Volatile Secondary Metabolites Research Articles

Taxonomic implications of volatile secondary metabolites emitted from birch (Betula L.) buds

The volatile secondary metabolites emitted from the buds of 22 different species and two varieties of birch were analyzed using headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME/GC-MS) methods. The volatile compositions of 21 birch buds are reported for the first time, to our knowledge. Both the mass spectral data and the calculated retention indices were used to identify the compounds. 273 different components were found and the structures of 200 compounds were precisely identified. An additional 46 compounds were classified according to their group. The terpenes were the biggest group of volatile compounds secreted by birch buds, including 13 monoterpenes, 10 C13 norterpenes, 12 norsesquiterpenes and 108 sesquiterpenes. Among the volatiles of the birch buds, 79 aliphatic compounds, 13 aromatics and six furan derivatives were also detected. Based on our chemical analyses, three different groups of birches were separated. Specific features of the first group included the presence of C13 norterpenes and norsesquiterpenes. Meanwhile, buds of the second group of birches were relatively abundant in sesquiterpenes while they did not emit C13 norterpenes or norsesquiterpenes. Buds from the third group of birches were rich in methyl and ethyl salicylates. Some characteristic features were also found for the eight other birch species that were not classified into either of the three groups. The study of the volatile secondary metabolites emitted by birch buds provided information useful for Betula genus chemotaxonomy.

Selected essential oils and their mechanisms for therapeutic use against public health disorders. An overview.

Today, the numbers of people suffering from lifestyle diseases like diabetes, obesity, allergies and depression increases mainly in industrialised states. That does not only lower patients' quality of life but also severely stresses the health care systems of these countries. Essential oils (EO) have been in use as therapeutic remedies for centuries against various complaints, but still their effectiveness is being underestimated. In the last decades, a great number of controlled studies have supported efficacy of these volatile secondary plant metabolites for various therapeutic indications. Besides others, EO has antidepressant, anti-obesity, antidiabetic, antifirogenic and antiallergic effects. In this review the pharmacological mechanisms for selected EO are summarised and discussed with the main attention on their impact against public health disorders. Additionally, toxicity of these oils as well as possible drug interactions is presented.

Achillea spp.: A comprehensive review on its ethnobotany, phytochemistry, phytopharmacology and industrial applications

The genus Achillea genus houses more than 100 species, a number of them are popularly used in traditional medicine for spasmodic gastrointestinal, gynecological and hepatobiliary disorders, hemorrhages, pneumonia, rheumatic pain, inflammation, wounds healing etc. Members of the genus contain a wide variety of volatile and non-volatile secondary metabolites, including terpenes, polyphenols, flavonoids and others. Multiple studies have assessed the biological effects and other aspects of Achillea spp. In a number of preclinical studies, Achillea plants and their essential oils have demonstrated promising antibacterial properties against a number of human and plant pathogens. Besides, the plants have displayed strong antioxidative and potent anti-proliferative and anticancer properties in various cellular and animal models. Achillea plants have widely been used as food preservative in food industry. Clinical studies have indicated its potential against multiple sclerosis (MS), irritable bowel syndrome (IBS), ulcerative colitis, episiotomy wound, primary dysmenorrhea, oral mucositis etc. The present work focuses to provide a brief overview on folk knowledge, phytochemistry, biological activity and applications of Achillea plants. There is a close relationship between the traditional ethnobotanical usage and pharmacological and clinical data from different Achillea spp. The application of Achillea plants and their extracts seems to be a promising alternative for antimicrobial and antioxidant purposes in food, pharmaceutical and cosmetic industries.

Antagonistic activity of volatile metabolites from Trichoderma asperellum

Trichoderma spp. is a kind of filamentous fungi with important biocontrol value. Twelve strains of Trichoderma spp. were isolated from the soils of different types of crops in Shaoxing, Zhejiang and Foshan, Guangdong. The antagonistic resistance to Fusarium oxysporum was compared by plate confrontation test. The further analysis of volatile secondary metabolites for two strains were carried out using HS-SPME-GC-MS analysis. The results showed that T. asperellum ZJSX5003 and GDFS1009 had fast growth ability, and the inhibition effects on F. oxysporum were 73% and 74% respectively. Six identical volatile metabolites were detected as follows 2-Methyl-1-propanol, 3-Methyl-1-butanol, 3-Methyl-3-buten-1-ol, Acetyl methyl carbinol, Butane-2,3-diol and 6-n-pentyl-2H-pyran-2-one (6-PAP). Among them, 6-PAP was validated to have a higher inhibitory effect on F. oxysporum in vitro. This study will provide basis for the development of biocontrol agents with metabolites of Trichoderma, such as 6-PAP.

Diversity and Distribution of Volatile Secondary Metabolites Throughout Bacillus subtilis Isolates.

Bacillus subtilis releases a broad range of volatile secondary metabolites, which are considered as long- and short distance infochemical signals mediating inter- and intra-specific processes. In addition, they often show antimicrobial or antifungal activities. This review attempts to summarize yet known volatile secondary metabolites produced and emitted by Bacillus subtilis isolates focusing on the structural diversity and distribution patterns. Using in vitro volatile-collection systems, 26 strains of B. subtilis isolated from different habitats were found to produce in total 231 volatile secondary metabolites. These volatile secondary metabolites comprised mainly hydrocarbons, ketones, alcohols, aldehydes, ester, acids, aromatics, sulfur- and nitrogen-containing compounds. Reviewed data revealed to a great extent isolate-specific emission patterns. The production and release of several volatile bioactive compounds was retained in isolates of the species B. subtilis, while volatiles without a described function seemed to be isolate-specifically produced. Detailed analysis, however, also indicated that the original data were strongly influenced by insufficient descriptions of the bacterial isolates, heterogeneous and poorly documented culture conditions as well as sampling techniques and inadequate compound identification. In order to get deeper insight into the nature, diversity, and ecological function of volatile secondary metabolites produced by B. subtilis, it will be necessary to follow well-documented workflows and fulfill state-of-the-art standards to unambiguously identify the volatile metabolites. Future research should consider the dynamic of a bacterial culture leading to differences in cell morphology and cell development. Single cell investigations could help to attribute certain volatile metabolites to defined cell forms and developmental stages.

Detection and Identification of Microbial Volatile Organic Compounds of the Green Mold Disease

Button mushrooms are one of the most commonly cultivated mushroom species facing different risks e.g.: viral, bacterial and fungal diseases. One of the most common problems is caused by Trichoderma aggressivum, or ‘green mould' disease. The presence or absence of mushroom disease-related moulds can sufficiently be detected from the air by headspace solid-phase microextraction coupled gas chromatography-mass spectrometry (HS SPME GC-MS) via their emitted microbial volatile organic compounds (MVOCs). In the present study, HS SPME GC-MS was used to explore the volatile secondary metabolites released by T. aggressivum f. europaeum on different nutrient-rich and -poor media. The MVOC pattern of green mould was determined, then media-dependent and independent biomarkers were also identified during metabolomic experiments. The presented results provide the basics of a green mould identification system which helps producers reducing yield loss, new directions for researchers in mapping the metabolomic pathways of T. aggressivum and new tools for policy makers in mushroom quality control.

Pharmacological characterisation of Seseli gracile Waldst. & Kit (Apiaceae) essential oil

Background/Aim. Phytochemical and pharmacological investigations of essential oils isolated from plant species of the genus Seseli have been intensified recently. These plant species have long-term use in nutrition and traditional medicine in the treatment of various disorders. Volatile secondary metabolites of Seseli gracile Waldst. & Kit (Apiaceae) have not been pharmacologically examined so far. The aim of the conducted research was to assess the antiradical, antimicrobial and spasmolytic activities of S. gracile essential oil isolated from the aerial parts of the plant. Methods. The antiradical activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test, antimicrobial activity using broth microdilution method with standard strains of Gram (+), Gram (-) bacteria and yeast, while spasmolytic activity was evaluated on isolated rat ileum, pre-contracted with a high concentration of potassium. Results. The results showed moderate antiradical (SC50 = 78.60 ?g/mL) and good spasmolytic activity (IC50 = 271.4 nL/mL) of S. gracile essential oil. In the range of tested concentrations, minimal inhibitory concentration (MIC) was determined only for the strain of Escherichia coli (500 ?g/mL). Conclusion. Results obtained in this study justify the need for further studies to elucidate exact molecular mechanism underlay this spasmolytic effect of S. gracile herb essential oil.

Volatile Metabolites in Liverworts of Ecuador.

Volatile metabolites from Frullania brasiliensis Raddi, Herbertus juniperoideus (Sw.) Grolle, Leptoscyphus hexagonus (Nees) Grolle, and Syzygiella anomala (Lindenb. & Gottsche) Steph collected in the south of Ecuador were investigated. Volatile secondary metabolites were extracted by hydrodistillation and analyzed by gas chromatography/flame ionization detector (GC/FID) and Gas chromatography/Mass spectrometry (GC/MS). Sixty-seven volatile compounds were identified in the four species, which represent between 80.12–90.17% of the total chemical composition. The major components were τ-muurolol (32.14%) and Germacrene-D (11.98%) in the essential oil of F. brasiliensis, bicyclogermacrene (18.23%), and Caryophyllene oxide (15.29%) in the oil of H. juniperoideus, Cabreuva oxide D (33.77%) and Elemol (18.55%) in the oil of Leptoscyphus hexagonus, and Silphiperfola-5,7(14)-diene (25.22%) and Caryophyllene oxide (8.98%) in the oil of Syzygiella anomala. This is the first report on volatile compounds for the species Herbertus juniperoideus, Leptoscyphus hexagonus, and Syzygiella anomala.

Elucidation of the life cycle of the endophytic genus Muscodor and its transfer to Induratia in Induratiaceae fam. nov., based on a polyphasic taxonomic approach

Molecular phylogenetic studies of cultures derived from some specimens of plant-inhabiting Sordariomycetes using ITS, LSU, rpb2 and tub2 DNA sequence data revealed close affinities to strains of Muscodor. The taxonomy of this biotechnologically important genus, which exclusively consists of endophytes with sterile mycelia that produce antibiotic volatile secondary metabolites, was based on a rather tentative taxonomic concept. Even though it was accommodated in Xylariaceae, its phylogenetic position had so far remained obscure. Our phylogeny shows that Muscodor species have affinities to the xylarialean genera Emarcea and Induratia, which is corroborated by the fact that their sexual states produce characteristic apiospores. These data allow for the integration of Muscodor in Induratia, i.e. the genus that was historically described first. The multi-locus phylogenetic tree clearly revealed that a clade comprising Emarcea and Induratia forms a monophylum separate from representatives of Xylariaceae, for which we propose the new family Induratiaceae. Divergence time estimations revealed that Induratiaceae has been diverged from the Xylariaceae + Clypeosphaeriaceae clade at 93 (69–119) million years ago (Mya) with the crown age of 61 (39–85) Mya during the Cretaceous period. The ascospore-derived cultures were studied for the production of volatile metabolites, using both, dual cultures for assessment of antimicrobial effects and extensive analyses using gas chromatography coupled with mass spectrometry (GC–MS). The antimicrobial effects observed were significant, but not as strong as in the case of the previous reports on Muscodor species. The GC–MS results give rise to some doubt on the validity of the previous identification of certain volatiles. Many peaks in the GC–MS chromatograms could not be safely identified by database searches and may represent new natural products. The isolation of these compounds by preparative chromatography and their subsequent characterisation by nuclear magnetic resonance (NMR) spectroscopy or total synthesis will allow for a more concise identification of these volatiles, and they should also be checked for their individual contribution to the observed antibiotic effects. This will be an important prerequisite for the development of biocontrol strains.

The role of volatile plant secondary metabolites as pre‐ingestive cues and potential toxins dictating diet selection by African elephants

Understanding the factors driving diet selection represents one of the main thrusts of contemporary foraging ecology. Many studies have focussed on nutritional factors and anti‐nutritional factors (such as tannins) that may describe diet selection of generalist mammalian herbivores, but these often do not explain the observed feeding patterns. Alternatively, generalist herbivores may be influenced by the presence, diversity and/or concentration of toxins. Plant volatiles have been understudied, yet may play an important role in this context. We aimed to determine whether diet selection by African elephants is better correlated with the presence and concentration of toxic plant secondary metabolites (PSMs) than with nutritional or anti‐nutritional factors. We also aimed to identify the specific aspects of the plant‐odour profiles that were correlated with dietary selection, which could be used as a pre‐ingestive cue for food selection. We found that elephant diet selection was not well described by crude protein, in vitro digestibility, tannin concentration and total polyphenol concentration. Instead, the best predictors of elephant diet choice were the number and absolute (total) emissions of potentially toxic volatile PSMs, specifically monoterpenes. Elephants avoided plant species that emitted a wider diversity of volatile PSMs, had higher total emissions, and higher numbers and emissions of monoterpenes. This suggests that PSMs with a high propensity to become toxins, such as monoterpenes, are likely a better indicator for elephant diet avoidance than nutritional or anti‐nutritional factors. Moreover, we demonstrated that elephants can differentiate between food items based on odour alone, specifically volatile monoterpenes, suggesting that these animals are relying on specific volatile cues emitted from plants to direct their foraging choices prior to ingesting selected plants.

Olea europaea L. Root Endophyte Bacillus velezensis OEE1 Counteracts Oomycete and Fungal Harmful Pathogens and Harbours a Large Repertoire of Secreted and Volatile Metabolites and Beneficial Functional Genes.

Oomycete and fungal pathogens, mainly Phytophthora and Fusarium species, are notorious causal agents of huge economic losses and environmental damages. For instance, Phytophthora ramorum, Phytophthora cryptogea, Phytophthora plurivora and Fusarium solani cause significant losses in nurseries and in forest ecosystems. Chemical treatments, while harmful to the environment and human health, have been proved to have little or no impact on these species. Recently, biocontrol bacterial species were used to cope with these pathogens and have shown promising prospects towards sustainable and eco-friendly agricultural practices. Olive trees prone to Phytophthora and Fusarium disease outbreaks are suitable for habitat-adapted symbiotic strategies, to recover oomycetes and fungal pathogen biocontrol agents. Using this strategy, we showed that olive trees-associated microbiome represents a valuable source for microorganisms, promoting plant growth and healthy benefits in addition to being biocontrol agents against oomycete and fungal diseases. Isolation, characterization and screening of root microbiome of olive trees against numerous Phytophthora and other fungal pathogens have led to the identification of the Bacillus velezensis OEE1, with plant growth promotion (PGP) abilities and strong activity against major oomycete and fungal pathogens. Phylogenomic analysis of the strain OEE1 showed that B. velezensis suffers taxonomic imprecision that blurs species delimitation, impacting their biofertilizers’ practical use. Genome mining of several B. velezensis strains available in the GenBank have highlighted a wide array of plant growth promoting rhizobacteria (PGPR) features, metals and antibiotics resistance and the degradation ability of phytotoxic aromatic compounds. Strain OEE1 harbours a large repertoire of secreted and volatile secondary metabolites. Rarefaction analysis of secondary metabolites richness in the B. velezenis genomes, unambiguously documented new secondary metabolites from ongoing genome sequencing efforts that warrants more efforts in order to assess the huge diversity in the species. Comparative genomics indicated that B. velezensis harbours a core genome endowed with PGP features and accessory genome encoding diverse secondary metabolites. Gas Chromatography-Mass Spectrometry (GC-MS) analysis of OEE1 Volatile Organic Compounds (VOCs) and Liquid Chromatography High Resolution Mass Spectrometry (LC-HRMS) analysis of secondary metabolites identified numerous molecules with PGP abilities that are known to interfere with pathogen development. Moreover, B. velezensis OEE1 proved effective in protecting olive trees against F. solani in greenhouse experiments and are able to inhabit olive tree roots. Our strategy provides an effective means for isolation of biocontrol agents against recalcitrant pathogens. Their genomic analysis provides necessary clues towards their efficient implementation as biofertilizers.

Characterization of Volatile Secondary Metabolites from Aerial Part of Mucuna sloanei

Characterization of Volatile Secondary Metabolites from Aerial Part of Mucuna sloanei

Chemical composition and biological activity of Mentha citrata Ehrh., essential oils growing in southern Algeria.

Three techniques, hydro distillation, steam distillation and microwave-assisted distillation, was used in this work to extract volatile secondary metabolites essential oils (EOs), from the aerial part of Mentha citrata Ehrh., plant (steams, leaves and flowers). The plant material was collected from a location called El-kobna in El-Oued province, southern Algeria during June 2018. The extracted Mentha citrata EOs, were analyzed using both gas chromatography coupled with flame ionization detector and gas chromatography attached with mass spectrometry detector techniques. The antioxidant activity of these EOs were evaluated in vitro using DPPH (2,2-diphenyl-1-picrylhydrazyl) free radicals scavenging activity and cytotoxic test. The results of the EOs analysis showed large variability of the chemical compositions for all techniques. Moreover, a promising cytotoxic activity on colon cancer cells was found.

Arctium Species Secondary Metabolites Chemodiversity and Bioactivities.

Arctium species are known for a variety of pharmacological effects due to their diverse volatile and non-volatile secondary metabolites. Representatives of Arctium species contain non-volatile compounds including lignans, fatty acids, acetylenic compounds, phytosterols, polysaccharides, caffeoylquinic acid derivatives, flavonoids, terpenes/terpenoids and volatile compounds such as hydrocarbons, aldehydes, methoxypyrazines, carboxylic and fatty acids, monoterpenes and sesquiterpenes. Arctium species also possess bioactive properties such as anti-cancer, anti-diabetic, anti-oxidant, hepatoprotective, gastroprotective, antibacterial, antiviral, antimicrobial, anti-allergic, and anti-inflammatory effects. This review aims to provide a complete overview of the chemistry and biological activities of the secondary metabolites found in therapeutically used Arctium species. Summary of pharmacopeias and monographs contents indicating the relevant phytochemicals and therapeutic effects are also discussed, along with possible safety considerations.

New Chemovariety of Lippia alba From Colombia: Compositional Analysis of the Volatile Secondary Metabolites and Some in vitro Biological Activities of the Essential Oil From Plant Leaves

Lippia alba is a plant widely studied due to both chemical diversity and bioactivities related to its ethnobotanical uses. In this work, the composition of the volatile secondary metabolites (volatile fractions/essential oil, EO) of the flower/leaves of L. alba (from northern region of Colombia) was determined by solid phase micro-extraction/distillation-solvent extraction/microwave-hydrodistillation/gas chromatography-mass spectrometry (MWHD/GC-MS), along with some in vitro biological properties (cytotoxicity and acetylcholinesterase enzyme [AChe] inhibition) from leaf EO. Outstanding results were found: (i) cis-piperitone oxide (~13%-46%), germacrene D (~11%-30%), and limonene (~10%-22%) characterized the volatile secondary metabolites from different parts of the plant; (ii) leaf EO showed a moderate hemolytic activity (HC50: 580 ± 1 µg/mL), a significant cytotoxicity on lymphocytes (LC50: 127 ± 3 µg/mL), a high cytotoxicity on HEp2 cell line (LC50: 38 ± 2 µg/mL), and a moderate inhibitory effect on AChE (IC50: 28 ± 2 µg/mL). Based on these results, a new chemovar of L. alba is reported (represented by cis-piperitone oxide) along with its promising cytotoxic and AChE inhibiting properties.

More Than “Push” and “Pull”? Plant-Soil Feedbacks of Maize Companion Cropping Increase Chemical Plant Defenses Against Herbivores

Plants can alter nutritional availability, structure, and chemistry of the soil they grow in. These soil changes can positively or negatively influence the growth and metabolism of other plants that co-occur or grow later in the conditioned soil. Plant-soil feedbacks could affect community interactions and dynamics but also be applied in sustainable agriculture to promote plant growth and resistance to pests. In this study, we use a maize companion cropping system, commonly known as “push-pull”, as a model to investigate soil-mediated effects of functional biodiversity, on maize plant growth and resistance against insect herbivores. We grew maize in soils collected from push-pull (polyculture) and non-push-pull (monoculture) fields. We evaluated maize performance by measuring plant growth, as well as resistance traits (herbivore oviposition and larval feeding, production of defense-related volatile and non-volatile secondary defense metabolites). Maize plants grown in soil conditioned by push-pull companion cropping had a higher growth rate compared to those grown in soil from non-push-pull monoculture fields. In addition, soil from push-pull fields induced a constitutively higher and qualitatively different emission of volatile organic compounds than soil from non-push-pull fields. Moreover, secondary defense metabolites such as 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), were produced in larger quantities in plants grown in soil from push-pull fields compared to those from monoculture fields. These soil-mediated alterations in plant secondary metabolism were associated with reduced herbivory by larvae of the stemboring pest Chilo partelllus. This study provides novel evidence that plant-soil feedbacks can affect plant metabolism, growth, and resistance to pests. The observed soil-mediated effects on maize plant secondary metabolism can be viewed as emergent properties of plant community composition as well as a potent mechanism of associational resistance. In addition, these soil-conditioning effects provide a novel pest control mechanism of push-pull companion cropping.

Volatile Secondary Metabolites with Potent Antidiabetic Activity from the Roots of Prangos pabularia Lindl.—Computational and Experimental Investigations

(1) Background: Almost 500 million people worldwide are suffering from diabetes. Since ancient times, humans have used medicinal plants for the treatment of diabetes. Medicinal plants continue to serve as natural sources for the discovery of antidiabetic compounds. Prangos pabularia Lindl. is a widely distributed herb with large reserves in Tajikistan. Its roots and fruits have been used in Tajik traditional medicine. To our best knowledge, there are no previously published reports concerning the antidiabetic activity and the chemical composition of the essential oil obtained from roots of P. pabularia. (2) Methods: The volatile secondary metabolites were obtained by hydrodistillation from the underground parts of P. pabularia growing wild in Tajikistan and were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Protein tyrosine phosphatase 1B (PTP-1B) inhibition assay and molecular docking analysis were carried out to evaluate the potential antidiabetic activity of the P. pabularia essential oil. (3) Results: The main constituents of the volatile oil of P. pabularia were 5-pentylcyclohexa-1,3-diene (44.6%), menthone (12.6%), 1-tridecyne (10.9%), and osthole (6.0%). PTP-1B inhibition assay of the essential oil and osthole resulted in significant inhibitory activity with an IC50 value of 0.06 ± 0.01 and 0.93 ± 0.1 μg/mL. Molecular docking analysis suggests volatile compounds such as osthole inhibit PTP-1B, and the results are also in agreement with experimental investigations. (4) Conclusions: Volatile secondary metabolites and the pure isolated compound (osthole) from the roots of P. pabularia exhibited potent antidiabetic activity, twenty-five and nearly two times more than the positive control (3-(3,5-dibromo-4-hydroxybenzoyl)-2-ethylbenzofuran-6-sulfonic acid-(4-(thiazol-2-ylsulfamyl)-phenyl)-amide)) with an IC50 value of 1.46 ± 0.4 μg/mL, respectively.

Active Essential Oils and Their Components in Use against Neglected Diseases and Arboviruses.

The term neglected diseases refers to a group of infections caused by various classes of pathogens, including protozoa, viruses, bacteria, and helminths, most often affecting impoverished populations without adequate sanitation living in close contact with infectious vectors and domestic animals. The fact that these diseases were historically not considered priorities for pharmaceutical companies made the available treatments options obsolete, precarious, outdated, and in some cases nonexistent. The use of plants for medicinal, religious, and cosmetic purposes has a history dating back to the emergence of humanity. One of the principal fractions of chemical substances found in plants are essential oils (EOs). EOs consist of a mixture of volatile and hydrophobic secondary metabolites with marked odors, composed primarily of terpenes and phenylpropanoids. They have great commercial value and were widely used in traditional medicine, by phytotherapy practitioners, and in public health services for the treatment of several conditions, including neglected diseases. In addition to the recognized cytoprotective and antioxidative activities of many of these compounds, larvicidal, insecticidal, and antiparasitic activities have been associated with the induction of oxidative stress in parasites, increasing levels of nitric oxide in the infected host, reducing parasite resistance to reactive oxygen species, and increasing lipid peroxidation, ultimately leading to serious damage to cell membranes. The hydrophobicity of these compounds also allows them to cross the membranes of parasites as well as the blood-brain barrier, collaborating in combat at the second stage of several of these infections. Based on these considerations, the aim of this review was to present an update of the potential of EOs, their fractions, and their chemical constituents, against some neglected diseases, including American and African trypanosomiasis, leishmaniasis, and arboviruses, specially dengue.

Evaluation of volatile bioactive secondary metabolites transfer from medicinal and aromatic plants to herbal teas: Comparison of different methods for the determination of transfer rate and human intake

A correct botanical identification and analytical quality control of volatile key-markers responsible for aroma and biological activities is necessary to monitor volatile compounds transferred from a plant to the related herbal tea and human intake to guarantee their safe use. This is mainly true for markers limited by regulations or by a recommended maximum amount of consumption per day.GC–MS is the elective technique to analyze volatiles, provided that for aqueous samples (herbal teas) an appropriate sample preparation procedure, and/or a water-compatible GC stationary phases are applied. Solid Phase Micro Extraction (SPME) on-line coupled to GC–MS in a fully automatic approach is here applied to sample and quantify key markers in plant material (headspace) and in the corresponding herbal tea (direct immersion). In parallel, a new generation of GC columns coated with ionic liquid based stationary phases compatible with aqueous samples (Watercol™) was applied to test direct injection of aqueous samples (DAI-GC-FID). The latter approach fully bypasses sample preparation thus speeding up quality control. This study deals with the quantitation of menthol, α- and β-thujone, estragole, and anethole contained in several plant species commonly used for herbal teas (i.e. peppermint, sage, wormwood, fennel, aniseed) and regulated by International Organizations. The two methods gave comparable results and are characterized by high repeatability, linearity and accuracy, although, as expected, their sensitivity was different because DAI-GC-FID implies injection of the sample as such without analyte concentration as for DI-SPME-GC–MS. For instance, LOD and LOQ of estragole were 0.03 and 0.1 mg L−1 with DI-SPME-GC–MS and 0.1 and 0.8 mg L−1 with DAI-GC-FID. The two methods are fully complementary and their adoption depends on the amount of marker(s) to be quantified.

The Effect of Trichoderma spp. on the Composition of Volatile Secondary Metabolites and Biometric Parameters of Coriander (Coriandrum sativum L.)

The aim of this work was to investigate the influence of Trichoderma spp. on volatile secondary metabolites and biometric parameters obtained from coriander (Coriandrum sativum L.). The fruits of coriander treated with liquid suspension spores of T. harzianum strain T22 and of T. asperellum strain B35 increased the yield of essential oil (by ∼36%); however, it was unaffected in its composition. Moreover, Trichoderma spp. influenced the yield and increased the number of seeds of coriander by ∼60%. Inoculation seeds with T. asperelleum strain B35 caused about 2-fold increase in the biomass of the aerial parts of coriander. There was also an increased root colonization by the fungus Trichoderma spp., limiting the number of phytopathogenic fungi from genus Fusarium observed.