Chemical Diversity in Indian Oregano (Origanum vulgare L.)

The terpenoid composition of the essential oils of 17 different populations of Origanum vulgare L., collected from wild populations and subsequently grown under similar conditions in the sub‐temperate region of the Western Himalaya, was studied. Analysis by GC (RI) and GC/MS allowed the identification of 51 components, representing 90.15 to 99.94% of the total oil. The two classes of the phenolic compounds and the monoterpenoids were predominant in all the essential oils. On the basis of the major constituents, i.e., marker compounds, and by comparison of the results with previous reports, new chemotypes could be identified. Principal component analysis was performed to determine the chemical variability within the different populations of O. vulgare collected and grown under similar conditions. Based on the marker compounds, six chemotypes with significant variations in their terpenoid profile were noticed within the 17 populations.     

Phytomorphological and Essential‐Oil Characterization in situ and ex situ of Wild Biotypes of Oregano Collected in the Campania Region (Southern Italy)

Oregano is an aromatic species of great interest, which spreads spontaneously over the Mediterranean area, but its genetic resources are not yet adequately developed. Moreover, the results of studies of wild strains of different origin – although quite numerous – are not always comparable, and, therefore, the influence of the environment and genotype on the variability cannot be distinguished. Hence, the plant morphology and the essential‐oil composition of three wild, white‐flowering biotypes of oregano collected in the Campania region (southern Italy) were characterized, and the effects of genotype and environment were assessed by comparison in situ and ex situ. This allowed deducing that the biotypes belonged to two different subspecies, i.e., Origanum vulgare ssp. virens and O. vulgare ssp. viridulum. The essential‐oil yield was higher for the biotype belonging to ssp. virens, and it was significantly correlated with the glandular and stomatal density. The chemical composition of the oils obtained by hydrodistillation was found to be influenced by the genotype and the conditions of plant growth.     

Correlations between Genetic,Morphological, and Chemical Diversities in a Germplasm Collection of the Medicinal Plant Origanum vulgare L.

In total, 42 accessions of Origanum vulgare L., mostly originating from Europe, were evaluated, to detect molecular, quantitative morphological, and chemotype polymorphisms and to discover possible correlations between them. Twelve traits related to morphological characteristics were measured. The components in the essential oils were identified by GC/MS analysis, and the oil contents of 18 major compounds were determined. A total of 477 molecular polymorphisms including 214 AFLP (amplified fragment length polymorphism) and 263 SAMPL (selectively amplified microsatellite polymorphic loci) were used for genotyping. Euclidean distances of morphological and chemotypic data and genetic distances (1 – Dice's similarity) of molecular markers were compared by applying Mantel tests to ascertain the congruencies between them. A relatively high correlation between chemotypic patterns and genetic markers was identified, while a lower correlation was found between the morphological and genetic matrices. Pairwise analyses of correlation among all traits showed that the stem diameter was correlated to the essential‐oil yield and the carvacrol content. Cluster analysis, population inference, and principal component analysis revealed a broad genetic and chemical variation among the accessions. The knowledge of these diversities, found in this study, will allow a plant improvement of Origanum vulgare related to pharmaceutical and spice uses.     

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.     

Essential‐Oil Composition of Daucus carota ssp. major (Pastinocello Carrot) and Nine Different Commercial Varieties of Daucus carota ssp. sativus Fruits

The chemical composition of the essential oils obtained by hydrodistillation from the pastinocello carrot, Daucus carota ssp. major (Vis.) Arcang . (flowers and achenes), and from nine different commercial varieties of D. carota L. ssp. sativus (achenes) was investigated by GC/MS analyses. Selective breeding over centuries of a naturally occurring subspecies of the wild carrot, D. carota L. ssp. sativus, has produced the common garden vegetable with reduced bitterness, increased sweetness, and minimized woody core. On the other hand, the cultivation of the pastinocello carrot has been abandoned, even if, recently, there has been renewed interest in the development of this species, which risks genetic erosion. The cultivated carrot (D. carota ssp. sativus) and the pastinocello carrot (D. carota ssp. major) were classified as different subspecies of the same species. This close relationship between the two subspecies urged us to compare the chemical composition of their essential oils, to evaluate the differences. The main essential‐oil constituents isolated from the pastinocello fruits were geranyl acetate (34.2%), α‐pinene (12.9%), geraniol (6.9%), myrcene (4.7%), epi‐α‐bisabolol (4.5%), sabinene (3.3%), and limonene (3.0%). The fruit essential oils of the nine commercial varieties of D. carota ssp. sativus were very different from that of pastinocello, as also confirmed by multivariate statistical analyses.     

Phytochemical and morphological characterization of Satureja khuzistanica Jamzad populations from Iran

Satureja khuzistanica is an endemic herb growing wild in Iran with interesting pharmacological and biological properties. Here, as an initial step of the domestication process, the variability of phytochemical and morphological traits among 69 individuals of eight natural populations of the plant was studied. The investigated characteristics were the essential oil content and composition, the rosmarinic acid (RA) content, and the leaf and flower morphologies. The Abdanan and Kaver populations showed the highest oil contents. The characterization by GC-FID and GC/MS analyses of the oils revealed that all 69 sampled individuals had carvacrol as the main component with very high contents (89.59-95.41%). The content of RA of the MeOH extracts of S. khuzistanica showed a high level of variability (coefficient of variation (CV) 50.0%) ranging from 0.59% (w/w) in the Paalam population to 1.81% (w/w) in the Abdanan population. The peduncle length and the leaf surface area (CVs of 47.39 and 47.21%, resp.) were the most variable morphological characteristics among the examined populations. The high level of phytochemical and morphological variability among the studied populations suggests a breeding approach during the domestication, to gain new, promising, and homogenous cultivars, attractive for the industry and agriculture.     

Phytochemical Diversity of the Essential Oils of Mexican Oregano (Lippia graveolens Kunth) Populations along an Edapho‐Climatic Gradient

Mexican oregano (Lippia graveolens) is an important aromatic plant, mainly used as flavoring and usually harvested from non‐cultivated populations. Mexican oregano essential oil showed important variation in the essential‐oil yield and composition. The composition of the essential oils extracted by hydrodistillation from 14 wild populations of L. graveolens growing along an edaphoclimatic gradient was evaluated. Characterization of the oils by GC‐FID and GC/MS analyses allowed the identification of 70 components, which accounted for 89–99% of the total oil composition. Principal component and hierarchical cluster analyses divided the essential oils into three distinct groups with contrasting oil compositions, viz., two phenolic chemotypes, with either carvacrol (C) or thymol (T) as dominant compounds (contents >75% of the total oil composition), and a non‐phenolic chemotype (S) dominated by oxygenated sesquiterpenes. While Chemotype C was associated with semi‐arid climate and shallower and rockier soils, Chemotype T was found for plants growing under less arid conditions and in deeper soils. The plants showing Chemotype S were more abundant in subhumid climate. High‐oil‐yield individuals (>3%) were identified, which additionally presented high percentages of either carvacrol or thymol; these individuals are of interest, as they could be used as parental material for scientific and commercial breeding programs.     

Biochemical Characterization of Helichrysum italicum (Roth) G.Don subsp. italicum (Asteraceae) from Montenegro: Phytochemical Screening,Chemotaxonomy, and Antioxidant Properties

The chemical composition and antioxidant properties of the essential oil and EtOH extract of immortelle (Helichrysum italicum (Roth) G.Don subsp. italicum, Asteraceae) collected in Montenegro were evaluated. The essential oil was characterized by GC/MS analysis, and the content of total phenolics and flavonoids in the EtOH extract was determined using the Folin? Ciocalteu reagent. The free‐radical‐scavenging capacity (RSC) of both the essential oil and the EtOH extract was assessed with the 2,2‐diphenyl‐1‐pycrylhydrazyl (DPPH) method. Moreover, the inhibition of hydroxyl radical (^.OH) generation by the EtOH extract of immortelle was evaluated for the first time here. Neryl acetate (28.2%) and γ‐curcumene (18.8%) were the main compounds in the essential oil, followed by neryl propionate (9.1%) and ar‐curcumene (8.3%). The chemical composition of the oils of the examined and additional 16 selected Helichrysum italicum taxa described in literature were compared using principal component (PCA) and cluster (CA) analyses. The results of the statistical analyses implied the occurrence of at least four different main and three subchemotypes of essential oils. Considering the antioxidant properties, the EtOH extract of immortelle exhibited similar potential as propyl gallate and quercetin, while the essential oil exhibited relatively weak DPPH^.‐scavenging capacity.     

Chemical Variability of the Leaf Essential Oil of Xylopia aethiopica (Dunal) A.Rich. from Côte d'Ivoire

The chemical composition of 48 essential‐oil samples isolated from the leaves of Xylopia aethiopica harvested in six Ivoirian forests was investigated by GC‐FID and ¹³C‐NMR analyses. In total, 23 components accounting for 82.5–96.1% of the oil composition were identified. The composition was dominated by the monoterpene hydrocarbons β‐pinene (up to 61.1%) and α‐pinene (up to 18.6%) and the sesquiterpene hydrocarbon germacrene D (up to 28.7%). Hierarchical cluster and principal component analyses allowed the distinction of two groups on the basis of the β‐pinene and germacrene D contents. The chemical composition of the oils of Group I (38 oil samples) was clearly dominated by β‐pinene, while those of Group II (10 samples) were characterized by the association of β‐pinene and germacrene D. The leaves collected in the four inland forests produced β‐pinene‐rich oils (Group I), while the oil samples belonging to Group II were isolated from leaves harvested in forests located near the littoral.     

Composition and Chemical Variability of Mentha suaveolens ssp. suaveolens and M. suaveolens ssp. insularis from Corsica

A detailed analysis of two essential oils from individual plants of Mentha suaveolens ssp. suaveolens growing wild in Corsica was carried out by combination of GC(RI), GC/MS, and ¹³C‐NMR analyses. One oil sample is characterized by the pre‐eminence of piperitenone oxide, and the second is dominated by piperitenone. In contrast, it was reported that the essential oil of M. suaveolens ssp. insularis, an endemic species to Corsica and Sardinia, contained pulegone and cis‐cis‐p‐menthenolide as main components. A principal‐component analysis (PCA) carried out on the composition of the essential oil of 59 individual plants of M. suaveolens sp. allowed the classification into three well‐defined groups. All the oil samples from Mentha suaveolens ssp. insularis belonged to the same group, while the oils from M. suaveolens ssp. suaveolens were distributed in the two other groups. The composition of the essential oil isolated from aerial parts of M. suaveolens ssp. has been shown to be an additional tool to differentiate the botanically close subspecies suaveolens and insularis.     

Essential‐Oil Composition of Helichrysum italicum (Roth) G.Don ssp. italicum from Elba Island (Tuscany,Italy)

The composition of 21 essential‐oil samples isolated from Helichrysum italicum collected in seven locations of Elba Island (Tuscany, Italy), characterized by different soil types, during three different periods (January, May, and October 2010) was determined by GC‐FID and GC/EI‐MS analyses. In total, 115 components were identified, representing 96.8–99.8% of the oil composition. The oils were characterized by a high content of oxygenated monoterpenes (38.6–62.7%), while monoterpene and sesquiterpene hydrocarbons accounted for 2.3–41.9 and 5.1–20.1% of the identified constituents, respectively. The main oxygenated derivatives were nerol (2.8–12.8%) and its ester derivative neryl acetate (5.6–45.9%). To compare the chemical variability of the species within Elba Island and between the island and other localities within the Mediterranean area, studied previously, multivariate statistical analysis was performed. The results obtained showed a difference in the composition of the essential oils of H. italicum from Elba Island, mainly due to the environment where the plant grows, and, in particular, to the soil type. These hypotheses were further confirmed by the comparison of these oils with essential oils obtained from H. italicum collected on other islands of the Tuscan archipelago.     

Variation in Volatile Leaf Oils of 13 Eucalyptus Species Harvested from Souinet Arboreta (Tunisia)

Hydrodistillation of the dried leaves of 13 species of the genus Eucalyptus L' Hér ., viz., E. bicostata Maiden, Blakely & Simmonds , E. cinerea F. Muell . ex Benth ., E. exerta F. Muell ., E. gigantea Hook . f ., E. gunnii Hook . f ., E. macarthurii Deane & Maiden ., E. macrorrhyncha F. Muell ., E. maidenii F. Muell ., E. odorata Behr ., E. pauciflora Sieber ex Sprengel , E. sideroxylon A. Cunn . ex Woolls , E. tereticornis Sm ., and E. viminalis Labill ., harvested from Souinet arboreta (region of Ain Draaham, north of Tunisia) in June 2006, afforded essential oils in yields varying from 0.5±0.2 to 3.9±0.4%, dependent on the species. E. cinerea and E. exerta provided the highest and the lowest percentage of essential oil amongst all the species examined, respectively. Analysis by GC (RI) and GC/MS allowed the identification of 142 components, representing 81.5 to 98.9% of the total oil. The contents of the different samples varied according to the species. The main components were 1,8‐cineole ( 1 ), followed by cryptone, spathulenol ( 4 ), p‐cymene ( 2 ), viridiflorol ( 6 ), globulol ( 7 ), β‐eudesmol, α‐terpineol ( 5 ), limonene ( 8 ), D ‐piperitone, α‐pinene ( 3 ), cuminal, and γ‐eudesmol. The principal component and the hierarchical cluster analyses separated the 13 Eucalyptus leaf essential oils into three groups, each constituting a chemotype.     

Variation in volatile leaf oils of seven eucalyptus species harvested from Zerniza arboreta (Tunisia)

Leaves of seven species of the genus Eucalyptus L'Hér., viz., E. cladocalyx F. Muell., E. citriodora Hook., E. diversicolor F. Muell., E. fasciculosa F. Muell., E. grandis W. Hill, E. ovata Labill., and E. botryoides Sm., were harvested from Zerniza arboreta (region of Sejnene, northwest of Tunisia) in June 2007. Of the latter species, leaves were collected from trees having two origins, Morocco and Italy. Hydrodistillation of the dried leaves provided essential oils in yields varying from 0.4±0.0 to 3.3±0.1%, according to the species. E. citriodora had the highest mean percentage of essential oil amongst the species examined, whereas the lowest one was obtained for E. botryoides originating from Morocco. Analysis by GC (RI) and GC/MS allowed the identification of 140 compounds, representing 92.5 to 99.4% of the total oil composition. The contents of the different samples varied according to the species. The main components were 1,8-cineole (2), followed by α-pinene (1), p-cymene, borneol, α-terpineol, cryptone, spathulenol, trans-pinocarveol (4), bicyclogermacrene (5), caryophyllene oxide, and β-phellandrene. Principal components analysis and hierarchical cluster analysis separated the eight Eucalyptus leaf essential oils into five groups, each constituting a chemotype.     

Variation in volatile leaf oils of five Eucalyptus species harvested from Jbel Abderrahman arboreta (Tunisia)

Hydrodistillation of the dried leaves of five species of the genus Eucalyptus L' Hér ., viz., E. dundasii Maiden , E. globulus Labill ., E. kitsoniana Maiden , E. leucoxylon F. Muell ., and E. populifolia Hook ., harvested from Jbel Abderrahman arboreta (region of Nabeul, northeast of Tunisia) in April 2006, afforded essential oils in yields varying from 0.9±0.3 to 3.8±0.6%, dependent on the species. E. globulus and E. Kitsoniana provided the highest and the lowest percentage of essential oil amongst the species examined, respectively. Analysis by GC (RI) and GC/MS allowed the identification of 127 compounds, representing 93.8 to 98.7% of the total oil composition. The contents of the different samples varied according to the species. The main components were 1,8‐cineole ( 2 ; 4.7–59.2%), followed by α‐pinene ( 1 ; 1.9–23.6%), trans‐pinocarveol ( 6 ; 3.5–21.6%), globulol ( 8 ; 4.3–12.8%), p‐cymene ( 3 ; 0.5–6.7%), α‐terpineol (1.5–4.5%), borneol (0.2–4.4%), pinocarvone (1.1–3.8%), aromadendrene (1.4–3.4%), isospathulenol (0.0–1.9%), fenchol ( 4 ; 0.1–2.5%), limonene (1.0–2.4%), epiglobulol (0.6–2.1%), viridiflorol ( 9 ; 0.8–1.8%), and spathulenol (0.1–1.6%). E. leucoxylon was the richest species in 2 . Principal component analysis (PCA) and hierarchical cluster analysis (HCA) separated the five Eucalyptus leaf essential oils into four groups, each constituting a chemotype.     

Chemical variations of the essential oils in flower heads of Chrysanthemum indicum L. from China

The volatile compositions of hydrodistilled essential oils in the flower heads of Chrysanthemum indicum L. from eight populations in China were analyzed by GC/MS. A total of 169 compounds representing 88.79-99.53% of the oils were identified, and some remarkable differences were found in the constituent percentages of the eight populations. The predominant components of the essential oils were 1,8-cineole (0.62-7.34%), (+)-(1R,4R)-camphor (0.17-27.56%), caryophyllene oxide (0.54-5.8%), β-phellandrene (0.72-1.87%), (-)-(1S,2R,4S)-borneol acetate (0.33-8.46%), 2-methyl-6-(p-tolyl)hept-2-ene (0.3-8.6%), 4,6,6-trimethylbicyclo[3.1.1]hept-3-en-2-yl acetate (0.17-26.48%), and hexadecanoic acid (0.72-15.97%). The chemotaxonomic value of the essential-oil compositions was discussed according to the results of cluster analysis (CA) and principal-component analysis (PCA). The eight populations were divided into five groups as different chemotypes (Groups A-E), and the scores together with the loadings revealed clearly different chemical properties of each population. In conclusion, GC/MS in combination with chemometric techniques provided a flexible and reliable method for characterizing the essential oils of different populations of C. indicum L.     

Variation in Volatile Leaf Oils of Twelve Eucalyptus Species Harvested from Hajeb Layoun Arboreta (Tunisia)

Hydrodistillation of the dried leaves of twelve species of the genus Eucalyptus L' Hér ., i.e., E. brockwayi C. A. Gardn ., E. gracilis F. Muell ., E. gillii Maiden , E. largiflorens F. Muell ., E. loxophleba Benth ., E. occidentalis Endl ., E. oldfieldii F. Muell ., E. salmonophloia F. Muell ., E. sargentii Maiden , E. stricklandii Maiden , E. torquata Luehm ., and E. woodwardii Maiden , harvested from Hajeb Layoun arboreta (region of Kairouan, central Tunisia) in January 2005, afforded essential oils in yields varying from 0.5±0.1 to 5.7±0.5%, dependent on the species. E. sargentii and E. brockwayi provided the highest and the lowest percentage of essential oil amongst all the species examined, respectively. Analysis by GC (RI) and GC/MS allowed the identification of 133 components, representing 92.9–98.8% of the total oil. The contents of the different samples varied according to the species. The main components were 1,8‐cineole, terpinen‐4‐ol, α‐pinene ( 2 ), p‐cymene, aromadendrene ( 1 ), globulol ( 5 ), trans‐pinocarveol ( 6 ), spathulenol ( 7 ), β‐eudesmol, torquatone ( 3 ), and 4‐methylpentan‐2‐yl acetate ( 8 ). The principal component analysis and the hierarchical clustering indicated that the volatile leaf oil composition of the twelve Eucalyptus species could be clearly differentiated.     

Chemical Diversity of Wild Growing Origanum majorana in Cyprus

The present work aims at tracing the essential‐oil diversity of wild growing Origanum majorana plants in Cyprus. The study of six populations scattered over the western part of the island has shown that the essential oils were rich either in trans‐sabinene hydrate/terpinen‐4‐ol or in α‐terpineol/trans‐sabinene hydrate. The former oil type is more common and responsible for the typical marjoram odor of the plants. The comparison of our results with published data concerning wild and cultivated O. majorana showed that the oil composition of the Cypriot populations had not been reported from wild plants from other parts of the Mediterranean region, while it is very common among the cultivated plants. Thus, it seems probable that the nowadays cultivated marjoram may originate from Cypriot wild populations.     

Chemical Variability of Cleistopholis patens (Benth.) Engl. et Diels Leaf Oil from Ivory Coast

The chemical composition of 48 leaf oil samples isolated from individual plants of Cleistopholis patens (Benth .) Engl. et Diels harvested in four Ivoirian forests was investigated by GC‐FID (determination of retention indices), GC/MS, and ¹³C‐NMR analyses. The main components identified were β‐pinene (traces–59.1%), sabinene (traces–54.2%), (E)‐β‐caryophyllene (0.3–39.3%), linalool (0.1–38.5%), (E)‐β‐ocimene (0.1–33.2%), germacrene D (0.0–33.1%), α‐pinene (0.1–32.3%), and germacrene B (0–21.2%). The 48 oil compositions were submitted to hierarchical clustering and principal components analyses, which allowed the distinction of three groups within the oil samples. The oil composition of the major group (Group I, 33 samples) was dominated by (E)‐β‐caryophyllene and linalool. The oils of Group II (eight samples) contained mainly β‐pinene and α‐pinene, while those of Group III (seven samples) were dominated by sabinene, limonene, and β‐phellandrene. Moreover, the compositions of the Ivoirian C. patens leaf oils differed from those of Nigerian and Cameroonian origins.     

Essential‐Oil Composition and Chemical Variability of Senecio vulgaris L. from Corsica

The chemical composition of the essential oils isolated from the aerial parts of Senecio vulgaris plants collected in 30 Corsican localities was characterized using GC‐FID and GC/MS analyses. Altogether, 54 components, which accounted for 95.2% of the total oil composition, were identified in the 30 essential‐oil samples. The main compounds were α‐humulene ( 1 ; 57.3%), (E)‐β‐caryophyllene ( 2 ; 5.6%), terpinolene ( 3 ; 5.3%), ar‐curcumene ( 4 ; 4.3%), and geranyl linalool ( 5 ; 3.4%). The chemical composition of the essential oils obtained from separate organs and during the complete vegetative cycle of the plants were also studied, to gain more knowledge about the plant ecology. The production of monoterpene hydrocarbons, especially terpinolene, seems to be implicated in the plant‐flowering process and, indirectly, in the dispersal of this weed species. Comparison of the present results with the literature highlighted the originality of the Corsican S. vulgaris essential oils and indicated that α‐humulene might be used as taxonomical marker for the future classification of the Senecio genus. A study of the chemical variability of the 30 S. vulgaris essential oils using statistical analysis allowed the discrimination of two main clusters according to the soil nature of the sample locations. These results confirmed that there is a relation between the soil nature, the chemical composition of the essential oils, and morphological plant characteristics. Moreover, they are of interest for commercial producers of essential oil in selecting the most appropriate plants.     

Variability in the Essential‐Oil Composition of Sideritis scardica Griseb. from Native Bulgarian Populations

The essential‐oil composition of six native populations of Sideritis scardica from Bulgaria was studied by GC‐FID and GC/MS analyses. Altogether, 37 components, representing 73.1 to 79.2% of the total oil content were identified. Among them, α‐pinene (4.4–25.1%), β‐pinene (2.8–18.0%), oct‐1‐en‐3‐ol (2.3–8.0%), phenylacetaldehyde (0.5–9.5%), β‐bisabolene (1.3–11.0%), benzyl benzoate (1.1–14.3%), and m‐camphorene ( 1 ; 0.3–12.4%) were the main compounds. All samples were characterized by low contents of oxygenated mono‐ and sesquiterpenes (≤1.6 and 2.3%, resp.). Principal component analysis (PCA) and cluster analysis (CA) showed a significant variability in the chemical composition of the studied samples as well as a correlation between the oil profiles and the ecological conditions of the natural habitats of S. scardica.