Terpenoid Diversity in the Leaf Essential Oils of Himalayan Lauraceae Species

The leaf terpenoid compositions of nine Lauraceae species, viz., Neolitsea pallens, Lindera pulcherrima, Dodecadenia grandiflora, Persea duthiei, Persea odoratissima, Persea gamblei, Phoebe lanceolata, Cinnamomum tamala, and Cinnamomum camphora, collected from the Himalayan region (India) were examined by GC, GC/MS, and NMR analyses in order to determine the similarities and differences among their volatile constituents. Furano‐sesquiterpenoids were the principal constituents of N. pallens, L. pulcherrima, and D. grandiflora. (E)‐Nerolidol, limonene, β‐pinene, and α‐pinene were the major constituents of P. duthiei; α‐pinene, sabinene, and β‐caryophyllene were predominant in P. odoratissima, while the oils of P. gamblei and P. lanceolata possessed β‐caryophyllene as common major constituent. C. camphora and C. tamala were marked by the presence of camphor and cinnamaldehyde, respectively. Cluster analysis of the oil composition was carried out in order to discern the differences and similarities within nine species of six genera of Lauraceae.     

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.     

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.     

Chemical Composition of the Essential Oils of Three Endemic Species of Anthemis Sect. Hiorthia (DC.) R.Fern. Growing Wild in Sicily and Chemotaxonomic Volatile Markers of the Genus Anthemis L.: An Update

The chemical composition of the essential oils isolated from the aerial parts of Anthemis pignattiorum Guarino, Raimondo & Domina and A. ismelia Lojac . and the aerial parts and flowers of Anthemis cupaniana Tod . ex Nyman , three endemic Sicilian species belonging to the section Hiorthia, was determined by GC‐FID and GC/MS analyses. (Z)‐Muurola‐4(14),5‐diene (27.3%) was recognized as the main constituent of the A. pignattiorum essential oil, together with isospathulenol (10.6%), sabinene (7.7%), and artemisyl acetate (6.8%), while in the oil obtained from the aerial parts of A. ismelia, geranyl propionate (8.8%), bornyl acetate (7.9%), β‐thujone (7.8%), neryl propionate (6.5%), and τ‐muurolol (6.5%) prevailed. α‐Pinene was the main compound of both the aerial part and flower oils of A. cupaniana (18.4 and 13.2%, resp.). Also noteworthy are the considerable amounts of artemisyl acetate (12.7%) and β‐thujone (11.8%) found in the oil from the aerial parts and those of tricosane (9.8%) and sabinene (7.6%) evidenced in the flower oil. Furthermore, an update on the main compounds identified in the essential oils of all the Anthemis taxa studied so far was presented, and cluster analyses were carried out, to compare the essential oils of these taxa.     

Chemical Composition of Essential Oils and Aromatic Waters from Different Italian Anthemis maritima Populations

The chemical composition of the essential oils and aromatic waters isolated from six Italian Anthemis maritima populations was determined by GC‐FID and GC/MS analyses. In total, 122 and 100 chemical compounds were identified in the essential oils and the aromatic waters, respectively. The main compound classes represented in the oils were monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, and terpene esters. Multivariate chemometric techniques such as cluster analysis (CA) and principal coordinate analysis (PCO) were used to classify the samples according to the geographical origin. Statistical analysis allowed the attribution of the analyzed populations to different chemotype groups.     

Variability of the Root Essential Oils of Seseli rigidum Waldst. & Kit. (Apiaceae) from Different Populations in Serbia

The chemical compositions of the essential oils of seven natural populations of Seseli rigidum were analyzed. The essential‐oil yield ranged from 0.16 to 2.09%. Analysis of variance (ANOVA) revealed that there were no statistically significant differences in the mean essential‐oil yields between the populations, and no significant influence of the climate or soil type on the oil yield was observed. In all 67 analyzed samples, the polyacetylene falcarinol was the main compound, followed by octanal, methyl linoleate, α‐muurolene, 3‐butylphthalide, falcarinone, muurola‐4,10(14)‐dien‐1β‐ol, β‐sesquiphellandrene, salvial‐4(14)‐en‐1‐one, δ‐amorphene, spathulenol, and isospathulenol. The principal component analysis (PCA), the canonical discriminant analysis (CDA), and the cluster analysis (CA) revealed differentiation between the populations based on the climate. Three groups of populations were formed; the first group was composed of samples growing in regions with a humid climate, with oils having high falcarinol and low sesquiterpene contents, and the second and third groups comprised samples exposed to semi‐arid climate, with oils characterized by a lower falcarinol and higher α‐muurolene, δ‐amorphene, β‐sesquiphellandrene, and salvial‐4(14)‐en‐1‐one contents. The semi‐arid populations were divided into two groups, which were distinguished based on the oil contents of sesquiterpenes, falcarinone, and 3‐butylphthalide. On the other hand, no clear separation between populations based on the different soil types could be observed.     

Chemical Diversity among the Essential Oils of Wild Populations of Stachys lavandulifolia Vahl (Lamiaceae) from Iran

The variation of the essential‐oil composition among ten wild populations of Stachys lavandulifolia Vahl (Lamiaceae), collected from different geographical regions of Iran, was assessed by GC‐FID and GC/MS analyses, and their intraspecific chemical variability was determined. Altogether, 49 compounds were identified in the oils, and a relatively high variation in their contents was found. The major compounds of the essential oils were myrcene (0.0–26.2%), limonene (0.0–24.5%), germacrene D (4.2–19.3%), bicyclogermacrene (1.6–18.0%), δ‐cadinene (6.5–16.0%), pulegone (0.0–15.1%), (Z)‐hex‐3‐enyl tiglate (0.0–15.1%), (E)‐caryophyllene (0.0–12.9), α‐zingiberene (0.2–12.2%), and spathulenol (1.6–11.1%). For the determination of the chemotypes and the chemical variability, the essential‐oil components were subjected to cluster analysis (CA). The five different chemotypes characterized were Chemotype I (germacrene D/bicyclogermacrene), Chemotype II (germacrene D/spathulenol), Chemotype III (limonene/δ‐cadinene), Chemotype IV (pulegone), and Chemotype V (α‐zingiberene). The high chemical variation among the populations according to their geographical and bioclimatic distribution imposes that conservation strategies of populations should be made appropriately, taking into account these factors. The in situ and ex situ conservation strategies should concern all populations representing the different chemotypes.     

Chemotaxonomic significance of the essential oils of 18 Ferula species (Apiaceae) from Iran

To evaluate the chemotaxonomic significance of the essential oils of 23 populations of 18 Iranian Ferula species, the chemical composition of the oils was investigated by GC/FID and GC/MS. Altogether, 84 constituents, representing 81.3-99.7% of the total composition of the oils, have been identified. The composition of six species of the genus, i.e., F. oopoda, F. foetida, F. behboudiana, F. diversivittata, F. galbaniflua, and F. hezarlalehzarica, has been reported for the first time. The main constituents identified were α-terpinyl acetate (73.3%), 2,3,4-trimethylthiophene (2; 49.0%), sabinene (75.3%), verbenone (5; 69.4%), β-pinene (59.0-66.3%), and (Z)-β-ocimene (41.7%). Cluster analysis (CA) of the percentage content of the essential oil components of the Ferula species resulted in the characterization of four groups, i.e., taxa containing either i) monoterpene hydrocarbons, ii) oxygenated monoterpenes, iii) organosulfur compounds, or iv) monoterpene, sesquiterpene, and aliphatic hydrocarbons as the principal classes of compounds. Based on the results obtained, the chemical independence of F. hirtella from F. szowitsiana and of F. galbaniflua from F. gummosa at the specific level was concluded and their positions as distinct species were confirmed. The chemotaxonomic relationships among the representatives of the genus Ferula have been discussed in detail.     

Chemical Composition and Antimicrobial Activity of the Essential Oils from Several Hypericum Taxa (Guttiferae) Growing in Central Italy (Appennino Umbro‐Marchigiano)

The chemical composition of the essential oils of nine taxa from seven sections of Hypericum L. (Guttiferae; H. perforatum subsp. perforatum, H. perforatum subsp. veronense, H. calycinum, H. montanum, H. richeri subsp. richeri, H. hyssopifolium, H. hirsutum, H. hircinum subsp. majus, and H. tetrapterum) occurring in central Italy (Appennino Umbro‐Marchigiano) was analyzed by GC/FID and GC/MS. A total of 186 compounds were identified in the different species and subspecies, accounting for 86.9–92.8% of the total oils. The major fraction of the oil was always represented by sesquiterpene hydrocarbons (30.3–77.2%), while quantitative differences occurred between the other classes of volatiles depending on the taxa considered. Chemical composition of the nine Hypericum entities with respect to the taxonomical classification was discussed. Essential oils obtained from six taxa, i.e., H. perforatum subsp. perforatum, H. perforatum subsp. veronense, H. calycinum, H. richeri subsp. richeri, H. hirsutum and H. tetrapterum, were also tested for their antimicrobial properties against five different microbial strains by the broth‐microdilution method, and they were found to have significant activity (expressed as MIC) on B. subtilis, moderate activity on C. albicans and S. aureus, and weak activity on E. coli and E. faecalis, the most active being those from H. hirsutum, H. richeri subsp. richeri, and H. tetrapterum.     

Variability of the Needle Essential Oils of Juniperus deltoides R.P.Adams from Different Populations in Serbia and Croatia

The essential‐oil compositions of one Croatian and three Serbian populations of Juniperus deltoides R.P.Adams have been determined by GC/MS analysis. In total, 147 compounds were identified, representing 97.3–98.3% of the oil composition. The oils were dominated by monoterpenes, which are characteristic components for the species of the section Juniperus. Two monoterpenes, α‐pinene and limonene, were the dominant constituents, with a summed‐up average content of 49.45%. Statistical methods were used to determine the diversity of the terpene classes and the common terpenes between the newly described J. deltoides populations from Serbia and Croatia. Only reports on several specimens from this species have been reported so far, and there are no studies that treat population diversity. Cluster analysis of the oil contents of 21 terpenes showed high correlation with the geographical distribution of the populations, separating the Croatian from the Serbian populations. The comparison of the essential‐oil compositions obtained in the present study with literature data, showed the separation of J. deltoides and J. oxycedrus ssp. oxycedrus from the western Mediterranean region.     

Volatile‐Oils Composition,and Bioactivity of the Essential Oils of Plectranthus barbatus,P. neochilus,and P. ornatus Grown in Portugal

Volatile‐oils chemical composition and bioactivity of the essentail oils from Plectranthus barbatus, P. neochilus, and P. ornatus (Lamiaceae) were assessed. Aerial parts from these three related Plectranthus species were collected from cultivated plants grown in Portugal, during vegetative and flowering phases. Volatiles, isolated by distillation? extraction, were analyzed by GC and GC/MS. Monoterpene hydrocarbons (12–74%) and sesquiterpene hydrocarbons (4–45%) constituted the main fractions in all volatiles. α‐Pinene ( 3 ; 12–67%), oct‐1‐en‐3‐ol ( 6 ; traces–28%), β‐pinene ( 7 ; 0.1–22%), and β‐caryophyllene ( 50 ; 7–12%) dominated P. barbatus volatiles. P. neochilus major volatile components were α‐terpenyl acetate ( 41 ; traces–48%), α‐thujone ( 2 ; 2–28%), β‐caryophyllene ( 50 ; 2–28%), β‐pinene ( 7 ; 1–25%), and α‐pinene ( 3 ; 1–19%). Oct‐1‐en‐3‐ol ( 6 ; 13–31%), β‐pinene ( 7 ; 11–24%), α‐pinene ( 3 ; 11–19%), and β‐caryophyllene ( 50 ; traces–11%) were the main constituents from P. ornatus volatiles. These chemical compositions were rather different from those previously found for specimens harvested in Africa and Brazil. Moreover, the volatiles from the flowers are herewith reported for the first time. Essential oils, isolated by hydrodistillation from leaves and stems, showed a yellowish color and unpleasant odor, with yields ranging from 0.08% to 0.84% (v/dry weight). Antioxidant and antimicrobial activities of the essential oils were evaluated by DPPH^. and TBARS assays, and agar disc‐diffusion method, respectively. Results showed low or moderate antioxidant capacity and significant antimicrobial activity against Gram‐positive bacteria.     

A Study on Chemical Components of Essential Oils from Citrus bergamia and Its Close Relatives and Its Taxonomy

Citrus bergamia Risso. is a rare perfumery plant. Taxonomists have different views on the taxonomy of C. bergamia. Chemical components of leaf and peel essential oils from C. bergamia, and its close relatives, C. limon, C. aurantifolia and three varieties of C. aurantium, were analyzed by GC and GC-MS. The analytical result shows that the chemical compositions of the leaf essential oils from C. bergamia are basically the same as those from three varieties of C. aurantium. Their main components are linalool (29.19-39.75% )and linalyl acetate (24.73-30.24% )etc., and contents of other components are also similar. But their peel essential oils are different. The peel essential oils from C. bergamia contain less limonene (29.94%) than those from C. aurantium (92.55-94.31% ) and less beta-pinene (3.00%) and y-terpinene(3.48% )than those from C. limon or C. aurantifolia (respectiyely 9.16% and 10.42% ) . The peel essential oils from C. bergamia contain not only as much linalool (22.20%) and linalyl acetate (32.66%)as those in the leaf essential oils from C. aurantium, but also as much limonene(29.94% )as that in the peel essential oils from C. limon or C. aurantifolia . The contents of limonene are close to those of the essential oils from C. aurantifolia. This result shows that C. bergamia may be a natural hybrid between C.aurantium and C. aurantifolia, as proposed by Sinclair W. B.     

Population Variability of Essential Oils of Pinus heldreichii from the Scardo‐Pindic Mountains Ošljak and Galičica

The needle‐terpene profiles of two natural Pinus heldreichii populations from Mts. O?ljak and Gali?ica (Scardo‐Pindic mountain system) were analyzed. Among the 68 detected compounds, 66 were identified. The dominant constituents were germacrene D (28.7%), limonene (27.1%), and α‐pinene (16.2%). β‐Caryophyllene (6.9%), β‐pinene (5.2%), β‐myrcene (2.3%), pimaric acid (2.0%), α‐humulene (1.2%), and seven additional components were found to be present in medium‐to‐high amounts (0.5–10%). Although the general needle‐terpene profile of the population from Gali?ica was similar to those of the populations from Lov?en, Zeletin, Bjelasica, and Zlatibor‐Pe?ter (belonging to the Dinaric Alps), the principle‐component analysis (PCA) of seven terpenes (β‐myrcene, limonene, β‐elemene, β‐caryophyllene, α‐humulene, δ‐cadinene, and germacrene D‐4‐ol) in 121 tree samples suggested a partial divergence in the needle‐terpene profiles between the populations from the Scardo‐Pindic mountain system and the Dinaric Alps. According to previously reported data, the P. heldreichii samples from the Balkan‐Rhodope mountains lack β‐caryophyllene and germacrene D, but contain γ‐muurolene in their terpene profile. Differences in the terpene composition between populations growing in the three above‐mentioned mountain systems were compared and discussed.     

Chemotaxonomic Investigations of Peel and Petitgrain Essential Oils from 17 Citron Cultivars

Chemical compositions of essential oils from 17 citron cultivars were studied using GC and GC/MS. To the best of our knowledge, chemical compositions of peel and petitgrain oils from seven of them were reported for the first time. Combined analysis of peel and petitgrain essential oils led to the identification of 37 components (amounting to 98.2–99.9% of the total oil) and 42 components (97.0–99.9%), respectively. Statistical analysis was applied to identify possible relationships between citron cultivars. The levels of seven components, i.e., limonene, β‐pinene, γ‐terpinene, neral, geranial, nerol, and geraniol, indicated that the cultivars could be classified in four main chemotypes for peel and petitgrain oils. Chemotaxonomic investigations were carried out to establish relations between the morphological characteristics of citron cultivars and their corresponding oil compositions.     

Chemotaxonomic Significance of the Terpene Composition in Natural Populations of Pinus nigra J.F.Arnold from Serbia

The essential‐oil variability in seven native populations belonging to different infraspecific taxa of Pinus nigra (ssp. nigra, var. gocensis, ssp. pallasiana, and var. banatica) growing wild in Serbia was analyzed. In the needles of 195 trees from seven populations, 58 essential‐oil components were identified. The major components were α‐pinene (43.6%) and germacrene D (29.8%), comprising together 73.4% of the total oil composition. Based on the average chemical profile of the main terpene components (with contents >5%), the studied populations were found to be the most similar to populations from central Italy and Greece (ssp. nigra). Cluster analysis showed the division of the populations into three principal groups: the first group consisted of Populations I, II, III, IV, and V (considered as ssp. nigra group), the second of Population VI (ssp. pallasiana group), and the third of Population VII, which had the most distinct oil composition (ssp. banatica group). The taxonomic implications of the essential‐oil profiles of the investigated taxa of this very complex species are discussed.     

Volatiles of Geranium purpureum Vill. and Geranium phaeum L.: Chemotaxonomy of Balkan Geranium and Erodium Species (Geraniaceae)

The essential oils obtained by hydrodistillation of Geranium purpureum and G. phaeum were characterized by GC‐FID and GC/MS analyses (the former for the first time in general). In total, 154 constituents were identified, accounting for 89.0–95.8% of the detected GC peak areas. The investigated essential oils consisted mainly of fatty acids and fatty‐acid‐derived compounds (45.4–81.3%), with hexadecanoic acid and (E)‐phytol as the major components. The chemotaxonomic significance of the variations in the essential‐oil composition/production of the presently and previously investigated Geranium and highly related Erodium taxa from Serbia and Macedonia was assessed by multivariate statistical analyses. The main conclusions drawn from the high chemical similarity of the two genera, visible from the obtained dendrograms and biplots, confirm the close phylogenetic relationship between the investigated Geranium and Erodium taxa, i.e., that there is no great intergeneric oil‐composition variability. Changes in the composition and production of essential oils of the herein investigated taxa and 60 other randomly chosen species belonging to different plant genera were also statistically analyzed. The results put forward pro arguments for the oil‐yield–oil‐composition correlation hypothesis.     

Components of essential oils extracted from leaves and shoots of abies species in Japan

The essential oils extracted from the leaves and the shoots of five Abies species (Pinaceae) growing in Japan, i.e., A. firma, A. homolepis, A. veitchii, A. mariesii, and A. sachalinensis, were characterized by GC-FID and GC/MS analyses. The yields of the essential oils extracted from A. sachalinensis were the highest among them. A significant amount of α-pinene was contained in the essential oils of all the Abies species examined. In A. homolepis and A. veitchii, significant differences in the content of the essential oils were found depending on whether these were extracted from the leaves or from the shoots. Regarding the enantiomeric ratio of α-pinene, the (+)-enantiomer was predominant in the oil extracted from the leaves of A. firma, while (-)-α-pinene was present in higher amounts in the oils of A. veitchii (leaves and shoots), A. mariesii (leaves and shoots), and A. sachalinensis (shoots). The fact that there may be a quantitative and qualitative difference in the components of the essential oils extracted from the different parts of a plant was investigated by cluster analysis.     

Essential Oils and Chemical Diversity of Southeast European Populations of Salvia officinalis L.

The essential oils of 25 populations of Dalmatian sage (Salvia officinalis L.) from nine Balkan countries, including 17 indigenous populations (representing almost the entire native distribution area) and eight non‐indigenous (cultivated or naturalized) populations were analyzed. Their essential‐oil yield ranged from 0.25 to 3.48%. Within the total of 80 detected compounds, ten (β‐pinene, 1,8‐cineole, cis‐thujone, trans‐thujone, camphor, borneol, trans‐caryophyllene, α‐humulene, viridiflorol, and manool) represented 42.60 to 85.70% of the components in the analyzed essential oils. Strong positive correlations were observed between the contents of trans‐caryophyllene and α‐humulene, α‐humulene and viridiflorol, and viridiflorol and manool. Principal component analysis (PCA) on the basis of the contents of the ten main compounds showed that four principal components had an eigenvalue greater than 1 and explained 79.87% of the total variation. Performing cluster analysis (CA), the sage populations could be grouped into four distinct chemotypes (A–D). The essential oils of 14 out of the 25 populations of Dalmatian sage belonged to Chemotype A and were rich in cis‐thujone and camphor, with low contents of trans‐thujone. The correlation between the essential‐oil composition and geographic variables of the indigenous populations was not significant; hence, the similarities in the essential‐oil profile among populations could not be explained by the physical proximity of the populations. Additionally, the southeastern populations tended to have higher EO yields than the northwestern ones.