Leaf essential oil composition of three species of Myrcianthes from Monteverde, Costa Rica

To examine the chemical diversity of essential oils from Myrcianthes species (Myrtaceae) as well as potential chemotaxonomic relationships between them, the leaf essential oils of M. fragrans (Sw.) McVaugh, M. rhopaloides (Kunth) McVaugh, and an undescribed species, Myrcianthes 'black fruit', from Monteverde, Costa Rica, were isolated by hydrodistillation and analyzed by GC/MS. The most abundant components of the essential oil of M. fragrans were 1,3,5-trimethoxybenzene (15.7%), (Z)-hex-3-en-1-ol (10.0%), alpha-cadinol (10.4%), eudesma-4(15),7-dien-1beta-ol (9.0%), caryophyllene oxide (7.8%), and spathulenol (7.5%). The leaf oils of two different samples of Myrcianthes rhopaloides were quantitatively different with one sample composed mostly of linalool (17.7%), alpha-cadinol (14.4%), spathulenol (11.1%), tau-cadinol (9.6%), and 1-epicubenol (6.9%), and the other was made up largely of (E)-hex-2-enal (46.1%), 1,8-cineole (12.5%), linalool (9.1%), alpha-cadinol (6.7%), and alpha-terpineol (4.4%). The major components in the leaf essential oil of Myrcianthes 'black fruit' were 1,8-cineole (38.3%), alpha-terpineol (21.2%), heptan-2-ol (15.5%), terpinen-4-ol (4.2%), and beta-pinene (3.8%). The leaf oil compositions of Myrcianthes in this study are very different from leaf oils from other members of Myrcianthes reported in the literature. A cluster analysis reveals large chemical variation not only between members of the genus, but also between samples of the same species.     

Leaf essential oil composition of 10 species of Ocotea (Lauraceae) from Monteverde,Costa Rica

The leaf essential oils of 10 species of Ocotea (Lauraceae) from Monteverde, Costa Rica (Ocotea floribunda, Ocotea holdridgeana, Ocotea meziana, Ocotea sinuata, Ocotea tonduzii, Ocotea valeriana, Ocotea veraguensis, Ocotea whitei, and two undescribed species, Ocotea new species “los llanos”, and Ocotea new species “small leaf”) have been obtained by hydrodistillation and analyzed by GC–MS in order to discern the differences and similarities between the volatile chemical compositions of these species. The principal common constituents of the 10 species of Ocotea were α-pinene, β-pinene, β-caryophyllene, and germacrene-D.     

Chemical composition and antibacterial activities of seven Eucalyptus species essential oils leaves

Background

In this paper, we have studied the essential oils chemical composition of the leaves of seven Eucalyptus species developed in Tunisia. Eucalyptus leaves were picked from trees growing in different arboretums in Tunisia. Choucha and Mrifeg arboretums located in Sedjnene, region of Bizerte (Choucha: E. maideni, E. astrengens et E. cinerea; Mrifeg : E. leucoxylon), Korbous arboretums located in the region of Nabeul, North East Tunisia with sub-humid bioclimate, (E. lehmani), Souiniet-Ain Drahem arboretum located in region of Jendouba (E. sideroxylon, E. bicostata). Essential oils were individually tested against a large panel of microorganisms including Staphylococcus aureus (ATCC 6539), Escherichia coli (ATCC 25922), Enterococcus faecalis (ATCC29212), Listeria ivanovii (RBL 30), Bacillus cereus (ATCC11778).

Results

The yield of essential oils ranged from 1.2% to 3% (w/w) for the different Eucalyptus species. All essential oils contain α-pinene, 1,8-cineol and pinocarveol-trans for all Eucalyptus species studied. The 1,8-cineol was the major compound in all species (49.07 to 83.59%). Diameter of inhibition zone of essential oils of Eucalyptus species varied from 10 to 29 mm. The largest zone of inhibition was obtained for Bacillus cereus (E. astrengens) and the lowest for Staphylococcus aureus (E. cinerea). The essential oils from E. maideni, E. astrengens, E. cinerea (arboretum of Bizerte), E. bicostata (arboretum of Aindraham) showed the highest antibacterial activity against Listeria ivanovii and Bacillus cereus.

Conclusion

The major constituents of Eucalyptus leaves essential oils are 1,8-cineol (49.07 to 83.59%) and α-pinene (1.27 to 26.35%). The essential oils from E. maideni, E. astrengens, E. cinerea, E. bicostata showed the highest antibacterial activity against Listeria ivanovii and Bacillus cereus, they may have potential applications in food and pharmaceutical products.     

Chemical composition and larvicidal activity of essential oils from Piper species

The larvicidal activity of essential oils of four species of Piper from the Amazon Forest was tested using third-instar larvae of Aedes aegypti. The oils were extracted by steam distillation and analyzed by GC and GC–MS. The main components isolated from each Piper species were as follows: viridiflorol (27.50%), aromadendrene (15.55%) and β-selinene (10.50%) from Piper gaudichaudianum; β-selinene (15.77%) and caryophyllene oxide (16.63%) from Piper humaytanum; dillapiol (54.70%) and myristicin (25.61%) from Piper permucronatum; and asaricin (27.37%) and myristicin (20.26%) from Piper hostmanianum. Amongst all essential oils tested, the most active against larvae of A. aegypti was the oil extracted from P. permucronatum, with a LC₅₀ = 36 μg/ml (LC₉₀ = 47 μg/ml), followed by the essential oil of P. hostmanianum, with a LC₅₀ = 54 μg/ml (LC₉₀ = 72 μg/ml). The oils with higher content of arylpropanoids were more active against larvae of A. aegypti.     

Essential oils of seven Stachys taxa from Croatia

The essential oils of Stachys alpina L., Stachys officinalis (L.) Trevis., Stachys palustris L., Stachys recta L. subsp. recta, S. recta L. subsp. subcrenata (Vis.) Briq., Stachys salviifolia Ten., and Stachys sylvatica L. were obtained by hydrodistillation and analysed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). Sesquiterpene hydrocarbons were the main group of constituents of all taxa, except S. alpina, which was rich in oxygenated sesquiterpenes. S. alpina and S. palustris had a significant aldehyde fraction and a high amount of alcohols. Some differences in the essential oil composition of two subspecies of S. recta (S. recta subsp. recta and S. recta subsp. subcrenata), growing under almost identical conditions, have been found.     

Chemical composition and antimicrobial activity of essential oils of Cupressus arizonica Greene

The chemical composition of the essential oils obtained by hydrodistillation from leaves, branches and female cones of Cupressus arizonica Greene cultivated in Tunisia was determined by GC and GC/MS analysis. Significant differences were found between the constituent percentages of the different oils. Among the 87 identified components α-pinene (60.5% in female cones), umbellulone (18.4% in leaves), δ-3-carene (15.6% in branches) and cis-muurola-4(14),5-diene (9.4% in leaves) were found to be the major ones.Composition of essential oils extracted from different organs of C. arizonica Greene growing in Tunisia showed remarkable differences from the same species cultivated in Algeria, Argentina, Iran, Italy, France and Texas based on a comparison with published results. The in vitro antibacterial activity of the essential oils samples was evaluated against some Gram positive and negative bacteria.     

Essential oil composition of two endemic Centaurea species from Turkey, Centaurea mucronifera and Centaurea chrysantha, collected in the same habitat

The essential oils of two endemic Centaurea species from Turkey, C. mucronifera and C. chrysantha, collected in the same habitat, have been studied. The main compounds of the former were germacrene D (29.3%), β-eudesmol (17.4%) and β-caryophyllene (7.3%), while in the latter germacrene D (27.4%), caryophyllene oxide (9.5%) and bicyclogermacrene (5.4%) were detected among its major constituents. The two species produced many similar compounds in their essential oils that could be justified by the similar ecological conditions of their habitat, but also many differences were found that could confirm their taxonomic separation.     

几种典型植物精油的化学成分与其抗菌活性

【目的】植物精油萃取自天然植物, 因具有抗菌活性, 近年来受到广泛关注。论文的目的是分析植物精油的化学成分, 测试其抗菌活性, 并研究其化学成分与抗菌活性之间的联系。【方法】实验选取了肉桂、山苍子、丁香、香茅、迷迭香和大蒜精油等6种典型植物精油, 通过气质联用分析方法研究了其化学组分, 并通过污染食物技术研究了其对黑曲霉和绳状青霉的抗真菌活性, 以及对大肠杆菌和金黄色葡萄球菌的抗细菌活性。【结果】气质联用分析结果表明, 肉桂、山苍子、香茅和迷迭香等4种植物精油的化学成分主要是醛类和醇类, 丁香精油的主要化学成分是丁香油酚, 大蒜精油化学成分基本上都是含硫的醚类, 其中二烯丙基三硫醚(大蒜素)含量最高。抗菌活性结果显示, 不同植物精油的抗菌活性不同, 6种植物精油的抗真菌活性由强到弱依次为: 肉桂>大蒜>丁香>山苍子=香茅>迷迭香, 抗细菌活性由强到弱依次为: 肉桂>山苍子>丁香>香茅=迷迭香>大蒜。【结论】植物精油的抗真菌、细菌活性与其化学组分密切相关, 肉桂、山苍子、香茅和迷迭香等4种精油的抗菌活性可能主要与其化学成分中的醛类和醇类有关, 丁香精油较高的抗菌活性可能主要源于丁香油酚; 大蒜精油具有高效的抗真菌活性主要源于其化学成分中的含硫醚。不同植物精油化学成分不同, 抗真菌、细菌活性也不同, 表明其可能有不同的抗真菌与抗细菌机制。     

Chemical composition and bioactivities of thirteen non-host plant essential oils against Plutella xylostella L. (Lepidoptera: Plutellidae)

The diamondback moth (DBM), Plutella xylostella (L.), is a globally destructive pest of cruciferous vegetables. Excessive use of synthetic pesticides to control this species results in negative effects on the environment, human health, and nontargeted organisms. The essential oils (EOs) derived from plants may be developed as effective alternatives to conventional pesticides. In this study, thirteen EOs were extracted by hydrodistillation, respectively. Their chemical compositions were identified by gas chromatography-mass spectrometry (GC–MS). Furthermore, the biological activities of EOs such as toxicity, antifeedant activity, and growth inhibition effect, toward DBM larvae were investigated. Against DBM second-instar larvae, the most toxic EO was Pelargonium graveolens (LC₅₀ = 0.36 μg/μl) after 72 hr of exposure, followed by Polygonum hydropiper (LC₅₀ = 0.53 μg/μl). The Ocimum basilicum EO exhibited the highest antifeedant effect to third-instar larvae at at all set concentrations. At 15 μg/μl, the EOs of Acorus calamus, O. basilicum, and P. graveolens completely inhibited the feeding activities of larvae (100%). The Ruta graveolens EO showed the lowest relative growth rate and the highest growth inhibition rate towards third-instar larvae at diverse concentrations. And the EOs of P. hydropiper, A. calamus, and O. basilicum showed promising growth inhibition activities. Overall, the five EOs (P. graveolens, O. basilicum, R. graveolens, P. hydropiper, and A. calamus) showed moderate to high bioactivity, whereas eight EOs were found to be less active against DBM larvae. These results indicate that the five tested EOs are promising to be developed as novel botanical insecticides to control DBM population.     

Essential oils of four Myrtaceae species from the Brazilian southeast

The essential oils of the leaves of Eugenia acutata, Eugenia candolleana, Eugenia copacabanensis and Myrcia splendens (Myrtaceae) from Brazil’s southeastern Atlantic Forest were obtained by hydrodistillation and analyzed by GC–MS. Oxygenated sesquiterpenes were predominant in E. copacabanensis (54.3%) and E. candolleana (50.9%) whilst hydrocarbon species predominated in E. acutata (83.4%) and M. splendens (94.5%). trans-Caryophyllene was the most abundant component in E. acutata. Isomers of guaiol and cadinol alcohols, followed by δ-elemene and viridiflorene, were the major components of the essential oil of the leaves of E. candolleana. Hydrocarbons and alcohols of the cadinane-type predominated in E. copacabanensis the most abundant being epi-cubenol (14%). M. splendens had 80% α-bisabolene in the leaf oil along with <5% β-farnesene. Additionally, E. copacabanensis exhibited 13.7% monoterpenes. Whereas the bisabolene-rich M. splendens oil is highly similar to that of other Myrcia species reported elsewhere, the Eugenia species oils corroborated the complex array and differing abundances of terpene classes within this genus. This study generated data which may provide further comprehension of the phylogenetic relationships between Myrtaceae genera and species.     

Constituents of the essential oils from three tetraploid species of Chrysanthemum

The chemical constituents of the volatile oils from Chrysanthemum indicum, C. yoshinaganthum and C. cuneifolium, three botanically related tetraploid species, are described. By spectroscopic methods, 42 compounds were identified, including 22 monoterpenoids, 17 sesquiterpenoids and 3 acetylenic compounds. The sesquiterpenoids estafiatin (C. yoshinaganthum) and valeranone (C. indicum) have been found for the first time in Chrysanthemum species.     

Terpenoid compositions, and antioxidant and antimicrobial properties of the rhizome essential oils of different Hedychium species

A phytochemical study of the rhizome essential oils of four different Hedychium species was performed by means of GC and GC/MS analyses. H. ellipticum mainly contained 1,8-cineole, sabinene, and terpin-4-ol, while H. aurantiacum possessed terpin-4-ol, para-cymene, and bornyl acetate as the major entities. Similarly, trans-meta-mentha-2,8-diene and linalool were noticed in H. coronarium. Three different collections (I-III) of H. spicatum showed amazing differences in the relative contents of their essential oils, 1,8-cineole and 10-epi-gamma-eudesmol being identified as markers for samples I and II, terpin-4-ol and sabinene being the major compounds in sample III. The rhizome essential oils of the above species were studied for their antioxidant activities by different methods, including their effect on the chelating properties of Fe(2+), DPPH radical-scavenging activity, and reducing power. Antimicrobial screenings of the oils by the paper-disc method were performed against Staphylococcus aureus, Shigella flexneri, Pasteurella multocida, Escherichia coli, and Salmonella enterica enterica, and the respective minimum-inhibitory-concentration (MIC) values were determined. The rhizome essential oils from all Hedychium species exhibited moderate-to-good Fe(2+) chelating activity. H. spicatum from collection site III showed a completely different DPPH radical-scavenging profile than the samples from the other collection sites.     

Chemical composition and antimicrobial activity of the essential oils of the Amazon Guatteriopsis species

The essential oils of Guatteriopsis blepharophylla, Guatteriopsis friesiana and Guatteriopsis hispida were obtained by hydrodistillation and analysed by GC and GC/MS. The main compound found in the leaf oil of G. blepharophylla was caryophyllene oxide (1) (69.25%). The leaf oil of G. friesiana contained predominantly beta-eudesmol (2) (51.60%), gamma-eudesmol (3) (23.70%), and alpha-eudesmol (4) (14.56%). The major constituents identified in the leaf of G. hispida were beta-pinene (38.18%), alpha-pinene (30.77%) and (E)-caryophyllene (20.59%). The antimicrobial activity of the essential oils was evaluated against 11 species of microorganisms. The oil of G. friesiana exhibited significant antimicrobial activity for all microorganisms tested, whereas that of G. hispida and G. blepharophyla had potent activity against Rhodococcus equi with MIC of 50 microg mL(-1). The major constituents of each oil were also tested separately, and showed lower activity compared to the oils. Moreover, mixtures of the main constituents, in the same proportions found in G. friesiana and G. hispida oils, did not show the same activity as the original oils.     

Chemical composition and larvicidal activity of essential oils of three Artemisia species

Aedes aegypti L. (Diptera: Culicidae) is a vector for serious diseases in tropical regions. This pest is mainly controlled by commercial larvicides but the application of such products has led to environmental problems. Essential oils (EO) have been consistently reported as molecules with insecticidal activity and can be used to produce more environmentally friendly larvicides in the control of A. aegypti. In this study, the larvicidal effect of essential oils (EO) from the leaves of three Artemisia species was evaluated against A. aegypti. The oils were obtained from steam distillation and their chemical composition was determined by gas chromatography–mass spectrometry. The EO of Artemisia camphorata was the most active in the screening bioassay and presented LC₅₀ and LC₉₅ of 64.95 and 74.18 μg ml⁻¹, respectively. In addition, we found that germacrene D-4-ol was the constituent responsible for the toxicity of this EO. Artemisia camphorata EO and its major constituent, germacrene D-4-ol, are promising for the development of natural larvicides against A. aegypti.     

Effects of essential oils on in vitro ruminal fermentation and ammonia release

Ruminal inoculum enriched with particle-associated microorganisms was collected from two lactating dairy cows fed an alfalfa hay/cereal silage/concentrate diet 1 h before feeding and used to evaluate effects of essential oils (EO) on ruminal fermentation in short-term in vitro incubations. Ruminal ammonia N was labeled with ¹⁵N and native and hydrolyzed casein were provided as sources of amino acids. Forty EO were tested at 10 and 100 mg/l final medium concentration. Monensin-Na, and sodium laurate were also incubated at 5 and 2000 mg/l, respectively. Compared with blanks (i.e., no addition of EO), sodium laurate increased medium pH and a number of EO reduced medium pH. Both sodium laurate and monensin reduced ammonia concentrations compared to the blank. Only one of the tested EO (i.e., Caraway) slightly reduced ammonia concentration, by 8%, compared with the blank. Monensin and sodium laurate resulted in higher (i.e., 9–34%, monensin, and 29–47%, sodium laurate) ¹⁵N enrichment of ammonia N, an indication of reduced deamination of amino acids in these treatments versus the blank. Several EO (i.e., FrankMyrrh, Gardenia, Hibiscus, Eucaliptus, and Peppermint) had similar effects, but of a smaller magnitude (i.e., 5–12%). Some EO increased medium total VFA concentration, primarily through an increase in acetate concentration. Overall, effects of EO on fermentation were subtle, and it is unlikely that these moderate in vitro effects would correspond to any substantive impact on ruminal fermentation in vivo.     

Yield,chemical composition,and bioactivity of essential oils from 12 species of Eucalyptus on Aedes aegypti larvae

The insecticidal activity of essential oils from 12 species of Eucalyptus (Myrtaceae) was evaluated on larvae of Aedes aegypti (L.) (Diptera: Culicidae), the most important vector of dengue and yellow fever in the Americas. Oils were obtained by hydrodistillation and their chemical composition was determined by gas chromatography coupled to mass spectrometry; yields ranged from 0.2 to 2.5%. Essential oils were mainly composed of 1,8‐cineole, α‐pinene, α‐phellandrene, β‐phellandrene, γ‐terpinene, 4‐terpineol, α‐terpineol, p‐cymene, and spathulenol. Larvicidal effects were tested on susceptible third or fourth stage Ae. aegypti larvae, determining median lethal concentration (LC₅₀) and median effective concentration (EC₅₀). Essential oils from Eucalyptus dunnii (Maiden), Eucalyptus gunnii (Hook), Eucalyptus tereticornis (Smith), Eucalyptus camaldulensis (Dehn), and Eucalyptus saligna (Smith) showed the best larvicidal activities with LC₅₀ values of 25.2, 21.1, 22.1, 26.8, and 22.2, respectively. No significant differences were observed between LC₅₀ and EC₅₀ values of the same oil. Regression analysis revealed a significant relationship between total essential oil yields and 1,8‐cineole concentration. Significant relationships were also revealed between larval mortality and the concentration of 1,8‐cineole and p‐cymene. This indicated that Eucalyptus species with high oil yields have higher 1,8‐cineole concentrations and lower p‐cymene concentrations and have less effect on Ae. aegypti. Our results suggest the potential of controlled crossing methods to obtain Eucalyptus trees with chemical profiles having enhanced activity against this mosquito.     

Chemical composition,intraspecies variation and seasonal variation in essential oils of Calendula arvensis L.

The essential oil composition of Calendula arvensis was established for the first time using GC and GC/MS. Eighty-five essential oil components were identified, which accounted for 90.3 g/100 g of essential oil. The oil contained a high concentration of sesquiterpenes, of which δ-cadinene and α-cadinol were the main components. The chemical composition of 25 Corsican C. arvensis oils was analyzed to determine intraspecies variation in essential oil composition. A matrix linking essential oil composition to sample location was composed to identify relationships between concentrations of volatile samples and the geographical origins of samples. Two main groups of compounds were identified according to the amount of sesquiterpenic compounds (hydrocarbons and alcohols) and soil characteristics. Seasonal variation (winter vs. spring) in the concentrations of two major compounds during the flowering period was observed.     

Chemical composition of the essential oils of two Rhodiola species from Tibet

The essential oils from rhizomes of Rhodiola crenulata and R. fastigiata in eastern Tibet were analyzed by using GC-MS. The major constituents were geraniol (53.3%), n-octanol (13.4%), 2-methyl-3-buten-2-ol (10.8%), citronellol (5.3%), 3-methyl-2-buten-1-ol (4.0%), myteol (3.0%), and linalool (2.4%) for R. crenulata and geraniol (45.3%), n-octanol (12.3%), 2-methyl-3-buten-2-ol (8.0%), linalool (5.1%), isogeraniol (4.5%), citronellol (4.4%), and cis-sabinenehydrate (3.6%) for R. fastigiata.     

Chemical composition, seasonal variation, and biosynthetic considerations of essential oils from Baccharis microdonta and B. elaeagnoides (Asteraceae)

The chemical composition and seasonal variation throughout one year of the essential oils from leaves of Baccharis microdonta and B. elaeagnoides, collected in Campos do Jordão, SP, were investigated. The composition of the latter species has been described for the first time. By GC (RI) and GC/MS analysis, 43 compounds were identified, and a predominance of oxygenated sesquiterpene derivatives was found in both species. The main components of the B. microdonta oils were elemol ( 31 ; 11.7–30.6%), spathulenol ( 34 ; 4.7–9.1%), β‐caryophyllene ( 19 ; 3.7–6.2%), and germacrene D ( 24 ; 2.9–12.2%), and those of the B. elaeagnoides oils were 34 (10.1–21.5%), viridiflorol ( 35 ; 3.6–18.4%), 24 (0.9–13.8%), and 19 (3.5–9.4%). The identified compounds were grouped according to their respective C‐skeletons, and the percentages of occurrence of the C‐skeletons in the essential oils of leaves collected in the four seasons allowed identifying the preferential accumulation of different types of C‐skeletons as well as the seasonal variation of the biosynthetic routes over the studied period.