Chemical Polymorphism Research Articles

Diterpenoids from Marine Ciliates: Chemical Polymorphism of Euplotes rariseta

AbstractA homogeneous, though multifaceted, secondary metabolic character emerges from a detailed investigation of secondary metabolites produced by the ciliate species Euplotes rariseta. In particular, from the strain NZ2, collected in New Zealand (Omaha Bay), two new irregular diterpenoids, omaholidenol (6) and omaholidenal (7), have been isolated which are the C5 homologues of rarisetenolide (1), the latter being previously found as the main secondary metabolite in different strains of the same species. On the other hand, from strain Ubt22, three new diterpenoids, ubatubaolidenal (8), ubatubadial A (9), and ubatubadial B (10), have been found. Finally, two new diterpenoids, epoxyfocardolide (11) and prenyl epoxyrarisetenolde (12), were isolated in low yields from the sister species Euplotes quinquecarinatus and Euplotes parkei, respectively. All these findings strongly suggest, in addition to a wide chemical polymorphism in E. rariseta populations, a close parallelism between the production pattern of secondary metabolites and the phylogenetic relationships of the species, confirming the chemotaxonomic utility of these compounds in the ciliate genus Euplotes.

Variations in the essential oils from ylang‐ylang (Cananga odorata [Lam.] Hook f. & Thomson forma genuina) in the Western Indian Ocean islands

ABSTRACTYlang‐ylang essential oil is an important raw material for the fragrance industry. Despite its economic importance, to the best of our knowledge, no study has yet been undertaken to assess the chemical polymorphism of the different production areas. This underestimated variability is an interesting source of raw material for perfumers. That is why the variation in the chemical composition of four fractions of the essential oils extracted from Cananga odorata, grown in four locations Grande Comore, Mayotte, Nossi Bé and Ambanja, was studied. A total of 119 compounds, representing 85.7–96.4% of the total essential oil composition, were identified using gas chromatography–mass spectrometry and quantified by gas chromatography with a flame ionization detector. Thirty‐two compounds previously unreported in ylang‐ylang essential oil were identified. The distinction between the Comoros and Madagascar groups was made on the basis of the chemical classes. It was possible to significantly distinguish the Grande Comore and Mayotte essential oil samples, as well as the Ambanja and Nossi Bé essential oil samples, on the basis of their main compounds. The aromatic compounds profile for the origin of each essential oil fraction was established. Regression trees were built, allowing the provenance of the essential oils prepared at the laboratory level to be easily differentiated on the basis of a limited number of major compounds. Copyright © 2012 John Wiley & Sons, Ltd.

Chemical composition of the essential oil from Stachys serotina

Stachys serotina (Host) Fritsch is an aromatic, erect, perennial plant similar to Stachys officinalis (L.) Trev. but distinguished clearly in very interrupted inflorescence and later flowering period. The aerial parts of S. serotina were collected on Adriatic island Krk in July 2010. The essential oils were isolated by hydrodistillation for 2 hours. The analyses of the obtained essential oil were performed by GC-FID and GC-MS. Results revealed several differences between Stahys serotina and other Stachys species in Croatia, indicating the existence of a chemical polymorphism. Sesquiterpene hydrocarbons were the most abundant class of isolated volatiles with a predominance of β-caryophyllene (22.6%) followed by δ-cadinene (9.6%), α-humulene (7.5%), germacrene D (6.0%) and minor percentages of others. Determined percentage of β-caryophyllene in Stahys serotina was the highest among other Stachys species from Croatia being most abundant in Stachys officinalis (14.6%). In addition, δ- cadinene was also found with largest abundance in comparison with other Stachys species. Monoterpenes were minor oil constituents of Stachys serotina dominated by monoterpene hydrocarbon α-pinene (11.1%).

Recurrent gene deletions and the evolution of adaptive cyanogenesis polymorphisms in white clover (Trifolium repens L.)

Understanding the molecular evolution of genes that underlie intraspecific polymorphisms can provide insights into the process of adaptive evolution. For adaptive polymorphisms characterized by gene presence/absence (P/A) variation, underlying loci commonly show signatures of long-term balancing selection, with gene-presence and gene-absence alleles maintained as two divergent lineages. We examined the molecular evolution of two unlinked P/A polymorphisms that underlie a well-documented adaptive polymorphism for cyanogenesis (hydrogen cyanide release with tissue damage) in white clover. Both cyanogenic and acyanogenic plants occur in this species, and the ecological forces that maintain this chemical defence polymorphism have been studied for several decades. Using a sample of 65 plants, we investigated the molecular evolution of sequences flanking the two underlying cyanogenesis genes: Ac/ac (controlling the presence/absence of cyanogenic glucosides) and Li/li (controlling the presence/absence of their hydrolysing enzyme, linamarase). A combination of genome walking, PCR assays, DNA sequence analysis and Southern blotting was used to test whether these adaptive P/A polymorphisms show evidence of long-term balancing selection, or whether gene-absence alleles have evolved repeatedly through independent deletion events. For both loci, we detect no signatures of balancing selection in the closest flanking genomic sequences. Instead, we find evidence for variation in the size of the deletions characterizing gene-absence alleles. These observations strongly suggest that both of these polymorphisms have been evolving through recurrent gene deletions over time. We discuss the genetic mechanisms that could account for this surprising pattern and the implications of these findings for mechanisms of rapid adaptive evolution in white clover.

Plant secondary chemistry mediates the performance of a nutritional symbiont associated with a tree‐killing herbivore

Many herbivores consume microbial food sources in addition to plant tissues for nutrition. Despite the ubiquity of herbivore-microbe feeding associations, few studies examine how host plant phenotypes affect microbial symbionts of herbivores. We tested the hypothesis that chemical polymorphism in a plant population mediates the performance of nutritional microbial symbionts. We surveyed the composition of ponderosa pine resin in northern Arizona, USA, for variation in six monoterpenes, and we approximated four chemical phenotypes. We reared populations of an herbivorous tree-killing beetle (Dendroctonus brevicomis) in ponderosa pine host material, controlling for three monoterpene compositions representing an alpha-pinene to delta-3-carene gradient. Beetles were reared in host material where the dominant monoterpene was alpha-pinene, delta-3-carene, or a phenotype that was intermediate between the two. We isolated nutritional fungal symbionts (Entomocorticium sp. B) from beetle populations reared in each phenotype and performed reciprocal growth experiments in media amended to represent four "average" monoterpene compositions. This allowed us to test the effects of natal host phenotype, chemical polymorphism, and the interaction between natal host phenotype and chemical polymorphism on a nutritional symbiont. Three important findings emerged: (1) fungal isolates grew 25-32% faster when acquired from beetles reared in the intermediate phenotype; (2) the mean growth rate of nutritional fungi varied up to 44% depending on which monoterpene composition media was amended with; and (3) fungal isolates uniformly performed best in the intermediate phenotype regardless of the chemical composition of their natal host. The performance of nutritional fungi related to both the chemical "history" of their associated herbivore and the chemical phenotypes they are exposed to. However, all fungal isolates appeared adapted to a common chemical phenotype. These experiments argue in favor of the hypothesis that chemical polymorphism in plant populations mediates growth of nutritional symbionts of herbivores. Intraspecific chemical polymorphism in plants contributes indirectly to the regulation of herbivore populations, and our experiments demonstrate that the ecological effects of plant secondary chemistry extend beyond the trophic scale of the herbivore-plant interaction.

Polymorphisme biochimique chez quelques halophytes autochtones du Nord Tunisien

Chemical polymorphism of some North Tunisian autochthonous halophytes. The study aims to explore and analyse osmoticums synthesized by four perennial halophytic Chenopodiaceae : Salicornia arabica, Atriplex portulacoides, Atriplex halimus and Suaeda fruticosa from Menzel Jemil, Soliman and Gammarth regions which belong to sub-humid and semi-arid bioclimatic zones. A sampling of aerial vegetative organs of these four halophytes has been made. Analyses focused on reducing sugars, starch, total proteins, soluble proteins and total lipids. Atriplex portulacoides harvested from Menzel Jemil station accumulates large amounts of starch, indicating a high photosynthetic activity. This could suggest that this species avoids drought and high salinity by an acceleration of its growth cycle and reproductive systems. Suaeda fruticosa is characterized by the highest levels in soluble sugars. This would mean that it is capable of synthesizing carbohydrate osmoticums for its osmotic adjustment. Atriplex sp. and Suaeda fruticosa have the highest levels of soluble protein indicating the possible intervention of amino acids in the regulation of intracellular osmotic pressure. This behavior was essentially observed at Soliman sampling site characterized by an upper semi-arid bioclimate and saline soils.

Chemical variation in essential oil of Cryptomeria fortunei from various areas of China

Essential oils were extracted by hydrodistillation from the leaves of Cryptomeria fortunei from the principal habitats in China. The essential oil yields of samples from various locations ranged from 0.61 to 1.66% (w/w). GC–MS analysis revealed eighty-seven compounds, constituting 85.89–94.75% of the total essential oils. The main constituents were kaurene (0–44.69%), phyllocladene (0.07–32.98%), kaur-16-ene (0–32.28%), elemol (5.28–18.92%), α-cadinol (0–11.39%), α-eudesmol (0–11.21%), α-pinene (2.32–9.15%). The samples were separated into 3 chemotypes by hierarchical cluster analysis, according to the composition of the corresponding essential oils. Chemical composition of essential oils was significantly related to nine geographic distributions among populations. Our results revealed chemical polymorphism in the essential oils of the C. fortunei leaf in China. The chemical variability could be attributed to genetic and environmental factors. The chemical diversity of the oils offers opportunity to choose C. fortunei leaves and essential oils with preferential compound for green plant protection, pharmaceutical, perfume and food industries.

Essential oil composition of Stachys anisochila

Continuing our research on the composition and chemical polymorphism of the essential oil of the genus Stachys L., species from Serbia, we now report the results on the volatile oil of S. anisochila. The results of the essential oil analysis of S. anisochila are presented in Table 1. GC and GC-MS analysis showed 76 compounds. The main compounds were: -pinene (7.6%), -pinene (5.28%), -copaene (6.25%), and -caryophyllene (4.48%). S. anisochila essential oil contains monoterpenes (34.02%), sesquiterpenes (23.8%), and diterpenes (7.5%). This species, together with S. menthifolia and S. plumosa, belongs to subgenus Stachys, sectio Swainsonniana subsectio Decumbentes [25]. Their essentail oil composition showed that there are remarkable differences in the major constituents. The essential oil of S. plumosa is characterized by high contents of monoterpenes (70%), comprising both - and -pinenes as S. anisochila. On the other hand, the essential oil of S. menthifolia has a very high content of diterpenes (38%). The main components of S. menthifolia were abietatriene (12.99%), kaurene (12.35%), valeranone (5%), and -cadinol (4.2%). The main components of S. plumosa were -pinene (35.84%), -pinene (31.74%), -bourbonene (8%), limonene (3.62%), and abietatriene (3.47%). In our previous work, the essential oil compositions of ten Stachys species from Serbia were analyzed. The sesquiterpenes dominated in all the investigated samples of essential oils of Stachys species. Monoterpenes were present as well, but in variable amounts. The essential oils of species belonging to the subgenus Betonica (S. officinalis and S. scardica) contain a large proportion of sequiterpenes (70–80%), but the content of monoterpenes is exceptionally low, whereas diterpene compounds are completely lacking. These results may be useful in chemotaxonomy, but it is necessary to analyze more species of these genera and more populations of each species from different localities, including analyses of other secondary metabolites (e.g., flavonoids). The essential oils of Stachys species are a perspective source of interesting natural compounds. Investigation of the biological activity of essential oils of Stachys species showed antibacterial, antifungal, and antioxidative activity, which can be related to the essential oil composition. Plant Material and Isolation Procedure. The aerial parts of S. anisochila were collected at the flowering stage in

Distribution and chemical polymorphism of the essential oils of Achillea cartilaginea growing wild in Lithuania

The essential oils from 14 Achillea cartilaginea samples (leaves and flowers) collected from natural habitats in Lithuania were analysed by GC-MS. In total, 97 compounds were identified, 69 of which have not been reported previously in this species. In general, the essential oils of A. cartilaginea were rich in oxygenated monoterpenes. Remarkable chemical polymorphism was observed within the population of A. cartilaginea in Lithuania. It was observed that 1,8-cineole, camphor, cis-chrysanthenol, β-thujone, sabinol, chrysanthenone, terpinen-4-ol, bornyl acetate and β-sesquiphellandrene were the major constituents in the oils of the analysed plants. Hierarchical cluster analysis, which was based on the 19 major components exceeding 5% in the total oil, indicates the presence of several main chemical groups in the analysed plant populations.

Chemical Polymorphism of Essential Oils from Populations of Laurus nobilis Grown on Tunisia, Algeria and France

The compositions of the essential oils isolated from the aerial parts of tree Mediterranean populations of Laurus nobilis L. collected during the flowering phase on Tunisia, Algeria and France, were studied by GC and GC-MS. The analysis has allowed identifying 54 components. The main components were 1,8-cineole, alpha-terpinyl acetate (10-18.6%), methyl eugenol (10-22.1%), sabinene (1.2-8%), eugenol (1.2-11.7%) alpha-pinene (tr-4.5%) and beta-pinene (0.4-4.2%). The monoterpene fraction was dominant in all the oils analysed and consisted mainly of oxygenated monoterpenes. The oils from the tree populations studied showed a clear chemical polymorphism. The principal component and the hierarchical cluster analyses separated the Laurus nobilis leaf essential oils into three groups.

Comparison of genetic diversity in Pogostemon cablin from China revealed by RAPD, morphological and chemical analyses

The genetic diversity of 16 patchouli populations by random amplified polymorphic DNA (RAPD), morphology and chemical composition was presented in this paper. Polymorphism of RAPD primers and the percentage of polymorphic bands revealed with RAPD were 79.21 and 78.40%, respectively, which indicated a high level of genetic diversity existed among Pogostemon cablin (Blanco) populations. A dendrogram based on RAPD analysis showed most populations from the same or adjacent regions were classified together. High polymorphism in morphological parameters was found among populations, but did not reflect completely the differences by geographic location. According to the relative contents of nine compounds in P. cablin, the tested samples were divided into two main clusters, pogostone-type and patchouliol-type. A correlation between genetic and chemical polymorphism (r2 = 0.816) was higher than that between genetic and morphological variations (r2 = 0.629). High morphological and chemical variability as well as genotypic polymorphism provided ecological advantages that might explain the extensive distribution of P. cablin. Key words: Pogostemon cablin (Blanco) Benth, genetic diversity, random amplified polymorphic DNA (RAPD), morphology, essential oil.

Fruit color, chemical and genetic diversity and structure of Myrtus communis L. var. italica Mill. morph populations

Abstract Myrtus communis presents two morphologies based on fruit color. Both morphs are present in some region of Tunisia, with the white morph being rare. In the present study, essential oil composition and AFLP markers were used to assess the chemical and genetic diversity and structure of four myrtle populations from each morph. A chemical polymorphism attributed to the morphs and the origin of populations was detected. The genetic diversity within population varied according to morphs. Variation in the dark blue morph populations was higher than that observed for the white ones. For each morph, a high genetic differentiation among populations was observed. Population structure based on AFLP markers is in accordance with that based on oil composition. Furthermore, a significant correlation between chemical and genetic data was observed. The conservation strategies of populations should be made for each morph according to its level of diversity and bioclimate.

Chemotypical variation in Vanilla planifolia Jack. (Orchidaceae) from the Puebla-Veracruz Totonacapan region

One of the threats in the diversity loss of the primary gene pool of Vanilla planifolia is the lack of information on existing level of polymorphism in cultivated germplasm, and the different expressions of this polymorphism. For this reason, it is proposed to study the chemical polymorphism of the four phytochemicals that define the vanilla aroma quality in fruits (vanillin, vanillic acid, p-hydroxybenzaldehyde, p-hydroxybenzoic acid) by HPLC analysis (High Performance Liquid Chromatography) of 25 collections of unknown genotype, grown in the region Totonacapan Puebla-Veracruz, Mexico. The results identified a selection process, domestication in fruit aroma of vanilla, during which increased the participation of vanillin and reduced the presence of three minor compounds (vanillic acid, p-hydroxybenzaldehyde and p-hydroxybenzoic acid) in the global aroma. We distinguished a total of six chemotypes of V. planifolia in the Totonacapan region, some chemotypes with wild aromatic characteristics (low participation of vanillin) related to the material less cultivated in the region and domesticated chemotypes with high participation of vanillin, for the most cultivated material. The results show that the diversification of the chemotypes of V. planifolia is not related to environmental variation. The data indicate that in the possible center of origin of vanilla, there is phytochemical polymorphism, which indirectly suggests the existence of genetic polymorphism, essential for the design of a breeding program for optimizing the use and conservation of diversity of the primary gene pool of Vanilla planifolia.

Both Gas Chromatography and an Electronic Nose Reflect Chemical Polymorphism of Juniper Shrubs Browsed or Avoided by Sheep

Chemical polymorphism may contribute to variation in browsing damage by mammalian herbivores. Earlier, we demonstrated that essential oil concentration in juniper, Juniperus communis, was negatively associated with herbivore browsing. The aim of the present study was to characterize the volatile chemical composition of browsed and non-browsed J. communis. By using either gas chromatography with flame ionization detection (GC-FID) or an electronic nose device, we could separate sheep-browsed or non-browsed juniper shrubs by their essential oil pattern and complex odor matrix. The main components of the essential oil from J. communis were monoterpenes. We distinguished three chemotypes, dominated either by α-pinene, sabinene, or δ-3-carene. Shrubs belonging to the α-pinene- or sabinene-dominated groups were browsed, whereas all individuals with the δ-3-carene chemotype were unused by the local herbivores. The electronic nose also separated the browsed and non-browsed shrubs indicating that their odor matrix could guide sheep browsing. Responses of sheep could integrate the post-ingestive effects of plant secondary metabolites with sensory experience that stems from odor-phytotoxin interactions. Chemotype diversity could increase the survival rate in the present population of J. communis as certain shrubs could benefit from relatively better chemical protection against the herbivores.

Chemotaxonomic study of the Lethariella cladonioides complex (lichenized Ascomycota, Parmeliaceae)

AbstractA chemotaxonomic study was carried out on the Lethariella cladonioides complex, including L. sernanderi and L. cashmeriana of the subgenus Chlorea, based on extensive field surveys and a detailed morphological and chemical analysis. Only one species, L. cladonioides made up of five chemical races, is recognized. Lethariella sernanderi and L. cashmeriana are reduced to synonyms under L. cladonioides. The presence of a remarkable chemical polymorphism within the population of L. cladonioides is demonstrated. New data on the chemistry and the distribution of the species are presented.

Inter-Population Variability of Terpenoid Composition in Leaves of Pistacia lentiscus L. from Algeria: A Chemoecological Approach

Three different altitudes were selected to study the variability of terpenoid composition from leaves of female plants of Pistacia lentiscus L. throughout the elevation gradient. GC-MS analyses showed that terpenoid contents change with altitude. Forty nine compounds were identified with a high interpopulation variability for low- and midaltitude sites that also exhibited the same major components when data were expressed on dry weight basis. However, Two-Way-ANOVA followed by Tukey’s post hoc test showed that monoterpene hydrocarbons increased with elevation, giving values of 21.7, 37.5 and 221.5 µg g−1 dw for low- mid- and highlands, respectively. On the other hand, applying P.C.A. with data expressed in percentage of the chromatogram of the volatile extract led to the identification of three chemotypes associated with altitudinal levels. In highlands (Group I), the major compounds were β-caryophyllene (12%), δ-cadinene (9.3%) and α-pinene (6.3%) while in midlands (Group II), β-caryophyllene (11.5%), δ-cadinene (8.6%) and caryophyllene oxide (6.8%) were the main components. In lowlands (Group III) δ-cadinene (10.9%), cubebol (10.5%) and β-bisabolene (7.7%) were chiefly present. Hence, the involvement of genetic factors, temperature and drought in the chemical polymorphism of P. lentiscus associated with elevation is discussed in this report.

Study of the essential oil of three species of thyme in their limit of distribution in Spain

We analyzed the essential oils of three cultivated thymes whose provenance was populations at the limit of their distribution in Spain. In the flowering stage, the Peninsular endemic Th. villosus subsp. lusitanicus has linalool (49.6%) as principal component, an evidence for the chemical polymorphism described for this taxon. For Th. caespititius, high values are obtained for α-terpineol (41.1%), confirming the chemical homogeneity in the Iberian Peninsula. The studied population of the Eurosiberian species Th. pulegioides, which is at its southern limit in the Iberian Peninsula, has as principal components γ-terpinene (31.7%), thymol (25.6%), p-cymene (16.4%), and carvacrol (3.5%), values which do not compare readily with the literature data. The chemical analyses performed for the fruiting stage are new. The only major differences with the flowering stage are found for Th. pulegioides.

Mathematical Methods to Analysis of Topology, Functional Variability and Evolution of Metabolic Systems Based on Different Decomposition Concepts

Complexity of metabolic systems can be undertaken at different scales (metabolites, metabolic pathways, metabolic network map, biological population) and under different aspects (structural, functional, evolutive). To analyse such a complexity, metabolic systems need to be decomposed into different components according to different concepts. Four concepts are presented here consisting in considering metabolic systems as sets of metabolites, chemical reactions, metabolic pathways or successive processes. From a metabolomic dataset, such decompositions are performed using different mathematical methods including correlation, stiochiometric, ordination, classification, combinatorial and kinetic analyses. Correlation analysis detects and quantifies affinities/oppositions between metabolites. Stoichiometric analysis aims to identify the organisation of a metabolic network into different metabolic pathways on the hand, and to quantify/optimize the metabolic flux distribution through the different chemical reactions of the system. Ordination and classification analyses help to identify different metabolic trends and their associated metabolites in order to highlight chemical polymorphism representing different variability poles of the metabolic system. Then, metabolic processes/correlations responsible for such a polymorphism can be extracted in silico by combining metabolic profiles representative of different metabolic trends according to a weighting bootstrap approach. Finally evolution of metabolic processes in time can be analysed by different kinetic/dynamic modelling approaches.

MOLECULAR AND VOLATILES CHARACTERIZATION OF PORTUGUESE THYMUS CAESPITITIUS CHEMOTYPES

21 individual aerial parts samples of Thymus caespititius were collected on Terceira, Sao Jorge, Flores and Graciosa (Azores) and on the mainland north of Portugal. The molecular approach was performed using 10 ISSR primers generating a total of 176 polymorphic bands. On the basis of the ISSR patterns, the individuals were grouped into 4 clusters with low correlation (S DICE =0.18) due the high genetic polymorphism detected (98.9%). Isolated by distillation-extraction, the volatiles were analyzed by GC and GC-MS. The volatile cluster analysis allowed samples separation on thymol, carvacrol, α-terpineol and sabinene chemotypes. No straight correlation between molecular and chemical assessments could be found. Other tools, such as terpene synthases studies, are currently under way to try to improve the understanding on this species chemical polymorphism.

Comparative Analysis of Essential Oil Components and Antioxidant Activity of Extracts of Nelumbo nucifera from Various Areas of China

This study was designed to examine the composition of extracts and essential oil components from Nelumbo nucifera leaves from the principal habitats in China. The amounts of phenolics, flavonoids, and proanthocyanidins in the lotus leaf extracts varied widely, ranging from 354 to 487 mg/g gallic acid equivalents, from 172 to 236 mg/g rutin equivalents, and from 124 to 179 mg/g catechin equivalents, respectively. All of the extracts had strong antioxidant activity in comparison to the standard compounds butylated hydroxytoluene and vitamin C. Wild lotus samples from Baiyangdian Lake and Weishan Lake exhibited a stronger free radical scavenging effect and greater reducing power than the cultural samples, but no such differences were observed in the inhibition of lipid oxidation. Chemical variation in the essential oils from the various samples was analyzed by GC-MS. The main constituents were l-(+)-ascorbic acid 2,6-dihexadecanoate (0-33.5%), trans-phytol (5.1-24.1%), hexahydrofarnesyl acetone (5.6-15.3%), pentadecyl acrylate (2.2-12.4%), geranyl acetone (1.9-8.0%), and beta-ionone (0-8.0%). The rhizome lotus and seed lotus samples were clustered into separate groups by hierarchical cluster analysis according to the composition of the corresponding essential oils. No significant relationship was found between essential oil composition and geographical distribution of the 11 populations. However, the results indicated that region of origin and growing conditions could significantly affect both the bioactivities of the lotus leaf and the content of bioactive compounds in the leaves. Thus, the existence of chemical polymorphism in the N. nucifera leaf in China was demonstrated.