Comparative study on the antiviral activity of selected monoterpenes derived from essential oils

Essential oils are complex natural mixtures, their main constituents, e.g. terpenes and phenylpropanoids, being responsible for their biological properties. Essential oils from eucalyptus, tea tree and thyme and their major monoterpene compounds α‐terpinene, γ‐terpinene, α‐pinene, p‐cymene, terpinen‐4‐ol, α‐terpineol, thymol, citral and 1,8‐cineole were examined for their antiviral activity against herpes simplex virus type 1 (HSV‐1) in vitro. These essential oils were able to reduce viral infectivity by >96%, the monoterpenes inhibited HSV by about >80%. The mode of antiviral action has been determined, only moderate antiviral effects were revealed by essential oils and monoterpenes when these drugs were added to host cells prior to infection or after entry of HSV into cells. However, both essential oils and monoterpenes exhibited high anti‐HSV‐1 activity by direct inactivation of free virus particles. All tested drugs interacted in a dose‐dependent manner with herpesvirus particles thereby inactivating viral infection. Among the analysed compounds, monoterpene hydrocarbons were slightly superior to monoterpene alcohols in their antiviral activity, α‐pinene and α‐terpineol revealed the highest selectivity index. However, mixtures of different monoterpenes present in natural tea tree essential oil revealed a ten‐fold higher selectivity index and a lower toxicity than its isolated single monoterpenes. Copyright © 2009 John Wiley & Sons, Ltd.     

Antibacterial activity of essential oils from Australian native plants

To date, of the Australian essential oils, only tea tree (Melaleuca alternifolia) and Eucalyptus spp. have undergone extensive investigation. In this study a range of Australian essential oils, including those from Anethole anisata, Callistris glaucophyllia, Melaleuca spp. and Thyptomine calycina, were assayed for in vitro antibacterial activity. M. alternifolia was also included for comparison purposes. Activity was determined using standard disc diffusion assays with each oil assayed at 100%, 10% and 1% against five bacteria (Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Pseudomonas aeruginosa and Alcaligenes faecalis) and the yeast, Candida albicans. All bacteria, with the exception of Ps. aeruginosa, were susceptible to one or more of the essential oils at 100%, with only Eremophilia mitchelli inhibiting the growth of any bacteria at 1% (inhibition of Sal. typhimurium). Where multiple samples of a single oil variety were tested variability in activity profiles were noted. This suggests that different methods of preparation of essential oils, together with variability in plant chemical profiles has an impact on whether or not the essential oil is of use as an antimicrobial agent. These results show that essential oils from Australian plants may be valuable antimicrobial agents for use alone or incorporated into cosmetics, cleaning agents and pharmaceutical products.     

Antibacterial activity of essential oils from Psidium and Pilocarpus species of plants

The antibacterial activity of six essential oils obtained from the leaves of Pilocarpus and Psidium species of plants have been studied. The leaf oils of Psidium guyanensis, Psidium pohlianum and Pilocarpus spicatus showed the most potent antibacterial activity (MIC 52.5–75.0 μg/mL) against Gram-negative Pseudomonas aeruginosa. Against Gram-positive Staphylococcus aereus, P. guyanensis demonstrated marked activity (MIC 75.0±15.0 μg/mL) followed by P. spicatus and Pilocarpus pauciflorus (MIC 100.0±28.9 μg/mL). The efficacy of some tested oils against P. aeruginosa, the most resistant organism may have significant clinical implication. © 1997 John Wiley & Sons, Ltd.     

药用植物挥发油驱蚊作用的研究进展

蚊虫吸食人血、传播疾病,严重危害人类的健康。长期以来,化学合成杀虫剂一直占据主要地位,但长期使用此类杀虫剂,不仅会使蚊虫产生抗药性,而且还会造成环境污染,因此环境友好型的蚊虫防治手段日益受到人们的关注。药用植物应用于驱蚊、灭蚊的防治由来已久,因其植物资源较为丰富、且毒副作用小,具有开发成为新型驱蚊剂和灭蚊剂的潜力。该文综述了近年来药用植物挥发油应用于驱蚊的研究现状,总结了植物挥发油应用于相关研究中存在的问题,并阐述了挥发油应用于驱蚊研究的局限性,为其进一步开发和深入研究提供参考。     

Studies on essential oils: part 10; antibacterial activity of volatile oils of some spices

The essential oils extracted from the seeds of seven spices, Anethum graveolens, Carum capticum, Coriandrum sativum, Cuminum cyminum, Foeniculum vulgare, Pimpinella anisum and Seseli indicum have been studied for antibacterial activity against eight pathogenic bacteria, causing infections in the human body. It has been found that the oil of C. capticum is very effective against all tested bacteria. The oil of C. cyminum and A. graveolens also gave similar results. These oils are equally or more effective when compared with standard antibiotics, at a very low concentration.     

Virucidal activity in aqueous extracts obtained from Cedrela tubiflora leaves

Crude extracts obtained from leaves of Cedrela tubiflora (CT) (Meliaceae family) show antiviral and virucidal effects against several viruses. Herpes simplex, pseudorabies and vesicular stomatitis viruses were extremely susceptible and a reduction of 3–5 log in infectivity occurred after 15 min of direct incubation with the plant extract. By contrast, poliovirus and the Tacaribe arenavirus are inhibited intracellularly. The inhibitory action is dose dependent and no cytotoxic effects were detected on Vero cells after 2 days of CT treatment.     

The spasmolytic activity of the essential oils of scented Pelargoniums (Geraniaceae)

A selection of essential oils obtained by steam distillation from scented-leaf Pelargonium species, hybrids and cultivars were assessed for their pharmacological activity using guinea-pig ileum in vitro. All the essential oils tested were spasmolytic. Their relative spasmolytic activity was related to the yield obtained from the leaves. The pharmacological activity was comparable to that of commercial geranium oils. The mechanism of action was postsynaptic and not atropine-like. Different Pelargonium oils could be exploited for their antispasmodic and possibly other functions. © 1997 John Wiley & Sons, Ltd.     

Chemical composition and antimicrobial activity of the essential oils from two species of Eucalyptus

The leaf-essential oil from Eucalyptus robusta and E. saligna, the latter in two phenologic stages, were analysed by gas chromatography coupled to mass spectrometry (GC-MS). The major constituent in E. robusta oil was the monoterpene alpha-pinene (73.0% of the total amount). The oil composition of the E. saligna was dependent of the phenologic stage. In the vegetative phase, the major constituents were p-cymene (54.2%) and gamma-terpinene (43.8%), while during the blossoming alpha-pinene became the major constituent followed by p-cymene (22.5%). Additionally, the antimicrobial activity for all three oils was evaluated against Staphylococcus aureus, Escherichia coli and Candida albicans. The E. robusta oil presented the highest growth inhibition for all the microorganisms tested.     

Insecticidal properties of several essential oils on the house fly (Musca domestica L.)

The insecticidal activity of 34 essential oils, extracted from plants, was screened against the house fly, Musca domestica L. under laboratory conditions. Essential oils from Pogostemon cablin proved to be the most efficient at a lethal dose of 3 microg/fly after topical application. Eight oils (P. roseum, O. vulgare, O. compactum, M. pulegium, O. basilicum, O. majorana, T. vulgaris and P. graveolens) were lethal in doses ranging from 10 to 20 microg (10, 13, 13, 13, 15, 17, 18 and 19 microg/fly, respectively). The lethal doses of another 13 oils were ascertained in the range 20-50 microg/fly, nine oils had lethal doses of 50-100 microg. For two oils, the lethal dose could not be for the topical application. In the fumigant test, the most efficient proved to be Mentha pulegium oil (4.7 microg/cm(2)). For 10 oils, a lethal dose between 5 and 10 microg/cm(2) was ascertained (T. bipinata, C. aurantifolia, T. occidentalis, T. matschiana, S. officinalis, T. vulgaris, M. quinquenervia, O. compactum, C. limonum and R. officinalis, respectively). For the other 10 oils a lethal dose from 10 but to 80 microg/cm(2) was ascertained, and for 13 oils the lethal dose was higher than the highest dose in the tests.     

In vitro antiviral activity of Phyllanthus orbicularis extracts against herpes simplex virus type 1

The antiviral activity of butanol- and acetic acid-soluble fractions, prepared from the leaves and stems of Phyllanthus orbicularis H.B.K., has been investigated against acyclovir-sensitive or -resistant herpes simplex virus type 1 (HSV-1) strains, using human foreskin fibroblast (HFF) and green ape kidney (Vero) cell lines. Both fractions showed antiviral selectivity indexes (SI) from 10.3 to 22.8, while their extracellular virucidal activities reached SI values ranging from 371 to 1,040. Time-addition experiments suggested that the active compounds present in the studied fractions acted on early steps of the virus replication cycle.     

Antibacterial and antifungal activity of essential oils of Mentha suaveolens

The essential oils (EO) of Mentha suaveolens, a wild Labiatae, which grows in several regions in Morocco, were characterized and their antimicrobial activity assessed. The main aromatic constituents of this plant, as characterized by IR, NMR and MS studies, were pulegone, piperitenone oxide (PEO) and piperitone oxide (PO) occurring in different amounts depending on the subspecies. These constituents as well as a series of other aromatic products such as carvone, limonene and menthone, were tested for their antimicrobial activity against 19 bacteria including Gram-positive and Gram-negative and against three fungi, using solid phase and microtitration assays. Pulegone-rich essential oil inhibited efficiently all the micro-organisms tested with MICs ranging between 0.69 and 2.77 ppm. Among the components from Mentha suaveolens EO, pulegone was the most effective against the tested microorganisms, followed by PEO and PO. The structure-activity relationship is discussed on the basis of the activity of the other aromatic derivatives tested such as carvone, limonene, menthone and the profile of the essential oils of Mentha suaveolens was compared with other Mentha species.     

The antioxidant activity of the essential oils of Artemisia afra, Artemisia abyssinica and Juniperus procera

The essential oils of Artemisia afra Jacq., Artemisia abyssinica Schultz-Bip. and Juniperus procera Hoechst ex Endl. were examined for their potential radical scavenging activities. First a rapid evaluation of antioxidants was made using a TLC screening method. The abilities of the volatile oils to act as nonspecific donors for hydrogen atoms or electrons were checked in the diphenylpicrylhydrazyl assay. Oils from all three species showed positive results and were examined further. The oils of A. afra and J. procera were also effective hydroxyl radical scavenging agents when assessed in the deoxyribose degradation assay, whilst oils from A. abyssinica exhibited a paradoxical effect. In the in vitro assay for non-enzymatic lipid peroxidation in liposomes, the oils of A. afra and J. procera also displayed antioxidant potential. It was not possible to measure the effect of A. abyssinica oil in this system because certain components, e.g. alk-2-enals, interfered with the assay. The compounds that contribute to the radical scavenging activities of A. afra and J. procera were identified and then assessed for their effects in the various test systems. Finally, the qualitative and quantitative compositions of the essential oils were studied by GC-MS.     

Insecticidal activity of essential oils on Triatoma infestans

Sixty-three essential oils isolated from Bolivian plants were tested on Triatoma infestans for ovicidal and larvicidal properties. Three types of test were used: topical application on insects, nymphs on impregnated paper and eggs on impregnated paper. Twenty oils showed an interesting activity on nymphs and eggs when the impregnated paper tests were used. These tests proved to be the most sensitive and were therefore chosen for studying the action of a dozen terpenes present in those active essential oils. © 1997 John Wiley & Sons, Ltd.     

植物精油抗肿瘤作用研究进展

植物精油是一类具有特殊芳香气味的含有天然生物活性化合物的挥发性混合物。通过对近5年报道的具有抗肿瘤作用的植物精油的化学成分、药理作用及其机制进行总结,表明植物精油可通过抑制增殖、诱导凋亡、阻遏细胞周期、诱导氧化应激、诱导自噬、抑制上皮-间质转化、抑制细胞侵袭迁移和抑制血管生成等途径来发挥抗肿瘤作用,同时归纳了其抗肿瘤作用机制涉及到B淋巴细胞瘤基因-2相关X蛋白（B-cell lymphoma-2 associated X protein,Bax）/B淋巴细胞瘤-2基因（B celllymphoma-2,Bcl-2）、磷脂酰肌醇3-激酶（phosphatidylinositol3-kinase,PI3K）/蛋白激酶B(proteinkinaseB,Akt)/雷帕霉素靶蛋白（mechanistic target of rapamycin,m TOR）、HIPPO/Yes激酶相关蛋白（Yes-associated protein,YAP）、表皮生长因子受体（epithelial growth factor receptor,EGFR）、核因子-κB(nuclear factor-κB,NF-...     

CNS activity of Mentha rotundifolia and Mentha longifolia essential oil in mice and rats

The essential oils of Mentha rotundifolia and Mentha longifolia were analyzed with GC and GC/MS. The major components were rotundifolone (10.4%) and piperitol (57.6%) in M. rotundifolia, and rotundifolone (33.2%) and diosphenol (47.7%) in M. longifolia. M. longifolia essential oil exhibited a stronger CNS depressant effect than that of M. rotundifolia; both essential oils were somnifacients.     

金银花挥发油GC指纹图谱研究

目的：建立10批金银花药材挥发油的指纹图谱。方法：用水蒸气蒸馏法提取，GC法分析对比10批金银花药材挥发油的成分。结果：10批金银花药材的挥发油相似度较高。结论：该指纹图谱方法简便，重现性好，可作为金银花药材的质量控制方法之一。     

Insecticidal activity of essential oils on Aedes aegypti larvae

The insecticidal activity of essential oils from 52 Bolivian plant species has been evaluated on Aedes aegypti larvae. The active components of essential oils showing an interesting larvicidal effect have been studied. The monoterpenes E-anethol and E-nerolidol were found to be the active principles of the most toxic essential oils. The lethal concentrations (LC₅₀ and LC₉₅) of some essential oils, E-anethol, E-nerolidol and a reference insecticide (Temephos) are given. © 1998 John Wiley & Sons, Ltd.     

中药挥发油安全性研究进展

中药挥发油因具有显著的药理活性，被广泛应用于芳香疗法和医疗保健领域，但其在安全性评价方面的研究相对较少，潜在的不良反应缺乏深入研究。通过查阅国内外的文献，对中药挥发油产生毒性的原因、毒性作用、毒性机制及安全性研究中存在的问题进行综述，以期为中医药产业和保健食品产业合理应用中药挥发油提供参考。     

柱果绿绒蒿挥发油化学成分及其抗氧化活性的研究

目的:分析柱果绿绒蒿挥发油的化学成分并进行抗氧化活性研究.方法:采用水蒸气蒸馏法获得挥发油,运用气相色谱-质谱联用进行成分分析,同时运用紫外分光光度计测定其对羟基自由基的清除能力,用酶标仪测定其对1,1-二苯基-2-三硝基苯肼(DPPH)自由基的清除能力,并与2,6--二叔丁基-4-甲基苯酚(BHT)比较.结果:从柱果绿绒蒿的挥发油中鉴定了47个化合物,占其总量的91.866％;挥发油对羟基自由基和DPPH自由基的清除能力均强于BHT.结论:柱果绿绒蒿挥发油的化学成分复杂,主要为十六烷酸(27.653％)和6,10,14-三甲基-2-十五烷酮(16.330％);其清除自由基的能力显示出良好的抗氧化活性.     

Chemical composition and antimicrobial activity of the essential oils of different samples of Thymus baeticus boiss

Gas chromatography was used to determine the chemical composition of the essential oil of female and hermaphrodite Thymus baeticus Boiss. collected in Ugijar (province of Granada, Spain). The results were compared with the chemical composition of other samples of the same species, collected in Lanjarón. These comparisons showed some qualitative differences, and more obvious quantitative differences, in the compositions of the essential oils. We also investigated the antimicrobial activity of all samples. This activity, although marked in all samples, was greater in essential oils containing larger amounts of geraniol.