Antibacterial effects of the essential oils of commonly consumed medicinal herbs using an in vitro model

The chemical composition and antibacterial activity of essential oils from 10 commonly consumed herbs: Citrus aurantium, C. limon, Lavandula angustifolia, Matricaria chamomilla, Mentha piperita, M. spicata, Ocimum basilicum, Origanum vulgare, Thymus vulgaris and Salvia officinalis have been determined. The antibacterial activity of these oils and their main components; i.e. camphor, carvacrol, 1,8-cineole, linalool, linalyl acetate, limonene, menthol, a-pinene, b-pinene, and thymol were assayed against the human pathogenic bacteria Bacillus subtilis, Enterobacter cloacae, Escherichia coli O157:H7, Micrococcus flavus, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella enteritidis, S. epidermidis, S. typhimurium, and Staphylococcus aureus. The highest and broadest activity was shown by O. vulgare oil. Carvacrol had the highest antibacterial activity among the tested components.     

Comparative volatile oil composition of four Ocimum species from northern India

The hydrodistilled essential oils of Ocimum basilicum L. cvs. 'Vikarsudha' and 'CIM-Soumya', Ocimum sanctum L. cvs. 'Green' (CIM-Ayu) and 'Purple', Ocimum gratissimum L. and Ocimum kilimandscharicum Guerke have been studied by capillary gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Phenylpropanoids (65.2-77.6%) constituted the major proportion of the essential oil compositions of O. sanctum, O. basilicum and O. gratissimum, whilst oxygenated monoterpenes (72.7%) constituted the major proportion of the oil composition of O. kilimandscharicum. The essential oil compositions of cvs. 'Green' and 'Purple' of O. sanctum were almost the same, and both cultivars were dominated by eugenol (67.4% and 72.8%), β-elemene (11.0% and 10.9%), β-caryophyllene (7.3% and 8.4%) and germacrene D (2.4% and 2.2%), whilst the major components in O. basilicum cvs. 'Vikarsudha' and 'CIM-Soumya' were methyl chavicol (68.0% and 64.9%) and linalool (21.9% and 25.6%), along with bicyclogermacrene (2.0% and 0.7%) and α-terpineol (1.2% and 0.1%). Eugenol (77.2%), 1,8-cineole (7.6%), germacrene D (2.7%) and β-caryophyllene (1.7%) were identified as the major constituents of O. gratissimum. On the contrary, the essential oil from O. kilimandscharicum was mainly dominated by monoterpenoids (95.8%), represented by camphor (64.9%), limonene (8.7%), camphene (6.4%) and (E)-β-ocimene (3.0%).     

Chemical and biological diversity in fourteen selections of four Ocimum species

Biomass, essential oil yield, essential oil composition diversity, and antibacterial and antifungal activities of 14 selections of 4 Ocimum species [Ocimum basilicum L. (selections: T1-T10), O. gratissimum L. (selections: T11-T12), O. tenuiflorum L.f., syn. O. sanctum L. (selection: T13) and O. kilimandscharicum Baker ex. Guerke (selection: T14)] were investigated. O. basilicum selections T9 (methyl chavicol: 87.0%) and T10 {(Z)- and (E)-methyl cinnamate: 69.1%} produced higher biomass (67.8 and 56.7 t/ha) and oil (203.4 and 141.7 kg/ha) yields relative to 8 (T1-T8) linalool (up to 58.9%), or methyl chavicol (up to 61.8%) rich selections. O. gratissimum selection T12 (eugenol: 84.1%, 254.6 kg/ha oil yield) was significantly superior to T11 (62.1% eugenol and 18.4% camphor). O. tenuiflorum (T13, methyl eugenol: 72.5%) and O. kilimandscharicum (T14, camphor: 51.7%) produced 171.7 and 96.2 kg/ha essential oil, respectively. The essential oils exhibited broad spectrum antibacterial (against 5 Gram-positive and 7 Gram-negative bacteria) and antifungal (against 10 fungi) activities. The bacterial species Bacillus subtilis, Staphylococcus aureus, Streptococcus mutans, and Enterococcus faecalis, and the fungal species Epidermophyton floccosum, Microsporum gypseum, and Sporothrix schenckii were more sensitive to the essential oils.     

Chemical composition and insecticidal activity of essential oils of two aromatic plants from Ivory Coast against Bemisia tabaci G. (Hemiptera: Aleyrodidae)

Essential oils of aromatic plants with insecticidal properties are nowadays considered as alternative insecticides to protect cultures from attack by insect pest. The aims of the present work were to evaluate the toxicity of the essential oils vapors of two aromatic plants (Lippia multiflora Mold. and Aframomum latifolium K. Schum) against Bemisia tabaci and to characterize their chemical composition. The highest fumigant toxicity against B. tabaci adults was observed with the L. multiflora oil: by exposure to 0.4 microL/L air, the lethal time inducing 90% mortality (LT90) was below 2 hours for this essential oil whereas it reached 15 h in the case of the A. latifolium oil. Both oils were analyzed by GC-FID and GC-MS on two capillary columns. The oil of L. multiflora contained a majority of oxygenated terpenoids mainly represented by the two acyclic components linalool (46.6%) and (E)-nerolidol (16.5%); the oil of A. latifolium was dominated by hydrocarbonated terpenoids among them beta-pinene (51.6%) and beta-caryophyllene (12.3%) were the two major components.     

Composition and antioxidant activity of essential oil of pimento (Pimenta dioica (L) Merr.) from Jamaica

The composition and antioxidant activity of the essential oil obtained through hydrodistillation of pimento berry [Pimenta dioica (L.) Merr] samples, namely P1 and P2, sourced from Jamaica, were studied. The chemical composition was analysed by GC and GC-MS methods. The antioxidant activities of the oils were evaluated in terms of their free-radical-scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical cation and superoxide anion (?[image omitted]). Total phenolic content, total reducing power and metal-chelating capacity of the oils were also estimated. Forty-five constituents were identified. The major compound identified was eugenol (74.71%, 73.35%), followed by methyl eugenol (4.08%, 9.54%) and caryophyllene (4.90%, 3.30%). The antioxidant assays showed that the oils possess very high radical scavenging activities (DPPH IC(50) 4.82 ± 0.08, 5.14 ± 0.11 μg mL(-1), ABTS IC(50) 2.27 ± 0.16, 2.94 ± 0.03 μg mL(-1), superoxide IC(50) 17.78 ± 1.31, 20.65 ± 0.82 μg mL(-1)). The metal chelating capacities (IC(50) 83.62 ± 2.10, 101.77 ± 1.01 μg mL(-1)) and reducing power were also very high. The results show that the essential oils possess significant antioxidant activity which is comparable to that of pure eugenol. Therefore the oil can be utilised as a natural antioxidant which gives good flavour as well as health benefits.     

Antioxidant capacity of Ocimum basilicum L. and Origanum vulgare L. extracts

The antioxidant properties of five different extracts (Et?O, CHCl?, EtOAc, n-BuOH, and H?O) of Ocimum basilicum L. and Origanum vulgare L. were studied. Antioxidant activity was assessed in six different model systems. Free radical scavenging capacity (RSC) was evaluated by measuring the scavenging capacity of extracts on DPPH, NO, O??? and OH radical, as well as on hydrogen peroxide (H?O?). In addition, the protective effects on lipid peroxidation in liposomes (LPx) were evaluated by TBA-assay using the Fe2?/ascorbate induction system. The amount of total phenolic compounds and content of total flavonoids was also determined. EtOAc, n-BuOH and H?O extracts of O. basilicum and O. vulgare expressed very strong scavenger activity. Furthermore, the mentioned extracts showed notable inhibition of LPx. On the other hand, Et?O and CHCl? extracts showed much weaker effect in the neutralization of DPPH, NO and O??? radicals and the neutralization of H?O?. When examining the production of OH radicals and inhibition of LPx, the Et?O and CHCl? extracts showed weak prooxidative properties. The observed differences in antioxidant activity could be partially explained by the levels of phenolics and flavonoids in the investigated O. basilicum and O. vulgare extracts.     

Comparative larvicidal activity of different species of Ocimum against Culex quinquefasciatus

Ocimum is a genus of aromatic herbs, undershurbs or shrubs distributed in the tropical and warm temperate regions of the world. Larvicidal activity of essential oils and different extracts of O. sanctum, O. basilicum and O. gratissimum were compared on laboratory reared and field collected larvae of Culex quinquefasciatus. Thin layer chromatographic analysis revealed that all the three species have similar components and results showed the presence of steroids and triterpenoids. The larvicidal activity was determined in terms of LD?? value on late third or early fourth instar larvae for a period of 24?h. A comparison of LD?? value has shown that O. basilicum is more active than the other two species. The LD?? value of O. basilicum and O. sanctum oil were 39.31 and 40.02 on laboratory reared larvae and 129.53 and 139.49 on field collected larvae. Laboratory reared larvae were more sensitive than field collected larvae.     

Phytotherapeutic inhibition of supragingival dental plaque

Antimicrobial activities and biofilm-formation preventive properties of Mentha piperita and Cuminum cyminum essential oils and chlorhexidine were assessed against Streptococcus mutans and Streptococcus pyogenes. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis led to the identification of 26 and 32 compounds in the essential oils of M. piperita and C. cyminum, respectively. Minimal bactericidal concentrations (MBC) of the oils and chlorhexidine and microbial decimal reduction time (D value) were determined. Antibacterial and in vivo biofilm preventive efficacies of all the concentrations of M. piperita oil were significantly (p<0.001) higher. The biofilm inhibitory properties in planktonic cultures were in M. piperita > chlorhexidine > C. cyminum order. In vivo experiments conducted on male and female volunteers who brushed with essential oil blended toothpastes indicated that lower concentrations of the oils, in particular the M. piperita oil, were significantly higher (p<0.001) and effective during the course of the study as compared to chlorhexidine. In conclusion, there may be a potential role for essential oils in the development of novel anticaries treatments.     

Essential oil analysis and phytotoxic activity of two ecotypes of Zataria multiflora Boiss. growing in Iran

This study was conducted to assess the allelopathic effect of essential oils (EOs) obtained from the aerial parts of two different ecotypes (ECTPs A and B) of Zataria multiflora Boiss. with the aim of evaluating their in vitro germination and growth inhibition potential. Gas chromatography (GC) and GC-mass spectrometry (GC-MS) analysis of the oils revealed that carvacrol and linalool (77.4% and 90.6%) were the two major oil components in ECTPs A and B, respectively, which were regarded as two different chemotypes. Other important volatile compounds found in ECTP A were α-pinene (2.7%), p-cymene (7.9%) and γ-terpinene (3.5%). However, in ECTP B these compounds were in lesser amounts and γ-terpinene was not detected. The inhibitory effects of both EOs of ECTPs at concentrations of 0, 80, 160, 320 and 640 μL L?1 on the seed germination and seedling growth of four noxious weeds were evaluated. A significant reduction (p ≤ 0.05) in germination rate, seedling length, root and stem fresh and dry weights were observed by ECTPs; the highest suppressing effect was observed at 320 and 640 μL L?1. The results reported in this study suggest that herbicidal properties of the two ECTP oils could be attributed to their major components.     

Chemical and biological evaluation of essential oils from two species of Myrtaceae - Eugenia uniflora L. and Plinia trunciflora (O. Berg) Kausel

The chemical composition and antimicrobial activity of essential oils obtained from leaves of two Myrtaceae species-Eugenia uniflora L. and Plinia trunciflora (O. Berg) Kausel-were determined. Analysis by GC/MS as well as determination of Kovatz indexes indicated atractylone (26.78%) and curzerene (17.96%) as major constituents of E. uniflora oil and α-cadinol (19.15%), apiole (11.15%) and cubenol (5.43%) as main components in P. trunciflora oil. Both essential oils were tested for antimicrobial activity against yeasts and bacteria. E. uniflora and P. trunciflora essential oils were active towards two Gram-positive bacteria, Streptococcus equi and Staphylococcus epidermis. In addition, biological activity of both essential oils was detected for pathogenic yeasts of the genus Candida and Cryptococcus. E. uniflora was active towards all yeast tested and exhibited interesting minimal inhibitory concentrations (0.11 to 3.75 mg/mL) across a broad spectrum of activity.     

Chemical polymorphism of essential oils from populations of Laurus nobilis grown on Tunisia, Algeria and France

The compositions of the essential oils isolated from the aerial parts of tree Mediterranean populations of Laurus nobilis L. collected during the flowering phase on Tunisia, Algeria and France, were studied by GC and GC-MS. The analysis has allowed identifying 54 components. The main components were 1,8-cineole, alpha-terpinyl acetate (10-18.6%), methyl eugenol (10-22.1%), sabinene (1.2-8%), eugenol (1.2-11.7%) alpha-pinene (tr-4.5%) and beta-pinene (0.4-4.2%). The monoterpene fraction was dominant in all the oils analysed and consisted mainly of oxygenated monoterpenes. The oils from the tree populations studied showed a clear chemical polymorphism. The principal component and the hierarchical cluster analyses separated the Laurus nobilis leaf essential oils into three groups.     

Commercial Origanum compactum Benth. and Cinnamomum zeylanicum Blume essential oils against natural mycoflora in Valencia rice

Chemical composition of commercial Origanum compactum and Cinnamomum zeylanicum essential oils and the antifungal activity against pathogenic fungi isolated from Mediterranean rice grains have been investigated. Sixty-one compounds accounting for more than 99.5% of the total essential oil were identified by using gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). Carvacrol (43.26%), thymol (21.64%) and their biogenetic precursors p-cymene (13.95%) and γ-terpinene (11.28%) were the main compounds in oregano essential oil, while the phenylpropanoids, eugenol (62.75%), eugenol acetate (16.36%) and (E)-cinnamyl acetate (6.65%) were found in cinnamon essential oil. Both essential oils at 300 μg/mL showed antifungal activity against all tested strains. O. compactum essential oil showed the best antifungal activity towards Fusarium species and Bipolaris oryzae with a total inhibition of the mycelial growth. In inoculated rice grains at lower doses (100 and 200 μg/mL) significantly reduced the fungal infection, so O. compactum essential oil could be used as ecofriendly preservative for field and stored Valencia rice.     

Determination of phenolic compounds by MALDI–TOF and essential oil composition by GC–MS during three development stages of Origanum majorana L.

This study aimed to investigate the effect of the maturation process of sweet marjoram (Origanum majorana L.) on essential oil composition, the phenolic profile of ethanolic extract and their antioxidant capacities. The essential oil composition was studied at three stages of maturity by GC–MS. Thirty compounds were detected representing 100% of the total essential oil. p‐Menth‐1‐en‐4‐ol was the major compound (37.15–76.94%) followed by cyclohexanol‐3,3,5 trimethyl (5.41–15.99%) and α‐terpineol (0.94–11.34%). During the maturation process, an accumulation of oxygenated monoterpenes was observed. The phenolic composition was studied using matrix‐assisted laser desorption/ionization time of flight. The analysis showed the presence of short flavonoid monomers at all stages of maturation. The antioxidant capacity of ethanolic extracts and essential oils was evaluated using the DPPH assay, iron chelating power and reducing power assay. The highest phenolic content and antioxidant capacity were found at flowering stage. These findings on essential oil composition, phenolic profile and antioxidant capacity of O. majorana at three different stages of development provide more information on how these secondary metabolites are accumulated.     

多花蔷薇花净油化学成分研究

多花蔷薇(Rose multiflora. cathayensis)又名红刺玫、刺花,系多年生落叶灌木,野生于甘肃省陇南山区,生长在海拔500～1900 m的山峰、河岸或山坡缘及灌木丛林中,花的资源丰富,是甘肃省目前需开发的野生芳香植物之一,多花蔷薇花为粉红色,花期为5月中旬至5月底,花中含芳香油,可用作化妆、皂用香精等,有关多花蔷薇花的化学成分,未见文献报道,我们将多花蔷薇花的石油醚浸膏用乙醇在0℃脱蜡3次得净油,再经硅胶柱层析分离得纯     

The composition and antimicrobial activities of Cyperus conglomeratus, Desmos chinensis var. lawii and Cyathocalyx zeylanicus essential oils

The essential oil compositions of the rhizomes of Cyperus conglomeratus (Cyperaceae) collected from Oman and the leaves of two Annonaceae plants, Desmos chinensis var. lawii and Cyathocalyx zeylanicus collected from India were studied by GC, GC-MS and 13C NMR spectroscopy. Twenty-six compounds, representing 84.4% of the oil were identified in C. conglomeratus, where eugenol (31.3%), alpha-cyperone (10.5%) and cyperotundone (8.4%) were the major compounds. Twelve compounds, constituting 100%, were identified in D. lawii oil, of which benzyl benzoate (58.7%), beta-caryophyllene (23.2%), limonene (4.9%) and alpha-humulene (4.0%) were the major constituents. Thirty-two compounds, comprising 98.0%, were identified in C. zeylanicus oil, of which beta-caryophyllene (21.6%), alpha-pinene (20.4%) and E-beta-ocimene (11.8%) were the major components. The antibacterial and antifungal activities of the oils were tested against a panel of five bacterial and two fungal strains. The oils showed moderate activity against all the tested microbial strains. The minimum inhibitory concentrations of the oils were also determined.     

Influence of viral infection on essential oil composition of Ocimum basilicum (Lamiaceae)

Ocimum basilicum L., popularly known as sweet basil, is a Lamiaceae species whose essential oil is mainly composed of monoterpenes, sesquiterpenes and phenylpropanoids. The contents of these compounds can be affected by abiotic and biotic factors such as infections caused by viruses. The main goal of this research was an investigation of the effects of viral infection on the essential oil profile of common basil. Seeds of O. basilicum L. cv. Genovese were sowed and kept in a greenhouse. Plants presenting two pairs of leaves above the cotyledons were inoculated with an unidentified virus isolated from a field plant showing chlorotic yellow spots and foliar deformation. Essential oils of healthy and infected plants were extracted by hydrodistillation and analyzed by GCMS. Changes in essential oil composition due to viral infection were observed. Methyleugenol and p-cresol,2,6-di-tert-butyl were the main constituents. However, methyleugenol contents were significantly decreased in infected plants.     

Essential oil composition and acaricidal activity of Schinus terebinthifolius from Atlantic Forest of Pernambuco, Brazil against Tetranychus urticae

The compositions of the essential oils from unripe (UFr) and ripe (RFr) fruits of Schinus terebinthifolius were analyzed by GC and GC/MS. The major compound identified in both oils was limonene (UFr = 44.1 +/- 1.3%; RFr = 31.8 +/- 1.2%), followed by alpha-phellandrene (15.7 +/- 0.4%) in the UFr oil and thujene (21.7 +/- 0.9%) in the RFr oil. Repellent and toxicity activities of the two oils were also evaluated, and the results compared with eugenol. The UFr oil was more active in the fumigation tests (LC50 = 1.46 microL/L of air), whereas the RFr oil was more active in the sealed dishes (SD) than open dishes (OD) contact assay (LC50 = 3.04 microL/cm2) and not significantly different from eugenol. Both oils exhibited significant repellent activity comparable with that of eugenol. The results suggest that the repellent activity of these oils in association with its toxicity could be a great advantage for the integrated management of T. urticae.     

Boiling temperatures and enthalpy changes of Essential oils

A capillary long neck glass sample holder is proposed for the determination of boiling temperatures of essential oils containing a majority component. Essential oils from Aniba dukei K. and Pimenta dioica L. containing linalool and eugenol, respectively, as major constituents were used after optimization of parameters such as scan rate, sample mass and starting temperature. Best performance in the determination of boiling temperatures was obtained with the proposed sample holder in comparison with commercial aluminum pans. Good agreement was obtained for the boiling temperature and enthalpy for the essential oil samples with the linalool and eugenol standards. This revised version was published online in August 2006 with corrections to the Cover Date.     

Multiple analytical approaches for the organic and inorganic characterization of Origanum vulgare L. samples

Origanum vulgare L. samples, marketed in different geographic locations, were characterized by their organic and inorganic chemical composition. A total of 35 commercial samples were collected from various sites and analyzed to determine the qualitative and quantitative profile of essential oils, phenolic compounds and some inorganic elements. The variation in the content and composition of the essential oil was assessed by GC and GC-MS analyses, the phenolic fraction was investigated by UPLC^®/PDA, and the inorganic elements were determined by ICP-MS. The Principal Component Analysis (PCA) was applied with the aim to sort out the Origanum vulgare L. samples with different composition according to the different belonging origins. The results showed appreciable qualitative and quantitative differences among samples from different geographic origin.     

Chemical composition and biological evaluation of the volatile constituents from the aerial parts of Nephrolepis exaltata (L.) and Nephrolepis cordifolia (L.) C. Presl grown in Egypt

The essential oil from the aerial parts of Nephrolepis exaltata and Nephrolepis cordifolia obtained by hydro-distillation were analyzed by gas chromatography/ mass spectrometry. The essential oils exhibited potential antibacterial and antifungal activities against a majority of the selected microorganisms. NEA oil showed promising cytotoxicity in breast, colon and lung carcinoma cells. The results presented indicate that NEA oil could be useful alternative for the treatment of dermatophytosis.

Comparative investigation of hydro-distilled volatile constituents from aerial parts (A) of Nephrolepis exaltata (NE) and Nephrolepis cordifolia (NC) (Family Nephrolepidaceae) was carried out. Gas chromatography/mass spectrometry revealed that oils differ in composition and percentages of components. Oxygenated compounds were dominant in NEA and NCA. 2,4-Hexadien-1-ol (16.1%), nonanal (14.4%), β-Ionone (6.7%) and thymol (2.7%) were predominant in NEA. β-Ionone (8.0%), eugenol (7.2%) and anethol (4.6%) were the main constituents in NCA. Volatile samples were screened for their antibacterial and antifungal activities using agar diffusion method and minimum inhibitory concentrations. The cytotoxic activity was evaluated using viability assay in breast (MCF-7), colon (HCT-116) and lung carcinoma (A-549) cells by the MTT assay. The results revealed that NEA oil exhibited potential antimicrobial activity against most of the tested organisms and showed promising cytotoxicity.