO. The most promising effects were observed in Spanish oregano and laurel treatments where no larvae were detected. Repellent effectiveness of EOs does not seem to be influenced when larvae did not get a chance to do a choice between treated and untreated leaves. This study highlights the effectiveness of EOs of aromatic or officinal plants as an alternative to synthetic insecticides for the control of T. absoluta.

Nanoencapsulation of Thyme Essential Oils: Formulation, Characterization, Storage Stability, and Biological Activity.

This study aimed to improve the effectiveness of Thymus capitatus and Thymus algeriensis essential oils (EOs), as food preservatives, through their encapsulation in different delivery systems (DSs), namely nanoemulsions and biopolymeric nanoparticles. DSs’ preparation is tailored to enhance not only physical stability but also resulting Eos’ antioxidant and antibacterial activities through different fabrication methods (high-pressure homogenization emulsification or antisolvent precipitation) and using different emulsifiers and stabilizers. DSs are characterized in terms of droplet size distribution, ζ-potential, and stability over time, as well as antioxidant and antibacterial activities of encapsulated EOs. The antioxidant activity was studied by the FRAP assay; the antibacterial activity was evaluated by the well diffusion method. EOs of different compositions were tested, namely two EOs extracted from Thymus capitatus, harvested from Tunisia during different periods of the year (TC1 and TC2), and one EO extracted from Thymus algeriensis (TA). The composition of TC1 was significantly richer in carvacrol than TC2 and TA. The most stable formulation was the zein-based nanoparticles prepared with TC1 and stabilized with maltodextrins, which exhibit droplet size, polydispersity index, ζ-potential, and encapsulation efficiency of 74.7 nm, 0.14, 38.7 mV, and 99.66%, respectively. This formulation led also to an improvement in the resulting antioxidant (60.69 µg/mg vs. 57.67 µg/mg for non-encapsulated TC1) and antibacterial (inhibition diameters varying between 12 and 33 mm vs. a range between 12 and 28 mm for non-encapsulated TC1) activities of EO. This formulation offers a promising option for the effective use of natural antibacterial bioactive molecules in the food industry against pathogenic and spoilage bacteria.

Lethal Toxicity of Thymus capitatus Essential Oil Against Planococcus citri (Hemiptera: Pseudococcidae) and its Coccinellid Predator Cryptolaemus montrouzieri (Coleoptera: Coccinellidae)

Abstract Botanical extracts, including essential oils, are promising alternatives to synthetic insecticides for pest control. In this study, we evaluated the fumigant toxicity of an essential oil extracted from Thymus capitatus (L.) Hoffmanns. &amp; Link against the citrus mealybug, Planococcus citri Risso (Hemiptera: Pseudococcidae), and its coccinellid predator Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) under laboratory conditions. Gas chromatography–mass spectrometry analysis indicated that the major chemical compounds identified from T. capitatus were carvacrol (65.15%), followed by p-cymene (11.79%) and γterpinene (7.48%). High mortality levels were registered for P. citri larvae (up to 100%) and adults (up to 96%) when exposed to the tested essential oil. The median lethal concentration values calculated for P. citri adults were higher than for larvae. Thymus capitatus essential oil applied at 10 and 20 µL/Lair showed high toxicity towards C. montrouzieri adults. These results highlighted the efficacy of T. capitatus essential oil as a promising tool to control P. citri in Tunisia. However, the adverse effects of this oil towards C. montrouzieri should be taken into consideration to enhance its practical implication in integrated pest management.