The in vitro antioxidant and antimicrobial activities of the essential oil and methanol extracts of Achillea biebersteini Afan. (Asteraceae)

The essential oil and methanol extracts from A. biebersteinii Afan. (Asteraceae) were evaluated for their antimicrobial and antioxidant activities in vitro. The oil showed stronger antimicrobial activity than the extracts. Their antioxidant features were also evaluated using diphenyl-1-picrylhydrazyl (DPPH), inhibition of superoxide and hydroxyl radicals and inhibition of the lipid peroxidation assays. Particularly, polar subfraction of the methanol extract showed antioxidant activity. The GC-MS analysis of the oil has resulted in the identification of 23 components; piperitone, eucalyptol, camphor, chrysanthenone and borneol were the main components. Antimicrobial activity tests carried out with the fractions of the oil showed that the activity was mainly observed in those containing eucalyptol and camphor, in particular, followed by borneol and piperitone.     

Composition and antimicrobial activity of Achillea clavennae L. essential oil

The volatile constituents of Achillea clavennae L. (Asteraceae), rare plant of Europe, have been analysed using GC/MS. Twenty- five components making up 81.6% of the oil were characterized with camphor (29.5%), myrcene (5.5%), 1,8-cineole (5.3%), beta-caryophyllene (5.1%) and linalool (4.9%) being the major constituents. The essential oil was evaluated for antibacterial and antifungal activities. The screening of the antimicrobial activity of essential oil was conducted by a disc diffusion test against Gram-positive (Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Streptococcus faecalis), Gram-negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis) and fungal organisms (Aspergillus niger, Aspergillus fumigatus, Candida albicans). The activity was more pronounced against Gram-negative and fungal organisms than against Gram-positive bacteria. A. clavennae oil was found to possess antimicrobial activity against Klebsiella pneumoniae, Pseudomonas aeruginosa and all fungal organisms.     

Spasmolytic action of the essential oil of Achillea ageratum L. in rats

The spasmolytic activity of Achillea ageratum L. essential oil in isolated rat duodenum has been in estigated. The essential oil was found to present a marked spasmolytic activity against acetylcholine and BaCl₂ via a non-competitive type of antagonism.     

Antioxidant and antimicrobial activity of the essential oil and methanol extracts of Achillea millefolium subsp. millefolium Afan. (Asteraceae)

The in vitro antimicrobial and antioxidant activities of the essential oil and methanol extracts of Achillea millefolium subsp. millefolium Afan. (Asteraceae) were investigated. GC-MS analysis of the essential oil resulted in the identification of 36 compounds constituting 90.8% of the total oil. Eucalyptol, camphor, alpha-terpineol, beta-pinene, and borneol were the principal components comprising 60.7% of the oil. The oil strongly reduced the diphenylpicrylhydrazyl radical (IC(50)=1.56 micro g/ml) and exhibited hydroxyl radical scavenging effect in the Fe(3+)-EDTA-H(2)O(2) deoxyribose system (IC(50)=2.7 micro g/ml). It also inhibited the nonenzymatic lipid peroxidation of rat liver homogenate (IC(50)=13.5 micro g/ml). The polar phase of the extract showed antioxidant activity. The oil showed antimicrobial activity against Streptococcus pneumoniae, Clostridium perfringens, Candida albicans, Mycobacterium smegmatis, Acinetobacter lwoffii and Candida krusei while water-insoluble parts of the methanolic extracts exhibited slight or no activity. This study confirms that the essential oil of Achillea millefolium possesses antioxidant and antimicrobial properties in vitro.     

Antimicrobial activity of the essential oil and extracts of Cordia curassavica (Boraginaceae)

In traditional Mexican medicine Cordia curassavica (Jacq) Roemer & Schultes is used to treat gastrointestinal, respiratory and dermatological disorders in Zapotitlán de las Salinas, Puebla (México). The aim of this work was to investigate antimicrobial activity of the essential oil, obtained by using Clevenger distillation apparatus, and hexane, chloroform and methanol extracts from aerial parts of Cordia curassavica. Antimicrobial activity was evaluated against 13 bacteria and five fungal strains. The oil and extracts exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria and five fungal strains. Sarcina lutea and Vibrio cholerae were the strains more sensitive to the essential oil effect (MIC=62 microg/mL) and Vibrio cholerae for the hexane extract (MIC=125 microg/mL). Rhyzoctonia solani was the strain more sensitive to the essential oil effect (IC(50)=180 microg/mL) and Trichophyton mentagrophytes for the hexane extract (IC(50)=230 microg/mL). The essential oil was examined by GC and GC-MS. A total 11 constituents representing 96.28% of the essential oil were identified: 4-methyl,4-ethenyl-3-(1-methyl ethenyl)-1-(1-methyl methanol)cyclohexane (37.34%), beta-eudesmol (19.21%), spathulenol (11.25%) and cadina 4(5), 10(14) diene (7.93%) were found to be the major components. The present study tends to confirm the use in the folk medicine of Cordia curassavica in gastrointestinal, respiratory and dermatological diseases.     

Cytostatic activity against HEp-2 cells and antibacterial activity of essential oil from Helichrysum picardii

Different samples of essential oil from Helichrysum picardii Boiss. & Reuter (Compositae) collected at the beginning of each season from the same locality have been tested for their cytostatic and antimicrobial activity. All the oil samples showed a stronger in vitro activity against HEp-2 cells than a 6-mercaptopurine solution used as a positive control. Gram-positive bacteria as well as the fungus Candida albicans were sensitive to the action of the essential oil, whereas none of the samples showed activity against the gram-negative bacteria.     

Antimicrobial activity of the essential oil of Calamintha nepeta and its constituent pulegone against bacteria and fungi

The chemical composition of the essential oil of Calamintha nepeta and its antimicrobial activity against Listeria monocytogenes, Bacillus cereus, Salmonella veneziana, S. paratyphi B, S. typhimurium, Fusarium moniliforme, Botrytis cinerea, Aspergillus niger and Pyricularia oryzae have been studied. Moreover the main constituents of the oil (limonene, menthone, pulegone, menthol) have been tested against the same microorganisms. Only pulegone showed antimicrobial activity, particularly against all the Salmonella species. Copyright © 1999 John Wiley & Sons, Ltd.     

Antimicrobial activity and chemical composition of essential oil from Hedychium coronarium

The essential oil from fresh and dried rhizomes of Hedychium coronarium on GC-MS analysis resulted in the identification of 44 and 38 constituents representing 93.91% and 95.41%, respectively. The major components of the essential oil from fresh and dried Hedychium coronarium rhizome were 1,8-cineole (41.42%, 37.44%), beta-pinene (10.39%, 17.4%) and alpha-terpineol (8.8%, 6.7%). The aromatic oil has antifungal as well as antibacterial effects. The antimicrobial activities of the essential oil were individually evaluated against four microorganisms, including two bacteria and two fungi. It was found that the antimicrobial activity was higher in the fresh sample than the dried. Both samples showed a better activity against Trichoderma sp. and Candida albicans than against the bacteria Bacillus subtilis and Pseudomonas aeruginosa.     

SFE-CO2萃取和水蒸气蒸馏提取熏衣草精油的抗菌活性比较与GC-MS分析

目的：考察用SFE-CO₂萃取(SFE-CO₂)技术和水蒸气蒸馏法(HD)提取的熏衣草精油的体外抗微生物活性，比较两者化学成分的差异。方法：采用滤纸片琼脂平板扩散法和琼脂稀释法检测SFE-CO₂和HD熏衣草精油对4种细菌和4种真菌的抗菌活性，采用GC-MS技术对其进行化学成分分析。结果：两种提取法的熏衣草精油对测试的所有微生物均具有不同程度抗菌作用，SFE-CO₂萃取物抗细菌与抗真菌作用均较HD精油强，其最低抑菌浓度(MIC)为0.63～3.33 g·L^-1,最低杀菌浓度(MBC/MFC)为1.04～5.00 g·L^-1。GC-MS法分别鉴定出SFE-CO₂和HD精油的34种和29种化合物，其质量分数为出峰物质总量的95.51 %和98.39 %，两者主要成分中乙酸芳樟酯和乙酸薰衣草酯含量相差较大。结论：SFE-CO₂和HD熏衣草精油均对试验菌株有抗菌活性，SFE-CO₂法提取的熏衣草精油抗菌活性较强。     

Chemical composition and antimicrobial activity of the essential oil of Cryptomeria japonica

The composition and the antibacterial activity of the essential oil obtained from Cryptomeria japonica D. Don on oral bacteria were studied. The chemical composition of the essential oil was analysed by GC and GC-MS. Sixty-eight compounds accounting for 95.82% of the oil were identified. The main compounds in the oil were alpha-pinene (6.07%), sabinene (8.86%), terpinen-4-ol (9.77%), alpha-terpineol (6.13%), elemol (11.17%) and 10(15)-cadinen-4-ol (7.16%). The essential oil and some of its major compounds were tested for antimicrobial activity against 15 different genera of oral bacteria. The essential oil of C. japonica exhibited considerable inhibitory effects against all bacteria tested (MICs, 0.025-0.05 mg/mL; MBCs, 0.025-0.1 mg/mL), while its major compounds demonstrated various degrees of growth inhibition.     

Composition and antimicrobial activity of the essential oil of Ballota pseudodictamnus L. Bentham

The chemical composition of the essential oil of Ballota pseudodictamnus obtained from the aerial parts was analysed by GC/MS. From the 52 identified constituents of the oil, caryophyllene oxide, phytol and gamma-muurolene were the major components. Furthermore, the essential oil was investigated for its antimicrobial activity.     

Composition and antimicrobial activity of Equisetum arvense L. essential oil

The volatile constituents of the sterile stems of Equisetum arvense L. (Equisetaceae) were investigated for the first time using GC, GC/MS and (13)C-NMR. Twenty-five compounds were identified. Hexahydrofarnesyl acetone (18.34%), cis-geranyl acetone (13.74%), thymol (12.09%) and trans-phytol (10.06%) were the major constituents. A disk diffusion method was used for the evaluation of the antimicrobial activity of this oil against a panel of microorganisms (bacteria: Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella enteritidis; fungi: Aspergillus niger and Candida albicans). The 1:10 dilution of the essential oil of Equisetum arvense L. was shown to possess a broad spectrum of a very strong antimicrobial activity against all tested strains.     

Spasmolytic activity of Thymus membranaceus essential oil

The spasmolytic activity of Thymus membranaceus essential oil in the duodenum isolated from rat has been investigated. The qualitative and quantitative composition of the essential oil was studied. The essential oil affects the duodenum in two ways, showing a spasmogenic action (due to 1,8-cineole) and, on the other hand, an antagonistic non-competitive effect against the contractions by acetylcholine (due to the phenols and hydrocarbons).     

Antimicrobial activity of clove and rosemary essential oils alone and in combination

In the present study, the antimicrobial activity of the essential oils from clove (Syzygium aromaticum (L.) Merr. et Perry) and rosemary (Rosmarinus officinalis L.) was tested alone and in combination. The compositions of the oils were analysed by GC/MS. Minimum inhibitory concentrations (MIC) against three Gram-positive bacteria, three Gram-negative bacteria and two fungi were determined for the essential oils and their mixtures. Furthermore, time-kill dynamic processes of clove and rosemary essential oils against Staphylococcus epidermidis, Escherichia coli and Candida albicans were tested. Both essential oils possessed significant antimicrobial effects against all microorganisms tested. The MICs of clove oil ranged from 0.062% to 0.500% (v/v), while the MICs of rosemary oil ranged from 0.125% to 1.000% (v/v). The antimicrobial activity of combinations of the two essential oils indicated their additive, synergistic or antagonistic effects against individual microorganism tests. The time-kill curves of clove and rosemary essential oils towards three strains showed clearly bactericidal and fungicidal processes of (1)/(2) x MIC, MIC, MBC and 2 x MIC.     

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.     

The chemical composition and biological activity of clove essential oil, Eugenia caryophyllata (Syzigium aromaticum L. Myrtaceae): a short review

The essential oil extracted from the dried flower buds of clove, Eugenia caryophyllata L. Merr. & Perry (Myrtaceae), is used as a topical application to relieve pain and to promote healing and also finds use in the fragrance and flavouring industries. The main constituents of the essential oil are phenylpropanoids such as carvacrol, thymol, eugenol and cinnamaldehyde. The biological activity of Eugenia caryophyllata has been investigated on several microorganisms and parasites, including pathogenic bacteria, Herpes simplex and hepatitis C viruses. In addition to its antimicrobial, antioxidant, antifungal and antiviral activity, clove essential oil possesses antiinflammatory, cytotoxic, insect repellent and anaesthetic properties. This short review addresses the chemical composition and biological effects of clove essential oil, and includes new results from GC/MS analysis and a study of its antimicrobial activity against a large number of multi-resistant Staphylococcus epidermidis isolated from dialysis biomaterials.     

Potentiation of antimicrobial activity of ciprofloxacin by Pelargonium graveolens essential oil against selected uropathogens

The recent approach of using herbs and antibiotics in combination constitutes a strategy to overcome the problems of resistance and side effects associated with conventional antibiotics. In the present study, the antimicrobial effect of Pelargonium graveolens L' Hér essential oil in combination with ciprofloxacin was evaluated on uropathogens, namely, Klebsiella pneumoniae KT2, Proteus mirabilis PRT3 and Staphylococcus aureus ST2. Minimum inhibitory concentrations of P. graveolens essential oil and ciprofloxacin were determined by the microbroth dilution method and further, the interaction between these two agents was studied by a checkerboard method. The fractional inhibitory concentration index (FICI) was calculated to be 0.375 for both K. pneumoniae KT2 and P. mirabilis PRT3, while for S. aureus ST2 it was found to be 0.5. The values of FICI for the tested microorganisms were found to be ≤0.5, which indicates synergism between P. graveolens essential oil and ciprofloxacin. The concave shaped curve in the isobolograms also depicted a synergistic effect of P. graveolens essential oil and ciprofloxacin against the tested microorganisms. Hence, the synergistic action of P. graveolens essential oil and ciprofloxacin may be applied for the treatment of UTIs, which have hitherto been treated by using only synthetic drugs.     

Antibacterial Activity and Composition of the Volatile Oil from Achillea Ageratum L.

Artemisia ketone, artemisia alcohol, β-caryophyllene oxide and 1,8-cineole were confirmed as the major components of the volatile oil from Achillea ageratum L. In an antibacterial diffusion assay, the volatile oil showed activity mainly against Gram-positive bacteria Bacillus sp. and Staphylococcus aureus . The oil also showed some activity against the Gram-negative bacteria, Escherichia coli .     

Antimicrobial activity of volatile components and various extracts of the red alga Jania rubens

The methanol, dichloromethane, hexane, chloroform and volatile oil extracts of the red alga Jania rubens were tested in vitro for their antimicrobial activity (five Gram-positive, four Gram-negative bacteria and Candida albicans ATCC 10239). GC-MS analysis of the volatile components of J. rubens identified 40 compounds which constituted 77.53% of the total. The volatile components of J. rubens consisted of n-docosane (6.35%), n-eicosane (5.77%) and n-tetratriacontane (5.58%) as major components. The methanol and chloroform extracts (4 mg/disc) showed more potent antimicrobial activity than the hexane and dichloromethane extracts and the volatile oil of J. rubens.     

植物精油缓解抗生素耐药研究现状

抗生素耐药性(AMR)问题已成为当代医学一个日益严重的现象和挑战,植物精油具有广谱的抗病原微生物的作用,对多种细菌、真菌,甚至病毒和寄生虫具有抑制作用。精油可以通过改变细菌外膜的通透性、抑制细菌外排泵、抑制细菌生物膜形成、抗细菌群体感应作用以及抑制细菌细胞分裂等方式缓解或应对病原微生物对抗生素的耐药。精油的抗菌研究正在蓬勃发展,并成为未来潜在的研究领域。但植物精油在应用过程中也出现了耐药的问题。因此精油的抗生素治疗或替代应基于不同精油或精油与其他抗生素的组合和轮换,以防止或延缓耐药菌株的出现。综述植物精油对抗生素耐药病原微生物作用的相关研究,为其进一步研究提供思路和建议。