Chemical Profile and Phytotoxic Action of Hibiscus trionum Essential Oil

The chemical profile and phytotoxic action of Hibiscus trionum essential oil (EO) was studied. In total 17 compounds were identified via GC/MS, representing 94.18 % of the entire oil, with phytol (40.37 %) being the dominant constituent. Bioassay revealed that the EO inhibited root elongation of Medicago sativa and Amaranthus retroflexus by 32.66 % and 61.86 % at 5 mg/mL, respectively; meanwhile, the major component phytol also exhibited significant phytotoxic activity, suppressing radical elongation of Pennisetum alopecuroides, M. sativa and A. retroflexus by 26.08 %, 27.55 % and 43.96 % at 1 mg/mL, respectively. The fact that the EO showed weaker activity than phytol implied that some constituents might trigger antagonistic action to decrease the oil's activity. Our study is the first on the chemical profile and phytotoxic effect of H. trionum EO.     

Chemical Composition of Ambrosia trifida Essential Oil and Phytotoxic Effect on Other Plants

This study aimed to identify the main components of an essential oil produced from leaves of Ambrosia trifida and to evaluate its potential allelopathic effect on seed germination and seedling growth of lettuce, watermelon, cucumber and tomato. The essential oil was obtained by hydrodistillation and characterized chemically by gas chromatography (GC) coupled with both mass spectrometry (MS) and flame ionization detector (FID). Total 69 compounds were identified, with limonene (20.7 %), bornyl acetate (15.0 %), borneol (14.7 %) and germacrene D (11.6 %) as the major components. The working solutions of the essential oil emulsified with Tween 20 and dissolved in distilled water were prepared at four concentration levels (0.01, 0.1, 0.5 % and 1 %, v/v). The results obtained showed that increase in essential oil concentration leads to decrease in seed germination, as well as shoot and radical length of lettuce, watermelon, cucumber and tomato. The obtained data revealed a highly significant effect (p<0.05) between control and 1 % and 0.5 % oil concentrations in all treatments. The essential oil of A. trifida exhibited more powerful phytotoxic effects on lettuce, watermelon and tomato than on cucumber regarding germination and early seedling growth.     

Antifungal Activity of the Essential Oil of Basil (Ocimum basilicum)

The antifungal and fungicidal effects of two chemotypes of basil (Ocimum basilicum) oil and its major individual components were studied in a series of in vitro and in vivo experiments. Mycelial growth of the plant pathogenic fungus Botrytis fabae was reduced significantly by both the methyl chavicol chemotype oil and the linalol chemotype oil, and the major individual components of the oils all reduced fungal growth, with methyl chavicol, linalol, eugenol and eucalyptol reducing growth significantly. Combining the pure oil components in the same proportions as found in the whole oil led to very similar reductions in fungal growth, suggesting that the antifungal effects of the whole oils were due primarily to the major components. When the fungus was exposed to the oils in liquid culture, growth was reduced by concentrations considerably smaller than those used in the Petri dish studies. Botrytis fabae and the rust fungus Uromyces fabae were also controlled in vivo, with the whole oils of both chemotypes, as well as pure methyl chavicol and linalol, reducing infection of broad bean leaves significantly. Most effective control of fungal infection was achieved if the treatments were applied 3 h postinoculation.     

Glandular Hairs and Essential Oil in Developing Leaves of Ocimum basilicum L. (Lamiaceae)

The types of glandular hairs and their pattern of distributionon leaves of Ocimum basilicum L. at different stages, were investigated.Their essential oil at the various stages was chemically analysed.The density of the glandular hairs appears to be very high onyoung meristematic leaves and on meristematic regions of olderleaves. When the leaf regions start to expand no new glandularhairs are produced and their density decreases. The essentialoil differs in the percentage of some of its components betweenyoung and mature leaf regions.Copyright 1993, 1999 AcademicPress Ocimum basilicum, sweet basil, glandular hairs, leaf development, essential oil, cugenol, methyl chavicol, 1,8-cineole     

Studies of the Essential Oil of Mentha rotundifolia

Rotundifolone, a new terpenic ketone, C₁₀H₁₄O₂ has been isolated from the essential oil of M. rotundifolia in Japan. This ketone is highly dextro-rotatory, and has a low, melting point 27.5° The wave lengths of the ultraviolet absorption maxima of rotundifolone and its semicarbazone are 260 mμ (log ε = 3.95) and 273 mμ (log ε = 4.12) respectively. This indicates that rotundifolone has an α,β-unsaturated carbonylic system.     

Chemical Composition and Allelopathic,Phytotoxic and Pesticidal Activities of Atriplex cana Ledeb. (Amaranthaceae) Essential Oil

The chemical composition and allelopathic, phytotoxic and pesticidal activities of Atriplex cana Ledeb . (Amaranthaceae) essential oil were investigated. Nineteen compounds were identified via GC/MS, representing 82.3 % of the total oil, and the most abundant constituents were dibutyl phthalate (21.79 %), eucalyptol (20.14 %) and myrtenyl acetate (15.56 %). The results showed that volatile organic compounds (VOCs) released by A. cana significantly inhibited seedling growth of Amaranthus retroflexus L. and Poa annua L., and 80 g of fresh stems and leaves of A. cana in a 1.5 L airtight container almost completely suppressed the seed germination of both plants. Meanwhile, 5 μg/mL essential oil completely inhibited the seed germination of A. retroflexus, Medicago sativa L., P. annua and Echinochloa crusgalli L. Pesticidal testing revealed that the essential oil had strong behavioral avoidance and lethal effects on Aphis pomi DeGeer . Five microliters of essential oil/Petri dish treatment resulted in an 84.5 % mortality rate after 12 h, and the mortality rate reached nearly 100 % after 48 h. This report is the first one on the chemical composition as well as the biological activity of the essential oil of A. cana, and our results indicate that the oil is valuable in terms of being further exploited as a bioherbicide/insecticide.     

The Essential Oil Compositions of Ocimum basilicum from Three Different Regions: Nepal,Tajikistan, and Yemen

The aerial parts of Ocimum basilicum L. were collected from four different geographical locations, Sindhuli and Biratnagar (Nepal), Chormaghzak village (Tajikistan), and Sana'a (Yemen). The essential oils were obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry. A cluster analysis of 179 essential oil compositions revealed six major chemotypes: Linalool, eugenol, estragole, methyl eugenol, 1,8‐cineole, and geraniol. All four of the basil oils in this study were of the linalool‐rich variety. Some of the basil oils were screened for bioactivity including antimicrobial, cytotoxicity in human cancer cells, brine shrimp lethality, nematicidal, larvicidal, insecticidal, and antioxidant. The basil oils in this study were not notably antibacterial, cytotoxic, antioxidant, nor nematicidal, but were active in the brine shrimp lethality test, and did show larvicidal and insecticidal activities.     

Toxicity of Essential Oil from a New Strain of Ocimum gratissimum (Clocimum) against Betelvine Pathogenic Fungi

The leaves of Ocimum gratissimum (Clocimum) exhibited strong volatile fungitoxicity against betelvine (Piper betle L.) pathogens—Alternaria alternata, Colletotrichum capsici and Sclerotium rolfsii. Fifteen compounds could be identified from the fungitoxic constituents—the essential oil. The oil at its minimum inhibitory concentrations of 50, 250 and 500 ppm against S. rolfsii, A. alternata and C. capsici, respectively, was fungistatic, although, fungicidal at higher concentrations. Eugenol was found to be the major fungitoxic principle in the oil. The oil was either equally effective or superior to synthetic commercial fungicides and was non-phytotoxic to the host plants. Thus, the oil can be used as a valuable indigenous and biodegradable agent against fungi that cause losses to the betelvine industry.     

Fungistatic Activity of Essential Oils from Ocimum basilicum Chemotypes

Essential Oils from Ocimum basilicum and their components showed different inhibition effects against Fusarium oxysporum f. sp. vasinfectum and Rhizopus nigricans, The different antifungal activity of the essential oils is determined mainly by the percentage of the main components: cineol, linalool, methylchavicol and eugenol.     

小花琉璃草精油成分的研究

用气相色谱-质谱联用法分析了小花琉璃草精油的化学成分,鉴定了茴香脑、爱草醚、小茴香酮、对-甲氧基-苯甲醚等64个化合物,并用气相色谱测定了精油中各成分的相对含量。     

Prevalence of Diterpenes in Essential Oil of Euphorbia mauritanica L.: Detailed Chemical Profile,Antioxidant, Cytotoxic and Phytotoxic Activities

Plants belonging to Euphorbia L. genus are considered very interesting from a medicinal point of view due to their diverse metabolites and bioactivities. The essential oil (EO) of Euphorbia mauritanica L. is not studied up to date. Therefore, the present study aimed to explore the chemical profile of this EO and evaluate its antioxidant, cytotoxic, and allelopathic potentialities. The EO was extracted from the whole plant via hydrodistillation and then, analyzed by gas chromatography/mass spectrometry (GC/MS). The correlation of E. mauritanica with the other Euphorbia plants was established using chemometric analysis. The antioxidant activity was determined based on scavenging of the free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The anti-proliferation of the EO on the Hep G2 and MCF-7 cells was evaluated. Finally the allelopathic activity of the EO was assessed against the two noxious weeds, Dactyloctenium aegyptium and Urospermum picroides. Forty-one compounds were identified using GC/MS analysis, with an abundance of terpenoids (91.54 %) that were categorized into mono- (30.75 %), sesqui- (15.23 %), and diterpenes (45.56 %). Interestingly, the results revealed the preponderance of diterpenoid constituents although they are rarely found in the EOs of the plant kingdom. The major compounds were (3E)-cembrene A (18.66 %), verticiol (17.05 %), limonene (7.91 %), eucalyptol (7.26 %), α-pinene (5.61 %), neo-cembrene A (3.52 %), kaur-16-ene (3.24 %), and cembrene (3.09 %). The EO showed moderate antioxidant activity where it attained IC₅₀ values of 83.34 and 64.21 μg mL⁻¹ for DPPH and ABTS compared to 23.01 and 19.23 μg mL⁻¹ for ascorbic acid as standard, respectively. The EO exhibited very weak cytotoxic effect on MCF-7 and Hep G2 cells. The EO showed significant allelopathic activities against the weeds D. aegyptium and U. picroides in a concentration-dependent manner. EO was found more effective against U. picroides than D. aegyptium with IC₅₀ values of 0.79, 0.45, and 0.67 mg mL⁻¹ and 1.17, 0.55, and 1.08 mg mL⁻¹ for germination, root, and shoot growth, respectively. Due to the high content of diterpenes in E. mauritanica, further study is recommended for more characterization of pure forms of the identified diterpenes as well as evaluating their bioactivity either solely or synergistically.     

Change in Chemical Composition of Sweet Basil (Ocimum basilicum L.) Essential Oil Caused by Alfalfa mosaic virus

The effects of Alfalfa mosaic virus (AMV) infection on essential oil (EO) content and composition of a Sweet Basil cv. Gigante di Napoli were evaluated. A 10‐fold lower extraction yield from infected plants was observed, suggesting that morphological alterations induced by the disease may affect abundance and efficacy of secretive tissues. Organoleptic properties and thus quality of EO were severely affected and EO composition resulted severely altered, with a great increase in sesquiterpenes (from 72.8 to 19.8%) and a decrease in both monoterpenes (from 35 to 11%) and phenylpropanoids (from 44.5 to 15.8%, despite a slight increase in eugenol). Such report is indicative of possible direct or indirect metabolic consequences of AMV in a commercially important species like Ocimum basilicum is. The possible consequences of linalool and trans‐β‐farnesene content changes on the dispersion of viruliferous aphids are also examined and discussed.     

牵牛子(黑丑)挥发油成分研究

目的:研究牵牛子的化学成分.方法:利用有机溶剂-水蒸气蒸馏法提取牵牛子(Semen pharbitidis)挥发油,采用GC -MS进行测定,并应用色谱峰面积归—化法计算各成分的相对百分含量.结果:鉴别出35个化学成分,其化学成分为庚醛( 14.368％);反,反-2.4 -葵二烯醛(6.887％);2-戊基呋喃(5.327％);2-羟基-4-甲氧基苯甲醛(5.312％);萜品烯-4-醇(3.772％);苯乙醛(3.458％);十六烷酸乙酯(2.063％)等.结论:该文首次采用气相色谱-质谱联用法对牵牛子中的挥发性成分进行.     

Studies on Chemical Constituents of Essential Oil from Leaves of Jiang-Zhang

Jiang-Zhang is a Physiological type of Cinnamomum porrectum (Roxb.) Kosterm. The essential oil of leaves of Jiang-Zhang can be extracted by steam distillation, with yields of 0.5–0.8%. It contained dtral (α-,β-citral) 64.11% and can be used in aromatic and medicinal industries. We used the methods of GC, IR, GC/MS/DS and prepared derivative and 47 chemical constituents were identified, as follows: α-thujene (0.06 %), α-pinene (2.42%), camphene (1.26%), sabinene (0.21%),β- pinene (1.38%) myrcene(0.38%), α-phellandrene (0.32%),△3-carene (0.01%), p-cymene(0.21%),α-limonene (1.57%), 1 8-cineole (0.82 % ), β-phellandrene (0.10 %), cis-linalool oxide(0.07 % ), linalool (8.43 % ) epicamphor(0.26 % ), camphor(1.10 %), borneol( 1.07 % ), β-citral (neral) (28.28 % ), geraniol (0.25%), nerol (0.47%), α-citral (geranial) (35.83%), methyl citronellate (0.12%), n-undecane (0.18), safrole (0.02), methyl geranate (0.23%), geranyl formate (0.09%), α-copaene (0.12%), trans-methyl cinnamate (0.02%), n-dodecane (0.20), β-elemene (0.12%), caryophyllene (4.67%), α-guaiene (0.04), β-guaiene (0.06%), β-selinene (0.97%), azulene (0.38%), β-cubebene (0.30%), n-pentadecane (0.05%), β-gurjunene (0.04 %), epi-β-santalene (0.46 %), aremophliene (0.05 % ), alloaromadendrene (0.03 % ), α-elemene (0.26%), trans-β-farnesene (0.04%), (z)-β-farnesene (0.30%), r-elemene (0.03%), β-bisaboiol(0.41%), cedrol (0.16%), respectively.     

四种裸子植物叶精油化学成分的研究

采用气相色谱—质谱—计算机联用仪对穗花杉、南方红豆杉、三尖杉和罗汉松叶精油化学成分的研究发现,三尖杉和穗花杉叶精油的组成特点极为相似,相同成分１３个,占各自精油组成的４８．０７％和３３．３２％．三尖杉和南方红豆杉叶精油的相同成分４个,占各自精油组成的１６．１４％和４０．５９％．在一定程度上支持三尖杉科和红豆杉科的亲缘关系接近,红豆杉科可能是通过穗花杉属和三尖杉科相联系的观点．罗汉松和穗花杉叶精油的相同成分４个,占各自叶精油组成的比例为２４．０９％和２０．８２％,比罗汉松和南方红豆杉、三尖杉之间组分的相似性要高．反映出罗汉松科和红豆杉科之间有一定联系,穗花杉属是认识红豆杉科、三尖杉科和罗汉松科之间系统关系的关键属     

Structural and Immunochemical Studies on the Phytotoxic Peptidorhamnomannan of Ceratocystis ulmi

A wilt-inducing peptidorhamnomannan produced by Ceratocystis ulmi, the causative agent in Dutch Elm disease, has been subjected to additional chemical and physical characterization. Gel filtration, reductive β elimination, hydrofluoric acid deglycosylation, and ultracentrifugation experiments provide evidence that the wilt-inducing polymer is polydisperse with a molecular weight range of approximately 105,000 to 120,000. The carbohydrate portion of each molecule is composed of small percentages of mannose, mannobiose, mannotriose, and a tetra- or pentasaccharide composed of mannose and rhamnose plus a major component consisting of two or three long rhamnomannan chains each with a molecular weight range of 32,000 to 34,000. All saccharide units are attached via O-glycosidic linkages to a protein with a molecular weight of approximately 35,000.     

Studies on the Mode of Action of Tomatine as a Fungitoxic Agent

Removal of 1 or more sugar residues from the alpha-tomatine molecule markedly decreased its fungitoxicity. While partial hydrolysis of alpha-tomatine did not greatly affect its surfactant properties, it did destroy the ability of this alkaloid to form a complex with cholesterol. Only unprotonated alpha-tomatine was capable of binding cholesterol; the protonated form did not. Since alpha-tomatine was far more toxic at a high pH than at a low pH, this suggests that the unprotonated alkaloid is the active form and that it acts by complexing with fungal sterols.