Antifungal Activity of the Essential Oil of Hyssop (Hyssopus officinalis)

The antifungal and fungicidal effects of hyssop ( Hyssopus officinalis ) oil and its individual components were studied in a series of in vitro and in vivo experiments. Mycelial growth of the plant pathogenic fungi Pyrenophora avenae and Pyricularia oryzae was completely inhibited by 0.4% hyssop oil. Volatile components diffusing from agar medium containing 0.4% hyssop oil also completely inhibited the growth of these two fungi. Various components of hyssop oil ( L -bornyl acetate, isopinocampheol and pinocamphone), used individually, reduced growth of P. avenae and, where combinations of individual components were used, any mixture containing isopinocampheol completely inhibited fungal growth. Growth of P. oryzae was less affected by individual components of the oil. Hyssop oil reduced germination of Botrytis fabae conidia and uredospores of Uromyces viciae-fabae , but in contrast to the data from in vitro experiments, its effects on pathogen infection were less clear cut. Thus, although 0.05% hyssop oil reduced rust infection of broad bean when applied 1, 2 or 3 days before, or 1 or 2 days after inoculation, its effects against barley powdery mildew and apple powdery mildew were variable. It is suggested that this variability might be the result of the volatile components of the oil diffusing away from leaf surfaces, thus reducing the concentration of active components on the leaf surface.     

Chemical Profiling and Antifungal Activity of Ziziphora clinopodioides Leaf Essential Oil against the Pathogen Verticillium dahliae

Essential oils (EOs) are often used as natural antifungal agents to control the growth of phytopathogenic fungi. The aim of this study was to determine the effect of Ziziphora clinopodioides leaf EO against Verticillium dahliae, a pathogenic fungus of cotton. Gas chromatography-mass spectrometry (GC/MS) analysis revealed the presence of 15 compounds of the total of extracted oil, which was consisted of 98.79 % monoterpenes and 0.61 % sesquiterpenes. The major constituents were pulegone (62.17 %), isomenthone (18.42 %), l-menthone (5.55 %) and piperitenone (3.99 %). The mycelial growth of Verticillium dahliae was completely inhibited at 0.24 μL/mL air under vapor phase condition. Considerable morphological variations were also observed in the fungal sclerotia at the contact phase at 3 μL/mL. This study demonstrated for the first time that Z. clinopodioides EO can effectively inhibit the growth of V. dahliae, implying that it has the potential to be explored as an antifungal agent against Verticillium Wilt of cotton.     

植物精油抑菌活性研究进展

本文综述了国内外植物精油在农用抑菌活性及抑菌活性成分研究方面所取得的成果。阐述了具有农用抑菌活性的31种植物精油及其抑菌效果,并列举了植物精油中13种具有开发潜力的抑菌活性成分,简要分析了植物精油及其主要活性成分的作用机理。     

几种药用植物精油的抗真菌活性研究

研究了作用浓度为0：7-4．0μL/mL的南方药用植物香茅（Cymbopogon citratus）、广藿香（Pogostemon cablin（Blanco）Benth）、大叶桉（Eucalyptus robusta Smith）和蛇床（Cnidium monnier（L.）Cusson）的精油对6种植物病原真菌的抑制活性。结果表明,大叶桉、广藿香和香茅精油对串珠镰刀病菌（Fussarium moniliforme）、玉米弯孢霉菌（Curvjlaria lunata）对多种供试植物病原真菌的生长有明显抑制活性,其中,香茅精油在浓度为3．3μL/mL时,能完全抑制大部分供试真菌的生长。但不同精油对于各病原真菌的抑制率有一定差异。本研究为复合植物精油抗真菌农药的开发提供依据。     

11种植物精油对6种植物病原真菌的抑菌活性研究

为筛选有效的植物杀菌成分,采用菌丝生长法,测定了香茅油、薰衣草油、菊花油、月桂油、柠檬油、广藿香油、肉桂油、天竺葵油、迷迭香油、茶树油、薄荷油对6种植物病原真菌的抑菌活性。发现在2 g/L的浓度下,上述11种精油对6种供试病菌均有明显的抑制作用,其中香茅油、肉桂油、天竺葵油、月桂油、茶树油和薄荷油对6种病原真菌的抑制率均为100%。剂量效应试验表明,肉桂油对灰葡萄孢（Botrytis cinerea）和禾谷镰孢菌（Fusariumgraminearum）的EC50值分别为29.05μg/mL和42.96μg/mL,而天竺葵油对灰葡萄孢（Botrytis cinerea）和禾谷镰孢菌（Fusarium graminearum）的EC50值分别为34.02μg/mL和68.48μg/mL。     

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.     

Antifungal Activities of Four Fatty Acids against Plant Pathogenic Fungi

The effect of the fatty acids linolenic acid, linoleic acid, erucic acid and oleic acid on the growth of the plant pathogenic fungi Rhizoctonia solani, Pythium ultimum, Pyrenophora avenae and Crinipellis perniciosa were examined in in vitro studies. Linolenic and linoleic acids exhibited activity against all of the fungi. However, whereas linolenic acid reduced mycelial growth of R. solani and C. perniciosa at 100 microM, the concentration had to be increased to 1000 microM before any effect on mycelial growth of P. ultimum and P. avenae was observed. Linoleic acid only reduced mycelial growth of R. solani, P. ultimum and P. avenae at 1000 microM, but led to a significant reduction in growth of C. perniciosa at 100 microM. In contrast, oleic acid had no significant effect on growth of R. solani or P. avenae, but gave significant reductions in mycelial growth of P. ultimum at 100 microM and reduced growth of C. perniciosa significantly at 1000 microM. All of the fatty acids reduced biomass production by all of the fungi significantly in liquid culture when added to the media at 100 microM. Erucic acid had no effect on fungal growth at any concentration examined. The antifungal activities exhibited by linolenic, linoleic and oleic acids may be useful in the search for alternative approaches to controlling important plant pathogens, such as those examined in this study.     

Fungicidal Activity of Essential Oils from Cinnamomum cassia against the Pathogenic Fungi of Panax notoginseng Diseases

The frequent disease of Panax notoginseng caused by the pathogenic fungi in field cultivation has become the major threaten to the sustainable development of it. The present study was conducted to find natural agent with potential inhibition against pathogen. Therefore, the inhibitory effects of Cinnamomum cassia (L.) J.Presl essential oils (EOs) against P. notoginseng associated pathogenic fungi were conducted both in vitro and in vivo experiments. The results of the Oxford cup test revealed that C. cassia dry bark EO (50 mg/mL) had significant inhibitory activity on the growth of all tested fungi, and the growth of various pathogens was completely inhibited, except for that of Fusarium solani. Therefore, the constituents of C. cassia EOs were analyzed by GC/MS, and the research demonstrated that the main constituents of C. cassia dry bark EO were trans‐cinnamaldehyde (75.65 %), (E)‐2‐methoxycinnamaldehyde (6.08 %), cinnamaldehyde (3.47 %) and cinnamyl acetate (1.02 %). The MIC results showed that C. cassia dry bark EO and the main compounds had good antifungal effect on the tested strains, and the inhibitory effect was similar to that of hymexazol (chemical pesticide). By analyzing the value of the fraction inhibitory concentration index (FICI), additive effects, irrelevant effects and synergistic effects were observed after the mixture of hymexazol against various pathogens. Moreover, in vivo model showed that C. cassia dry bark EO could reduce the occurrence of anthrax in P. notoginseng. To widen the resources of C. cassia available, the compositions of both C. cassia fresh bark and leaf EOs were also tested and many common compositions existed among them. Taken together, it was concluded that C. cassia EO had the potential use in the field to reduce the pathogenic disease.     

侧柏乙醇提取物对21种植物病原真菌的抑菌活性

采用菌丝生长速率法测定了侧柏(Platycladus orientalis)叶、小枝、球果和种子4个不同部位乙醇提取物对21种植物病原真菌的抑菌活性。结果显示:(1)在供试浓度为50g/L(相当于干样)时,侧柏各部位乙醇提取物对4种供试植物病原真菌均具有较好抑制作用,其中侧柏叶提取物的抑菌效果最好,对供试葡萄白腐病菌(Conio-thyrium diplodiella)、葡萄黑痘病菌(Elsinoe ampelina)、番茄绵腐病菌(Phytophthora melongenae)和青霉病菌(Penicilliu mexpansum)的EC50分别为:5.424、3.186、8.913和19.000g/L。(2)侧柏叶乙醇提取物的石油醚萃取物和乙酸乙酯萃取物抑菌活性均较好,在供试浓度为0.5g/L时,石油醚萃取物对苹果腐烂病菌(Valsa mali)和葡萄黑痘病菌(E.ampelina)的抑菌率分别为80.35%和60.23%;乙酸乙酯萃取物对以上2种植物病原菌的抑菌率分别为81.88%和64.06%。结果表明:侧柏叶、小枝、球果和种子乙醇提取物均具有一定抑菌活性,叶乙醇提取物的活性最好,活性成分主要集中在石油醚萃取物和乙酸乙酯萃取物中。     

Inhibitory effects of essential oils from Ocimum basilicum and Ocimum gratissimum on Colletotrichum musae: The causal agent of bananas anthracnose

This study aimed to investigate the fungicidal effects of essential oils (EO) from Ocimum sp. on Colletotrichum musae. The fungus was isolated from bananas that showed typical symptoms of anthracnose followed by molecular identification. Oils were obtained by hydro‐distillation, and the chemical constituents were analysed using gas chromatography. The antifungal activity of the oils was tested in vitro against mycelia growth and conidia germination. In situ tests were carried out by spraying the oil on healthy bananas followed by the inoculation with C. musae conidia and the assessment of the necrosis symptoms. The obtained results revealed that the yield of the oil extracted from Ocimum basilicum and Ocimum gratissimum were 0.17% and 0.40%, respectively. Thujanol (24.38%), eugenol (23.78%) and (Z)‐ß‐ocimene (16.59%) were the main components found in O. basilicum while thymol (42.65%), trans‐sabinene hydrate (21.63%) and limonene (8.68%) were the major components found in O. gratissimum. The total reduction in the C. musae mycelial growth was observed at 800 and 275 µl/L, for the O. basilicum and O. gratissimum oils, respectively. These oils also inhibited completely the conidia germination at 400 and 185 µl/L. In situ tests showed the necrosis reduction bananas anthracnose. The minimum inhibitory concentration (MIC) for the preventive and curative test after the application of O. basilicum oil was 6,000 and 4,000 µl/L, respectively, whereas for the O. gratissimum oil, the MIC was 3,000 and 1,000 µl/L, jointly. Positive correlations were identified between the oil concentration and the reduction in bananas necrosis. These results indicated that the O. gratissimum EOs might be used as a biocide for the control of bananas anthracnose disease.     

Chemical Constituents of the Essential oil from Cuminum cyminum L. and Its Antifungal Activity against Panax notoginseng Pathogens

Cuminum cyminum L. (Cumin) is a flavoring agent that is commonly used worldwide, and is rich in essential oil. Essential oils (Eos) have been intensively investigated in regard to their potential for disease control in plants, which is provided a chance for the blossom of green pesticides. The chemical components of Cumin essential oil (CEO) were revealed by GC/MS, such as cuminaldehyde (44.53 %), p-cymene (12.14 %), (−)-β-pinene (10.47 %) and γ-terpinene (8.40 %), and found they can inhibit the growth of P. notoginseng-associated pathogenic fungi in vitro and the inhibitory effect of cuminaldehyde was similar to that of hymexazol. SEM and TEM images demonstrated that cuminaldehyde and CEO increased cell permeability and disrupted membrane integrity. The expression of disease-related genes of Fusarium oxysporum showed that CEO induced the expression of most genes, which disrupted biosynthesis, metabolism and signaling pathways. These studies verified the potential of CEO as a plant fungicide that is environmentally friendly and provided ideas for developing new products for controlling root diseases that affect P. notoginseng.     

Salinity-induced changes in essential oil,pigments and salts accumulation in sweet basil (Ocimum basilicum) in relation to alterations of morphological development

The objective of the project was to study salinity-induced effects on essential oil, pigments and salts accumulation in sweet basil (Ocimum basilicum, the cultivar Perrie) in relation to the alteration of plant morphological development and yield production. Hydroponically grown plants were exposed to one of six NaCl concentrations (1, 25, 50, 75, 100 and 130 mM NaCl). Inhibitory effects of salinity on biomass production of the shoot and the root, and area of individual leaves were apparent already under cultivation with 25 mM NaCl. Elevation of salinity from 1 to 100 mM NaCl induced 63% and 61% reductions in fresh and dry herb biomass production, respectively. The stress-induced reduction of foliage biomass sourced mainly from inhibition of leaf area development rather than reduction of internode and leaf number. Cl and Na concentrations in the leaves, stems and roots increased with elevation of NaCl concentration in the cultivation solution. While the extent of Cl accumulation was leaves>stems>roots, Na was largely excluded from the leaves and was preferentially accumulated in roots and the stems, potentially accounting for the moderate sensitivity of the leaf tissue to salinity. Salt stress increased the contents of essential oil and carotenoids in the leaves that may further account for the moderate sensitivity of sweet basil to salinity and suggest a potential for agro-industrial production. A twofold increase in both carotenoid concentration and the percent of essential oil in the fresh tissue was observed by elevation of the salinity from 1 to 130 mM NaCl. Overall, the stress induced increase of the percent of essential oil in the tissue in the salinity range 1–75 mM NaCl was about 50%, and thereby compensated for the similar reduction of biomass production in this salinity range, so that oil production on per plant basis was not reduced by salinity.     

UV-B is required for normal development of oil glands in Ocimum basilicum L. (sweet basil)

Plants of Ocimum basilicum L. grown under glass were exposed to short treatments with supplementary UV-B. The effect of UV-B on volatile essential oil content was analysed and compared with morphological effects on the peltate and capitate glandular trichomes. In the absence of UV-B, both peltate and capitate glands were incompletely developed in both mature and developing leaves, the oil sacs being wrinkled and only partially filled. UV-B was found to have two main effects on the glandular trichomes. During the first 4 d of treatment, both peltate and capitate glands filled and their morphology reflected their 'normal' mature development as reported in the literature. During the following days there was a large increase in the number of broken oil sacs among the peltate glands as the mature glands broke open, releasing volatiles. Neither the number of glands nor the qualitative or quantitative composition of the volatiles was affected by UV-B. There seems to be a requirement for UV-B for the filling of the glandular trichomes of basil.     

Essential‐Oil Variability in a Collection of Ocimum basilicum L. (Basil) Cultivars

Ocimum basilicum L. (Lamiaceae) is an aromatic plant of great tradition in the Mediterranean area. Its economic importance is growing up determining an expansion of cultivation. This paper evaluated the morphological traits, the chemical profiles, and antibacterial activity of 21 cultivars of basil belonging to ?Genovese?, ?Napoletano?, and ?Purple basil? types. The cultivars were characterized by different growth rate and morphological traits. The chemical composition of the oils analyzed by GC and GC/MS analysis, supported by the PCA analysis, underlined the strong influence of chemotype. It is noteworthy that estragole, never present in Genovese and purple basil types, occurred in Napoletano type. The high presence of eugenol, methyl eugenol, and linalool in the majority of cultivars, belonging both to Genovese and to Napoletano types was registered. Of great interest resulted the composition of the purple basil ?Opal?. All the samples tested exhibited similar antibiotic profiles with moderate antibacterial activity. The results enhanced the importance of determination of essential‐oil profile in the selection of cultivars characterized by diverse morphological traits and are useful for different purposes.     

Antifungal activity of six Saudi medicinal plant extracts against five phyopathogenic fungi

Six medicinal plants such as Amaranthus spinosus, Barbeya oleoides, Clutia lanceolata, Lavandula pubescens, Maerua oblongifolia and Withania somnifera collected from different locations in the southwestern part of Saudi Arabia were tested for antifungal activities against five plant pathogenic fungi causing serious diseases of vegetable crops. These fungi were Alternaria brassicae, Alternaria solani, Botrytis fabae, Fusarium solani and Phytophthora infestans. Aqueous plant extracts reduced mycelial growth and inhibited spore germination of all fungi tested. It is clear that the aqueous extract of Lavandula pubescens leaves was the best for controlling all phytopathogenic fungi under study. These results suggested that medicinal plant extracts play an important role in controlling the phytopathogenic fungi.     

Antichemotactic and Antifungal Action of the Essential Oils from Cryptocarya aschersoniana,Schinus terebinthifolia,and Cinnamomum amoenum

The purpose of this work was to determine the chemical composition and evaluate the antichemotactic, antioxidant, and antifungal activities of the essential oil obtained from the species Cryptocarya aschersoniana Mez , Cinnamomum amoenum (Ness & Mart .) Kosterm. , and Schinus terebinthifolia Raddi , as well as the combination of C. aschersoniana essential oil and terbinafine against isolates of dermatophytes. Allo‐aromadendrene, bicyclogermacrene, and germacrene B were identified as major compounds in essential oils. The essential oil of C. aschersoniana shown 100 % inhibitory effect on leukocyte migration at the concentration of 10 μg/mL while S. terebinthifolia oil presented 80.1 % inhibitory effect at the same concentration. Only S. terebinthifolia oil possessed free‐radical‐scavenging activity which indicates its antioxidant capacity. The essential oils were also tested against fungal isolates of dermatophyte species (Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis and Microsporum gypseum), resulting in MIC ranging from 125 μg/mL to over 500 μg/mL. C. aschersoniana oil combined with terbinafine resulted in an additive interaction effect. In this case, the essential oil may act as a complement to conventional therapy for the topical treatment of superficial fungal infections, mainly because it is associated with an anti‐inflammatory effect.     

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.     

独蒜兰提取物对植物病原真菌的抑菌活性

【目的】研究独蒜兰假鳞茎乙醇提取物对植物病原真菌的抑菌作用,为植物源杀菌剂的开发提供依据。【方法】采用菌丝生长速率法,研究独蒜兰假鳞茎乙醇提取物对15种植物病原菌的抑制活性;以西瓜尖孢镰刀菌作为供试菌,进一步研究该提取物对病原真菌的菌丝干重、细胞膜、过氧化氢酶（CAT）、过氧化物酶（POD）和超氧化物歧化酶（SOD）等的影响。【结果】独蒜兰假鳞茎提取物对辣椒疫霉病菌、西瓜尖孢镰刀菌、番茄灰霉病菌和非洲隐地疫霉菌的抑菌效果明显,其EC₅₀值分别为0.849、0.782、0.813和1.161 mg·mL^-1;经独蒜兰提取物处理后的西瓜尖孢镰刀菌菌丝干重随着药剂浓度的增加而减少;细胞膜丙二醛含量和相对电导率增加;菌丝体细胞内CAT、POD和SOD 3种保护酶活性增加。【结论】独蒜兰假鳞茎提取物对植物病原真菌具有较好的抑菌活性,其抑菌作用可能与其干扰菌丝生长、使菌丝细胞膜正常功能受损等有关。     

玫瑰精油的化学成分及其抗菌活性

通过水蒸汽同步蒸馏法提取玫瑰精油,采用GC-MS方法分析了玫瑰精油的化学组成,共鉴定出其中14个化学成分并测定其相对含量,占总含量的95.25%。香茅醇为玫瑰精油的主要成分,相对含量为90.37%。体外抑菌实验表明,玫瑰精油除对黑曲霉没有抗菌活性外,对其它7种供试菌均具有不同程度的抑制作用,其中对表皮葡萄球菌、金黄色葡萄球菌和大肠杆菌的最小抑菌浓度(MIC)为0.063%(v/v),对枯草芽孢杆菌、变形杆菌和白色念珠菌的最小抑菌浓度（MIC）为0.125%(v/v),而对绿脓杆菌(Pseudomonas aeruginosa)的抗菌活性相对较弱,MIC为0.5%(v/v)。抑菌直径结果也表明了玫瑰精油除对黑曲霉、绿脓杆菌的抗菌活性较弱外,对其它6种菌株的抑菌直径都大于8.5 mm。考察了玫瑰精油对3种敏感菌株包括金黄色葡萄球菌(革兰氏阳性菌)、大肠杆菌(革兰氏阴性菌)和白色念珠菌(真菌)的杀菌动态过程,为玫瑰精油的应用提供了理论依据。