Geographic variation in leaf essential oils and RAPDs of Juniperus polycarpos K. Koch in central Asia

Variations in the composition of the leaf essential oils and DNA fingerprints (RAPDs) of Juniperus excelsa, J. polycarpos, J. seravschanica, and J. turcomanica were examined. Juniperus procera was also included in the analyses to aid in determining the specific status of J. polycarpos. Based on these analyses, J. polycarpos is recognized as a distinct species from J. excelsa. The common, multi-seeded juniper of central Asia is J. polycarpos. Juniperus seravschanica and J. turcomanica are treated as part of the J. polycarpos complex but are not recognized as formal taxonomic groups at this time. The Balochistan, Pakistan juniper, usually called J. excelsa var. polycarpos or J. macropoda should be referred to as J. polycarpos in the future.     

In vitro fungitoxicity of the essential oil of Syzygium aromaticum

The in vitro antifungal activity of clove oil was studied against four test fungi namely Alternaria alternata, Fusarium chlamydosporum, Helminthosporum oryzae and Rhizoctonia bataticola by the agar well diffusion method. These test fungi were found to be highly sensitive to clove oil at a concentration of 100 μl/well. The inhibition zone diameter was found to be in the range of 55–65 mm. The toxicity of clove oil on the germination and growth of A. alternata was further examined in liquid medium. Concentration- and time-dependent toxicity was recorded from 0.05 to 20% (v/v) concentration. The minimum fungistatic concentration was found to be 0.05%. Above this concentration, lysis of conidia and inhibition of mycelial growth were detected. Microscopic analysis showed 20–40% lysis of conidia after 72 h of incubation at 5% concentration. However at higher clove oil concentration (10%), up to 20% of conidia were lysed within 24 h of incubation. Similar concentration- and time-dependent toxicity was observed at different concentrations and time intervals. The findings indicated that clove oil possesses fungicidal activity against phytopathogenic fungi. Further study is required to determine whether it could have value in the management of plant infectious diseases. This revised version was published online in July 2006 with corrections to the Cover Date.     

Antifungal activity of the essential oil of Agastache rugosa Kuntze and its synergism with ketoconazole

AIMS: To evaluate the fungitoxic activity of the essential oil of Agastache rugosa alone and to determine its combination effect with ketoconazole against Blastoschizomyces capitatus. METHODS AND RESULTS: The antifungal activities of the essential oil of A. rugosa and its main constituent estragole were investigated using the broth microdilution, disk diffusion methods and checkerboard microtitre assay. Both estragole and the essential oil exhibited strong activities against the tested fungi and showed synergism with ketoconazole against B. capitatus. CONCLUSIONS: Both estragole and the essential oil of A. rugosa have significant growth-inhibiting activities against B. capitatus showing strong synergistic effect with ketoconazole. SIGNIFICANCE AND IMPACT OF THE STUDY: The essential oil of A. rugosa, combined with ketoconazole, may be particularly useful against B. capitatus, a rare pathogenic fungus documented to cause severe and fatal mycoses in immunocompromised patients.     

Effect of the antifungal activity of oxygenated aromatic essential oil compounds on the white-rot Trametes versicolor and the brown-rot Coniophora puteana

Essential oils and their constituents have a long history of applications as antimicrobial agents, but their use as wood preservatives has not yet been reported. In this study, 22 essential oil phenols, phenol ethers, and aromatic aldehydes have been tested for their antifungal activity against the wood-decaying fungi Trametes versicolor and Coniophora puteana. Minimal inhibitory concentrations of the selected compounds added to potato dextrose agar (PDA) in defined concentrations were determined by a screening test with the agar dilution method. A significant difference in the tolerance of the tested fungi towards the selected compounds was discovered and attributed to the differences in their metabolic characteristics. The influence of the chemical structure of the tested essential oil compounds on their antifungal activity is also discussed.     

Chemical composition and fungitoxic activity of essential oil of Thuja orientalis L. grown in the north-western Himalaya

The essential oil from fresh leaves of Thuja orientalis L. grown in the north-western Himalaya was isolated by means of hydrodistillation and analyzed by GC and GC/MS. Twenty-two compounds representing 94.0% of the total oil were identified. The leaf oil contained alpha-pinene (29.2%), Delta-3-carene (20.1%), alpha-cedrol (9.8%), caryophyllene (7.5%), alpha-humulene (5.6%), limonene (5.4%), alpha-terpinolene (3.8%) and alpha-terpinyl acetate (3.5%) as major constituents. The essential oil showed antifungal activity against Alternaria alternata in a direct bioautography assay. Two main bioactive compounds named as b1 (Rf = 0.54) and b2 (Rf = 0.80) were observed and tested for antifungal activity; they produced an inhibition zone of 5 and 10 mm in diameter, respectively. The components b1 and b2 were further purified by preparative thin layer chromatography and their antifungal efficacy was re-tested. The minimum inhibitory amount (MIA) of b1 and b2 against A. alternata was determined as 30.5 and 4.5 microg, respectively, using a bioautography assay. The bioactive constituent corresponding to b1 was determined as alpha-cedrol by using GC/MS analysis. The potential of essential oils as a source of natural biocides is discussed.     

Dr. Alfred Jeske 75 jahre

The chemical composition, phytotoxic and antifungal activities of the essential oils isolated by hydrodistillation from the needles of Tunisian Aleppo pine harvested from different provenances were evaluated. The chemical composition analysed by gas chromatography/mass spectrometry (GC/MS) revealed variability among provenances displaying interesting chemotypes, (Z)-caryophyllene (16.16–28.9%), β-myrcene (8.5–22.9%), α-pinene (11.7–13.14%), β-pinene (3.13–11.8%), bicyclogermacrene (5.2–12.37%), α-terpinolene (8.11–11.01%) and α-humulene (2.85–5.2%), which were the main components in the oil. Antifungal ability of Aleppo pine oils was tested by disc agar diffusion against 10 phytopathogenic fungi. Weak antifungal activity was observed for the essential oils isolated. Furthermore, in contrast, the herbicidal activity investigated for three common weeds in Tunisian cereal crops was very strong and seed germination was inhibited at a low concentration and their herbicidal effects were higher than those of a commercial herbicide.     

Antifungal activity of the carrot seed oil and its major sesquiterpene compounds

Carrot seed oil is the source of the carotane sesquiterpenes carotol, daucol and beta-caryophyllene. These sesquiterpenic allelochemicals were evaluated against Alternaria alternata isolated from the surface of carrot seeds cultivar Perfekcja, a variety widely distributed in horticultural practise in Poland. Alternaria alternata is one of the most popular phytotoxic fungi infesting the carrot plant. The strongest antifungal activity was observed for the main constituent of carrot seed oil, carotol, which inhibited the radial growth of fungi by 65% at the following concentration.     

Antifungal effects of the volatile oils from Allium plants against Trichophyton species and synergism of the oils with ketoconazole

In an attempt to develop stable and safe antifungal agents from natural products (daily foodstuffs in particular), the activities of essential oils from Allium sativum for. pekinense, A. cepa, and A. fistulosum against three Trichophyton species responsible for severe mycoses in humans were investigated and compared with activity of allicin in this study. The fungistatic activities of Allium oils were evaluated by the broth dilution method and disk diffusion assay. The combined effects of Allium oils with ketoconazole were tested by the checkerboard titer test. Among the tested oils, A. sativum for. pekinense oil exhibited the strongest inhibition of growth of T. rubrum, T. erinacei, and T. soudanense with MICs (minimum inhibiting concentrations) of 64microg/ml, while the activities of A. cepa and A. fistulosum were relatively mild. The inhibiting activities of the oils on Sabouraud agar plates were dose dependent against Trichophyton species. Additionally, these oils showed significant synergistic antifungal activity when combined with ketoconazole in the checkerboard titer test and disk diffusion test.     

小桐子内生真菌及其抗真菌活性研究

从药用植物小桐子的根和茎中分离到内生真菌57株,经鉴定,它们分属于15个不同的分类单元。其中拟盘多毛孢为优势属,其次为拟茎点霉属和茎点霉属。用杨桃炭疽菌,香蕉疫霉和镰刀菌作指示菌对这些内生真菌的抗真菌活性进行检测,结果表明,有2株菌对杨桃炭疽菌具有抑菌活性。     

Detection of phlD gene in some fluorescent pseudomonads isolated from Iran and its relative with antifungal activities

Fluorescent pseudomonads that produce antibiotic 2,4-diacetylphloroglocinol (2,4-DAPG) are important group of PGRP that inhibit a broad spectrum of plant pathogenic fungi. Studying on genetic diversity of 2,4-diacetylphloroglucinol-producing fluorescent pseudomonads has been shown with special importance. The first step to investigate the genetic diversity of these bacteria is detecting of the genes required for the biosynthesis of this antibiotic. The objectives of the current study were detection of phlD gene within fluorescent pseudomonads by a PCR-based assay, and comparison of phenotypic and genotypic characteristics of fluorescent pseudomonads with proven biocontrol potential against some soil-borne phytopathogenic fungi. We used a collection of 47 fluorescent Pseudomonas spp. some with known biological control activity against Macrophomina phaseolina, Rhizoctonia solani, Phytophthora nicotianae var. parasitica, Pythium sp. and Fusarium sp. in vitro and the potential to produce known secondary metabolites such as, siderophore, HCN and protease. The results indicated that 66, 40.42, 63.82,48.94 and 27.65% of strains revealed antagonistic activity against R. solani, M. phaseolina, Pythium sp., P. nicotianae and Fusarium sp., respectively. Rhizoctonia solani recognized as the most vulnerable fungus. Among 47 strains, 76.59, 97.87 and 17% of strains produced protease, siderophore and HCN, respectively. We could detect phlD gene in strains P-5, P-32, P-47. Strain CHA0 was used as positive control for the detection this gene. Overall, there was no obvious link between the existence of phlD gene and inhibition of fungal growth or production of the antifungal metabolites in vitro. But in some strains such as CHA0 and P-5, we saw a link between the existence of phlD and antifungal activities. Studying on detection and diversity of phlD provides a fundamental knowledge for developing a rapid genetic screening system to identify a potential biocontrol strains.     

Seasonal variations in the production of antifungal substances by some dictyotales (brown algae) from the french mediterranean coast

Hexane extracts of some algae belonging to the Dictyotales collected over a 12 month period were tested for their antifungal activity using human pathogenic fungi (yeasts, moulds and dermatophytes) and phytopathogenic fungi responsible for diseases in Mediterranean plants and trees. The three algal species tested (Dictyota dichotoma, Dictyota dichotoma var. implexa, Dilophus spiralis) exhibited a wide spectrum of antifungal activity which varied during the seasons.     

Antimicrobial and antioxidant activities of methanol extracts of <Emphasis Type="Italic">Evax pygmaea</Emphasis> (Asteraceae) growing wild in Tunisia

Antimicrobial activity of methanolic extracts obtained from the aerial parts of Evax pygmaea was tested against five bacteria and two strains of phytopathogenic fungi using the agar diffusion and broth microdilution methods. Antioxidant properties were evaluated through the ability of the different fractions to scavenge the stable ABTS (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) and DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals. The TEAC (Trolox Equivalent Antioxidant Capacity) and IC₅₀ values of the fractions were calculated and compared. The experimental data indicated that all fractions exhibit moderate to appreciable antibacterial activities against all Gram-positive cocci and Gram-negative rods except Pseudomonas aeruginosa, but no antifungal activity was observed. Ethyl acetate and methanol fractions were found to cause significant free radical-scavenging effects in both assays. These results may suggest that E. pygmaea could be used as a natural preservative ingredient in the food and/or pharmaceutical industries.     

Evaluation of in vitro antifungal activity of medicinal plants against phytopathogenic fungi

Fourteen medicinal plants belonging to 13 families were collected and extracted with petroleum ether (PE), chloroform, methanol and water to yield 60 crude extracts. Using agar diffusion method, these extracts were evaluated for antifungal activity on the growth of five phytopathogenic fungi. Among all the extracts tested, PE, chloroform and methanol extracts of Piper betle L. and PE and chloroform extracts of Allamanda cathartica exhibited promising antifungal activity. Minimum inhibitory concentration (MIC) values of the above promising extracts were determined using broth dilution technique and observed that chloroform extract of P. betle L. exhibited the least MIC value ranging from 280 to 1130 μg ml^?1. In this study, we report chloroform extract of P. betle L. to be thermally stable even when steam sterilised for the first time and that it could be stored at 4°C with almost no change in its activity for a period of 180 days.     

Chemical characterization and antifungal activity of essential oil of capitula from wild Indian Tagetes patula L.

Summary. The essential oil extracted by steam distillation from the capitula of Indian Tagetes patula, Asteraceae, was evaluated for its antifungal properties and analyzed by gas chromatography and gas chromatography–mass spectrometry. Thirty compounds were identified, representing 89.1% of the total detected. The main components were piperitone (24.74%), piperitenone (22.93%), terpinolene (7.8%), dihydro tagetone (4.91%), cis-tagetone (4.62%), limonene (4.52%), and allo-ocimene (3.66%). The oil exerted a good antifungal activity against two phytopathogenic fungi, Botrytis cinerea and Penicillium digitatum, providing complete growth inhibition at 10 μl/ml and 1.25 μl/ml, respectively. The contribution of the two main compounds, piperitone and piperitenone, to the antifungal efficacy was also evaluated and ultrastructural modifications in mycelia were observed via electron microscopy, evidencing large alterations in hyphal morphology and a multisite mechanism of action. Correspondence and reprints: Dipartimento delle Risorse Naturali e Culturali, Università di Ferrara, Corso Porta di Mare 2, 44100 Ferrara, Italy.     

Evaluation of the antifungal activity of Rumex vesicarius L. and Ziziphus spina-christi (L) Desf. Aqueous extracts and assessment of the morphological changes induced to certain myco-phytopathogens

Many Plant extracts had proved a potential antifungal activity against a wide range of phytopathogenic fungi. The aim of this study was to evaluate the antifungal activity of the aqueous extracts of Rumex vesicarius L. and Ziziphus spina-christi (L) Desf. against some fungal species. The effect on growth inhibition, conidia germination, sporogenesis, morphological, and ultrastructural characterizations of fungal growth by scanning and transmission electron microscopes, have been investigated. Both plant extracts exhibited an antifungal activity against Fusarium, Helminthosporium, Alternaria, and Rhizoctonia species, besides, the sporogenesis of Alternaria and Fusarium species was suppressed. Both plants induced severe morphological changes in the hyphal shape and surface. We concluded that the aqueous extracts of these plants had strong antifungal activities. More investigations should be performed to evaluate the possible applications in agriculture and in vivo.     

Antimicrobial and insecticidal activities of essential oil isolated from Turkish Salvia hydrangea DC. ex Benth.

The hydrodistillated essential oil of Salvia hydrangea was analyzed by GC–MS. Fifty-four different components representing 95.9% of the compounds in the oil were identified. Camphor (54.2%), -humulene (4.0%), cis-sesquisabinene hydrate (2.8%), myrtenol (2.6%), β-bisabolol (2.2%) and 1,8-cineole (2.1%) were found to be predominant components. The oil was also characterized by relatively high amount of oxygenated monoterpenes (69.6%). The oil was tested for fungitoxic effects against 33 agricultural pathogenic fungi using in vitro microbial growth inhibition assays. The oil exhibited considerable antifungal activity against a broad spectrum of tested fungi. Antibacterial activity of the oil was determined against 30 bacterial strains using the disc diffusion method. The oil had a very wide spectrum of antibacterial activity. However, it was not as active as penicillin. The oil showed 68.3–75.0% mortality against adults of Sitophilus granarius and Tribolium confusum, the major pests of wheat and wheat products, respectively. It can be concluded that the oil of S. hydrangea has a potential against agricultural pathogenic fungi and two stored pests, S. granarius and T. confusum.     

Bacillus amyloliquefaciens CCMI 1051in vitro activity against wood contaminant fungi

Bacillus amyloliquefaciens CCMI 1051 displays antifungal activity against surface contaminant fungi, blue stain fungi and phytopathogenic fungi. The antifungal potential ofB. amyloliquefaciens CCMI 1051 is based on the production of metabolites with antifungal activity. The activity was revealed both in the exponential growth phase and in the stationary phase, being associated both to microbial growth and to secondary metabolism.     

Essential oil composition of Angelica archangelica L. (Apiaceae) roots and its antifungal activity against plant pathogenic fungi

This study reports the results of gas chromatography–mass spectrometry (GC–MS) analyses of the essential oil of Angelica archangelica L. (Apiaceae) roots, as well as its in vitro antifungal activity against 10 plant pathogenic fungi. Moreover, the essential oil was evaluated for its antifungal activity using the agar dilution method, and also minimum inhibitory concentrations and minimum fungicidal concentrations were determined. The major compounds identified by GC–MS were α-pinene (21.3%), δ-3-carene (16.5%), limonene (16.4%), and α-phellandrene (8.7%). The oil showed in vitro antifungal activity against some species of the Fusarium genus, Botrytis cinerea, and Alternaria solani. Our study indicates that the oil of A. archangelica could be used as a control agent for plant pathogenic fungi in natural formulations.     

Antifungal activity of essential oil and its constituents from Calocedrus macrolepis var. formosana Florin leaf against plant pathogenic fungi

Resistance to conventional fungicides causes the poor disease control of agriculture. Natural products from plants have great potential as novel fungicide sources for controlling pathogenic fungi. In this study antipathogenic activity of the leaf essential oil and its constituents from Calocedrus macrolepis var. formosana Florin were evaluated in vitro against six plant pathogenic fungi. Chemical analysis of leaf oil by GC/MS allowed identification of alpha-pinene (44.2%), limonene (21.6%), beta-myrcene (8.9%), beta-caryophyllene (8.2%), caryophyllene oxide (2.4%), alpha-cadinol (1.6%), beta-pinene (1.2%), and T-muurolol (1.1%) as main components. Sesquiterpenoid components of the oil were more effective than monoterpenoid components of the oil. In particular, T-muurolol and alpha-cadinol strongly inhibited the growth of Rhizoctonia solani and Fusarium oxysporum, with the IC(50) values < 50 microg ml(-1). These compounds also efficiently inhibited the mycelial growths of Colletotrichum gloeosporioides, P. funerea, Ganoderma australe and F. solani. These results showed that T-muurolol and alpha-cadinol possess antifungal activities against a broad spectrum of tested plant pathogenic fungi and could be used as potential antifungal agents for the control of fungal diseases in plants.     

Cyclosporin C is the main antifungal compound produced by Acremonium luzulae.

A strain of Acremonium luzulae (Fuckel) W. Gams was selected in screening new microorganisms for biological control of fruit postharvest diseases, especially gray and blue mold diseases on apples and strawberries. This strain manifests a very strong activity against a large number of phytopathogenic fungi. In this work, the product responsible for this antifungal activity was isolated from modified Sabouraud dextrose broth cultures of A. luzulae. It was purified to homogeneity by reverse-phase column chromatography. On the basis of UV, infrared, and 1H and 13C nuclear magnetic resonance spectra, mass spectral analysis, and the amino acid composition of the acid hydrolysates, the antibiotic was determined to be cyclosporin C. Cyclosporin C showed a broad-spectrum activity against filamentous phytopathogenic fungi but no activity against bacteria or yeasts. Its antifungal activity is only fungistatic. In contrast to Tolypocladium inflatum, another cyclosporin-producing strain, A. luzulae, did not produce additional cyclosporins. This was confirmed by in vivo-directed biosynthesis.