Chemical composition, antioxidant and antimicrobial activities of essential oil of Thymus algeriensis wild-growing in Libya

The composition of essential oil isolated from Thymus algeriensis growing wild in Libya was analyzed by GC and GC-MS. The essential oil was characterized with thymol (38.50%) as the major component. The oil was screened for antioxidant activity using DPPH assay, and compared to thymol and carvacrol. Antioxidant activity was high, with the IC₅₀ of 0.299 mg/ml, compared to 0.403 and 0.105 mg/ml for thymol and carvacrol, and 0.0717 mg/ml for BHA. In addition, antimicrobial activity was tested against eight bacteria and eight fungi. T. algeriensis oil showed inhibitory activity against tested bacteria at 0.001–0.05 mg/ml, while bactericidal activity (MBC) was achieved at 0.0025–0.05 mg/ml. For antifungal activity MICs ranged 0.0005–0.025 mg/ml and MFC 0.001–0.05 mg/ml. High antimicrobial activity against the fungi in particular suggests that the essential oil of Thymus algeriensis could have a useful practical application.     

Chemical composition and antimicrobial activity of the essential oil of Teucrium ramosissimum (Lamiaceae)

The phytochemical composition of the essential oil of Teucrium ramosissimum (aerial parts), harvested in a mountainous region of Tunisia, was analyzed. A total of 68 compounds, accounting for 99.44% of the essential oil, were identified by GC and GC/MS. The major compounds were beta-eudesmol (61; 44.52%), caryophyllene oxide (56; 9.35%), alpha-thujene (1; 5.51%), sabinene (4; 4.71%), and T-cadinol (59; 3.9%). The essential oil, which is being used in Tunisian folk medicine against infectious diseases, was tested for its antimicrobial properties against five different bacteria, and found to have weak to moderate activity, with minimal-inhibitory-concentration (MIC) and minimal-bactericidal-concentration (MBC) values in the range 0.24-0.36 and 1.3-2.9 mg/ml, resp.     

Phytochemical analysis and in vitro evaluation of the biological activity against herpes simplex virus type 1 (HSV-1) of Cedrus libani A. Rich.

Cedrus libani are widely used as traditional medicine in Lebanon for treatment of different infection diseases. In the present study we reported the phytochemical composition analyzed by GC-MS of wood essential oil and cones and leaves ethanol extracts. The main components of wood essential oil were himachalol (22.50%), beta-himachalene (21.90%), and alpha-himachalene (10.50%). Leaves ethanol extract was characterized by a high content of germacrene d (29.40%). The same extract obtained from cones essentially contained alpha-pinene (51.0%) and beta-myrcene (13.0%). Moreover, we investigated extracts, essential oil, and identified compounds for their in vitro antiviral activities against herpes simplex virus type 1 (HSV-1). Cytotoxicity was evaluated by MTT assay in Vero cells. Cones and leaves ethanol extracts exhibited an interesting activity with IC50 of 0.50 and 0.66 mg/ml, respectively, at non-cytotoxic concentration. A comparable activity was found when essential oil was tested (IC50 of 0.44 mg/ml).     

Antibacterial and antioxidant activity and essential oil composition of Grammosciadium scabridum Boiss. from Iran

The in vitro antibacterial and antioxidant activity of the essential oil and its two main components of Grammosciadium scabridum Boiss. (Apiaceae) growing wild in Iran, as well as the composition of its essential oil were studied. A total of 19 compounds representing 99.9% of the oil has been identified. Gamma-Terpinene (73.5%), p-cymene (14.2%) and (E)-beta-farnesene (5.3%) were characterized as the main components. The oil showed remarkable activity against three Gram-negative and four Gram-positive test bacteria, with minimal inhibitory concentration (MIC) values ranging from 0.31 to 10.00 mg/ml. The oil and its two main components were also subjected to screening for their possible antioxidant activity by using the 2,2-diphenyl-l-picrylhydrazyl (DPPH) assay. The free radical scavenging capacity of the oil was determined with an IC50 value of 6.6 mg/ml.     

Phytotoxicity and volatile constituents from leaves of Callicarpa japonica Thunb

The essential oil from the leaves of Callicarpa japonica was analyzed by GC-MS, and 84 compounds were identified. The main constituents of the essential oil were spathulenol (18.1%), germacrene B (13.0%), bicyclogermacrene (11.0%), globulol (3.3%), viridiflorol (2.6%), alpha-guaiene (2.3%), and gamma-elemene (2.0%). The essential oil constituents of C. japonica were significantly different from those found in our previous work on Callicarpa americana. The oil of C. japonica was selectively phytotoxic to bentgrass compared to lettuce seeds, with 80-100% growth reduction observed at 0.3 mg/ml.     

Chemical Composition of Hydrodistilled Essential Oil of Artemisia incana (L.) Druce and Antimicrobial Activity against Foodborne Microorganisms

The oil obtained by hydrodistillation from the aerial parts of Artemisia incana (L.) Druce from Turkey was analyzed by GC and GC/MS. Sixty‐three compounds were characterized, representing 97.2% of the total components detected, and camphor (19.0%), borneol (18.9%), 1,8‐cineole (14.5%), bornyl acetate (7.8%), camphene (4.9%), and α‐thujone (4.8%) were identified as predominant components. The essential oil was also tested for its antimicrobial activity against 44 different foodborne microorganisms, including 26 bacteria, 15 fungi, and 3 yeast species. The essential oil of A. incana exhibited considerable inhibitory effects against all bacteria, fungi, and yeast species tested. However, the oil showed lower inhibitory activity against the tested bacteria than the reference antibiotics.     

Antibacterial activity and composition of the essential oil of Ziziphora clinopodioides subsp. bungeana (Juz.) Rech. f. from Iran

The chemical composition of the essential oil obtained from the aerial flowering parts of Ziziphora clinopodioides subsp. bungeana (Juz.) Rech. f. was analyzed by GC and GC-MS. Thirty-two components representing 97.1% of the total oil were identified. Oxygenated monoterpenes (94.3%) were the predominant fraction of the oil with pulegone (65.2%), isomenthone (11.9%), 1,8-cineole (7.8%) and piperitenone (6.5%) as the main constituents. Antibacterial activity of the oil and also its two main components (pulegone and 1,8-cineole) were tested against seven bacteria. It was found that the oil exhibited interesting antibacterial activity against Staphylococcus epidermidis, S. aureus, Escherichia coli and Bacillus subtilis with MIC values of 3.75 mg/ml.     

小花假泽兰精油化学成分及其抑菌活性初步研究

利用GC-MS技术分析了小花假泽兰全株精油的化学成分及其含量,并初步测定了精油的抑菌效果.从小花假泽兰全株精油中共鉴定出49种成分,占色谱峰总面积的57.28%,主要成分为22,23-二羟基豆甾烷醇(7.34%)、氧化丁子香烯(3.34%)、罗汉柏烯(2.92%)、cubenol(2.81%)等.生长速率法测定表明,小花假泽兰精油对番茄灰霉病菌、小麦纹枯病菌和小麦赤霉病菌菌丝生长抑制作用较强,在1 000 mg/L剂量下抑制率均在90%以上;果实针刺法测试表明,该精油对番茄灰霉病菌具明显保护作用和治疗作用,但治疗效果低于保护效果,在2 000mg/L剂量下,后者达70.79%,前者仅51.79%.     

Essential oils from wild populations of Algerian Lavandula stoechas L.: composition, chemical variability, and in vitro biological properties

In an effort to develop local productions of aromatic and medicinal plants, a comprehensive assessment of the composition and biological activities of the essential oils (EOs) extracted from the aerial flowering parts of wild growing Lavandula stoechas L. collected from eleven different locations in northern Algeria was performed. The oils were characterized by GC‐FID and GC/MS analyses, and 121 compounds were identified, accounting for 69.88–91.2% of the total oil compositions. The eleven oils greatly differed in their compositions, since only 66 compounds were common to all oils. Major EO components were fenchone ( 2 ; 11.27–37.48%), camphor ( 3 , 1.94–21.8%), 1,8‐cineole ( 1 ; 0.16–8.71%), and viridiflorol ( 10 ; 2.89–7.38%). The assessed in vitro biological properties demonstrated that the DPPH‐based radical‐scavenging activities and the inhibition of the β‐carotene/linoleic acid‐based lipid oxidation differed by an eight‐fold factor between the most and the least active oils and were linked to different sets of molecules in the different EOs. The eleven EOs exhibited good antimicrobial activities against most of the 16 tested strains of bacteria, filamentous fungi, and yeasts, with minimum inhibitory concentrations (MICs) ranging from 0.16 to 11.90 mg/ml.     

Chemical composition and larvicidal activity of leaf essential oil from Clausena dentata (Willd) M. Roam. (Rutaceae) against the chikungunya vector,Aedes aegypti Linn. (Diptera: Culicidae)

Larvicidal activity of essential oil and isolated compounds from Clausena dentata leaves were tested against early fourth instar Aedes aegypti larvae. GC–MS analysis of essential oil revealed the presence of fourteen compounds of which the major compounds were sabinene (21.27%), biofloratriene (19.61%), borneol (18.34%) and β-bisabolol (17.68%). The essential oil of C. dentata exhibited significant larvicidal activity, with 24 h LC₅₀ and LC₉₀ values of 140.2 and 341.6 mg/l, respectively. Larvicidal activities of the four major compounds of essential oil were also tested. The LC₅₀ values of sabinene, biofloratriene, borneol and β-bisabolol were 27.3, 47.4, 43.5 and 33.2 mg/l, respectively. Results of this study show that the leaf essential oil of C. dentata and its four major compounds may be a potent source of natural larvicides.     

Antitumor Effect of the Essential Oil from Leaves of Guatteria pogonopus (Annonaceae)

Guatteria pogonopus Martius , a plant belonging to the Annonaceae family, is found in the remaining Brazilian Atlantic Forest. In this study, the chemical composition and antitumor effects of the essential oil isolated from leaves of G. pogonopus was investigated. The chemical composition of the oil was determined by GC‐FID and GC/MS analyses. The in vitro cytotoxicity was evaluated against three different tumor cell lines (OVCAR‐8, NCI‐H358M, and PC‐3M), and the in vivo antitumor activity was tested in mice bearing sarcoma 180 tumor. A total of 29 compounds was identified and quantified in the oil. The major compounds were γ‐patchoulene (13.55%), (E)‐caryophyllene (11.36%), β‐pinene (10.37%), germacrene D (6.72%), bicyclogermacrene (5.97%), α‐pinene (5.33%), and germacrene B (4.69%). The essential oil, but neither (E)‐caryophyllene nor β‐pinene, displayed in vitro cytotoxicity against all three tumor cell lines tested. The obtained average IC₅₀ values ranged from 3.8 to 20.8 μg/ml. The lowest and highest values were obtained against the NCI‐H358M and the OVCAR‐8 cell lines, respectively. The in vivo tumor‐growth‐inhibition rates in the tumor‐bearing mice treated with essential oil (50 and 100 mg/kg/d) were 25.3 and 42.6%, respectively. Hence, the essential oil showed significant in vitro and in vivo antitumor activity.     

Chemical composition and antimicrobial activity of Satureja hortensis L. essential oil

Essential oil of Satureja hortensis L. was analyzed by GC and GC/MS and tested by a broth micro-well dilution method for activity against multiresistant clinical isolates of pathogenic bacteria from 10 different genera: Klebsiella, Escherichia, Proteus, Staphylococcus, Streptococcus, Pseudomonas, Enterococcus, Enterobacter, Citrobacter and Acinetobacter. The main compounds in the oil were carvacrol (67%), γ-terpinene (15.3%) and p-cymene (6.73%). The oil showed activity against all tested strains. MIC/MBC values were in the range of 0.78-25 μl/ml, with the exception of the strain P. aeruginosa. Microbicidal concentration for this particular strain (50 μl/ml) was the highest tested concentration. The oil showed inhibitory and bactericidal effect at the same concentration (MIC=MBC) for all but three strains.     

Antimicrobial activity, essential oil composition and micromorphology of trichomes of Satureja laxiflora C. Koch from Iran

The antimicrobial activity, essential oil composition and micromorphology of trichomes of Satureja laxiflora C. Koch, a native plant from Iran, were studied. The essential oil was obtained from the aerial parts at the flowering stage by hydrodistillation, and analyzed by GC and GC/MS. Thirty-three compounds representing 99.1% of the total oil were characterized. The major compounds were thymol (63.9%) and gamma-terpinene (11.9%) followed by carvacrol (4.8%), p-cymene (3.9%), geraniol (3.2%) and geranyl acetate (3.1%). Furthermore, the essential oil and its three main components were tested against two bacteria and three fungi. The result of the bioassays has been shown that the oil possesses potent antimicrobial property. Chemical studies confirmed that a major portion of this antimicrobial activity is due to thymol present in the oil. Micromorphological analysis by SEM of both vegetative and reproductive organs revealed the presence of abundant sessile capitate and sparse short-stalked glandular trichomes along with retrorse eglandular hairs, giving useful diagnostic characters for identification of this medicinal plant.     

Chemical Composition and Phytotoxic Effects of Essential Oils Obtained from Ailanthus altissima (Mill.) Swingle Cultivated in Tunisia

Ailanthus altissima Mill. Swingle (Simaroubaceae), also known as tree of heaven, is used in the Chinese traditional medicine as a bitter aromatic drug for the treatment of colds and gastric diseases. In Tunisia, Ailanthus altissima is an exotic tree, which was introduced many years ago and used particularly as a street ornamental tree. Here, the essential oils of different plant parts of this tree, viz., roots, stems, leaves, flowers, and samaras (ripe fruits), were obtained by hydrodistillation. In total, 69 compounds, representing 91.0–97.2% of the whole oil composition, were identified in these oils by GC‐FID and GC/MS analyses. The root essential oil was clearly distinguishable for its high content in aldehydes (hexadecanal ( 1 ); 22.6%), while those obtained from flowers and leaves were dominated by oxygenated sesquiterpenes (74.8 and 42.1%, resp.), with caryophyllene oxide ( 4 ) as the major component (42.5 and 22.7%, resp.). The samara oil was rich in the apocarotenoid derivative hexahydrofarnesyl acetone ( 6 ; 58.0%), and the oil obtained from stems was characterized by sesquiterpene hydrocarbons (54.1%), mainly β‐caryophyllene (18.9%). Principal component and hierarchical cluster analyses separated the five essential oils into four groups, each characterized by the major oil constituents. Contact tests showed that the germination of lettuce seeds was totally inhibited by all the essential oils except of the samara oil at a dose of 1 mg/ml. The flower oil also showed a significant phytotoxic effect against lettuce germination at 0.04 and 0.4 mg/ml (?55.0±3.5 and ?85.0±0.7%, resp.). Moreover, the root and shoot elongation was even more affected by the oils than germination. The inhibitory effect of the shoot and root elongation varied from ?9.8 to ?100% and from ?38.6 to ?100%, respectively. Total inhibition of the elongation (?100%) at 1 mg/ml was detected for all the oils, with the exception of the samara oil (?74.7 and ?75.1% for roots and shoots, resp.).     

Chemical composition and antimicrobial activity of the essential oil of endemic Dalmatian black pine (Pinus nigra ssp. dalmatica)

The chemical composition and the antimicrobial activity of the essential oil isolated from the needles of endemic Dalmatian black pine (Pinus nigra ssp. dalmatica) from Croatia were investigated. The chemical composition of the essential oil was determined by GC and GC/MS analyses, and the main compounds identified were α-pinene, β-pinene, germacrene D, and β-caryophyllene. Disc-diffusion and broth-microdilution assays were used for the in vitro antimicrobial screening. The Dalmatian black pine essential oil exhibited a great potential of antibacterial activity against Gram-positive bacteria (MIC=0.03-0.50% (v/v)) and a less pronounced activity against Gram-negative bacteria (MIC=0.12-3.2% (v/v)). The volatile compounds also inhibited the growth of all fungi tested, including yeast.     

椪柑精油及其主要抑菌组分对菌核青霉的抑制作用

采用水蒸气蒸馏法提取椪柑(Citrus reticulate Blanco)果皮精油,并用GC-MS对其成分进行分析,共鉴定出46种成分,主要包括柠檬烯(57.67%)、β-芳樟醇(5.36%)、2-蒈烯(4.47%)、β-蒎稀(4.31%)、γ-松油烯(4.08%)、α-蒎烯(3.27%)、1,2-二异丙烯基环丁烷(2.87%)、β-月桂烯(2.77%)、α-侧柏烯(2.40%)、β-水芹烯(2.24%)、癸醛(1.80%)和香茅醇(1.49%)等。采用污染食物技术(poisoned food technique)和液体培养法(liquid culture)测定了不同浓度椪柑精油以及主要抑菌组分对菌核青霉的抑制作用。结果表明:不同浓度(0.5~20μl/ml)的椪柑精油对菌核青霉生长均有一定的抑制,且抑菌效果与浓度呈正相关。无论是采用污染食物技术还是液体培养法,20μl/ml椪柑精油均能完全抑制菌核青霉生长;随着培养 时间延长到7d, 20μl/ml椪柑精油抑菌效果有所下降,但仍能显著抑制菌核青霉生长。采用污染食物技术考察了椪柑精油中7种常见抑菌成分对菌核青霉的影响。结果表明,0.04μl/ml柠檬醛和1.07μl/ml β-芳樟醇能显著抑制菌核青霉生长,而其他组分无明显作用。实验结果表明,椪柑精油的抑菌作用可能归功于其所含的柠檬醛和β-芳樟醇。     

Fumigant activity of plant essential oils and components from Schizonepeta tenuifolia against Lycoriella ingenua (Diptera: Sciaridae)

Plant essential oils from 21 plant species were tested for their insecticidal activities against larvae of Lycoriella ingenua Dufour (Diptera: Sciaridae) by using a fumigation bioassay. Good insecticidal activity against larvae of L. ingenua was achieved with essential oils of Acorus gramineus Solander, Schizonepeta tenuifolia Briquet, and Zanthoxylum piperitum De Candolle at 25 microg/ml air. S. tenuifolia oil showed the most potent insecticidal activity among the plant essential oils. At 12.5 microg/ml air concentration, S. tenuifolia oil caused 96.6% mortality, but mortality decreased to 60% at 3.125 microg/ml air. Analysis by gas chromatography-mass spectrometry led to identification of three major compounds from S. tenuifolia oil. These three compounds were tested individually for their insecticidal activities against larvae of L. ingenua and compared with the toxicity of dichlorvos. Pulegone was the most toxic, followed by menthone and limonene with LC50 values of 1.21, 6.03, and 15.42 microg/ml, respectively. LC50 of dichlorvos was 8.13 microg/ml. Effects of S. tenuifolia and its components on growth of Pleurotus ostreatus (Jacq. ex Fr.) Kummer also were investigated.     

Chemical Composition and Antipathogenic Activity of Artemisia annua Essential Oil from Romania

The essential oil extracted by hydrodistillation from Romanian Artemisia annua aerial parts was characterized by GC/MS analysis, which allowed the identification of 94.64% of the total oil composition. The main components were camphor (17.74%), α‐pinene (9.66%), germacrene D (7.55%), 1,8‐cineole (7.24%), trans‐β‐caryophyllene (7.02%), and artemisia ketone (6.26%). The antimicrobial activity of this essential oil was evaluated by determining the following parameters: minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), minimal fungicidal concentration (MFC), and minimal biofilm eradication concentration (MBEC). Moreover, the soluble virulence factors were quantified with different biochemical substrates incorporated in the culture media. The reference and resistant, clinical strains proved to be susceptible to the A. annua oil, with MICs ranging from 0.51 to 16.33 mg/ml. The tested essential oil also showed good antibiofilm activity, inhibiting both the initial stage of the microbial cell adhesion to the inert substratum and the preformed mature biofilm. When used at subinhibitory concentrations, the essential oil proved to inhibit the phenotypic expression of five soluble virulence factors (hemolysins, gelatinase, DNase, lipases, and lecithinases). Briefly, the present results showed that the A. annua essential oil contained antimicrobial compounds with selective activity on Gram‐positive and Gram‐negative bacterial strains as well as on yeast strains and which also interfere with the expression of cell‐associated and soluble virulence factors.     

Antifungal activities of the essential oils in Syzygium aromaticum (L.) Merr. Et Perry and Leptospermum petersonii Bailey and their constituents against various dermatophytes

This study was carried out in order to investigate the potential of using plant oils derived from Leptospermum petersonii Bailey and Syzygium aromaticum L. Merr. Et Perry as natural antifungal agents. The antifungal effects of essential oils at concentrations of 0.05, 0.1, 0.15, and 0.2 mg/ml on the dermatophytes Microsporum canis (KCTC 6591), Trichophyton mentagrophytes (KCTC 6077), Trichophyton rubrum (KCCM 60443), Epidermophyton floccosum (KCCM 11667), and Microsporum gypseum were evaluated using the agar diffusion method. The major constituents of the active fraction against the dermatophytes were identified by gas chromatography-mass spectrometry and high-performance liquid chromatography analysis. The antifungal activities of S. aromaticum oil (clove oil) against the dermatophytes tested were highest at a concentration of 0.2 mg/ml, with an effectiveness of more than 60%. Hyphal growth was completely inhibited in T. mentagrophytes, T. rubrum, and M. gypseum by treatment with clove oil at a concentration of 0.2 mg/ml. Eugenol was the most effective antifungal constituent of clove oil against the dermatophytes T. mentagrophytes and M. canis. Morphological changes in the hyphae of T. mentagrophytes, such as damage to the cell wall and cell membrane and the expansion of the endoplasmic reticulum, after treatment with 0.11 mg/ml eugenol were observed by transmission electron microscopy (TEM). At a concentration of 0.2 mg/ml, L. petersonii oil (LPO) was more than 90% effective against all of the dermatophytes tested, with the exception of T. rubrum. Geranial was determined to be the most active antifungal constituent of L. petersonii oil. Taken together, the results of this study demonstrate that clove and tea tree oils exhibited significant antifungal activities against the dermatophytes tested in this study.     

牛至挥发油的化学成分及其化感作用

为探究牛至挥发油的化学成分及其化感作用,本文采用水蒸气蒸馏法提取牛至全草挥发油,利用气相色谱(GC)和气相色谱-质谱联用(GC-MS)从牛至挥发油中鉴定出14种化学成分,占总出峰面积的93.6%,主要成分为甲基丁香酚(16.5%)、肉豆蔻醚(15.6%)、香芹酚(15.0%)、百里香酚(9.8%)、洋芹脑(9.4%)等。通过测定挥发油对小麦、绿豆和萝卜种子萌发及幼苗生长的影响,评价挥发油的化感潜力。结果表明: 牛至挥发油对3种受体植物的种子萌发有抑制作用,其中,对小麦的抑制作用最强,萝卜和绿豆次之,挥发油对供试植物地上部分生长的抑制作用大于地下部分。挥发油对3种供试植物幼茎及小麦和萝卜幼根生长的抑制作用与浓度成正相关,对绿豆幼根长度则表现为“低促高抑”现象。本研究证实牛至挥发油中含有化感物质,其活性化合物及作用机制有待进一步研究。