Altered growth and polyamine catabolism following exposure of the chocolate spot pathogen Botrytis fabae to the essential oil of Ocimum basilicum

Biomass of the fungal pathogen Botrytis fabae in liquid culture amended with two chemotypes of the essential oil of basil, Ocimum basilicum, was reduced significantly at concentrations of 50 ppm or less. The methyl chavicol chemotype oil increased the activity of the polyamine biosynthetic enzyme S-adenosylmethionine decarboxylase (AdoMetDC), but polyamine concentrations were not significantly altered. In contrast, the linalol chemotype oil decreased AdoMetDC activity in B. fabae, although again polyamine concentrations were not altered significantly. However activities of the polyamine catabolic enzymes diamine oxidase (DAO) and polyamine oxidase (PAO) were increased significantly in B. fabae grown in the presence of the essential oil of the two chemotypes. It is suggested that the elevated activities of DAO and PAO may be responsible, in part, for the antifungal effects of the basil oil, possibly via the generation of hydrogen peroxide and the subsequent triggering of programmed cell death.     

Variability in essential oil composition of Turkish basils (Ocimum basilicum L.)

Sweet basil (Ocimum basilicum L.), one of the most popular aromatic plants, shows great variation in both morphology and essential oil components. In this study, the composition of 18 Turkish basil essential oils was investigated by GC and GC–MS. Variation of essential oils in the landraces was subjected to cluster analysis, and seven different chemotypes were identified. They were (1) linalool, (2) methyl cinnamate, (3) methyl cinnamate/linalool, (4) methyl eugenol, (5) citral, (6) methyl chavicol (estragol), and (7) methyl chavicol/citral. Methyl chavicol with high citral contents (methyl chavicol/citral) can be considered as a “new chemotype” in the Turkish basils. Because methyl eugenol and methyl chavicol have structural resemblance to carcinogenic phenylpropanoids, chemotypes having high linalool, methyl cinnamate or citral contents and a mixture of these is suitable to cultivate for use in industry.     

Chemotaxonomic Analysis of the Aroma Compounds in Essential Oils of Two Different Ocimum basilicum L. Varieties from Iran

Hydrodistilled essential oils of 21 accessions of Ocimum basilicum L. belonging to two different varieties (var. purpurascens and var. dianatnejadii) from Iran were characterized by GC‐FID and GC/MS analyses. The oil yield was found to be between 0.6 and 1.1% (v/w). In total, 49 compounds, accounting for 96.6–99.7% of the oil compositions, were identified. Aromatic compounds, represented mainly by methyl chavicol (33.6–49.1%), and oxygenated monoterpenes, represented by linalool (14.4–39.3%), were the main components in all essential oils. Monoterpene hydrocarbons were present in the essential oils of all accessions of the purpurascens variety, whereas they were completely absent in those of the dianatnejadii variety, indicating that monoterpene hydrocarbons might be considered as marker constituents of the purpurascens variety. The chemotaxonomic value of the essential‐oil compositions was discussed according to the results of the cluster analysis (CA). The CA showed a clear separation of the O. basilicum var. purpurascens accessions and the O. basilicum var. dianatnejadii accessions, although the data showed no major chemotype variation between the studied varieties. Indeed, the CA revealed only one principal chemotype (methyl chavicol/linalool) for both varieties. In conclusion, GC/MS analyses in combination with CA showed to be a flexible and reliable method for the characterization of the chemical profiles of different varieties of Ocimum basilicum L.     

Essential oils from New Zealand manuka: triketone and other chemotypes of Leptospermum scoparium

The triketone chemotype of manuka, Leptospermum scoparium (Myrtaceae), is commercially important because of its antimicrobial activity. Oils from 36 individual plants on the East Cape of New Zealand all showed similar high triketone contents (>20% total triketones) with little seasonal variation. Analyses of oils from 261 individual manuka plants collected from 87 sites throughout New Zealand showed that the high triketone chemotype was localised on the East Cape, although oils with triketone levels up to 20% were found in the Marlborough Sounds area of the South Island. Cluster analysis revealed other chemotypes localised on other areas. Ten further chemotypes are described: alpha-pinene; sesquiterpene-rich with high myrcene; sesquiterpene-rich with elevated caryophyllene and humulene; sesquiterpene-rich with an unidentified sesquiterpene hydrocarbon; high geranyl acetate; sesquiterpene-rich with high gamma-ylangene + alpha-copaene and elevated triketones; sesquiterpene-rich with no distinctive components; sesquiterpene-rich with high trans-methyl cinnamate; high linalol; and sesquiterpene-rich with elevated elemene and selinene. Some of the chemotypes contained aroma compounds at relatively high levels, with a geranyl acetate-rich oil being most notable. Possible origins for this complex array of chemotypes are proposed.     

Effect of fungicidal essential oils against Botrytis cinerea and Rhizopus stolonifer rot fungus in vitro conditions

The development of natural crop protection products as alternatives to the use of synthetic fungicides is currently popular. The aim of this study is to evaluate the antifungal effects of several essential oils against the fungal pathogens, Botrytis cinerea and Rhizopus stolonifer, under in vitro condition. Four essential oils (fennel, black caraway, peppermint and thyme) were each tested at five concentrations (0, 200, 400, 600 or 800 μl l^?1). In vitro results showed that the essential oil of black caraway and fennel had the highest fungicidal effect against B. cinerea and R. stolonifer, respectively. The growth of B. cinerea was completely inhibited by the essential oil of black caraway at 400 μl l^?1. Fennel oil perfectly inhibited growth of R. stolonifer fungus colonies at concentration higher than 600 μl L^?1 in potato dextrose agar medium. Percentage of spores germination was the lowest in medium of Fennel and black caraway essential oils, and was the highest in Thyme ones. These results show that plant essential oils can have a strong effect on reducing post-harvest decay. These plant essential oils could provide an alternative to synthetic chemicals to control post-harvest phytopathogenic fungi on fruit.     

Chemical and Olfactory Analysis of the Volatile Fraction of Ocimum gratissimum Concrete from Madagascar

The chemical composition of the volatile fraction of Ocimum gratissimum concrete (romba) from Madagascar has been determined for the first time by GC/MS and GC-FID. A methyl cinnamate chemotype has been determined for this material, along with a set of compounds typical in essential oils and extracts from plants of the Ocimum genus. Variability was mostly observed on terpenes and terpenoids components. GC-O-MS was also used for a sensory evaluation of this material performed by a master perfumer. The chemical composition of this O. gratissimum extract was then compared with literature data to assess subtle differences between chemotypes of the same species and other species of the same genus within natural variability. A mapping illustrates the occurrence of the cinnamate chemotype in Eastern Africa, India and now Madagascar, while other origins generally present eugenol, thymol, camphor, or linalool chemotypes.     

Biochemical changes in infection droplets containing spores of Botrytis spp. Incubated in the seed cavities of pods of bean (Vicia faba L.)

Infection droplets containing spores of Botrytis cinerea become inhibitory to the growth of germ tubes of the fungus within 18 hr. of their incubation in bean pods. The inhibition is caused by an ether-soluble substance, which has been partially purified, and which counteracts the stimulatory effect of sucrose, glucose, fructose, galacturonic acid and several amino acids, which are also present in the infection droplets. Changes in concentration of these substances have been described in the first 24 hr. after placing infection droplets in pods. The only major difference between droplets containing B. fabae and B. cinerea concerns the nature of the ether-soluble substances produced. Following B. fabae infection a biologically inactive u.v. absorbing substance appears in high yield in place of the antifungal substance formed following B. cinerea infections.     

RAPD and essential oil characterization of Turkish basil (Ocimum basilicum L.)

Sweet basil (Ocimum basilicum L., Lamiaceae), an important medicinal plant and culinary herb due to its delicate aroma and fragrance, shows great variation in both morphology and essential oil components. Genetic variation among basil accessions in Turkey has not been extensively examined with molecular markers. Genetic diversity was determined using random amplified polymorphic DNA (RAPD) markers of 14 genotypes of basil. A total of 375 bands were obtained from the RAPD analysis, and 273 of them (70.3 %) were polymorphic. The RAPD analysis allowed the grouping of samples into two main clusters. Genetic similarity values among the basil genotypes ranged between 0.46 and 0.87. Considerable genetic diversity was determined among basil genotypes. Essential oils were obtained by hydro-distillation and were characterized by gas chromatography. A total of 17 chemical components were identified. The evaluated genotypes of O. basilicum can be classified into seven chemotypes: (1) Linalool (7, 12, 16, 22, 25A and 33), (2) Methyl chavicol (6, 10A), (3) Citral/methyl chavicol (10L, 17), (4) Methyl eugenol (11), (5) Methyl cinnamate/linalool (23), (6) Linalool/methyl eugenol (25K), and (7) Methyl chavicol/linalool (Let). The chemical variability obtained from the essential oil composition of the genotypes in the study was remarkable. The chemical characterization of genotypes 10L and 17 was rich in citral (42.17 and 44.80 %) and methyl chavicol (30.56 and 32.03 %). Citral/methyl chavicol can be assessed as a new chemotype of basil cultivated in Turkey. The basil genotypes were grouped into two major clusters for both the RAPD analysis and chemical characterization with very few exceptions (genotype n. 6). A correlation analysis of the genetic distance matrix and the Euclidian distance matrix showed relatively low values (r = ?0.40). The results demonstrated a certain degree of correspondence between chemical and molecular data.     

Essential Oils as Biocides for the Control of Fungal Infections and Devastating Pest (Tuta absoluta) of Tomato (Lycopersicon esculentum Mill.)

Thymus capitatus and Tetraclinis articulata essential oils as well their major components (carvacrol and α‐pinene) were evaluated for their antifungal and insecticidal activities. Both oils showed good in vitro antifungal activity against Fusarium oxysporum, Aspergillus niger, Penicillium sp., Alternaria alternata, and Botrytis cinerea, the fungi causing tomato rot. In vivo results indicate the efficacies of both essential oils and carvacrol of reduce postharvest fungal pathogens, such as B. cinerea and Al. alternata that are responsible of black and gray rot of tomato fruit. Disease incidence of Al. alternata and B. cinerea decreased on average from 55% to 80% with essential oil of Th. capitatus and pure carcvacrol, while Te. articulata essential oil exhibited inhibition of fungal growth of 55% and 25% against Al. alternata and B. cinerea, respectively, with concentration of 0.4 μl/l air. The insecticidal activity of Th. capitatus and Te. articulata essential oils exhibited also a good insecticidal activity. At the concentration of 0.2 μl/ml air, the oils caused mortality over 80% for all larval stages of Tuta absoluta and 100% mortality for the first‐instar after 1.5 h only of exposure. α‐Pinene presented lower insecticidal and antifungal activities compared to essential oils of Th. capitatus, Te. articulata and pure carvacrol. Thus, these essential oils can be used as a potential source to develop control agents to manage some of the main pests and fungal diseases of tomato crops.     

Chemical Diversity in Himalayan Elsholtzia Species

The terpenoid composition of essential oils from the leaves of five Elsholtzia species, viz., E. eriostachya Benth ., E. cristata Willd ., E. polystachya Benth ., E. flava Benth ., and E. pilosa Benth ., collected from the Himalayan region (India), was examined by GC, GC/MS, and NMR analyses. Comparison of the results with previous reports revealed new chemotypes. Cluster analysis was carried out in order to discern the similarities and differences within the essential‐oil compositions at their subspecies/chemotype level. Based on the major constituents of the essential oils, six chemical groups were obtained.     

Changes in wyerone acid concentrations in leaves of Vicia faba after infection by Botrytis cinerea or B.fabae

Wyerone acid was produced by leaves of Vicia faba in response to infection by both Botrytis cinerea and B.fabae. Host cell death caused by either fungus appeared to be the trigger for rapid wyerone acid synthesis, although the phytoalexin was not confined to brown cells. At B. cinerea inoculation sites wyerone acid concentration increased rapidly, at the time of fungal invasion of the epidermis, to levels greater than that completely inhibitory to mycelial growth. Wyerone acid is therefore probably the primary cause of the inhibition of B. cinerea within infected tissue. The partial blackening of B.fabae inoculation sites and surrounding peripheral tissues was accompanied by an increase in wyerone acid. There followed a striking decrease as tissues became completely blackened and invaded by B.fabae. B.fabae appeared to metabolize wyerone acid and prevent its accumulation in invaded tissues. Mycelial growth of B. fabae was less sensitive to wyerone acid than was B. cinerea. The differing abilities of B.fabae and B. cinerea to spread from lesions after both have induced wyerone acid production probably depend on both their differing sensitivities to the phytoalexin and their abilities to metabolize it to less toxic products.     

The Essential Oils and Glandular Hairs in Different Chemotypes of Origanum vulgare L.

Leaves and flowers of four chemotypes of Origanum vulgare L.were examined for the main components of their essential oiland for the types and distribution of their glandular hairs.Two varieties have high phenol content, one thymol and the othercarvacrol, in their essential oils; one has a moderate thymolcontent and the fourth has a low phenol content and a high alcoholcontent. The percentage of essential oil and the number of peltatehairs were higher in the flowers than in the leaves, the highestbeing in the flowers of a chemotype with a high phenol (thymol)concentration. While there were no differences in structureof the peltate and two types of capitate hairs between chemotypes,the density of the peltate hairs varied and appeared to be correlatedwith the total essential oil content. Origanum vulgare L., essential oils, glandular hairs     

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 variation in the leaf essential oil of Melaleuca quinquenervia (Cav.) S.T. Blake

An examination of the leaf oils of Melaleuca quinquenervia over its geographical range in Australia and Papua New Guinea has shown wide variation in chemical composition but only two major chemotypes. Chemotype 1 is comprised of E-nerolidol (74–95%) and linalool (14–30%) and is found from Sydney, north along the east coast of Australia to Selection Flat, New South Wales, with an isolated occurrence near Maryborough, Queensland. Two divisions occur in this chemotype which are based on the presence or absence of significant proportions of linalool (14–40%). Chemotype 2 contains 1,8-cineole (10–75%), viridiflorol (13–66%), α-terpineol (0.5–14%) and β-caryophyllene (0.5–28%) in varying proportions and order of dominance in the oils. It is found throughout the distribution of the species, from Sydney to Papua New Guinea and New Caledonia. Within chemotype 2 there appears to be a continuous spread of oil composition without formation of any further discrete divisions as in chemotype 1.Analyses have shown that M. quinquenervia trees that occur at latitudes south of 25°S have high oil yields (1–3% w/w%, fresh leaves) and comprise chemotypes 1 and 2. North of 25°S, however, chemotype 1 does not occur and oil yields amongst the Australian populations are uniformly low (0.1–0.2%).     

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.     

Essential‐Oil Composition of the Tunisian Endemic Cypress (Cupressus sempervirens L. var. numidica Trab.)

The essential oils isolated from leaves, wood, and cones of the Tunisian endemic cypress Cupressus sempervirens L. var. numidica Trab. collected from three natural populations were characterized by GC‐FID and GC/MS analyses. In the wood, leaf, and cone oils, 38, 35, and 26 constituents, representing 94.4, 97.8, and 98.5% of the total oil composition, respectively, were identified. Monoterpenes constituted the major fraction of the oils from all organs and for all populations. The oils were found to be of an α‐pinene (64.2%)/δ‐car‐3‐ene (11.1%) chemotype with considerable contents of α‐humulene (3.4%) in the leaf oil, cedrol (2.8%) in the wood oil, and sabinene (3.2%) in the cone oil, respectively. α‐Pinene, δ‐car‐3‐ene, limonene, carvacrol methyl ether, α‐humulene, and α‐amorphene were the main components that differentiated the oils of the three organs in the cypress of Makthar.     

Chemical Diversity and Antimicrobial Activity of Salvia multicaulis Vahl Essential Oils

The chemical compositions and antimicrobial activities of the essential oils (EOs) of aerial parts of Salvia multicaulis Vahl , collected during the same week from two different Lebanese regions, were investigated. The EOs were obtained by hydrodistillation using a Clevenger‐type apparatus and characterized by GC and GC/MS analyses. The minimum inhibitory concentrations of these EOs were determined against one Gram‐negative and two Gram‐positive bacteria, one yeast, and five dermatophytes using the broth microdilution technique. One EO was notably active against Staphylococcus aureus, methicillin‐resistant S. aureus, and all of the Trichophyton species tested. Nerolidol was found to be the major compound in the active oil; nerolidol was also absent from the inactive oil. This study demonstrated that nerolidol shows antimicrobial activity and therefore significantly contributes to the antimicrobial potential of the oil. The chemical diversity of worldwide S. multicaulis EOs was analyzed, revealing that the EOs of this study belong to two different chemotypes found in the literature. The nerolidol chemotype appears to be restricted to Lebanon, and it can be used as antimicrobial agent against external bacterial and fungal infections.     

Effect of essential oils on postharvest decay and quality factors of tomato in vitro and in vivo conditions

For increasing the shelf life and control of devastating fungal pathogen grey mould (Botrytis cinerea), tomato fruits during storage were applied different concentrations of ammi (Carum copticum) and anise (Pimpinella anisum) essential oils. First, antifungal activities of essential oils were tested on artificial growth media. The growth of grey mould was completely inhibited by ammi and anise essential oils at relatively higher concentrations. In second stage, fruits were infected artificially by grey mould spore and then treated with different concentrations of these essential oils. The results of in vivo conditions showed that ammi and anise essential oils applied at all concentrations were increasing the shelf life and inhibited the grey mould growth on tomato fruits completely in comparison to control. Fruits treated with these essential oils had significantly higher total soluble solids (TSS), ascorbic acid, β-carotene and lycopene content compared to control fruits.     

Essential oil variability of Thymus hyemalis growing wild in Southeastern Spain

Essential oils obtained by steam-distillation of individual samples of Thymus hyemalis were examined for variability in their volatile components by means of gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The thymol chemotype is widespread and is found in most of the vegetal formations where Thymus hyemalis is predominant and does not interact with other species. The carvacrol chemotype is found in isolated individual plants among those containing thymol. Although the chemotypes are usually mutually exclusive, the two phenols occasionally found with similar quantities in the same plant. The linalool chemotype has not previously been described for Thymus hyemalis. Other nonphenolic compounds (1,8-cineole, borneol, α-pinene) are present in low to medium percentages that reflect localized interactions with other species of thyme (Thymus vulgaris, Thymus baeticus) that sometimes produce hybridized or introgressive, morphologically distinguishable individuals.This chemical variability is analyzed by Principal Component Analysis (PCA) and Cluster Analysis (CA), a closely-related phenolic group of samples being revealed separated from less well represented non-phenolic chemotypes or mixed chemotypes. Multidimensional Scaling Analysis (MDS) based on percentage concentration was used to show the relationships between the most important components of the essential oil, the opposite orientation of vectors that represent phenolic compounds (and their precursors) and linalool, being of note. The data set presents positive correlation between camphor and altitude.     

Chemical Composition and Biological Activity of the Essential Oil of Origanum vulgare ssp. hirtum from Different Areas in the Southern Apennines (Italy)

The chemical composition of the essential oils of Origanum vulgare ssp. hirtum, growing wild in three different localities in the Southern Apennines, was studied by GC‐FID and GC/MS analyses. In total, 103 compounds were identified. The oils were mainly composed of phenolic compounds and all oils belonged to the chemotype carvacrol/thymol. The three essential oils were evaluated for their in vitro phytotoxic activity by determining their influence on the germination and initial radicle elongation of Sinapis arvensis L., Phalaris canariensis L., Lepidium sativum L., and Raphanus sativus L. The seed germination and radicle growth were affected in various degrees. Moreover, the antifungal activity of the three essential oils was assayed against three species causing pre‐ and postharvest fruit decay (Monilinia laxa, M. fructigena, and M. fructicola). At 1000 ppm, the three oils completely inhibited fungal growth. The hemolytic activity of the oils was assayed and showed no effect on the cell membranes of bovine erythrocytes.