Essential oil variability within and among populations of Cunila incisa Benth.

To evaluate the intra- and interpopulational variability of volatile compounds in Cunila incisa, 72 samples representing 12 populations, were collected all over the distribution area of the species in Rio Grande do Sul State. The samples were extracted by steam distillation and analyzed using GC and GC–MS. A total of 19 volatile compounds were detected and identified. In average, the main compounds were 1,8-cineole, α-terpineol, p-cymene, sabinene, terpinene-4-ol, and γ-terpinene. Negative correlation was detected between the concentrations of 1,8-cineole and α-terpineol. Significant variation in the concentration of volatile compounds was detected within and among populations. Multivariate analysis of volatile oil composition identified three groups. Most populations exhibited low intra-populational variation indicating foundation effect. Relation between geographic distribution and chemical composition was observed.     

Chemical Profiling of the Essential Oils of Syzygium aqueum,Syzygium samarangense and Eugenia uniflora and Their Discrimination Using Chemometric Analysis

The essential oil compositions of the leaves of three related Myrtaceae species, namely Syzygium aqueum, Syzygium samarangense and Eugenia uniflora, were investigated using GLC/MS and GLC/FID. Altogether, 125 compounds were identified: α‐Selinene (13.85%), β‐caryophyllene (12.72%) and β‐selinene constitute the most abundant constituents in S. aqueum. Germacrene D (21.62%) represents the major compound in S. samarangense whereas in E. uniflora, spathulenol (15.80%) represents the predominant component. Multivariate chemometric analyses were used to discriminate the essential oils using hierarchical cluster analysis (HCA) and principal component analysis (PCA) based on the chromatographic results. The antimicrobial activity of the popularly used E. uniflora essential oil was assessed using broth microdilution method against six Gram‐positive, three Gram‐negative bacteria and two fungi. The oil showed moderate antimicrobial activity against Bacillus licheniformis exhibiting MIC and MMC of 0.63 mg/ml. The cytotoxic activity of E. uniflora essential oil was investigated against Trypanosoma brucei brucei (T. b. brucei) and MCF‐7 cancer cell line using MTT assay. It showed moderate activity against MCF‐7 cells with an IC₅₀ value of 76.40 μg/ml. On the other hand, T. brucei was highly susceptible to E. uniflora essential oil with IC₅₀ of 11.20 μg/ml, and a selectivity index of 6.82.     

Antileishmanial Screening,Cytotoxicity, and Chemical Composition of Essential Oils: A Special Focus on Piper callosum Essential Oil

Leishmania amazonensis is the etiological agent of tegumentary leishmaniasis, a disease characterized by the emergence of cutaneous and mucocutaneous ulcerated lesions that can evolve into severe destruction of skin tissue. Treatment of the disease is often accompanied by high toxicity and variable efficacy. Essential oils stand out for having diverse pharmacological properties. Here, we screened a panel of fourteen essential oils for their anti-L. amazonensis activity, cytotoxicity, and chemical profile. Lippia sidoides (LSEO) and Piper callosum (PCEO) oils displayed the best anti-promastigote and anti-amastigote activities with IC₅₀ of 31 and 21 μg/ml, respectively. PCEO was the safest oil with a desirable selectivity index >10. In addition, PCEO showed no cytotoxicity against the VERO line and erythrocytes. PCEO-treated amastigotes displayed mitochondrial membrane depolarization and high levels of intracellular ROS. Safrole (54.72 %) was the main component of PCEO. The results described here highlight the use of essential oils to combat tegumentary leishmaniasis.     

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.     

薇甘菊挥发油的化学成分及其对昆虫的生活活性

用GC／MS分析和薇甘菊挥发油的化学成分,共鉴定了22个化 的,单萜和倍半萜及其醇和酮的衍生物是其主要成分,并研究了薇甘菊挥发油对昆虫的生物活性,结果表明,在5－10μl·株^-1的用量时,它对小菜蛾、黄曲条跳甲和猿叶虫有显著的产卵驱避作用,同时也具有一定的触杀毒力,在500、750、1000mg·L^-1浓度时,对萝卜蚜的校正虫口减退率分别为50.0%、59.86%和62.51%,然而,在500mg·L^-1浓度时,对萝卜蚜、小菜蛾和黄曲条跳甲等不同受试虫态却无熏蒸毒杀作用。     

广西小叶红叶藤挥发油化学成分及抗氧化性研究

采用气相色谱-质谱联用技术对小叶红叶藤挥发油的化学成分进行分析,并用DPPH·法、ABTS,+法和铁氰化钾还原法对其抗氧化能力进行研究.结果表明:从小叶红叶藤挥发油分离出221个色谱峰,共鉴定64个化合物,占挥发油总量的95.72％,主要成分为dl-薄荷酮(53.43％)、(E)-薄荷酮(14.20％)、5-甲基-2-...     

Essential oil analysis and antimicrobial activity of eight Stachys species from Greece

The volatile composition of eight Stachys species has been studied. The investigated taxa were St. alopecuros (L.) Bentham., St. scardica (Griseb.) Hayek, St. cretica L. ssp. cretica, St. germanica L. ssp. heldreichii (Boiss.) Hayek, St. recta L., St. spinulosa L., St. euboica Rech. and St. menthifolia Vis., growing wild in Greece. The essential oils were obtained by hydrodistillation in a modified Clevenger-type apparatus, and their analyses were performed by GC and GC-MS. Identification of the substances was made by comparison of mass spectra and retention indices with literature records. Sesquiterpene hydrocarbons were shown to be the main group of constituents of all taxa. Furthermore, the obtained essential oils were tested against the following six bacteria: Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 35210), Bacillus subtilis (ATCC 10907), Bacillus cereus (clinical isolates), Micrococcus flavus (ATCC 10240), Staphylococcus epidermidis (ATCC 2228), as well as against the following five fungi: Aspergillus niger (ATCC 6275), Penicillium ochrochloron (ATCC 9112), Epidermophyton floccosum (clinical isolates), Candida albicans (clinical isolates) and Trichophyton mentagrophytes (clinical isolates). The tested essential oils showed better activity against bacterial species than against fungi. Pseudomonas aeruginosa was the most resistant strain, as none of the essential oils was active against this strain. The essential oil of St. scardica has been proven most active against both bacteria and fungi.     

Chemical Composition and Antimicrobial Activity of the Essential Oil from the Edible Aromatic Plant Aristolochia delavayi

The essential oil obtained by hydrodistillation from the aerial parts of Aristolochia delavayi Franch. (Aristolochiaceae), a unique edible aromatic plant consumed by the Nakhi (Naxi) people in Yunnan, China, was investigated using GC/MS analysis. In total, 95 components, representing more than 95% of the oil composition, were identified, and the main constituents found were (E)‐dec‐2‐enal (52.0%), (E)‐dodec‐2‐enal (6.8%), dodecanal (3.35%), heptanal (2.88%), and decanal (2.63%). The essential oil showed strong inhibitory activity (96% reduction) of the production of bacterial volatile sulfide compounds (VSC) by Klebsiella pneumoniae, an effect that was comparable with that of the reference compound citral (91% reduction). Moreover, the antimicrobial activity of the essential oil and the isolated major compound against eight bacterial and six fungal strains were evaluated. The essential oil showed significant antibacterial activity against Providencia stuartii and Escherichia coli, with minimal inhibitory concentrations (MIC) ranging from 3.9 to 62.5 μg/ml. The oil also showed strong inhibitory activity against the fungal strains Trichophyton ajelloi, Trichophyton terrestre, Candida glabrata, Candida guilliermondii, and Cryptococcus neoformans, with MIC values ranging from 3.9 to 31.25 μg/ml, while (E)‐dec‐2‐enal presented a lower antifungal activity than the essential oil.     

薇甘菊挥发油的化学成分及其对昆虫的生物活性

用GC/MS分析了薇甘菊挥发油的化学成分,共鉴定了22个化合物,单萜和倍半萜及其醇和酮的衍生物是其主要成分,并研究了薇甘菊挥发油对昆虫的生物活性.结果表明,在5～10μl·株^-1的用量时,它们对小菜蛾、黄曲条跳甲和猿叶虫有显著的产卵驱避作用.同时也具有一定的触杀毒力,在500、750、1000mg·L^-1浓度时,对萝卜蚜的校正虫口减退率分别为50.0%、59.86%和62.51%.然而,在500mg·L^-1浓度时,对萝卜蚜、小菜蛾和黄曲条跳甲等不同受试虫态却无熏蒸毒杀作用.     

Interspecific variations in the habitats of Reichardia tingitana (L.) Roth leading to changes in its bioactive constituents and allelopathic activity

Reichardia tingitana is an annual plant growing in different habitats of the Egyptian deserts. Little is known about variation among the habitats occupied by this species, its distribution, chemical composition, and allelopathic activity. The present study aimed to (a) assess the vegetation composition of three different habitats (Western Coast, Delta Coast, and Wadi Hagoul) of R. tingitana in Egypt, (b) determine their correlation to soil factors, (c) identify the changes in the bioactive constituents of R. tingitana in the three regions, and (d) evaluate the allelopathic activity regarding the variation in the habitat. Density and cover of all plant species associated with R. tingitana were estimated within 52 plots, representing three regions. Physical and chemical parameters of soil were analyzed in each plot. R. tingitana aboveground biomass was collected from each habitat, and the bioactive composition was analyzed using HPLC. The allelopathic effect against two weeds (Amaranthus lividius and Chenopodium murale) was assessed. The floristic composition showed the presence of 133 species belonging to 27 families. In the Delta Coast habitat of R. tingitana, Zygophyllum aegyptium and Calligonum polygonoides co-dominate, while Lycium shawii dominate the Western Coast habitat and finally the habitat of Wadi Hagoul was dominated by Haloxylon salicornicum. Soil analysis revealed little variations among habitats, especially salinity and organic matter. Fifteen compounds, mainly phenolics (60% of the total identified compounds) were identified from all R. tingitana samples. The major compounds were quercetin, naringenin, ellagic, gallic, chlorogenic, and caffeic acids. These compounds varied in diversity or quantity among different habitats. The Western Coast sample was the richest in species, followed by Delta Coast sample. Our study showed that salinity is the crucial factor that induces the production of bioactive constituents in R. tingitana, especially phenolics and flavonoids. The R. tingitana extracts significantly reduced the germination and growth of Chenopodium and Amaranthus. However, the Western Coast sample showed potent allelopathic activity, where the germination was wholly inhibited at 75 mg L⁻¹ and 50 mg L⁻¹, respectively. Thereby, this extract could be used as eco-friendly bioherbicide and may be integrated into weed control strategies.     

飞机草挥发油的化学组成及其对植物、真菌和昆虫生长的影响

飞机草挥发油对5种植物幼苗生长有显著的抑制作用,受抑制的大小排序为黑麦草＞白菜＞萝卜＞四季豆＞水稻．中等浓度(800mg·L-1)飞机草挥发油对水稻稻温病菌的抑制作用最强,对长春花疫病菌的抑制作用次之,对香蕉枯萎病菌的抑制作用最弱;其抑茵串分别为61．40％、29．27％和14．44％．10-20μl·株^-1的飞机草挥发油对小菜峨和黄曲条跳甲有显著的驱避产卵作用．经GC／MS,飞机草挥发油的化学成分主要是萜类化合物,如反式—石竹烯(16．58％)、δ—杜松烯(15．85％)、α—可巴烯(11．58％)、氧化石竹烯(9．63％)、大根香叶烯(4．96％)和α—Lu草烯(4．32％)。     

黄蒿挥发油对蚊虫的毒杀活性及其化学成分

采用培养板浸液法和三角瓶药膜法研究了黄蒿挥发油对蚊虫幼虫和成虫的毒杀效果,采用GC MS-DS联用分析了其化学成分.结果表明,挥发油对淡色库蚊幼虫和成虫具有较高的作用效果,且作用速度较快.对幼虫处理后2 d的LC₅₀值约为12.5 mg·L^-1.综合毒力测定显示,挥发油对成虫具有明显的击倒和致死作用,1 μg·cm^-2和10 μg·cm^-2剂量24 h致死率分别为70%和100%.黄蒿含挥发油0.38％,共鉴定出38种化合物,检出物占总质量87.53％,其中萜烯类12种,占45.04％,为黄蒿挥发油的主要成分.     

Chemical composition and antibacterial activity of the essential oil of Drimys granadensis L.f. leaves from Colombia

Drimys granadensis L.f., a native plant from Colombia, has been included in the Vademecum de Plantas Medicinales de Colombia by the Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, due to its widespread use in the folk medicine for the treatment of gastrointestinal ailments. The chemical composition of the essential oil of Drimys granadensis obtained by hydrodistillation of the leaves was analyzed by GC and GC/MS analyses. A total of 85 components were identified, with the major compounds germacrene D (1, 14.7%), sclarene (9.5%), a-cadinol (7.3%), longiborneol acetate (2, 6.3%), drimenol (4.2%), (Z)-β-ocimene (3, 4.2%), a-pinene (4, 3.2%), and β-elemene (5, 2.7%). The essential oil was also tested against eight bacteria using the Kirby-Bauer disk-diffusion method. Most of the Gram-positive bacteria tested were susceptible to the D. granadensis essential oil, while the Gram-negative bacteria tested were not.     

Essential Oil of Indian Propolis: Chemical Composition and Repellency against the Honeybee Apis florea

Hitherto unknown biological properties and the chemical composition of the essential oil isolated from propolis of Indian origin were established. GC/MS Analysis of the essential oil revealed the presence of 32 constituents, of which ten were major compounds, nine had intermediate contents, and 13 were minor compounds. With the exception of six minor constituents, that could not be identified, their identification was based on the comparison of their mass spectra and Kovats retention indices with those listed in the NIST and Wiley mass spectral libraries. Their structural assignment was confirmed by GC/MS co‐injection of the essential oil with authentic compounds. Quantification of the components was done by GC‐FID analyses. Moreover, the essential oil was shown to possess repellent activity against the honeybee Apis florea. The activity was found to be dose dependent. The average repellency (ΔR) increased with increasing essential‐oil concentration up to 24 μg/ml and remained constant for the formulation with the higher concentration. These findings established the chemical constitution of the essential oil and might be useful to beekeepers for the improvement of the bee management.     

Essential Oil of Deverra tortuosa Aerial Parts: Detailed Chemical Profile,Allelopathic, Antimicrobial,and Antioxidant Activities

Essential oils (EOs) are a promising group of natural products of the aromatic plants due to their various biological effects such as allelopathic, antioxidant, antimicrobial activities. The present study aimed to construct the detailed chemical profile of the EO derived from Deverra tortuosa aerial parts along with assessing its allelopathic, antimicrobial, and antioxidant potentialities. The EO was extracted by hydrodistillation and analyzed via gas chromatography-mass spectrometry (GC/MS). The allelopathic activity of the EO was assessed against the germination and seedling growth of the weed Chenopodium murale. Also, the EO was tested against five microbes. The antioxidant activity was determined using the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The GC/MS analysis of EO revealed the presence of 86 compounds with a preponderance of oxygenated sesquiterpenes and monoterpene hydrocarbons. Widdrol, β-phellandrene, piperitol, cubedol, α-terpinene, (E)-10-heptadecen-8-ynoic acid methyl ester, citronellyl tiglate, and m-cymene were the major compounds. A comparative profile was established between the EOs constituents of our study with the documented EOs of D. tortuosa and the other Deverra species around the world via agglomerative hierarchical clustering (AHC) and principal components analysis (PCA). The EO showed a substantial allelopathic activity against C. murale, as well as it showed considerable antimicrobial and antioxidant activities. Thereby, the EO of D. tortuosa could be considered as a promising environmental-friendly bioherbicide against weeds. Also, it could be integrated into food preservation due to its potent antimicrobial and antioxidant activities. However, further study is recommended for more characterization of the major compounds and evaluation of their activities, either singular or synergistic, and assess their efficiency and biosafety.     

The Chemical Diversity of Lantana camara: Analyses of Essential Oil Samples from Cuba,Nepal, and Yemen

The aerial parts of Lantana camara L. were collected from three different geographical locations: Artemisa (Cuba), Biratnagar (Nepal), and Sana'a (Yemen). The essential oils were obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry. A cluster analysis of 39 L. camara essential oil compositions revealed eight major chemotypes: β‐caryophyllene, germacrene D, ar‐curcumene/zingiberene, γ‐curcumen‐15‐al/epi‐β‐bisabolol, (E)‐nerolidol, davanone, eugenol/alloaromadendrene, and carvone. The sample from Cuba falls into the group dominated by (E)‐nerolidol, the sample from Nepal is a davanone chemotype, and the sample from Yemen belongs to the β‐caryophyllene chemotype. The chemical composition of L. camara oil plays a role in the biological activity; the β‐caryophyllene and (E)‐nerolidol chemotypes showed antimicrobial and cytotoxic activities.     

Chemical composition of Thuja orientalis L. essential oils and study of their allelopathic potential on germination and seedling growth of weeds

The chemical composition of essential oils isolated by hydrodistillation from needles and cones of Thuja orientalis L. was analysed by gas chromatography-flame ionisation detection and gas chromatography–mass spectrometry. Twenty-one compounds were identified; quantitative differences, mainly, between cone and needle oils were observed. Both oils were rich in monoterpene hydrocarbons and the major constituents were α-pinene (64.2 and 49.3%, respectively, in cones and needles), β-phellandrene (6.7–9.6%) and α-cedrol (3.9 and 8.2%). Herbicidal properties of Thuja essential oils were assessed against three invasive weed species in crops: Sinapis arvensis L., Phalaris paradoxa L. and Lolium rigidum Gaud. The study of herbicidal activity was carried out on the weed germination, seed vigour and seedling growth. Our results showed a strong inhibitory effect on all tested weeds following a dose-dependent manner, property that could be valourised in managing biocontrol of weeds.     

Chemical composition and in vitro schistosomicidal activity of the essential oil of Plectranthus neochilus grown in Southeast Brazil

The chemical composition and the in vitro schistosomicidal effects of the essential oil of Plectranthus neochilus (PN-EO) grown in Southeast Brazil was studied. β-Caryophyllene (1; 28.23%), α-thujene (2; 12.22%), α-pinene (3; 12.63%), β-pinene (4; 6.19%), germacrene D (5; 5.36%), and caryophyllene oxide (6; 5.37%) were the major essential oil constituents. This chemical composition differed from that previously reported for specimens harvested in Africa. Concerning the in vitro schistosomicidal activity against adult Schistosoma mansoni worms, PN-EO was considered to be active, but less effective than the positive control praziquantel (PZQ) in terms of separation of coupled pairs, mortality, decrease in the motor activity, and tegumental alterations. However, PN-EO caused an interesting dose-dependent reduction in the number and the percentage of developed S. mansoni eggs. These results suggest that PN-EO might be very promising for the development of new schistosomicidal agents.     

外源水杨酸调控水稻化感抑草作用及其分子生理特性

为了探讨外源水杨酸（SA）调控水稻化感抑草效应的可行性,研究了不同浓度的外源SA对强化感水稻PI312777抑草效应的影响及其生理生化特性,并运用实时定量RT-PCR(FQ-PCR)技术检测SA介导的关键酶苯丙氨酸解氨酶基因（ZB8）的相对表达量.结果表明：外源SA能够诱导水稻化感抑草效应增强,而且这种诱导效应与SA的浓度和处理时间相关.叶面喷施SA后,PI312777对稗草的抑制率显著提高,其根系活力、超氧化物歧化酶（SOD）和过氧化物酶（POD）活性增强,过氧化氢酶（CAT）活性降低;而伴生杂草稗草的相应生理指标的变化趋势则相反.PI312777植株中的苯丙氨酸解氨酶（PAL）活性增强,总酚含量升高.0.2 mmol·L^-1的SA诱导水稻化感抑草效应最显著,该浓度下目的基因ZB8的相对表达丰度随处理时间先上调后下调,在24 h达到表达高峰.     

红豆树叶挥发油化学成分及其抗氧化和抑菌活性研究

为探究红豆树叶挥发油的化学组成及其生物活性,本研究首次采用水蒸气蒸馏法提取红豆树叶挥发油,并通过气相色谱-质谱联用技术(GC-MS)分析其化学成分,结合DPPH和ABTS法及抑菌圈法,评价其体外抗氧化和抑菌活性。结果表明,从红豆树叶挥发油中共检测出化合物36个,占挥发油总量的90.50%;挥发油主要成分为1,4-二十烷二烯(25.72%)、1,19-二十烷二烯(10.85%)、2,6-二叔丁基对甲酚(10.14%)、邻苯二甲酸正丁基异丁基酯(9.75%)、(Z,Z)-6,9-二十烷二烯(7.60%)、(E,E)-α-金合欢烯(7.51%)、叶醇(4.74%)和2-异丙烯基-5-甲基-6-庚烯-1-醇(4.04%)。红豆树叶挥发油对DPPH自由基和ABTS自由基清除作用的半数有效量(ED₅₀)分别为0.27、0.14 mg/mL,且抗氧化活性与挥发油浓度呈量效相关。红豆树叶挥发油浓度为7.1 mg/mL时,其对枯草芽孢杆菌(Bacillus subtilis)、金黄色葡萄球菌(Staphylococcus aureus)、绿脓杆菌(Pseudomonas aeruginosa)和大肠杆菌(Escherichia coli)的抑菌圈分别为11.29、9.88、10.85和11.03 mm。本研究为红豆树叶资源的综合开发利用提供了理论基础。