Autoantibodies in children with chronic hepatitis B infection and the influence of interferon alpha

Biological Efficacy of Essential Oils and Plant Extracts of Cultivated and Wild Ecotypes of Origanum vulgare L

Current study describes discrepancy in biological efficacy of methanolic and ethanolic extracts and essential oil procured from cultivated and wild accessions of Origanum vulgare. Simultaneously, quantification of carvacrol, thymol, caryophyllene, ocimene, and terpinen-4-ol contents was determined via GC-MS and GC in both accessions. The results revealed significantly a higher antioxidant potential by methanolic extracts displaying IC₅₀ of 19.9 μg/ml compared to essential oil with IC₅₀ of 10 μg/ml, and ethanolic extracts were found to be less effective even at the concentration of 3 μg/ml. However, essential oil from wild and cultivated accessions of O. vulgare exhibited significantly high antimicrobial activity against all 39 bacteria, 16 fungi, and 2 yeast species tested due to higher concentrations of carvacrol and thymol as revealed by GC analysis. Inhibition of tyrosinase activity in a C6 cell line displayed 81.0%–87.0% depigmentation potential of the methanolic extracts, while ethanolic extracts revealed a maximum of 88.54–99.02% inhibition of reactive oxygen species (ROS) in H₂O₂-treated cells. Hence, the study determines efficacy of essential oil against microbial pathogenesis, methanolic extracts as potent depigmentation agents, and ethanolic extracts as potent free radical scavenger.

Comparison of ultrastructural changes and the anticarcinogenic effects of thymol and carvacrol on ovarian cancer cells: which is more effective?

Ovarian cancer is the seventh most common cancer worldwide in women. Many anticancer drugs are currently used clinically have been isolated from plant species or are based on such substances. Thymol (5-methyl-2-isopropylphenol) and carvacrol are oxygenated aromatic compounds from the monoterpene group. They are the main constituents of thyme essential oil and show antiproliferative, antioxidant, and antiseptic properties. The aim of this study is to compare the antiproliferative and apoptotic effects of thymol and carvacrol on SKOV-3 ovarian cancer cell line. The cancer cells were treated with different concentrations of thymol and carvacrol (100, 200, 400, 600 µM) at 24 h and 48 h durations. The cell viability was investigated by MTT assay and analysis of apoptosis with annexin V assay was determined. The study show that thymol and carvacrol significantly induced apoptosis in all groups as dose and time-dependent (p < .05). The data in the present study demonstrated that thymol and carvacrol have apoptotic and antiproliferative properties in a concentration-dependent manner toward ovarian cancer cells. SKOV-3 cancer cell line was much more sensitive to the toxic effect of thymol than carvacrol.

Antioxidants and antioxidant methods: an updated overview

Antioxidants had a growing interest owing to their protective roles in food and pharmaceutical products against oxidative deterioration and in the body and against oxidative stress-mediated pathological processes. Screening of antioxidant properties of plants and plant-derived compounds requires appropriate methods, which address the mechanism of antioxidant activity and focus on the kinetics of the reactions including the antioxidants. Many studies evaluating the antioxidant activity of various samples of research interest using different methods in food and human health have been conducted. These methods are classified, described, and discussed in this review. Methods based on inhibited autoxidation are the most suited for termination-enhancing antioxidants and for chain-breaking antioxidants, while different specific studies are needed for preventive antioxidants. For this purpose, the most common methods used in vitro determination of antioxidant capacity of food constituents were examined. Also, a selection of chemical testing methods was critically reviewed and highlighted. In addition, their advantages, disadvantages, limitations and usefulness were discussed and investigated for pure molecules and raw extracts. The effect and influence of the reaction medium on the performance of antioxidants are also addressed. Hence, this overview provides a basis and rationale for developing standardized antioxidant methods for the food, nutraceuticals, and dietary supplement industries. In addition, the most important advantages and shortcomings of each method were detected and highlighted. The chemical principles of these methods are outlined and critically discussed. The chemical principles of methods of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS^·+) scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH·) radical scavenging, Fe³⁺-Fe²⁺ transformation assay, ferric reducing antioxidant power (FRAP) assay, cupric ions (Cu²⁺) reducing power assay (Cuprac), Folin-Ciocalteu reducing capacity (FCR assay), peroxyl radical (ROO·), superoxide radical anion (O₂^·-), hydrogen peroxide (H₂O₂) scavenging assay, hydroxyl radical (OH·) scavenging assay, singlet oxygen (¹O₂) quenching assay, nitric oxide radical (NO·) scavenging assay and chemiluminescence assay are outlined and critically discussed. Also, the general antioxidant aspects of main food components were discussed by a number of methods, which are currently used for the detection of antioxidant properties of food components. This review consists of two main sections. The first section is devoted to the main components in the food and pharmaceutical applications. The second general section comprises some definitions of the main antioxidant methods commonly used for the determination of the antioxidant activity of components. In addition, some chemical, mechanistic and kinetic basis, and technical details of the used methods are given.

Effects of the solid lipid nanoparticle of carvacrol on rodents with lung injury from smoke inhalation

The aim of this present study was to evaluate the effect of solid lipid nanoparticles (SLN) containing carvacrol over the lung damage of airway smoke inhalation. The study was conducted with 30 rats subjected to smoke inhalation and divided into 5 groups such as, normal control, negative control, oxygen group, SLN alone, and SLN+CARV group. The animals were sacrificed 24 h after the induction of inhalation injury further, the tissues of larynx, trachea, and lungs were collected for the histological, hematological, myeloperoxidase, and malondialdehyde analysis. The obtained results showed that treatment with CARV+SLN minimized the inhalation injury, since it reduced malondialdehyde significantly, when compared to the negative control group and minimized the histological changes which proves the absence of pulmonary emphysema and exudate in laryngeal and tracheal lumen in the CARV+SLN-treated group. Meanwhile, the presence of lesion with chronic characteristics was observed in the negative control and oxygen groups. It is suggested that the SLN containing carvacrol minimized oxidative stress and histological damages generated from smoke inhalation in rodents.

Heterocyclic β-keto sulfide derivatives of carvacrol: Synthesis and copper (II) ion reducing capacity

Sixteen β-keto sulfide derivatives of carvacrol (4-19) incorporating phenyl or N, O and S heterocyclic moieties were synthesized in three steps. The relationships between heterocyclic structure and cupric, Cu(II), ion reducing antioxidant capacity (CUPRAC) were examined. Nine of the compounds (8-9 and 13-19) showed better CUPRAC activity than trolox at neutral pH, with trolox equivalent antioxidant capacity (TEAC) coefficients ranging between 1.20 and 1.75. Two derivatives (11-12) showed comparable reducing capacity to trolox, with TEAC values of 0.95 for 11 and 1.02 for 12. Compounds 8-9 and 11-19 were more effective at reducing the Cu(II) ion than ascorbic acid and the parent compound, carvacrol. The most effective antioxidants were those containing an oxadiazole, thiadiazole or triazole moiety. In particular, the methyl thiadiazole derivative (15) had the highest Cu(II) ion reducing capacity, with a TEAC coefficient of 1.73.

Medicinal Plant Compounds for Combating the Multi-drug Resistant Pathogenic Bacteria: A Review

BACKGROUND

Globally, people utilize plants as the main source of remedy to heal various ailments. Medicinal plants have been utilized to treat ailments since the invention of modern scientific systems of medicine. The common remedy of infectious diseases mainly depends on the inhibition capacity of compounds or killing potential. The issue may give a clue for the development of a novel antimicrobial agent.

METHODS

Currently, microorganisms which are resistant towards antibiotics are probably a matter of serious concern for the overall well-being of health. At the moment, new therapeutic targets aside from the microorganism wall-based activities are in progress. For instance, the autoinducer molecules produced by the quorum sensing system are used to control antibiotic resistance and biofilm formation.

RESULTS

This therapeutic target is well-studied worldwide, however, the scientific data are not updated and only current studies started to gain insight into its perspective as a target to struggle against infectious diseases. Microbial resistance against antimicrobial compounds is a topic of serious concern in recent time.

CONCLUSION

Hence, this paper aims to confer a current overview of the novel compounds, quorum sensing, quorum quenching, biofilm formation in the development of antibiotic resistance and an update on their importance as a potential target for natural substances.

Thymol, alpha tocopherol, and ascorbyl palmitate supplementation as growth enhancers for broiler chickens

Consumer concern on the quality of products and animal welfare has greatly increased during the past decades. Dietary synthetic antibiotic products used as growth promoters have been restricted or banned in many countries. Edible plants, essential oils, or their main components were suggested as natural feed supplements to improve growth, products' quality, and welfare-related parameters. Thymol (THY), a main component of oregano essential oil, has been proved as an effective antimicrobial and antioxidant compound. Tocopherol (TOC) evidenced antioxidant activity with potential as a growth promoter and a synergic antioxidant activity between TOC and ascorbyl palmitate (AP) has also been reported. Herein, we evaluated whether broiler diet supplementation with THY, and THY with a formulation mix containing TOC and AP (1:0.5:0.5, respectively) have potential as growth enhancers under commercial conditions. Potential protective effects against foot pad dermatitis and hock burns were also evaluated. Newly hatched male broiler chicks with similar body weight (BW) were randomly assigned to 1 of 7 groups (4 replicates each) as follows: Basal (no feed supplements added), Promotor (Basal + 6.26 μmol flavomycin/kg feed), BHT (Basal + 1.33 mmol of buthylated hidroxytoluene (BHT)/kg feed), Prom-BHT (Basal + 6.26 μmol flavomycin/kg feed + 1.33 mmol of BHT/kg feed), TOC-AP (Basal + 0.67 mmoles of TOC + 0.67 mmoles of AP/kg feed), THY (Basal + 1.33 mmoles of THY/kg feed), and THY-TOC-AP (Basal + 0.67 mmoles of THY + 0.67 mmoles of a mix 1:1 of TOC-AP). Along 7 wk, BW, feed intake, and feed conversion ratio were evaluated. Skin injuries were assessed at 35 d of age. At the end of the study (42 d), compared to Basal group, similarly enhanced final BW were observed in all groups but TOC-AP. No main differences between groups were detected in feed intake, feed conversion ratio, or skin injuries. Findings suggest that THY itself or in combination with TOC-AP may have value as a natural growth enhancer alternative for broilers.

Acaricidal activity and enzyme inhibitory activity of active compounds of essential oils against Psoroptes cuniculi

Plant essential oils and its chemical compositions are commonly applied in medicinal and other industries due to their broad advanced pharmacological activities. In the present study, we systematically evaluated the acaricidal activities of twelve compounds of essential oils against Psoroptes cuniculi in vitro and in vivo. In addition, to support the clinic uses, their toxicities against immortalized human keratinocytes (HaCaT) and human liver cells (HL-7702) and skin irritation were studied for evaluating the liver and skin safety. The possible mechanism of action of certain chemical were investigated by determining the inhibitory activities against cytochrome P450 (P450) acetylcholinesterase (AChE) and glutathione-S-transferase (GST). Among all tested compounds, eugenol exhibited the best acaricidal activity with LC₅₀ value of 56.61 μg/ml in vitro. Meanwhile, after the treatment of eugenol for five times within 10 days, the P. cuniculi were eliminated in the naturally infested rabbits, no skin irritation was found in rabbits treated by eugenol. Moreover, eugenol presented no or weak cytotoxicity against HaCaT cells and HL-7702 cells with IC₅₀ values of greater than 100 μg/ml. Furthermore, the moderate inhibitory activities of eugenol against mites P450 and AChE were demonstrated. Above results indicated that eugenol presented the promising acaricidal activity against P. cuniculi in vitro and in vivo, is safe for both humans and animals at the given doses. This work lays the foundation for the development of eugenol as an environmentally friendly acaricide agent.

Antioxidant and Antimicrobial Activity of Mexican Oregano (Poliomintha longiflora) Essential Oil, Hydrosol and Extracts from Waste Solid Residues

Poliomintha longiflora is a Mexican oregano, which has not been widely studied. This work aimed to describe the chemical composition, antimicrobial and antioxidant activities present in P. longiflora essential oil (EO), the hydrosol from EO extraction and extracts from waste solid residues (WSRs), identified as ethanol extract, ethyl acetate extract and the subfractions of ethanol and ethyl acetate extracts. The chemical characterization of the EO, hydrosol and WSR extracts was performed by GC–MS and HPLC. Their antioxidant activity was evaluated using two methods, and their antimicrobial activity was evaluated against Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, and Salmonella Typhimurium. Thirty-one chemical components were identified in the EO. The subfractions from the ethanol and ethyl acetate extracts contain methylmaleic anhydride, thymoquinone, thymol, carvacrol, thymol acetate, carvacrol acetate, and phenolic acids. The EO presented the highest biological activities for antioxidant (136.05 mg equivalent of ascorbic acid/g (AAE/g); IC50 83.70 μg/mL of 2, 2-diphenyl-1-picrylhydrazyl (DPPH)) and antimicrobial tests (minimal inhibitory concentration (MIC) value of 250–750 mg/L), while the hydrosol and the ethyl acetate extract from WSRs had the lowest antioxidant activity (14.16 and 12.29 mg AAE/g respectively), and the hydrosol had the lowest antimicrobial activity (MIC of 3000 mg/L). The data suggest that Mexican oregano P. longiflora hydrosol and extracts from waste solid residues can still have compounds with antimicrobial and antioxidant capacities.

Date palm wood as a new source of phenolic antioxidants and in preparation of smoked salmon

The potential of date palm wood (DPW) as a new source of phenolic antioxidants was investigated in this contribution. The total phenolic content and antiradical activity of soluble and insoluble-bound fractions of DPW was compared to those of maple wood (MW). Furthermore, salmon was smoked with DPW and MW. Irrespective of the wood type, volatile phenolic compounds were mainly methoxyphenols, with the highest contribution from eugenol followed by guaiacol and their corresponding derivatives, as evaluated by solid-phase microextraction and gas chromatography-mass spectrometry. Salmon smoked with DPW showed a higher oxidative stability than that of MW during 21 days of storage at 4°C, which was explained by the higher content of volatile phenolic compounds in the smoke generated from DPW. Minor differences were detected for the instrumental color between both samples of smoked salmon. Therefore, smoking with DPW may be used for industrial meat and fish smoking purposes. PRACTICAL APPLICATIONS: Smoking has long been used to preserve fish and meat products. The process changes the appearance and gives a desirable flavor to the product. However, high temperatures applied during smoking may also induce lipid oxidation, the extent of which is counterbalanced by the antioxidant action of phenolics in woodsmoke. In this sense, the desired interactions of the smoke volatiles in the food matrix dictates the quality of the final product. Volatile phenolics released upon smoking are dependent on the type of wood. Thus, use of a specific wood might provide unique products, hence date palm wood (DPW) used in this work may not only provide special smoked fish products but its use could be extended to other smoked products. Hence, this contribution extends the possible feedstocks for the preparation of smoked products.

Eugenol Confers Cadmium Tolerance via Intensifying Endogenous Hydrogen Sulfide Signaling in Brassica rapa

Eugenol, a plant-derived small compound, shows great medicinal potential. However, whether and how eugenol regulates crop physiology remains elusive. Here we reported that eugenol induced Cd (cadmium) tolerance in the root of Brassica rapa. Roots were treated with eugenol and CdCl₂ simultaneously (eugenol + Cd) or pretreated with eugenol followed by CdCl₂ treatment (eugenol → Cd). Eugenol significantly attenuated Cd-induced growth inhibition, ROS accumulation, oxidative injury, and cell death, which were confirmed by in vivo histochemical analysis. Eugenol remarkably decreased free Cd²⁺ accumulation in root. Eugenol intensified GSH (glutathione) accumulation in roots upon CdCl₂ exposure, which explained the decrease in free Cd²⁺ and attenuation of oxidative injury. Eugenol stimulated endogenous H₂S (hydrogen sulfide) generation by upregulating the expression of BrLCD ( l-cysteine desulfhydrase) and BrDCD ( d-cysteine desulfhydrase) as well as their enzymatic activities in CdCl₂-treated root. Application of H₂S biosynthesis inhibitor or H₂S scavenger led to the decrease in endogenous H₂S level in Cd-treated root, which further compromised all the above effects of eugenol. These findings suggested that eugenol triggered H₂S → GSH signaling cassette in plants to combat Cd stress, which shed new light on eugenol-modulated plant physiology and the interaction between eugenol and H₂S.

Discovery and synthesis of novel magnolol derivatives with potent anticancer activity in non-small cell lung cancer

EGFR T790 M accounts for 50% to 60% of cases of non-small-cell lung carcinoma (NSCLC) resistance to the first-generation EGFR tyrosine kinase inhibitors (TKIs). Hence, identifying novel compounds with activity against TKIs resistant is of great value. In this study, twenty honokiol and magnolol derivatives were isolated from the EtOH extract of Magnolia officinalis and the antiproliferative activity was evaluated on HCC827 (19del EGFR mutation), H1975 (L858 R/T790 M EGFR mutation), and H460 (KRAS mutation) cell lines. Among the isolated compounds, piperitylmagnolol (a 3-substituted magnolol derivative) showed the best antiproliferative activity against those three cell lines with the IC₅₀ values of 15.85, 15.60 and 18.60 μM, respectively, which provided a direction for the structural modification of magnolol. Further structural modification led to the synthesis of thirty-one magnolol derivatives, and compounds A13, C1, and C2 exhibited significant and broad-spectrum antiproliferative activity with the IC₅₀ values ranging from 4.81 to 13.54 μM, which were approximately 4- and 8-fold more potent than those of honokiol and magnolol, respectively. Moreover, their aqueous solubility was remarkably improved with 12-, 400- and 10⁵ fold greater than those of honokiol and magnolol. Anti-tumor mechanism research revealed that these three compounds were able to induce cell cycle arrest at G0/G1 phase, cause efficient apoptosis in H1975 cells, and also prevent the migration of HUVECs in a dose-dependent manner through Cdk2, Cdk4, Cyclin E, and Cyclin D1 inhibition as well as up-regulation of cleaved-PARP and cleaved-caspase 3 levels. In in vivo antitumor activity, C2 (10, 30 and 100 mg/kg, po) dose-dependently inhibited the tumor growth in H1975 xenograft model with the tumor inhibition rate of 46.3%, 59.3% and 61.2% respectively, suggesting that C2 is a potential oral anticancer agent deserving further investigation.

Extraction, profiling and bioactivity analysis of volatile glucosinolates present in oil extract of Brassica juncea var. raya

Cruciferous vegetables are rich source of glucosinolates (GSLs), which in presence of myrosinase enzyme cause hydrolytic cleavage and result in different hydrolytic products like isothiocyanates, thiocyanates, nitriles and epinitriles. The GSLs hydrolytic products are volatile compounds, which are known to exhibit bioactivities like antioxidant, fungicidal, bioherbicidal and anticancer. Among the Brassicaceae family, Brassica juncea is very well known for high content of GSLs. In the present study, the isolation of volatile oil of B. juncea var. raya was done by hydrodistillation method using clevenger apparatus and further there extraction was done by solvents ethyl acetate and dichloromethane. The volatile compounds present in the extract were analysed by gas chromatography/gas chromatography-mass spectrometry (GC/GC-MS). Fatty acid esters, sulphur and/or nitrogen compounds, carbonyl compounds and some other volatile compounds were also identified. Besides the analytical studies, the extracts were analysed for their bioactivities including radical scavenging activity by using DNA nicking assay and cytotoxic effect using different human cancer cell lines viz. breast (MCF-7 and MDA-MB-231), prostate (PC-3), lung (A-549), cervix (HeLa) and colon (HCT116) by MTT assay. The oil extracts were efficiently able to reduce the increase of cancer cells in a dose-dependent manner. Among all cell lines, the most effective anticancer activity was observed in case of breast (MCF-7) cancer cell line. So, MCF-7 cells were used for further mechanistic studies for analysing the mechanism of anticancer activity. Confocal microscopy was done for analysing morphological changes in the cells and the images confirmed the features typical of apoptosis. For evaluating the mode of cell death, spectrofluorometric determination of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) was done. The volatile oil extract treated MCF-7 cells had a significant increase in number of ROS, also there was a rise in percentage of cells with increased disruption of MMP. So, the present study marks necessary indication that B. juncea (raya) oil extracts significantly induces apoptosis in all the above mentioned cancer cells lines through a ROS-mediated mitochondrial pathway and thus play a remarkable role in death of cancer cells.

Isothiocyanates: cholinesterase inhibiting, antioxidant, and anti-inflammatory activity

Finding a new type of cholinesterase inhibitor that would overcome the brain availability and pharmacokinetic parameters or hepatotoxic liability has been a focus of investigations dealing with the treatment of Alzheimer's disease. Isothiocyanates have not been previously investigated as potential cholinesterase inhibitors. These compounds can be naturally produced from their glucosinolate precursors, secondary metabolites widely distributed in our daily Brassica vegetables. Among 11 tested compounds, phenyl isothiocyanate and its derivatives showed the most promising inhibitory activity. 2-Methoxyphenyl ITC showed best inhibition on acetylcholinesterase with IC₅₀ of 0.57 mM, while 3-methoxyphenyl ITC showed the best inhibition on butyrylcholinesterase having 49.2% at 1.14 mM. Assessment of the antioxidant efficacy using different methods led to a similar conclusion. The anti-inflammatory activity was also tested using human COX-2 enzyme, ranking phenyl isothiocyanate, and 3-methoxyphenyl isothiocyanate as most active, with ∼99% inhibition at 50 μM.

Chitosan nanoparticles functionalized with β-cyclodextrin: a promising carrier for botanical pesticides

Carvacrol and linalool are natural compounds extracted from plants and are known for their insecticidal and repellent activities, respectively. However, their low aqueous solubility, high photosensitivity, and high volatility restrict their application in the control of agricultural pests. The encapsulation of volatile compounds can be an effective way of overcoming such problems. Inclusion complexes between beta-cyclodextrin (β-CD) and carvacrol (CVC) or linalool (LNL) were investigated. Inclusion complexes were prepared by the kneading method. Both complexes presented 1:1 host:guest stoichiometry and the highest affinity constants were observed at 20 °C for both molecules. The nanoparticles containing carvacrol and linalool had mean diameters of 175.2 and 245.8 nm, respectively and high encapsulation efficiencies (<90%) were achieved for both compounds. Biological assays with mites (Tetranychus urticae) showed that the nanoparticles possessed repellency, acaricidal, and oviposition activities against this organism. Nanoencapsulated carvacrol and linalool were significantly more effective in terms of acaricidal and oviposition activities, while the unencapsulated compounds showed better repellency activity. The nanoformulations prepared in this study are good candidates for the sustainable and effective use of botanical compounds in agriculture, contributing to the reduction of environmental contamination, as well as promoting the effective control of pests in agriculture.

Development of Burdock Root Inulin/Chitosan Blend Films Containing Oregano and Thyme Essential Oils

In this study, inulin (INU) extracted from burdock root was utilized as a new film base material and combined with chitosan (CHI) to prepare composite films. Oregano and thyme essential oils (OT) were incorporated into the INU-CHI film to confer the films with bioactivities. The physical and optical properties as well as antioxidant and antimicrobial activities of the films were evaluated. INU film alone showed poor physical properties. In contrast, the compatibility of INU and CHI demonstrated by the changes in attenuated total reflectance-Fourier transformation infrared spectrum of the INU-CHI film increased tensile strength and elongation at break of the INU film by 8.2- and 3.9-fold, respectively. In addition, water vapor permeability, water solubility, and moisture content of the films decreased proportionally with increasing OT concentration in the INU-CHI film. Incorporation of OT also increased the opacity of a and b values and decreased the L value of the INU-CHI films. All INU-CHI films containing OT exhibited antioxidant and antimicrobial properties. Particularly, the INU-CHI film with 2.0% OT exhibited the highest 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), 2,2-diphenyl-1-picrylhydrazyl radical scavenging, and antimicrobial activities against four pathogens. Thus, the INU-CHI film containing OT developed in this study might be utilized as an active packaging material in the food industry.

Thymol/cyclodextrin inclusion complex nanofibrous webs: Enhanced water solubility, high thermal stability and antioxidant property of thymol

The development of novel nanomaterials that provide an efficient encapsulation and protection for the active food additives is one of the main focuses of current research efforts at food application areas. From this point of view, in this study, nanofibrous webs from inclusion complexes (IC) of modified cyclodextrins (hydroxypropyl-β-cyclodextrin (HPβCD), hydroxypropyl-γ-cyclodextrin (HPγCD) and methyl-β-cyclodextrin (MβCD)) and essential oils compound (i.e. thymol) was produced through electrospinning technique. While pure thymol has a highly volatile nature, the volatility of thymol was effectively suppressed by the inclusion complexation and ~88-100% (w/w) of thymol was preserved in electrospun thymol/cyclodextrin inclusion complex nanofibers (Thymol/CD-IC NF). The aqueous solubility enhancement for hydrophobic thymol was demonstrated by phase solubility diagram which also suggested the 1:1M inclusion complexation between thymol and CD molecules. Besides, Thymol/CD-IC NF displayed quite fast disintegration in water compared to poorly water soluble thymol. By inclusion complexation, high temperature stability for volatile thymol was achieved for Thymol/CD-IC NF samples. The loading of thymol in Thymol/CD-IC NF conferred DPPH radical scavenging ability to these nanofibrous webs. So, the Thymol/CD-IC NF have shown antioxidant activity along with enhanced water solubility and high thermal stability of thymol. In brief, encapsulation of essential oil compounds such as thymol in electrospun CD-IC nanofibers can promote its potential application in food and oral-care products by associating the large surface area of nanofibrous webs along with CD inclusion complexation which provides enhanced water solubility and antioxidant property, and high temperature stability for thymol.

Perspectives on medicinal properties of natural phenolic monoterpenoids and their hybrids

Carvacrol, thymol and eugenol belong to a class of naturally presenting phenols with a ten-carbon unit, which are present in essential oils of many plants. These versatile molecules are incorporated as useful ingredients in many food products and find applications in agricultural, pharmaceutical, fragrance, cosmetic, flavor and other industries. They are wide ranging of biological and pharmaceutical activities: anti-inflammatory, antimicrobial, analgesic, anticancer and antioxidant. This review summarizes pharmacological and medicinal activities of these phytochemicals and their synthetic hybrids.

Pharmacological Properties and Molecular Mechanisms of Thymol: Prospects for Its Therapeutic Potential and Pharmaceutical Development

Thymol, chemically known as 2-isopropyl-5-methylphenol is a colorless crystalline monoterpene phenol. It is one of the most important dietary constituents in thyme species. For centuries, it has been used in traditional medicine and has been shown to possess various pharmacological properties including antioxidant, free radical scavenging, anti-inflammatory, analgesic, antispasmodic, antibacterial, antifungal, antiseptic and antitumor activities. The present article presents a detailed review of the scientific literature which reveals the pharmacological properties of thymol and its multiple therapeutic actions against various cardiovascular, neurological, rheumatological, gastrointestinal, metabolic and malignant diseases at both biochemical and molecular levels. The noteworthy effects of thymol are largely attributed to its anti-inflammatory (via inhibiting recruitment of cytokines and chemokines), antioxidant (via scavenging of free radicals, enhancing the endogenous enzymatic and non-enzymatic antioxidants and chelation of metal ions), antihyperlipidemic (via increasing the levels of high density lipoprotein cholesterol and decreasing the levels of low density lipoprotein cholesterol and low density lipoprotein cholesterol in the circulation and membrane stabilization) (via maintaining ionic homeostasis) effects. This review presents an overview of the current in vitro and in vivo data supporting thymol's therapeutic activity and the challenges concerning its use for prevention and its therapeutic value as a dietary supplement or as a pharmacological agent or as an adjuvant along with current therapeutic agents for the treatment of various diseases. It is one of the potential candidates of natural origin that has shown promising therapeutic potential, pharmacological properties and molecular mechanisms as well as pharmacokinetic properties for the pharmaceutical development of thymol.

Essential Oils and Eugenols Inhibit Biofilm Formation and the Virulence of Escherichia coli O157:H7

Enterohemorrhagic Escherichia coli O157:H7 (EHEC) has caused foodborne outbreaks worldwide and the bacterium forms antimicrobial-tolerant biofilms. We investigated the abilities of various plant essential oils and their components to inhibit biofilm formation by EHEC. Bay, clove, pimento berry oils and their major common constituent eugenol at 0.005% (v/v) were found to markedly inhibit EHEC biofilm formation without affecting planktonic cell growth. In addition, three other eugenol derivatives isoeugenol, 2-methoxy-4-propylphenol, and 4-ethylguaiacol had antibiofilm activity, indicating that the C-1 hydroxyl unit, the C-2 methoxy unit, and C-4 alkyl or alkane chain on the benzene ring of eugenol play important roles in antibiofilm activity. Interestingly, these essential oils and eugenol did not inhibit biofilm formation by three laboratory E. coli K-12 strains that reduced curli fimbriae production. Transcriptional analysis showed that eugenol down-regulated 17 of 28 genes analysed, including curli genes (csgABDFG), type I fimbriae genes (fimCDH) and ler-controlled toxin genes (espD, escJ, escR, and tir), which are required for biofilm formation and the attachment and effacement phenotype. In addition, biocompatible poly(lactic-co-glycolic acid) coatings containing clove oil or eugenol exhibited efficient biofilm inhibition on solid surfaces. In a Caenorhabditis elegans nematode model, clove oil and eugenol attenuated the virulence of EHEC.

A carvacrol-thymol blend decreased intestinal oxidative stress and influenced selected microbes without changing the messenger RNA levels of tight junction proteins in jejunal mucosa of weaning piglets

Recent studies indicate that intestinal oxidative stress and microbiota imbalance is involved in weaning-induced intestinal dysfunction in piglets. We have investigated the effect of feeding a carvacrol-thymol blend supplemented diet on intestinal redox status, selected microbial populations and the intestinal barrier in weaning piglets. The piglets (weaned at 21 days of age) were randomly allocated to two groups with six pens per treatment and 10 piglets per pen. At weaning day (21 days of age), six piglets were sacrificed before weaning to serve as the preweaning group. The weaned group was fed with a basal diet, while the weaned-CB group was fed with the basal diet supplemented with 100 mg/kg carvacrol-thymol (1 : 1) blend for 14 days. On day 7 post-weaning, six piglets from each group were sacrificed to determine intestinal redox status, selected microbial populations, messenger RNA (mRNA) transcript levels of proinflammatory cytokines and biomarkers of intestinal barrier function. Weaning resulted in intestinal oxidative stress, indicated by the increased concentration of reactive oxygen species and thiobarbituric acid-reactive substances present in the intestine. Weaning also reduced the population of Lactobacillus genus and increased the populations of Enterococcus genus and Escherichia coli in the jejunum, and increased mRNA levels of tumor necrosis factor α (TNF-α), interleukin 1β and interleukin 6 (IL-6). In addition, decreased mRNA levels of zonula occludens and occludin in the jejunal mucosa and increased plasma diamine oxidase concentrations indicated that weaning induced dysfunction of the intestinal barrier. On day 7 post-weaning, supplementation with the carvacrol-thymol blend restored weaning-induced intestinal oxidative stress. Compared with the weaned group, the weaned-CB group had an increased population of Lactobacillus genus but reduced populations of Enterococcus genus and E. coli in the jejunum and decreased mRNA levels of TNF-α. The results indicated that weaning induced intestinal oxidative stress and dysfunction of the intestinal barrier. Dietary supplementation with 100 mg/kg carvacrol-thymol (1 : 1) decreased the intestinal oxidative stress and influenced selected microbial populations without changing the biomarkers of intestinal barrier in weaning piglets.

Bioactive Secondary Metabolites from Schizogyne sericea (Asteraceae) Endemic to Canary Islands

Schizogyne sericea (Asteraceae) is a halophytic shrub endemic to the Canary Islands and traditionally employed as analgesic, astringent, anti-inflammatory, and vulnerary. A comprehensive phytochemical investigation was conducted on the flowering aerial parts by analyzing both essential oil constituents and polar compounds. The essential oil was dominated by p-cymene, with the noteworthy occurrence of β-pinene and thymol esters. From the EtOH extract, eight compounds were isolated and structurally elucidated. Essential oil, polar fractions, and isolates (2), (4), and (5) were separately in vitro assayed for antiproliferative activity on human tumor cell lines (A375, MDA-MB 231, and HCT116) by MTT assay, for antioxidant potential by DPPH, ABTS, and FRAP assays, and for antimicrobial activity by the agar disk diffusion method. Results revealed that essential oil and compounds 1 and 2 exert a strong inhibition on tumor cells, and in some cases, higher than that of cisplatin. Fractions containing thymol derivatives (1 and 2) and caffeoylquinic acid derivatives 4 and 5 displayed antioxidant activity comparable to that of Trolox, making S. sericea extract an interesting natural product with potential applications as preservative or in the treatment of diseases in which oxidative stress plays an important role.

Biological and Nonbiological Antioxidant Activity of Some Essential Oils

Fifteen essential oils, four essential oil fractions, and three pure compounds (thymol, carvacrol, and eugenol), characterized by gas chromatography and gas chromatography-mass spectrometry, were investigated for biological and nonbiological antioxidant activity. Clove oil and eugenol showed strong DPPH (2,2-diphenyl-1-picrylhydrazyl) free-radical scavenging activity (IC50 = 13.2 μg/mL and 11.7 μg/mL, respectively) and powerfully inhibited reactive oxygen species (ROS) production in human neutrophils stimulated by PMA (phorbol 12-myristate 13-acetate) (IC50 = 7.5 μg/mL and 1.6 μg/mL) or H2O2 (IC50 = 22.6 μg/mL and 27.1 μg/mL). Nutmeg, ginger, and palmarosa oils were also highly active on this test. Essential oils from clove and ginger, as well as eugenol, carvacrol, and bornyl acetate inhibited NO (nitric oxide) production (IC50 < 50.0 μg/mL). The oils of clove, red thyme, and Spanish oregano, together with eugenol, thymol, and carvacrol showed the highest myeloperoxidase inhibitory activity. Isomers carvacrol and thymol displayed a disparate behavior in some tests. All in all, clove oil and eugenol offered the best antioxidant profile.

Determination of formation constants and structural characterization of cyclodextrin inclusion complexes with two phenolic isomers: carvacrol and thymol

Carvacrol and thymol have been widely studied for their ability to control food spoilage and to extend shelf-life of food products due to their antimicrobial and antioxidant activities. However, they suffer from poor aqueous solubility and pronounced flavoring ability that limit their application in food systems. These drawbacks could be surpassed by encapsulation in cyclodextrins (CDs). Applications of their inclusion complexes with CDs were reported without investigating the inclusion phenomenon in deep. In this study, inclusion complexes were characterized in terms of formation constants (K_f), complexation efficiency (CE), CD:guest molar ratio and increase in bulk formulation by using an UV–visible competitive method, phase solubility studies as well as ¹H and DOSY ¹H NMR titration experiments. For the first time, a new algorithmic treatment that combines the chemical shifts and diffusion coefficients variations for all guest protons was applied to calculate K_f. The position of the hydroxy group in carvacrol and thymol did not affect the stoichiometry of the inclusion complexes but led to a different binding stability with CDs. 2D ROESY NMR experiments were also performed to prove the encapsulation and illustrate the stable 3D conformation of the inclusion complexes. The structural investigation was accomplished with molecular modeling studies. Finally, the radical scavenging activity of carvacrol and thymol was evaluated by the ABTS radical scavenging assay. An improvement of this activity was observed upon encapsulation. Taken together, these results evidence that the encapsulation in CDs could be valuable for applications of carvacrol and thymol in food.