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.     

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.     

Chemical Characterization of basil (Ocimum Spp.) found in the markets and used in traditional medicine in Brazil

Ocimum species are used both in Brazilian traditional medicine against bronchitis, coughs, and sorethroat, and in foods and flavorings. The traditional uses of basil in Brazil are reviewed and fourteen accessions of basil, O. americanum (1), O. basilicum (3), O. campechianum (3), O. gratissimum (5), and O. selloi (2) were collected and brought from Brazil to the USA and grown at Purdue University. Upon flowering, the volatile oils were extracted by hydrodistillation and chemically analyzed by GC/ MS. Accessions ofO. gratissimum showed high eugenol (40-66%) and high thymol (31%), as a relative percentage of total volatile oil. Ocimum campechianum accessions showed high 1,8-cineole (62%) and ß-caryophyllene (78.7%). Accessions of O. basilicum were found to be rich in 1,8-cineole (22%), linalool (49.7%), methyl chavicol (47%) or methyl (E)-cinnamate (65.5%). An O. americanum var. americanum accession showed high methyl (E)-cinnamate (>90%). Volatile oils of O. basilicum and O. gratissimum naturalized in Brazil reflected the range of chemotypes found in their country of origin. Unusual basils from other Ocimum species were identified that can serve as genetic sources of aroma chemicals for crop improvement.     

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.     

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.     

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.     

The synergistic preservative effects of the essential oils of sweet basil (Ocimum basilicum L.) against acid-tolerant food microflora

Essential oils extracted by hydrodistillation from five different varieties of Ocimum basilicum L. plants (Anise, Bush, Cinnamon, Dark Opal and a commercial sample of dried basil) were examined for antimicrobial activity against a wide range of foodborne Gram-positive and -negative bacteria, yeasts and moulds by an agar well diffusion method. All five essential oils of basil showed antimicrobial activity against most of the organisms tested with the exception of Flavimonas oryzihabitans and Pseudomonas species. The inhibitory effect of Anise oil, in comparison with mixtures of the predominant components of pure linalool and methyl chavicol, against the acid-tolerant organisms, Lactobacillus curvatus and Saccharomyces cerevisiae , was examined in broth by an indirect impedance method. Synergistic effects between Anise oil, low pH (pH 4·2) and salt (5% NaCl) were determined. The antimicrobial effect of Anise oil was also assessed in a tomato juice medium by direct viable count, showing that the growth of Lact. curvatus and S. cerevisiae was completely inhibited by 0·1% and 1% Anise oil, respectively. The results of the current study indicate the need for further investigations to understand the antimicrobial effects of basil oils in the presence of other food ingredients and preservation parameters.     

The effect of essential oils of basil on the growth of Aeromonas hydrophila and Pseudomonas fluorescens

Basil essential oils, including basil sweet linalool (BSL) and basil methyl chavicol (BMC), were screened for antimicrobial activity against a range of Gram-positive and Gram-negative bacteria, yeasts and moulds using an agar well diffusion method. Both essential oils showed antimicrobial activity against most of the micro-organisms examined except Clostridium sporogenes , Flavimonas oryzihabitans , and three species of Pseudomonas . The minimum inhibitory concentration (MIC) of BMC against Aeromonas hydrophila and Pseudomonas fluorescens in TSYE broth (as determined using an indirect impedance method) was 0·125 and 2% (v/v), respectively; the former was not greatly affected by the increase of challenge inoculum from 10³ to 10⁶ cfu ml⁻¹. Results with resting cells demonstrated that BMC was bactericidal to both Aer. hydrophila and Ps. fluorescens . The growth of Aer. hydrophila in filter-sterilized lettuce extract was completely inhibited by 0·1% (v/v) BMC whereas that of Ps. fluorescens was not significantly affected by 1% (v/v) BMC. In addition, the effectiveness of washing fresh lettuce with 0·1 or 1% (v/v) BMC on survival of natural microbial flora was comparable with that effected by 125 ppm chlorine.     

Identification and functional characterization of the CVOMTs and EOMTs genes promoters from Ocimum basilicum L.

Plant Cell, Tissue and Organ Culture (PCTOC) - Methyl chavicol and methyl eugenol are important phenylpropanoid compounds previously purified from basil. These compounds are significantly enhanced...     

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.     

Essential oil chemotypes of Aloysia citrodora (Verbenaceae) in Northwestern Argentina

Chemical biodiversity of essential oils of natural populations of Aloysia citrodora Palau (“lemon verbena”, “cedrón”) in Northwestern Argentina was assessed by collecting in the same sites through different years. A total of 36 samples were collected in the Provinces of Salta (El Maray, La Paya, El Sunchal, El Alisal, Chorrillos), Jujuy (Chilcayo, San Roque), Catamarca (Mutquin, Colana) and Tucumán (Amaicha del Valle) in Argentina.Essential oils were obtained by hydrodistillation (Clevenger) of naturally air-dried plant material. Yields ranged from 0.16% to 1.93% (v/w), being the highest those of the collections of Mutquin. More than 65 compounds were identified by CG-FID-MS. Only 19 of these constituents, accounting from 77.3 to 98.9% of the total oil, present in more than 4.0% in at least one sample, were considered as variables for statistical analysis. Agglomerative Hierarchical Cluster analysis was conducted, showing at 65% of similarity, five groups. This grouping was in direct accordance to the biosynthetic pathways of main compounds (chemotypes).In the two sites of Jujuy, 21 collections evidenced four different chemotypes, named after the dominant component as follows: thujones, citronellal, carvone, and citral (neral + geranial). In the populations of Salta and Catamarca, linalool appeared as a new different chemotype.Though cedron is considered as a citral-bearing plant, curiously, in the 36 samples collected in the NW of Argentina, only two samples contained citral as main constituent. On the other hand, a dominance of citronellal and thujones compositions were found in the bulk of the samples collected, while others had very high content of linalool or carvone and its derivatives. Northwestern Argentina has repeatedly been mentioned as the center of biodiversity of this species.The new evidences found on the chemical biodiversity of essential oils of Aloysia citrodora in natural populations in this region, reinforce firmly this idea.     

Effects of two sodium salts on fatty acid and essential oil composition of basil (Ocimum basilicum L.) leaves

The effects of two sodium salts on growth, fatty acids, and essential oil compositions were investigated in a medicinal and aromatic plant, Ocimum basilicum cultivated in hydroponic medium. Plants were subjected to an equimolar concentration of Na₂SO₄ (25 mM) and NaCl (50 mM) for 15 days. Our results showed that leaf growth rate was more depressed by 25 mM Na₂SO₄ than by 50 mM NaCl. The total fatty acid contents did not show any change in plants. α-Linolenic, palmitic, and linoleic acids were the major fatty acids. The identification of basil leaf fatty acids has not been previously studied and this work revealed the predominance of polyunsaturated fatty acids. Under both salts, leaf fatty acid composition remained unchanged. Regarding the essential oil yield, it decreased significantly by 28 % under 25 mM Na₂SO₄ and showed an increase by 27 % under 50 mM NaCl. The major volatile compound in leaves was linalool with 34.3 % of total essential oil constituents, followed by eugenol (19.8 %), 1.8-cineole (14.4 %) and methyl eugenol (5.2 %). Further, levels of eugenol and methyl eugenol were most modulated by salt, and the negative correlation between these two compounds reflects the stimulation of O-methyltransferase activity under both salts.     

Terpenoids inhibit Candida albicans growth by affecting membrane integrity and arrest of cell cycle

Anti-Candida potential of six terpenoids were evaluated in this study against various isolates of Candida albicans (n = 39) and non-C. albicans (n = 9) that are differentially susceptible to fluconazole. All the six terpenoids tested, showed excellent activity and were equally effective against isolates of Candida sps., tested in this study. Linalool and citral were the most effective ones, inhibiting all the isolates at ≤0.064% (v/v). Five among the six terpenoids tested were fungicidal. Time dependent kill curve assay showed that MFCs of linalool and eugenol were highly toxic to C. albicans, killing 99.9% inoculum within seven min of exposure, while that of citronellal, linalyl acetate and citral required 15 min, 1 h and 2 h, respectively. FIC index values (Linalool - 0.140, benzyl benzoate - 0.156, eugenol - 0.265, citral - 0.281 and 0.312 for linalyl acetate and citronellal) and isobologram obtained by checker board assay showed that all the six terpenoids tested exhibit excellent synergistic activity with fluconazole against a fluconazole resistant strain of C. albicans. Terpenoids tested arrested C. albicans cells at different phases of the cell cycle i.e. linalool and LA at G1, citral and citronellal at S phase and benzyl benzoate at G2-M phase and induced apoptosis. Linalool, citral, citronellal and benzyl benzoate caused more than 50% inhibition of germ tube induction at 0.008%, while eugenol and LA required 0.032 and 0.016% (v/v) concentrations, respectively. MICs of all the terpenoids for the C. albicans growth were non toxic to HeLa cells. Terpenoids tested exhibited excellent activity against C. albicans yeast and hyphal form growth at the concentrations that are non toxic to HeLa cells. Terpenoids tested in this study may find use in antifungal chemotherapy, not only as antifungal agents but also as synergistic agents along with conventional drugs like fluconazole.     

Essential oil variability in Thymbra capitata (L.) Cav. growing wild in Southern Apulia (Italy)

Essential oils of Thymbra capitata (Thymus capitatus) collected from Southern Apulia (Italy) were analysed using gas chromatography and gas chromatography–mass spectrometry techniques, to check for chemical variability. The study showed that among the 75 components of the oils the most recurrent ones were thymol and carvacrol, which always constituted more than 50% of the oils, as well as γ-terpinene, borneol and p-cymene. Cluster analysis led to the identification of three chemotypes: thymol, carvacrol and thymol/carvacrol; this was presumably a crossbreed between the other two chemotypes. Principal component analysis showed the direct correlation among myrcene, α-terpinene and γ-terpinene; anti-correlation between thymol and carvacrol, and the inverse correlation between linalool and myrcene. Moreover, lower thymol concentrations were accompanied by an increase in myrcene, α-terpinene and γ-terpinene.     

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.     

Repellent and acaricidal activities of basil (Ocimum basilicum) essential oils and rock dust against Ixodes scapularis and Dermacentor variabilis ticks

Repellent and acaricidal activity of essential oils extracted from three varieties of basil (Ocimum basilicum L.) were evaluated on blacklegged ticks (Ixodes scapularis Say) and American dog ticks (Dermacentor variabilis Say) in laboratory conditions. Essential oils were extracted and characterized through gas chromatography-mass spectrometry, and tested at different concentrations for long-term repellent activity using horizontal bioassays. In addition, basil essential oils were combined with an inert material (i.e., granite rock dust) with known insecticidal and miticidal properties to assess acaricidal activities against adult ticks. Among the tested basil varieties, var. Jolina essential oil at 15% vol/vol concentration repelled 96% of tested ticks up to 2 h post-treatment. The EC₅₀ for I. scapularis nymphs was 4.65% vol/vol (95% confidence interval: 4.73–4.57). In acaricidal tests, the combination of essential oil from var. Aroma 2 at 10% wt/wt with rock dust resulted in 100% tick mortality after only 24 h post-exposure, with a LD₅₀ of 3.48% wt/wt (95% CI 4.05–2.91) for freshly prepared treatment tested on I. scapularis adults. The most common compounds detected in basil essential oils by GC–MS were linalool (52.2% in var. Nu Far, 48.2% in Aroma 2, 43.9% in Jolina), sabinene (6.71% in Nu Far, 8.99% in Aroma 2, 8.11% in Jolina), eugenol (11.2% in Jolina, 8.71% in Aroma 2), and estragole (18.2% in Nu Far). The use of essential oils alone and in combination with rock dust provides an innovative and environmentally friendly approach for managing ticks and inhibiting vector-borne disease transmission.

     

An investigation of the storage and biosynthesis of phenylpropenes in sweet basil

Plants that contain high concentrations of the defense compounds of the phenylpropene class (eugenol, chavicol, and their derivatives) have been recognized since antiquity as important spices for human consumption (e.g. cloves) and have high economic value. Our understanding of the biosynthetic pathway that produces these compounds in the plant, however, has remained incomplete. Several lines of basil (Ocimum basilicum) produce volatile oils that contain essentially only one or two specific phenylpropene compounds. Like other members of the Lamiaceae, basil leaves possess on their surface two types of glandular trichomes, termed peltate and capitate glands. We demonstrate here that the volatile oil constituents eugenol and methylchavicol accumulate, respectively, in the peltate glands of basil lines SW (which produces essentially only eugenol) and EMX-1 (which produces essentially only methylchavicol). Assays for putative enzymes in the biosynthetic pathway leading to these phenylpropenes localized many of the corresponding enzyme activities almost exclusively to the peltate glands in leaves actively producing volatile oil. An analysis of an expressed sequence tag database from leaf peltate glands revealed that known genes for the phenylpropanoid pathway are expressed at very high levels in these structures, accounting for 13% of the total expressed sequence tags. An additional 14% of cDNAs encoded enzymes for the biosynthesis of S-adenosyl-methionine, an important substrate in the synthesis of many phenylpropenes. Thus, the peltate glands of basil appear to be highly specialized structures for the synthesis and storage of phenylpropenes, and serve as an excellent model system to study phenylpropene biosynthesis.     

Genetic relationships between some Tunisian Citrus species based on their leaf volatile oil constituents

Volatile oil constituents of Tunisian sweet orange (Citrus sinensis Osbeck) cv. Meski (MES), Valencia Late (VAL), Thomson Navel (THN) and Maltaise Blanc (MAB); mandarin (Citrus reticulata Blanco); sour orange (Citrus aurantium L. cv. Amara (AM)) and pummelo (Citrus grandis Osbeck) were obtained by hydrodistillation and analysed by gas chromatography (GC) combined with a flame ionisation detector (FID) and mass spectrometry (MS). A total of 41 components accounting for more than 95% of the total essential oils were identified, and oxygenated monoterpenes (69.5–99.9%) were found as the most prominent fraction in all oil samples. The main constituents were linalool (3.1–73%), isoborneol (0–55.8%) and tepinen-4-ol (1.1–19.2%). A high degree of inter-and intraspecific chemical variability between species and cultivars was found to be genetically determined, and a set of distinctive traits (chemical markers) in the essential oils profile was established. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) of all identified components grouped the oils into two main chemotypes (linalool/isoborneol and isoborneol/linalool).     

In vitro antifungal, anti-elastase and anti-keratinase activity of essential oils of Cinnamomum-, Syzygium- and Cymbopogon-species against Aspergillus fumigatus and Trichophyton rubrum

This study was aimed to evaluate effects of certain essential oils namely Cinnamomum verum, Syzygium aromaticum, Cymbopogon citratus, Cymbopogon martini and their major components cinnamaldehyde, eugenol, citral and geraniol respectively, on growth, hyphal ultrastructure and virulence factors of Aspergillus fumigatus and Trichophyton rubrum. The antifungal activity of essential oils and their major constituents was in the order of cinnamaldehyde>eugenol>geraniol=C. verum>citral>S. aromaticum>C. citratus>C. martini, both in liquid and solid media against T. rubrum and A. fumigatus. Based on promising antifungal activity of eugenol and cinnamaldehyde, these oils were further tested for their inhibitory activity against ungerminated and germinated conidia in test fungi. Cinnamaldehyde was found to be more active than eugenol. To assess the possible mode of action of cinnamaldehyde, electron microscopic studies were conducted. The observations revealed multiple sites of action of cinnamaldehyde mainly on cell membranes and endomembranous structures of the fungal cell. Further, test oils were also tested for their anti-virulence activity. More than 70% reduction in elastase activity was recorded in A. fumigatus by the oils of C. verum, C. martini, eugenol, cinnamaldehyde and geraniol. Similar reduction in keratinase activity in A. niger was recorded for the oils of C. martini and geraniol. Maximum reduction (96.56%) in elastase activity was produced by cinnamaldehyde whereas; geraniol caused maximum inhibition (97.31%) of keratinase activity. Our findings highlight anti-elastase and anti-keratinase activity of above mentioned essential oils as a novel property to be exploited in controlling invasive and superficial mycoses.