Chemical Polymorphism Research Articles

Evaluation of the Essential Oil Composition of Five Thymus Species Native to Greece

The genus Thymus encompasses a wide array of taxa, many of which remain underexplored in terms of their phytochemical profile. In this study, we investigated the phytochemical composition of volatile compounds of five Thymus species native to Greece using gas chromatography combined with mass spectrometry. Two samples of T. parnassicus collected from Mts Parnitha and Parnassos were studied. The predominant compounds in the Parnitha sample were α-cadinol (13.53%), E-caryophyllene (11.83%) and selin-11-en-4α-ol (7.29%). The sample from Mt. Parnassos exhibited a high concentration of E-caryophyllene (35.20%) followed by β-bisabolene (10.41%). Additionally, two species, namely T. leucotrichus subsp. leucotrichus and T. atticus, were collected on Mt. Chelmos (Peloponnese). The essential oil of T. leucotrichus was rich in elemol (35.56%), α-eudesmol (11.15%) and β-eudesmol (6.11%). Thymus atticus exhibited a high concentration in linalool (63.04%) and p-cymene (25.63%). In addition, two samples of T. holosericeus collected from Kefalonia Ιsland were both rich in geraniol (89.9% and 87.7%, respectively). We also examined the volatile profile of T. laconicus, a local endemic species of SE Peloponnese (Lakonia area), which remains unexplored. Carvacrol (32.7%) and p-cymene (29.7%) were identified as the dominant compounds. Our study contributes valuable insights into the chemical profile of Thymus spp. and sheds further light on the well-known chemical polymorphism within this genus.

High chemodiversity in the structural and enantiomeric composition of volatiles emitted by Kermes oak populations in Southern France

Investigating the intraspecific variability of volatiles produced by vegetation is of fundamental importance in the understanding of their ecological roles and in correctly assessing their fluxes from vegetation covers. We characterized foliar emissions and CO2/H2O-gas exchanges from 80 seed-grown Kermes oak (Quercus coccifera L.) saplings originating from 4 populations located on a northeast–southwest transect in Southern France. Emissions of a large range of volatiles including chiral isomers were determined under environmentally controlled conditions by online and offline gas chromatography. All saplings emitted principally α-, β-pinene, sabinene, myrcene, eucalyptol, and limonene plus traces of other monoterpenes (MTs), sesquiterpenes, and isoprene. The enantiomers of α- and β-pinene were highly correlated with a predominance of the (+)-forms in the emissions. On average, the total isoprenoid emission rate was 772 ± 398 ng m−2 s−1. The compositional fingerprint varied in a discontinuous manner among individuals unrelated to the emission quantity and little influenced by season and leaf age. Cluster analyses revealed 4 main chemotypes plus 2 subtypes, which could be explained by a combination of 5 putative MTs synthases producing predominantly myrcene, limonene, eucalyptol, (+)-pinenes, and sabinene plus (−)-pinenes, respectively. The frequency of chemotypes, the average fraction of single volatiles and the ratios of pinene enantiomers were significantly different among populations without clear geographic or climatic cline. However, plants of one chemotype, which was most abundant in the population of the driest site, expressed an increased photosynthetic water use efficiency. Overall, the results revealed a marked ubiquitous chemical polymorphism in Kermes oak populations with similarities to that observed in other MT producing oak species, especially with its closely related and sympatric congener Holm oak.

Genetic variants of antioxidant and xenobiotic metabolizing enzymes and their association with prostate cancer: A meta-analysis and functional in silico analysis

The development and progression of prostate cancer (PCa) depends on complex interactions between genetic, environmental and dietary factors that modulate the carcinogenesis process. Interactions between chemical exposures and genetic polymorphisms in genes encoding xenobiotic metabolizing enzymes (XME), antioxidant enzymes and DNA repair enzymes have been reported as the main drivers of cancer. Thus, a better understanding of the causal risk factors for PCa will provide avenues to identify men at increased risk and will contribute to develop effective detection and prevention methods. We performed a meta-analysis on 17,518 cases and 42,507 controls obtained from 42 studies to determine whether seven SNPs and one CNV pertaining to oxidative stress, xenobiotic detoxification and DNA repair enzymes are associated with the risk of PCa (GPX1 (rs1050450), XRCC1 (rs25487), PON1 (rs662), SOD2 (rs4880), CAT (rs1001179), GSTP1 (rs1695) and CNV GSTM1). A significant increased risk of PCa was found for SOD2 (rs4880) ORGG+GA vs. AA 1.08; 95%CI 1.01–1.15, CAT (rs1001179) ORTT vs. TC+CC 1.39; 95%CI 1.17–1.66, PON1 (rs662) ORCT vs. CC+TT 1.17; 95%CI 1.01–1.35, GSTP1 (rs1695) ORGG vs. GA+AA 1.20; 95%CI 1.05–1.38 and GSTM1 (dual null vs. functional genotype) ORN vs. NN1+NN2 1.34; 95%CI 1.10–1.64. The meta-analysis showed that the CNV GSTM1, and the SNPs GSTP1 (rs1695) and CAT (rs1001179) are strongly associated with a greater risk of PCa and, to a lesser extent, the genetic variants SOD2 (rs4880) and PON1 (rs662). Although several antioxidant enzymes and XME play an important role in the PCa development, other risk factors such as chemical exposures should also be considered to gain insight on PCa risk. The functional in silico analysis showed that the genetic variants studied had no clinical implication regarding malignancy, except for GPX1 (rs1050450) SNP.

Phytochemical diversity within and among Sardinian populations of the endemic Teucrium marum L. (Lamiaceae) is determined by ecological factors

Wild aromatic plants present high intra- and inter-population chemical polymorphisms which are of great ecological and economic interest; however, the factors influencing the phytochemical diversity of aromatic plants remain still unexplored for many species. Here, Teucrium marum L. (Lamiaceae) has been studied, a plant endemic to the western Mediterranean islands, very well-known from the phytochemical point of view but scarcely investigated regarding the ecological factors that influence its phytochemical diversity within and among populations. The specific aims were to: 1) define the chemical composition variability of its essential oils; 2) determine its inter- and intra-population chemical variability; and 3) evaluate whether the elevation, climatic factors and/or the soil substrate determined the phytochemical variability of T. marum along a gradient from coastal to mountain wild populations on the island of Sardinia (Italy). Fresh T. marum aerial parts were randomly collected from ten individuals in six different localities in Sardinia: three coastal and three mountainous. Dried leaf samples were hydrodistillated using a classical Clevenger apparatus to obtain the corresponding essential oils. The composition of each essential oil was chemically characterised and analyzed by gas chromatography coupled to mass spectrometry. Ninety compounds were identified: among the others, the two compounds that mainly characterised the essential oils of the studied populations, dolichodial and (E)-β-caryophyllene, are of great economic interest. Statistical analyses showed significant differences in phytochemical essential oil composition among and within the studied populations, which clustered following a geographical pattern rather than a simple climatic or edaphic grouping. Taken together the results here shown shed light on the environmental and geographical conditions that determine the chemical variability of essential oils in T. marum, highlighting a clear coastal vs mountain clustering, which has an ecological and economic relevance, especially for the potential utilization of dolichodial as an environmental-friendly insecticide.

Prospects for the use of seedling technologies in medicinal plant production

Relevance. The article highlights the issues of growing medicinal and essential oil crops, the seeds shortage and the problem of chemical polymorphism of raw materials. As a possible way to solve this problem is considered a wide introduction of seedling technologies for medicinal and essential oil crops. An analysis was carried out and information was systematized on individual elements of the technological process.Purpose. To analyze and explore the possibilities for the introduction of seedling technologies in medicinal plant growing, taking into account the experience at other branches of plant growing, primarily vegetable growing.Methods. Information obtained from literary sources was systematized by individual elements of the technological process, presented in a logical sequence and analyzed for applicability in medicinal plant production.Results. The result of the literary sources analysis, the personal experience of researchers on the use of the seedling method for medicinal, and essential oil crops growing, they showed the prospect the seedlings technology for generatively and vegetatively propagated plants. Thanks to modern growth regulators and fertilizers, it is possible to intensify the process of seedling production, and specifically to increase the germination and energy of seed germination, rooting of cuttings, shorten the period from sowing (planting cuttings) to planting in the ground and get cassette seedlings with a well-developed root system. The mechanization of the sowing and planting processes can significantly reduce the costs of these operations, a longer interval for planting allows you to prepare the field with the highest quality and successfully fight weeds by mechanical means. The technique used for these operations in commercial vegetable growing is suitable for medicinal and essential oil crops without further modification. Conclusion. The widespread introduction of the seedling method can be the best solution to the problem of lack of seeds, difficulties of direct sowing in the ground and a long germination phase, care after planting and weed control in the first period, and will also allow obtaining raw materials with a stable biochemical composition.

Volatile Profiling of Magnolia champaca Accessions by Gas Chromatography Mass Spectrometry Coupled with Chemometrics.

Magnolia champaca (L.) Baill. ex Pierre of family Magnoliaceae, is a perennial tree with aromatic, ethnobotanical, and medicinal uses. The M. champaca leaf is reported to have a myriad of therapeutic activities, however, there are limited reports available on the chemical composition of the leaf essential oil of M. champaca. The present study explored the variation in the yield and chemical composition of leaf essential oil isolated from 52 accessions of M. champaca. Through hydrodistillation, essential oil yield was obtained, varied in the range of 0.06 ± 0.003% and 0.31 ± 0.015% (v/w) on a fresh weight basis. GC-MS analysis identified a total of 65 phytoconstituents accounting for 90.23 to 98.90% of the total oil. Sesquiterpene hydrocarbons (52.83 to 65.63%) constituted the major fraction followed by sesquiterpene alcohols (14.71 to 22.45%). The essential oils were found to be rich in β-elemene (6.64 to 38.80%), γ-muurolene (4.63 to 22.50%), and β-caryophyllene (1.10 to 20.74%). Chemometrics analyses such as PCA, PLS-DA, sPLS-DA, and cluster analyses such as hierarchical clustering, i.e., dendrogram and partitional clustering, i.e., K-means classified the essential oils of M. champaca populations into three different chemotypes: chemotype I (β-elemene), chemotype II (γ-muurolene) and chemotype III (β-caryophyllene). The chemical polymorphism analyzed in the studied populations would facilitate the selection of chemotypes with specific compounds. The chemotypes identified in the M. champaca populations could be developed as promising bio-resources for conservation and pharmaceutical application and further improvement of the taxa.

Variations in the Chemical Composition of Essential Oils in Native Populations of Korean Thyme, Thymus quinquecostatus Celak.

The genus Thymus (Lamiaceae) contains numerous medicinally important species. Among them, Thymus quinquecostatus Celak. has been extensively utilized as a traditional medicine and a food flavoring agent in the Korean peninsula, owing to its unique aroma. In particular, T. quinquecostatus has been used for the treatment of gastroenteritis, inflammation, stomach problems, liver disease, arthritis, arteriosclerosis, and menstrual problems. This study aimed to investigate the chemical diversity of essential oils among 103 Korean native populations of T. quinquecostatus. For this purpose, seedlings of T. quinquecostatus populations were purchased from different regions in the Korean Peninsula, and seedlings were grown in the experimental field under the same environmental conditions. The chemical compositions of steam-distilled essential oils were determined using GC-MS. In total, 212 components were identified from 103 populations of T. quinquecostatus. Furthermore, principal component analysis (PCA) was performed in order to understand variations in the essential oil compositions among 103 Korean native populations of T. quinquecostatus. According to the essential oil compositions, 30 components were selected for PCA. Based on the most abundant essential oil components, four chemotypes were identified in T. quinquecostatus populations. PCA and cluster analyses revealed that 103 individuals of T. quinquecostatus could be classified into four clusters, such as thymol, geraniol, geranyl acetate, and linalool. Furthermore, dendrogram construction demonstrated that geraniol and geranyl acetate, as well as linalool and thymol groups, were closely related. This study suggested the significant chemical polymorphism of essential oils in local populations of T. quinquecostatus in Korea. It could be concluded that the intraspecific variations in the essential oil compositions may be associated with genetic diversity among the individuals.

Impact of Edaphic and Climatic Factors on Thymus pulegioides Essential Oil Composition and Potential Prevalence of Chemotypes.

Intraspecific chemical polymorphism is characteristic of essential oil bearing Thymus pulegioides (Lamiaceae). Soil chemical composition and climatic conditions can influence not only quantitative and qualitative composition of essential oils, but also on prevalence of different chemotypes in space. The purpose of study was to determine the impact of edaphic and climatic factors on T. pulegioides essential oil composition and potential chemotypes prevalence. It were investigated 131 habitats of T. pulegioides in all ten climatic sub-districts of Lithuania. Essential oils were isolated by hydrodistillation and analysed by GC-FID and GC-MS. The content of humus was estimated by oxidation method, the content of mobile potassium (K2O) and mobile phosphorus (P2O5)—flame photometry using 0.2 M HCl solution, the soil pH—electrometrically and 15 elements of soil—by energy-dispersive X-ray fluorescence. The meteorological data (temperature, rainfall, photosynthetically active solar radiation and sunshine duration) were obtained from the meteorological bulletins. Results showed that humus in soil positively, manganese and cobalt—negatively influenced on the essential oil accumulation in T. pulegioides. Carvacrol was the most common compound in the essential oil of T. pulegioides; higher amounts of sulphur and mobile phosphorus, lower amounts of sodium in soil, higher rainfall in blooming period are favourable for this compound and for potential prevalence of carvacrol chemotype. Geraniol was frequent in the eastern and the central part of Lithuania, where the temperature in vegetation season is higher, and in soils characterised by higher and lower amounts of sodium and chlorine, respectively. Thymol, linalool and α-terpinyl acetate were rare. Edaphic and climatic conditions can differently influence on essential oil yield and chemical composition of species as well as on potential prevalence of different chemotypes of same species in space.

Importance of chemical polymorphism in modern crop protection.

The development of agrochemical products faces many scientific challenges. After selection of an agrochemical candidate its properties will have to be optimized to guarantee best bioavailability and stability under many different conditions in various formulation types. These challenges are influenced by the solid‐state properties of the active ingredient and this makes the selection of an optimized solid‐state form of modern agrochemicals at early development stages very valuable. The increasing awareness of the solid state of agrochemicals is reflected in the importance of polymorphism patent applications, which may enhance the risk of litigations. This review aims to present strategies for the solid‐form selection process of agrochemical development candidates. It introduces the different techniques for crystallization and analytics and demonstrates the influence of the solid state on different formulation types. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Essential Oil Biodiversity of Achillea ligustica All. Obtained from Mainland and Island Populations.

Background: The genus Achillea is rich in essential oil (EO) with high chemical diversity. In this study, eight EO samples obtained from flowers and leaves of Achillea ligustica All. collected on the Mediterranean mainland and island locations were analyzed to evaluate their possible chemical diversity. Methods: Sixteen samples of EO were analyzed by GC-MS, leading to the identification of 95 compounds in the leaves and 86 compounds in the flowers; a statistical analysis was performed to determine the chemical polymorphism. Results: Monoterpenes, such as β-pinene, borneol, ɑ-terpineol and isobornyl acetate, were more abundant in the continental samples, while the insular samples were richer in 1,8-cineole. Fragranyl acetate and fragranol were detected in remarkable concentrations in sample 8. The fruits of sample 8 were then cultivated under controlled agronomic conditions, providing plants rich in these compounds (sample 9). The geographical variability influenced the EO compositions, with unique observed chemotypes and a high degree of diversity among samples collected in various areas (mainland or island). Statistical analyses did not reveal any pattern between the geographical provenience and the compositions. Conclusion: Samples were distributed based on the plant organ, confirming the already reported high degree of chemical polymorphism of this species. Sample 8 could be used as a source of fragranol and fragranyl acetate, with potential applications in the insecticidal and pheromone industries.

From genotype to phenotype: Genetic redundancy and the maintenance of an adaptive polymorphism in the context of high gene flow.

A central question in evolution is how several adaptive phenotypes are maintained within a species. Theory predicts that the genetic determination of a trait, and in particular the amounts of redundancy in the mapping of genotypes to phenotypes, mediates evolutionary outcomes of phenotypic selection. In Mediterranean wild thyme, numerous discrete chemical phenotypes (chemotypes) occur in close geographic proximity. Chemotypes are defined by the predominant monoterpene produced by individual plants in their essential oil. In this study, we analyze the ecological genetics of six chemotypes nested within two well‐established chemical families (hereafter ecotypes). Ecotypes, and chemotypes within ecotypes, are spatially segregated, and their distributions track local differences in the abiotic environment. By combining population genomic, phenotypic, and environmental data from 700 individuals, we show how the genetics of ecotype determination mediates this evolutionary response. Variation in three terpene‐synthase loci explains variation in ecotype identity, with one single locus accounting for as much as 78% of this variation. Phenotypic selection combined with low segregating genotypic redundancy of ecotypes leaves a clear footprint at the genomic level: alleles associated with ecotype identity track environmental variation despite extensive gene flow. Different chemotypes within each ecotype differentially track environmental variation. Their identity is determined by multiple loci and displays a wider range of genotypic redundancy that dilutes phenotypic selection on their characteristic alleles. Our study thus provides a novel illustration of how genetic redundancy of a phenotype modulates the ability of selection to maintain adaptive differentiation. Identifying the precise genetics of the chemical polymorphism in thyme is the next crucial step for our understanding of the origin and maintenance of a polymorphism that is present in many aromatic plants.

Variation of the Chemical Composition of Essential Oils and Total Phenols Content in Natural Populations of Marrubium vulgare L.

Marrubium vulgare is a valuable source of natural bioactive molecules with high preventive and therapeutic effectiveness. Therefore, this study aimed to study the chemical polymorphism of natural populations of M. vulgare in Tunisia by quantitative chemical markers and the estimation of divergence between populations. Phytochemical analyses of the eight natural populations of Tunisian Marrubium vulgare prospected in different bioclimatic stages, revealed 42 compounds of essential oils representing 96.08% to 100% of the total oil. Hydrocarbon sesquiterpenes were the main fraction of all the populations studied and β-bisabolene was the major compound (from 30.11% to 71.35% of the total oil). The phytochemical investigation of the M. vulgare plant indicated the presence of essential oil with significant percentages of phenolic compounds. A significant quantitative and qualitative variation in the essential oils is detected for both major and minor compounds. The principal components analysis (PCA) performed in the single and combined traits provides a good distinction among populations, not according to their geographical and/or bioclimatic origins. Moreover, the phytochemical analysis of the leaves showed that the Tunisian populations, i.e., the populations of Kasserine, Kef, and Beja, were very rich in phenolic compounds (from 20.8 to 44.65 mg GAE/g DW). Flavonoids compounds were also the main class of total polyphenols present in all the tested populations (from 8.91 to 37.48 mg RE/g DW). The quantitative genetic diversity estimated by the population’s structure, based on PCA analysis, was an adaptation to the changes in the environmental conditions. Overall, our study indicated that natural populations of M. vulgare had different chemotypes of essential oils and they were rich in phenolic compounds, particularly flavonoids, which opens a new prospect for industrial use and differential exploitation of this species.

Inter- and Intrasexual Variation in Cuticular Hydrocarbons in Trichrysis cyanea (Linnaeus, 1758) (Hymenoptera: Chrysididae).

Simple SummaryThe biology of many species of cuckoo wasps (Chrysididae) is largely unknown, except for, if at all, the host species of these brood parasites. Cuticular hydrocarbons (CHCs), which form a waxy layer on the body surface of insects, have been shown to be mimicked by host-specific cuckoo wasp species. We studied the CHC profiles of a rather generalist brood parasitic cuckoo wasp species, Trichrysis cyanea, in detail. We found sex-related differences in CHCs and three different chemotypes among females. Genetic data reject the possibility that these different chemotypes represent different (cryptic) species. The CHC polymorphism could be an adaptation for females to sneak into nesting holes of hosts with the different female chemotypes representing adaptations to a broader host range. However, since information on the CHC profiles of the hosts is missing, it remains unclear whether these different CHC profiles are used for chemical mimicry or are simply age-related, reflecting the females’ reproductive state. Cuckoo wasps (Chrysididae, Hymenoptera) are known for their parasitoid or cleptoparasitic life histories. Indeed, the biology of only a few species has been studied in detail and often only little more is known than the host species. By mimicking their hosts’ cuticular hydrocarbon (CHC) profiles, species that parasitize single (or a few closely related) host species manage to deceive their hosts. However, the variability of the CHC profile in generalist cuckoo-wasp species is still unknown. Here, we used gas chromatography—mass spectrometry (GC-MS) and DNA barcoding to study intraspecific variation in cuticular hydrocarbons of one less host-specific species of cuckoo wasps, Trichrysis cyanea. Cuticular hydrocarbon (CHC) patterns were found to differ between males and females. Additionally, we found chemical polymorphism among females, which formed three distinct chemical subgroups characterized by different alkene patterns. A lack of divergence in the DNA barcoding region suggests that these different chemotypes do not represent cryptic species. Whether this intrasexual CHC-profile variation is an adaptation (mimicry) to different host species, or simply signaling the reproductive status, remains unclear.

Morphological properties and chemical composition of three Calligonum species Growing-wild in Tunisian Desert: A chemotaxonomic study

The essential oils of three wild species of Calligonum (C. azel, C. arich and C. comosum) growing in Tunisian desert were obtained by hydrodistillation and were analyzed in order to discern the differences and similarities between the volatiles chemical compositions of these species. A total of 110 compounds, which accounted for 93.95-99.68 % of the total composition of the oils, have been identified. The main constituents were viridiflorol (9.59 %) in C. azel, palmitic acid (20.06%) in C. arich and 9-Octadecenoic acid (19.76 %) in C. comosum. Morphological similarity study shows two groups: the first one contains C. azel and C. comosum and the second group is formed by C. arich. Based on their chemical composition, two chemotaxonomic groups may be established: C. azel on one hand, C. arich and C. comosum on the other hand. As a consequence, the morphological diversity of these species doesn’t reflect their chemical polymorphism.

Comparative Chemical Profiles of Lavandula Species Essential Oils Grown in Egypt and others from France and Australia: Evidence from Chemometric Analysis

Genus Lavandula belongs to Lamiaceae family containing almost 40 different species, many hybrids, and nearly 400 registered cultivars (Upson and Andrews 2004). Mane folk uses and biological activities of Lavandula species are reported in addition to their uses in the pharmaceutical and other industries benefits. The biological activities of Lavandula leaves are usually correlated to the essential oils (EOs) and volatiles that represented the main constituents of the leaves. Many compounds were identified and characterized in the extracted EOs from Lavandula leaves around the world. Chemical polymorphism is a phenomenon where the same species showed variation in the chemical composition of the bioactive compounds. This phenomenon is well known for the EOs of various plants. Therefore, the present work aimed for chemical profiling of three EOs isolated from the leaves of Lavandula species grown in Egypt (L. angustifolia, Lavandula x intermedia or L. hybrid and L. spica) and other three from French and Australia (L. angustifolia and L. latifolia from Australia and L. stoechas L. from French ). In addition, established the chemical based relationship among the five species using chemometric analysis. The qualitative and quantitative analyses of the main constituents of the EOs were studied. A total of 74 volatile compounds were identified from the aerial parts of L. angustifolia, L. latifolia from Australia and L. stoechas from French and lavandin (Lavandula hybrida), L. angustifolia and L. spica cultivated in Egypt, representing 99.87, 98.94, 98.93, 98.89, 99.89 and 99.28% of the total mass, respectively. The identified compound classes were characterized as mono-, sesqui- oxygenated and non-oxygenated terpenoids. The main constituents in the different species were linalool (39.5%), lianlyl acetate (26.7%), eucalyptol (43.08%), tau-cadinol (28.63%), linalyl acetate (46.41%) and tau-cadinol (19.08%) for AUS Lavander, Fren. lavnder, lavandin, L. angistifolia, L. latifolia, and L. asp, respectively. Major components analysis showed that there is significant variation between species in the quality and quantity of EO composition. All lavandula species/varieties appeared to be richest in oxygenated monoterpenes. These major compounds have been reported as biologically effective compounds with various activities. The characterization of chemotypes in cultivated plants is crucial for agriculture application, chemistry purposes, and pharmacological uses.

Volatile constituents of three Thymus sipyleus Boiss. subspecies from different sites in Turkey.

This study was designed to reveal the chemical diversity of some Thymus sipyleus subspecies growing wild in Turkey and to compare the volatile compound profiles by using micro(hydro)distillation technique. For this purpose, volatile compounds isolated by microdistillation from nine samples (three plant samples collected from different regions in Antalya) of Thymus sipyleus Boiss. subsp. sipyleus var. sipyleus, T. sipyleus Boiss. subsp. sipyleus var. davisianus Ronniger, and T. sipyleus Boiss. subsp. rosulans (Borbas) Jalas were analyzed by GC and GC-MS systems. 1,8-Cineole, p-cymene, α-terpineol and carvacrol were identified as major compounds in T. sipyleus subsp. sipyleus var. sipyleus samples. Geranial, neral, 1,8-cineole and β-caryophyllene, and α-terpineol and geranial were the main compounds in T. sipyleus subsp. sipyleus var. davisianus samples. β-Caryophyllene, intermedeol, 1,8-cineole and α-terpineol, α-pinene were the major compounds in T. sipyleus subsp. rosulans samples. As known, thymol is the main compound in most Thymus species in Turkey, but, according to our study, chemical polymorphism has been found among the T. sipyleus subspecies.

Intraspecific variability in yield and chemical composition of essential oil of the endemic species Hypericum gaitii from different natural habitats of Eastern India

Hypericum gaitii (Hypericaceae) is an endemic and endangered perennial shrub having ethnobotanical and medicinal importance. In the present study, the variation in the yield and chemical composition of essential oil (EO) isolated from aerial parts of plants belonging to seven wild populations of H. gaitii from Eastern India was investigated for the first time. The essential oil yield obtained through hydrodistillation varied in the range of 0.20 and 0.45% (v/w) on fresh weight basis. GC-FID and GC-MS analysis led to the identification of 83 chemical constituents accounting for 79.04-99.7% of the total oil. The essential oils were rich in α-pinene (0.09-58.55%), allo-aromadendrene (0.32-24.54%), δ-cadinene (0.09-22.17%), n-nonane (5.04-16.23%), β-caryophyllene (0.08-14.00%) and α-selinene (0.18-20.64%). Agglomerative hierarchical clustering (AHC) and principal component analysis (PCA) grouped the essential oils of H. gaitii populations into three different chemotypes: chemotype I (α-pinene), chemotype II (allo-aromadendrene) and chemotype III (δ-cadinene). The result demonstrated that geographical origin of populations and environmental factors greatly influence the yield and chemical composition of the essential oil of H. gaitii. The chemical polymorphism detected in the studied populations would facilitate selection of genotypes with specific compounds or desired essential oil properties suitable for specific industrial applications and for conservation.

Evaluation of the Miscibility of Novel Cocoa Butter Equivalents by Raman Mapping and Multivariate Curve Resolution-Alternating Least Squares.

Cocoa butter (CB) is an ingredient traditionally used in the manufacturing of chocolates, but its availability is decreasing due to its scarcity and high cost. For this reason, other vegetable oils, known as cocoa butter equivalents (CBE), are used to replace CB partially or wholly. In the present work, two Peruvian vegetable oils, coconut oil (CNO) and sacha inchi oil (SIO), are proposed as novel CBEs. Confocal Raman microscopy (CRM) was used for the chemical differentiation and polymorphism of these oils with CB based on their Raman spectra. To analyze their miscibility, two types of blends were prepared: CB with CNO, and CB with SIO. Both were prepared at 5 different concentrations (5%, 15%, 25%, 35%, and 45%). Raman mapping was used to obtain the chemical maps of the blends and analyze their miscibility through distribution maps, histograms and relative standard deviation (RSD). These values were obtained with multivariate curve resolution–alternating least squares. The results show that both vegetable oils are miscible with CB at high concentrations: 45% for CNO and 35% for SIO. At low concentrations, their miscibility decreases. This shows that it is possible to consider these vegetable oils as novel CBEs in the manufacturing of chocolates.

Chemical Composition of Hexane-Extracted Plectranthus amboinicus Leaf Essential Oil: Maximizing Contents on Harvested Plant Materials

Plectranthus amboinicus (Lour.) Spreng, also known locally as “Bangun-bangun”, is an aromatic medicinal herb known for its therapeutic and nutritional properties attributed to its terpenoid-rich phytochemicals. Information to assist in initiating appropriate harvesting time to maximize the yield of targeted chemicals in harvested plant tissues remains an issue that is seldom highlighted. This study reports on the essential oil distribution in P. amboinicus leaves, and total phenolic and flavonoid contents, in addition to GC-MS analysis of hexane extracts of the leaf samples collected at various times throughout the day. The influence of environmental factors on γ-terpinene, p-cymene, carvacrol, and thymoquinone are also discussed. Oil Red O staining showed the highest oil deposition at 2 p.m., which was consistent with the phenolic and flavonoid contents of this plant. GC-MS analysis of the leaf extract showed carvacrol (47.00–60.00%), γ-terpinene (8.00–10.00%), caryophyllene (~6.00%), p-cymene (4.90–6.50%), trans-α-bergamotene (4.70–5.00%), and thymoquinone (3.30–5.60%) were the major components of this plant. Interestingly, thymoquinone, a phytochemical associated with Nigella sativa, was also detected in this hexane-extracted sample with maximum accumulation during midday and a decrease at night, which could be due to the lower temperature and dimmer light conditions. The chemical polymorphism in the oil content indicated that environmental factors such as light exposure and temperature should be considered during harvesting to ensure consistent quality of the phytochemicals extracted from the plant materials. This study indicates that oversight in selecting plant materials might compromise the yield of quality phytochemicals extracted from harvested tissues.

Genetic trade-offs underlie divergent life history strategies for local adaptation in white clover.

Local adaptation is common in plants, yet characterization of its underlying genetic basis is rare in herbaceous perennials. Moreover, while many plant species exhibit intraspecific chemical defence polymorphisms, their importance for local adaptation remains poorly understood. We examined the genetic architecture of local adaptation in a perennial, obligately-outcrossing herbaceous legume, white clover (Trifolium repens). This widespread species displays a well-studied chemical defence polymorphism for cyanogenesis (HCN release following tissue damage) and has evolved climate-associated cyanogenesis clines throughout its range. Two biparental F2 mapping populations, derived from three parents collected in environments spanning the U.S. latitudinal species range (Duluth, MN, St. Louis, MO and Gainesville, FL), were grown in triplicate for two years in reciprocal common garden experiments in the parental environments (6,012 total plants). Vegetative growth and reproductive fitness traits displayed trade-offs across reciprocal environments, indicating local adaptation. Genetic mapping of fitness traits revealed a genetic architecture characterized by allelic trade-offs between environments, with 100% and 80% of fitness QTL in the two mapping populations showing significant QTL×E interactions, consistent with antagonistic pleiotropy. Across the genome there were three hotspots of QTL colocalization. Unexpectedly, we found little evidence that the cyanogenesis polymorphism contributes to local adaptation. Instead, divergent life history strategies in reciprocal environments were major fitness determinants: selection favoured early investment in flowering at the cost of multiyear survival in the southernmost site versus delayed flowering and multiyear persistence in the northern environments. Our findings demonstrate that multilocus genetic trade-offs contribute to contrasting life history characteristics that allow for local adaptation in this outcrossing herbaceous perennial.