Carvacrol methyl ether

Antioxidant and Antibacterial Capacities of Origanum vulgare L. Essential Oil from the Arid Andean Region of Chile and its Chemical Characterization by GC-MS.[Pubmed:33081116]

Metabolites. 2020 Oct 16;10(10). pii: metabo10100414.

This study aimed to characterize the in vitro antioxidant and antibacterial properties of oregano (Origanum vulgare) essential oil, as well as its chemical composition. To our best knowledge, there are few studies on oregano grown in the arid Andes region, but none on the metabolites produced and their bioactivity. This work identified fifty metabolites by Gas Chromatography-Mass Spectrometry (GC-MS)-monoterpene hydrocarbons, oxygenated monoterpenes, phenolic monoterpenes, sesquiterpene hydrocarbons, and oxygenated sesquiterpenes-present in the essential oil of oregano collected in the Atacama Desert. The main components of essential oregano oil were thymol (15.9%), Z-sabinene hydrate (13.4%), gamma-terpinene (10.6%), p-cymene (8.6%), linalyl acetate (7.2%), sabinene (6.5%), and Carvacrol methyl ether (5.6%). The antibacterial tests showed that the pathogenic bacteria Staphylococcus aureus and Salmonella enterica and the phytopathogenic bacteria Erwinia rhapontici and Xanthomonas campestris were the most susceptible to oregano oil, with the lowest concentrations of oil necessary to inhibit their bacterial growth. Moreover, oregano oil showed antibacterial activity against bacteria associated with food poisoning. In conclusion, O. vulgare from the arid Andean region possesses an important antibacterial activity with a high potential in the food industry and agriculture.

Bioassay-guided isolation of active compounds from Adenosma buchneroides essential oil as mosquito repellent against Aedes albopictus.[Pubmed:30471377]

J Ethnopharmacol. 2019 Mar 1;231:386-393.

ETHNOPHARMACOLOGICAL RELEVANCE: A folk herb Adenosma buchneroides found in the previous ethnobotanical investigation plays an important role as an insect repellent among the Aini people in southwest of China, but the active compounds responsible for repellent activity of the plant have not yet been investigated. AIM OF THE STUDY: The main purpose of the study is to identify the active components of the essential oil which responsible for its repellent activity against Aedes albopictus to support the usage of the plant as mosquito repellent by Aini people. In addition, to supply a class of potential alternatives characterized carvacrol analogues to develop natural repellent products. MATERIAL AND METHODS: The essential oil from aerial part of Ad. buchneroides was extracted by hydrodistillation. A systematic bioassay-guided isolation of repellent compounds from the essential oil was conducted through chromatographic fractionation combined with in-cage mosquito repellent bioassay. The identification of the essential oil components was accomplished by GC-MS and GC-FID techniques. The structural elucidation of compounds was performed on the basis of IR, HR-ESI-MS and NMR. Larvicidal activity and cytotoxicity of all repellent compounds also tested by larval bioassays and MTS assays, respectively. Structure-activity relationship (SAR) of carvacrol analogues was investigated by in-cage mosquito repellent bioassay. RESULTS: The essential oil of the plant showed strong mosquito repellent activity with minimum effective dosage (MED) of 0.019+/-0.007mg/cm(2), compared to reference standard N,N-diethyl-3-methylbenzamide (DEET) (0.031+/-0.014mg/cm(2)). 26 compounds representing 97.8% of the essential oil were identified. Carvacrol, Carvacrol methyl ether and a new fragrant compound, adenosmin A (1) were found to be repellent compounds by systematic bioassay-guided isolation, with MEDs in the range of 0.011-0.125mg/cm(2). An investigation on SAR of carvacrol analogues led to the discover of three analogues with further lower MEDs (0.002-0.009mg/cm(2)) than that of DEET, and other three compounds with similar MEDs (0.029-0.039mg/cm(2)) to that of DEET. Carvacrol (LD50 of 24.8ppm) was the best larvicide among tested repellent compounds. The essential oil and repellent compounds against seven mammalian cell lines revealed low or no cytotoxicity. CONCLUSIONS: Scientific evidences reported here validate the plant's traditional use as insect repellent and imply promising application of the essential oil and carvacrol analogues as natural mosquito repellents.

alpha-Glucosidase Inhibition and Antibacterial Activity of Secondary Metabolites from the Ecuadorian Species Clinopodium taxifolium (Kunth) Govaerts.[Pubmed:29324657]

Molecules. 2018 Jan 11;23(1). pii: molecules23010146.

The phytochemical investigation of both volatile and fixed metabolites of Clinopodium taxifolium (Kunth) Govaerts (Lamiaceae) was performed for the first time. It allowed the isolation and characterization of the essential oil and six known compounds: carvacrol (1), squalane (2), uvaol (3), erythrodiol (4), ursolic acid (5), and salvigenin (6). Their structures were identified and characterized by Nuclear Magnetic Resonance (NMR) and Gas Chromatography coupled to Mass Spectroscopy (GC-MS), and corroborated by literature. The essential oil of the leaves was obtained by hydrodistillation in two different periods and analyzed by GC-MS and GC coupled to Flame Ionization Detector (GC-FID). A total of 54 compounds were detected, of which 42 were identified (including trace constituents). The major constituents were Carvacrol methyl ether (18.9-23.2%), carvacrol (13.8-16.3%) and, carvacryl acetate (11.4-4.8%). The antibacterial activities were determined as Minimum Inhibition Concentration (MIC) against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa and Micrococcus luteus. The hexane and methanol extracts exhibited activity only against Klebsiella pneumoniae (250 and 500 mug/mL respectively), while the ethyl acetate extract was inactive. The hypoglycemic activity was evaluated by the in vitro inhibition of alpha-glucosidase. The ethyl acetate (EtOAc) extract showed strong inhibitory activity with IC50 = 24.88 microg/mL, however methanolic and hexanic extracts showed weak activity. As a pure compound, only ursolic acid showed a strong inhibitory activity, with IC50 = 72.71 muM.

The anti-dermatophyte activity of Zataria multiflora essential oils.[Pubmed:28347599]

J Mycol Med. 2017 Jun;27(2):232-237.

OBJECTIVE: Dermtophytes are a group of pathogenic fungi and the major cause of dermatophytosis in humans and animals. Fighting dermatophytes by natural essential oils is one important issue in new researches. MATERIALS AND METHODS: In this investigation, we evaluated the anti-dermatophyte activities of three samples of Z. multiflora essential oils against dermatophytes along with analysis of chemical compositions of the essential oils and their anti-elastase activities on elastase production in dermatophytes. RESULTS: Carvacrol (1.5-34.4%), thymol (25.8-41.2%), Carvacrol methyl ether (1.9-28.3%) and p-cymene (2.3-8.3%) were the main components of Z. multiflora essential oils. Z. multiflora essential oils (100ppm) inhibited the mycelium growth of dermatophytes (6+/-1.7-47.0+/-1.4%) and had the minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) values of 0.03-0.25mul/ml against dermatophytes. Essential oils inhibited elastase produced in dermatophytes and pure porcine elastase. CONCLUSION: Z. multiflora essential oils can be used as natural anti-dermatophyte agent for fighting dermatophytes in further preclinical and clinical studies.

Variations in Essential Oil Compositions of Lavandula pubescens (Lamiaceae) Aerial Parts Growing Wild in Yemen.[Pubmed:27701813]

Chem Biodivers. 2017 Mar;14(3).

Lavandula pubescens Decne. is one of five Lavandula species growing wild in Yemen. The plant is used in Yemeni traditional medicine, and the essential oil tends to be rich in carvacrol. In this work, L. pubescens was collected from eight different locations in Yemen, the essential oils obtained by hydrodistillation, and the oils analyzed by gas chromatography/mass spectrometry (GC/MS). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to differentiate between the L. pubescens samples. The essential oils were rich in carvacrol (60.9 - 77.5%), with lesser concentrations of Carvacrol methyl ether (4.0 - 11.4%), caryophyllene oxide (2.1 - 6.9%), and terpinolene (0.6 - 9.2%). The essential oil compositions in this study showed very high similarity, but it was possible to discern two separate groups based on minor components, in particular the concentrations of terpinolene, Carvacrol methyl ether, m-cymen-8-ol, and caryophyllene oxide.

Compositional Analysis of Lavandula pinnata Essential Oils.[Pubmed:27169176]

Nat Prod Commun. 2016 Mar;11(3):287-90.

The genus Lavandula includes about thirty species plus a number of intraspecific taxa and hybrids, which are distributed in the Mediterranean area. The traditional use of lavender both as perfume or medicinal plant is known since antiquity. Nowadays several species are extensively cultivated for the extraction of their essential oils (EOs) which are used in manufactured products like cosmetics and perfumes or in phytotherapy. Lavandula pinnata L. f. (syn L. pinnata Lundmark) is a rare species native to the Canary Islands used in folk medicine as relaxant and also a valuable remedy against bites. To the best of our knowledge, EOs from L. pinnata have been very little studied. The present paper reports on the quali- and quantitative compositional profile of the EOs distilled (by a Spring type apparatus) from the aerial parts (flowers and leaves) of this species cultivated in soilless conditions. Chemical analyses by means of GC and GC-MS techniques have indicated that oxygenated monoterpenes are the main constituents of both the flowers (68.30%) and the leaves (83.65%). Carvacrol is the main compound which characterizes the EOs of this species. In addition, discrete amounts of spathulenol (12.22%) and caryophyllene oxide (14.62%) have been detected in flowers EOs, while leaves EOs contained small amounts of Carvacrol methyl ether (2.52%).

Essential oil diversity of European Origanum vulgare L. (Lamiaceae).[Pubmed:26454793]

Phytochemistry. 2015 Nov;119:32-40.

This investigation focused on the qualitative and quantitative composition of essential oil compounds of European Origanum vulgare. Extracts of 502 individual O. vulgare plants from 17 countries and 51 populations were analyzed via GC. Extracts of 49 plants of 5 populations of Israeli Origanum syriacum and 30 plants from 3 populations of Turkish Origanum onites were included to exemplify essential oil characteristics of 'high-quality' oregano. The content of essential oil compounds of European O. vulgare ranged between 0.03% and 4.6%. The monoterpenes were primarily made up of sabinene, myrcene, p-cymene, 1,8-cineole, beta-ocimene, gamma-terpinene, sabinene hydrate, linalool, alpha-terpineol, Carvacrol methyl ether, linalyl acetate, thymol and carvacrol. Among the sesquiterpenes beta-caryophyllene, germacrene D, germacrene D-4-ol, spathulenol, caryophyllene oxide and oplopanone were often present in higher amounts. According to the proportions of cymyl-compounds, sabinyl-compounds and the acyclic linalool/linalyl acetate three different main monoterpene chemotypes were defined. The cymyl- and the acyclic pathway were usually active in plants from the Mediterranean climate whereas an active sabinyl-pathway was a characteristic of plants from the Continental climate.

Composition, in vitro Anti-inflammatory, Antioxidant and Antimicrobial Activities of Essential Oils from Leaf and Twig Parts of Cupressus cashmeriana.[Pubmed:26434142]

Nat Prod Commun. 2015 Aug;10(8):1461-4.

The chemical composition and in vitro anti-inflammatory, antioxidant and antimicrobial activities of the essential oils isolated from the leaf and twig of Cupressus cashmeriana have been investigated. The essential oils were isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS, respectively. The leaf oil mainly consisted of alpha-pinene (21.8%), epizonarene (8.0%), sabinene (7.9%), limonene (7.6%), gamma-terpinene (7.0%), and allo-aromadendrene (7.0%); the twig oil was mostly Carvacrol methyl ether (35.4%), manool (16.1%), carvacrol (14.2%), and (2Z,6E)-farnesol (6.9%). Twig oil, but not leaf oil, was able to reduce nitric oxide production by lipopolysaccharide-activated murine macrophages RAW 264.7 without reducing the cell viability. In addition, twig oil showed better antioxidant and antimicrobial activities than leaf oil. The major ingredient of the twig oil that was responsible for the anti-inflammatory, antioxidant and antimicrobial activities was carvacrol.

Physicochemical and antioxidative characteristics of Iranian pomegranate (Punica granatum L. cv. Rabbab-e-Neyriz) juice and comparison of its antioxidative activity with Zataria multiflora Boiss essential oil.[Pubmed:25610584]

Vet Res Forum. 2014 Fall;5(4):313-8.

Pomegranate juice (PJ) and its products are directly used in foods due to their pleasant taste and palatability as well as preservative effects. In spite of useful effects of essential oils such as zataria multiflora Boiss essential oil (ZEO) on prolonging shelf-life of foods, their application is restricted due to their vigorous taste and aroma. In the present study, physicochemical characteristics, chemical compositions and antioxidative activities of two Iranian native plants, PJ (Rabbab-e-Neyriz cultivar) and ZEO were investigated. 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and reducing power tests were used for measuring antioxidant activity. The level of total phenolic of them were also determined. Total soluble solids content, pH value, titratable acidity content and total anthocyanins content of PJ were also measured. Chemical compositions of ZEO were determined using gas-chromatography, mass-spectrometry (GC-MS). The results of antioxidative tests indicated that the ZEO was significantly more potent (p < 0.05) than PJ. Also the phenolic content in ZEO (262.52 mg per g) was significantly higher (p < 0.05) than PJ (154.90 mg per 100g). Chemical compositions analysis of ZEO indicated that its major components were carvacrol (59.17%), linalool (23.67%), trans-caryophyllene (3.07%) and Carvacrol methyl ether (2.44%). In the present study, physicochemical and antioxidative characteristics of Rabbab-e-Neyriz PJ were determined for first time. It was aslo found that ZEO in comparison with PJ had higher antioxidative activity and total phenolic content.

Cytotoxicity and antimicrobial activity of the essential oil from Satureja montana subsp. pisidica (Lamiceae).[Pubmed:24868886]

Nat Prod Commun. 2014 Apr;9(4):569-72.

The antimicrobial and cytotoxic activities of the essential oil of Satureja montana ssp. pisidica from two localities (mountains Korab and Galicica) were studied. Forty-nine components were identified in the each sample. Oxygenated monoterpene hydrocarbons were the major compounds: carvacrol, thymol, Carvacrol methyl ether and beta-linalool. Both tested essential oils showed very high and similar antimicrobial activity. Minimal inhibitory concentrations ranged from 12.5 microg/mL against S. epidermidis to 50 microg/mL against P. aeruginosa and C. albicans. The cytotoxic effect of the essential oils was tested against MDA-MB-361, MDA-MB-453, HeLa, LS174 and MRC5 cells. The essential oil from Korab demonstrated significantly better results than the oil from Galicica, particularly against HeLa and MDA-MB-453 cell lines, with IC50 values of 63.5 and 72.3 microg/mL, while the oil from Galicica was the most active on the human epithelial cervical cancer HeLa cells (IC50 99.7 microg/mL).

Bioassay-guided investigation of two Monarda essential oils as repellents of yellow fever mosquito Aedes aegypti.[Pubmed:23919579]

J Agric Food Chem. 2013 Sep 11;61(36):8573-80.

As part of an ongoing research program to identify active mosquito repellents, Monarda bradburiana Beck and Monarda fistulosa L. essential oils showed good repellent activity with minimum effective dosages (MED) of 0.055 +/- 0.036 and 0.078 +/- 0.027 mg/cm(2), respectively, compared to reference standard N,N-diethyl-3-methylbenzamide (DEET) (0.039 +/- 0.014 mg/cm(2)). Systematic bioassay-guided fractionation of essential oils of both Monarda species was performed to identify the active repellent compounds, and isolated pure compounds were individually tested for repellency. Of the isolated compounds, carvacrol, thymol, eugenol, and Carvacrol methyl ether were found to be the repellent compounds with MEDs in the range of 0.013-0.063 mg/cm(2). Active repellent compounds were also tested for larvicidal activity against 1-day-old Aedes aegypti larvae. Thymol was the best larvicide among the tested individual compounds (LD50 of 13.9 ppm). None of the individual compounds showed cytotoxicity against mammalian cells; however, the essential oils were toxic to all cell lines.