Showing papers on "Terpene published in 2019"

Terpene Derivatives as a Potential Agent against Antimicrobial Resistance (AMR) Pathogens.

Abstract: The evolution of antimicrobial resistance (AMR) in pathogens has prompted extensive research to find alternative therapeutics. Plants rich with natural secondary metabolites are one of the go-to reservoirs for discovery of potential resources to alleviate this problem. Terpenes and their derivatives comprising of hydrocarbons, are usually found in essential oils (EOs). They have been reported to have potent antimicrobial activity, exhibiting bacteriostatic and bactericidal effects against tested pathogens. This brief review discusses the activity of terpenes and derivatives against pathogenic bacteria, describing the potential of the activity against AMR followed by the possible mechanism exerted by each terpene class. Finally, ongoing research and possible improvisation to the usage of terpenes and terpenoids in therapeutic practice against AMR are discussed.

Therapeutic and Medicinal Uses of Terpenes

Abstract: Terpenes, also known as terpenoids are the largest and most diverse group of naturally occurring compounds. Based on the number of isoprene units they have, they are classified as mono, di, tri, tetra, and sesquiterpenes. They are mostly found in plants and form the major constituent of essential oils from plants. Among the natural products that provide medical benefits for an organism, terpenes play a major and variety of roles. The common plant sources of terpenes are tea, thyme, cannabis, Spanish sage, and citrus fruits (e.g., lemon, orange, mandarin). Terpenes have a wide range of medicinal uses among which antiplasmodial activity is notable as its mechanism of action is similar to the popular antimalarial drug in use—chloroquine. Monoterpenes specifically are widely studied for their antiviral property. With growing incidents of cancer and diabetes in modern world, terpenes also have the potential to serve as anticancer and antidiabetic reagents. Along with these properties, terpenes also allow for flexibility in route of administration and suppression of side effects. Certain terpenes were widely used in natural folk medicine. One such terpene is curcumin which holds anti-inflammatory, antioxidant, anticancer, antiseptic, antiplasmodial, astringent, digestive, diuretic, and many other properties. Curcumin has also become a recent trend in healthy foods and open doors for several medical researches. This chapter summarizes the various terpenes, their sources, medicinal properties, mechanism of action, and the recent studies that are underway for designing terpenes as a lead molecule in the modern medicine.

Terpenes and isoprenoids: a wealth of compounds for global use.

Abstract: Role of terpenes and isoprenoids has been pivotal in the survival and evolution of higher plants in various ecoregions. These products find application in the pharmaceutical, flavor fragrance, and biofuel industries. Fitness of plants in a wide range of environmental conditions entailed (i) evolution of secondary metabolic pathways enabling utilization of photosynthate for the synthesis of a variety of biomolecules, thereby facilitating diverse eco-interactive functions, and (ii) evolution of structural features for the sequestration of such compounds away from the mainstream primary metabolism to prevent autotoxicity. This review summarizes features and applications of terpene and isoprenoid compounds, comprising the largest class of secondary metabolites. Many of these terpene and isoprenoid biomolecules happen to be high-value bioproducts. They are essential components of all living organisms that are chemically highly variant. They are constituents of primary (quinones, chlorophylls, carotenoids, steroids) as well as secondary metabolism compounds with roles in signal transduction, reproduction, communication, climatic acclimation, defense mechanisms and more. They comprise single to several hundreds of repetitive five-carbon units of isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP). In plants, there are two pathways that lead to the synthesis of terpene and isoprenoid precursors, the cytosolic mevalonic acid (MVA) pathway and the plastidic methylerythritol phosphate (MEP) pathway. The diversity of terpenoids can be attributed to differential enzyme and substrate specificities and to secondary modifications acquired by terpene synthases. The biological role of secondary metabolites has been recognized as pivotal in the survival and evolution of higher plants. Terpenes and isoprenoids find application in pharmaceutical, nutraceutical, synthetic chemistry, flavor fragrance, and possibly biofuel industries.

Oleoresin defenses in conifers: chemical diversity, terpene synthases and limitations of oleoresin defense under climate change.

Abstract: Conifers have evolved complex oleoresin terpene defenses against herbivores and pathogens. In co-evolved bark beetles, conifer terpenes also serve chemo-ecological functions as pheromone precursors, chemical barcodes for host identification, or nutrients for insect-associated microbiomes. We highlight the genomic, molecular and biochemical underpinnings of the large chemical space of conifer oleoresin terpenes and volatiles. Conifer terpenes are predominantly the products of the conifer terpene synthase (TPS) gene family. Terpene diversity is increased by cytochromes P450 of the CYP720B class. Many conifer TPS are multiproduct enzymes. Multisubstrate CYP720B enzymes catalyse multistep oxidations. We summarise known terpenoid gene functions in various different conifer species with reference to the annotated terpenoid gene space in a spruce genome. Overall, biosynthesis of terpene diversity in conifers is achieved through a system of biochemical radiation and metabolic grids. Expression of TPS and CYP720B genes can be specific to individual cell types of constitutive or traumatic resin duct systems. Induced terpenoid transcriptomes in resin duct cells lead to dynamic changes of terpene composition and quantity to fend off herbivores and pathogens. While terpenoid defenses have contributed much to the evolutionary success of conifers, under new conditions of climate change, these defences may become inconsequential against range-expanding forest pests.

Biosynthesis and function of terpenoid defense compounds in maize (Zea mays).

Abstract: Maize produces an array of herbivore-induced terpene volatiles that attract parasitoids to infested plants and a suite of pathogen-induced non-volatile terpenoids with antimicrobial activity to defend against pests Plants rely on complex blends of constitutive and dynamically produced specialized metabolites to mediate beneficial ecological interactions and protect against biotic attack One such class of metabolites are terpenoids, a large and structurally diverse class of molecules shown to play significant defensive and developmental roles in numerous plant species Despite this, terpenoids have only recently been recognized as significant contributors to pest resistance in maize (Zea mays), a globally important agricultural crop The current review details recent advances in our understanding of biochemical structures, pathways and functional roles of maize terpenoids Dependent upon the lines examined, maize can harbor more than 30 terpene synthases, underlying the inherent diversity of maize terpene defense systems Part of this defensive arsenal is the inducible production of volatile bouquets that include monoterpenes, homoterpenes and sesquiterpenes, which often function in indirect defense by enabling the attraction of parasitoids and predators More recently discovered are a subset of sesquiterpene and diterpene hydrocarbon olefins modified by cytochrome P450s to produce non-volatile end-products such kauralexins, zealexins, dolabralexins and β-costic acid These non-volatile terpenoid phytoalexins often provide effective defense against both microbial and insect pests via direct antimicrobial and anti-feedant activity The diversity and promiscuity of maize terpene synthases, coupled with a variety of secondary modifications, results in elaborate defensive layers whose identities, regulation and precise functions are continuing to be elucidated

Chemical Characterization and Evaluation of the Antibacterial Activity of Essential Oils from Fibre-Type Cannabis sativa L. (Hemp)

Abstract: Volatile terpenes represent the largest group of Cannabis sativa L. components and they are responsible for its aromatic properties. Even if many studies on C. sativa have been focused on cannabinoids, which are terpenophenolics, little research has been carried out on its volatile terpenic compounds. In the light of all the above, the present work was aimed at the chemical characterization of seventeen essential oils from different fibre-type varieties of C. sativa (industrial hemp or hemp) by means of GC-MS and GC-FID techniques. In total, 71 compounds were identified, and the semi-quantitative analysis revealed that α- and β-pinene, β-myrcene and β-caryophyllene are the major components in all the essential oils analysed. In addition, a GC-MS method was developed here for the first time, and it was applied to quantify cannabinoids in the essential oils. The antibacterial activity of hemp essential oils against some pathogenic and spoilage microorganisms isolated from food and food processing environment was also determined. The inhibitory effects of the essential oils were evaluated by both the agar well diffusion assay and the minimum inhibitory concentration (MIC) evaluation. By using the agar diffusion method and considering the zone of inhibition, it was possible to preliminarily verify the inhibitory activity on most of the examined strains. The results showed a good antibacterial activity of six hemp essential oils against the Gram-positive bacteria, thus suggesting that hemp essential oil can inhibit or reduce bacterial proliferation and it can be a valid support to reduce microorganism contamination, especially in the food processing field.

Essential Oils and Isolated Terpenes in Nanosystems Designed for Topical Administration: A Review.

Abstract: Essential oils are natural products with a complex composition. Terpenes are the most common class of chemical compounds present in essential oils. Terpenes and the essential oils containing them are widely used and investigated by their pharmacological properties and permeation-enhancing ability. However, many terpenes and essential oils are sensitive to environmental conditions, undergoing volatilization and chemical degradation. In order to overcome the chemical instability of some isolated terpenes and essential oils, the encapsulation of these compounds in nanostructured systems (polymeric, lipidic, or molecular complexes) has been employed. In addition, nanoencapsulation can be of interest for pharmaceutical applications due to its capacity to improve the bioavailability and allow the controlled release of drugs. Topical drug administration is a convenient and non-invasive administration route for both local and systemic drug delivery. The present review focuses on describing the current status of research concerning nanostructured delivery systems containing isolated terpenes and/or essential oils designed for topical administration and on discussing the use of terpenes and essential oils either for their biological activities or as permeation enhancers in pharmaceutic formulations.

Analysis of Terpenes in Cannabis sativa L. Using GC/MS: Method Development, Validation, and Application.

Abstract: Terpenes are the major components of the essential oils present in various Cannabis sativa L. varieties. These compounds are responsible for the distinctive aromas and flavors. Besides the quantification of the cannabinoids, determination of the terpenes in C. sativa strains could be of importance for the plant selection process. At the University of Mississippi, a GC-MS method has been developed and validated for the quantification of terpenes in cannabis plant material, viz., α-pinene, β-pinene, β-myrcene, limonene, terpinolene, linalool, α-terpineol, β-caryophyllene, α-humulene, and caryophyllene oxide. The method was optimized and fully validated according to AOAC (Association of Official Analytical Chemists) guidelines against reference standards of selected terpenes. Samples were prepared by extraction of the plant material with ethyl acetate containing n-tridecane solution (100 µg/mL) as the internal standard. The concentration-response relationship for all analyzed terpenes using the developed method was linear with r2 values > 0.99. The average recoveries for all terpenes in spiked indoor cultivated samples were between 95.0 – 105.7%, with the exception of terpinolene (67 – 70%). The measured repeatability and intermediate precisions (% relative standard deviation) in all varieties ranged from 0.32 to 8.47%. The limit of detection and limit of quantitation for all targeted terpenes were determined to be 0.25 and 0.75 µg/mL, respectively. The proposed method is highly selective, reliable, and accurate and has been applied to the simultaneous determination of these major terpenes in the C. sativa biomass produced by our facility at the University of Mississippi as well as in confiscated marijuana samples.

In vitro anti-inflammatory activity of terpenes via suppression of superoxide and nitric oxide generation and the NF-κB signalling pathway.

Abstract: Terpenes are considered the main components of essential oils and an important source for the identification of novel lead molecules. This study aimed to investigate the in vitro anti-inflammatory activity of l-carveol, l-carvone, and m-cimene (monoterpenes) and of valencene and guaiene (sesquiterpenes). The influence on intracellular nitric oxide (NO) and pro- and anti-inflammatory cytokine (TNF-α, IL-1α and IL-10) production and on nuclear factor kappa B (NF-κB) activity was determined using Griess reagent, immunoenzymatic assay kits (ELISA) and chemiluminescence measurements in cell-based assays, respectively. Antioxidant activity was assayed through the protective effect against cellular oxidative damage produced by superoxide anion production (O 2 ·− ) and hydrogen peroxide on macrophages and by the quenching activity of the NO radical. Terpenes reduced the pro-inflammatory cytokines TNF-α and IL-1α and increased the production of IL-10. In addition, the terpenes, especially guaiene (53.3 ± 2.4%) and m-cymene (38.1 ± 0.6%), significantly inhibited NO production in a macrophage cell culture-based assay, whereas no effect was observed in the scavenging activity of this radical. l-carveol and m-cymene significantly inhibited O 2 ·− production with reductions of approximately 68.6 ± 2.2% and 48.2 ± 4.2%, respectively, at a concentration of 10 μM. Moreover, these terpenes were verified to suppress NF-κB activity. The results indicate that these terpenes have therapeutic potential and may be used to suppress inflammatory diseases or as a leading compounds.

Myrcene and terpene regulation of TRPV1.

Abstract: Nociceptive Transient Receptor Potential channels such as TRPV1 are targets for treating pain. Both antagonism and agonism of TRP channels can promote analgesia, through inactivation and chronic desensitization. Since plant-derived mixtures of cannabinoids and the Cannabis component myrcene have been suggested as pain therapeutics, we screened terpenes found in Cannabis for activity at TRPV1. We used inducible expression of TRPV1 to examine TRPV1-dependency of terpene-induced calcium flux responses. Terpenes contribute differentially to calcium fluxes via TRPV1 induced by Cannabis-mimetic cannabinoid/terpenoid mixtures. Myrcene dominates the TRPV1-mediated calcium responses seen with terpenoid mixtures. Myrcene-induced calcium influx is inhibited by the TRPV1 inhibitor capsazepine and Myrcene elicits TRPV1 currents in the whole-cell patch-clamp configuration. TRPV1 currents are highly sensitive to internal calcium. When Myrcene currents are evoked, they are distinct from capsaicin responses on the basis of Imax and their lack of shift to a pore-dilated state. Myrcene pre-application and residency at TRPV1 appears to negatively impact subsequent responses to TRPV1 ligands such as Cannabidiol, indicating allosteric modulation and possible competition by Myrcene. Molecular docking studies suggest a non-covalent interaction site for Myrcene in TRPV1 and identifies key residues that form partially overlapping Myrcene and Cannabidiol binding sites. We identify several non-Cannabis plant-derived sources of Myrcene and other compounds targeting nociceptive TRPs using a data mining approach focused on analgesics suggested by non-Western Traditional Medical Systems. These data establish TRPV1 as a target of Myrcene and suggest the therapeutic potential of analgesic formulations containing Myrcene.

The Terroir of Cannabis: Terpene Metabolomics as a Tool to Understand Cannabis sativa Selections.

Abstract: The phytochemical diversity of Cannabis chemovars is not well understood, and many chemovars were created in informal breeding programs without records of parentage or the criteria for selection. Key criteria for selection sometimes included aroma notes and visual cues, which some breeders associated with pharmacological activity. We hypothesized that the process of selection for scents believed to be related to specific tetrahydrocannabinol levels has resulted in modified terpene biosynthesis in these chemovars. Thirty-two cannabinoids, 29 monoterpenes and 38 sesquiterpenes were measured in 33 chemovars from 5 licensed producers. A classification system based on cannabinoid content was used with targeted metabolomic tools to determine relationships in the phytochemistry. Three monoterpenes, limonene, β-myrcene, and α-pinene, and two sesquiterpenes, caryophyllene and humulene, were abundant in the majority of chemovars. Nine terpenes were present in tetrahydrocannabinol-dominant chemovars. Three monoterpenes and four sesquiterpenes were predominantly found in cannabidiol-containing chemovars. Low abundance terpenes may have been the aromatic cues identified by breeders. The medicinal activity of some of the terpenes is likely to contribute to the pharmacological effect of specific chemovars. Together, these data demonstrate the synergy of compounds in Cannabis chemovars and point to the need for additional research to understand the phytochemical complexity.

Arctium Species Secondary Metabolites Chemodiversity and Bioactivities.

Abstract: 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.

Cobalt-catalyzed hydroxymethylarylation of terpenes with formaldehyde and arenes

Abstract: Terpenes, consisting of isoprene monomer units, represent a family of naturally abundant compounds. The difunctionalization of terpenes is highly appealing yet remains challenging, since the multiple unbiased CC bonds of terpenes lead to difficulty in controlling the regioselectivity. Herein, a cobalt(III)-catalyzed C–H activation strategy has been developed to facilitate hydroxymethylarylation of terpenes with formaldehyde and arenes with high chemo- and regio-selectivities. These (chemo- and regio-) selectivities are governed by the coordination abilities of isoprene, directing groups and the steric effect. This terpene difunctionalization also features high atom and step economy through a C–H addition pathway.

Essential Oils: From Extraction to Encapsulation

Abstract: Essential oils are volatile liquids obtained from plant material and have an aroma distinct to their plant source. As different plants store their oil in different parts of their histological structure, the extraction and synthesis of their respective aromatic liquids vary accordingly. The study of the extraction and encapsulation techniques of essential oils is important as these oily substances have a wide range of applications. The secretory structures have a different morphology and functions. There are two main types of tissues, categorized according to the position of secretion. Essential oils are complex mixtures comprising volatile compounds of terpenoid and hydrocarbon terpenes. Terpenes are formed from the condensation of a pentacarbonate unit with two unsaturated bonds of isoprene. The biosynthesis of terpenes involves two universal precursors, namely isopentenyl pyrophosphate and dimethylallyl diphosphate. The most commonly-known use of essential oils is in perfumes and cosmetics as they provide a pleasant aroma.

Terpenes, hormones and life: isoprene rule revisited.

Abstract: The year 2019 marks the 80th anniversary of the 1939 Nobel Prize in Chemistry awarded to Leopold Ruzicka (1887-1976) for work on higher terpene molecular structures, including the first chemical synthesis of male sex hormones. Arguably his crowning achievement was the 'biogenetic isoprene rule', which helped to unravel the complexities of terpenoid biosynthesis. The rule declares terpenoids to be enzymatically cyclized products of substrate alkene chains containing a characteristic number of linear, head-to-tail condensed, C5 isoprene units. The number of repeat isoprene units dictates the type of terpene produced (i.e., 2, monoterpene; 3, sesquiterpene; 4, diterpene, etc.). In the case of triterpenes, six C5 isoprene units combine into C30 squalene, which is cyclized into one of the signature carbon skeletons from which myriad downstream triterpenoid structures are derived, including sterols and steroids. Ruzicka also had a keen interest in the origin of life, but the pivotal role of terpenoids has generally been overshadowed by nucleobases, amino acids, and sugars. To redress the balance, we provide a historical and evolutionary perspective. We address the potential abiotic generation of isoprene, the crucial role that polyprene terpenoids played in early membranes and cellular life, and emphasize that endocrinology from microbes to plants and vertebrates is firmly grounded on Ruzicka's pivotal insights into the structure and function of terpenes. A harmonizing feature is that all known lifeforms (including bacteria) biosynthesize triterpenoid substances that are essential for cellular membrane formation and function, from which signaling molecules such as steroid hormones and cognate receptors are likely to have evolved.

Terpene Biosynthesis in Red Algae Is Catalyzed by Microbial Type But Not Typical Plant Terpene Synthases

Abstract: Red algae (Rhodophyta) and land plants belong to the monophyletic clade Archaeplastida, and taxa of both groups are rich producers of terpene secondary metabolites. The terpene carbon skeletons of land plants are made by two types of terpene synthases: typical plant terpene synthases and microbial-type terpene synthases (MTPSLs); however, terpene biosynthesis in red algae is poorly understood. By systematic sequence analysis of seven genomes and 34 transcriptomes of red algae, MTPSL homologs were identified within one genome and two transcriptomes, whereas no homolog of typical plant terpene synthase genes was found. Phylogenetic analysis showed that red algae MTPSLs group with bacterial terpene synthases. Analysis of the genome assembly and characterization of neighboring genes demonstrated red algal MTPSLs to be bona fide red algal genes and not microbial contaminants. MTPSL genes from Porphyridium purpureum and Erythrolobus australicus were characterized via heterologous expression in Escherichia coli and demonstrated to have sesquiterpene synthase activities. We detected a number of volatile sesquiterpenes in the headspace of P. purpureum and E. australicus cultures, most identical to the in vitro products of the respective MTPSLs. Expression of the MTPSL gene in P. purpureum was found to be induced by methyl jasmonate, suggesting a role for this gene in host defense. In summary, this study indicates that the formation of terpene carbon skeletons in red algae is carried out by MTPSLs that are phylogenetically unrelated to typical plant terpene synthases and most likely originated in Rhodophyta via horizontal gene transfer from bacteria.

Delineating the Biofilm Inhibition Mechanisms of Phenolic and Aldehydic Terpenes against Cryptococcus neoformans

Abstract: The recalcitrant biofilm formed by fungus Cryptococcus neoformans is a life-threatening pathogenic condition responsible for further intensifying cryptococcosis. Considering the enhanced biofilm resistance and toxicity of synthetic antifungal drugs, the search for efficient, nontoxic, and cost-effective natural therapeutics has received a major boost. Phenolic (thymol and carvacrol) and aldehydic (citral) terpenes are natural and safe alternatives capable of efficient microbial biofilm inhibition. However, the biofilm inhibition mechanism of these terpenes still remains unclear. In this study, we adopted an integrative biophysical and biochemical approach to elucidate the hierarchy of their action against C. neoformans biofilm cells. The microscopic analysis revealed disruption of the biofilm cell surface with elevation in surface roughness and reduction in cell height. Although all terpenes acted through ergosterol biosynthesis inhibition, the phenolic terpenes also selectively interacted via ergosterol binding. Further, the alterations in the fatty acid profile in response to terpenes attenuated the cell membrane fluidity with enhanced permeability, resulting in pore formation and efflux of the K+/intracellular content. Additionally, mitochondrial depolarization caused higher levels of reactive oxygen species, which led to increased lipid peroxidation and activation of the antioxidant defense system. Indeed, the oxidative stress caused a significant decline in the amount of extracellular polymeric matrix and capsule sugars (mannose, xylose, and glucuronic acid), leading to a reduced capsule size and an overall negative charge on the cell surface. This comprehensive data revealed the mechanistic insights into the mode of action of terpenes on biofilm inhibition, which could be exploited for formulating novel anti-biofilm agents.

Terpene core in selected aromatic and edible plants: natural health improving agents.

Abstract: Aromatic plants synthesize and produce aromatic molecules, among these compounds some of them belong to terpenes and terpenoids. Plant species have specific genes involved in secondary metabolism which allows them to synthesize various compounds with terpene core. These kinds of plant species are also known as herbal drugs and they are primarily used as components in medicinal products or simply as health foods. This chapter will focus on terpene and terpenoid compounds found in selected edible and aromatic plants belonging to several plant families. Selected plant species are briefly discussed. Biologically active compounds with terpene core are most frequently found in essential oils of the edible and aromatic species, as well as they are separately isolated and identified from the extracts. Health beneficial effects coming from terpene compounds found in edible and aromatic plants are further presented and include antimicrobial, antiviral, cytotoxic, anticancer, anti-inflammatory and many other pharmacological activities.

High marker density GWAS provides novel insights into the genomic architecture of terpene oil yield in Eucalyptus

Abstract: Terpenoid-based essential oils are economically important commodities, yet beyond their biosynthetic pathways, little is known about the genetic architecture of terpene oil yield from plants. Transport, storage, evaporative loss, transcriptional regulation and precursor competition may be important contributors to this complex trait. Here, we associate 2.39 million single nucleotide polymorphisms derived from shallow whole-genome sequencing of 468 Eucalyptus polybractea individuals with 12 traits related to the overall terpene yield, eight direct measures of terpene concentration and four biomass-related traits. Our results show that in addition to terpene biosynthesis, development of secretory cavities, where terpenes are both synthesized and stored, and transport of terpenes were important components of terpene yield. For sesquiterpene concentrations, the availability of precursors in the cytosol was important. Candidate terpene synthase genes for the production of 1,8-cineole and α-pinene, and β-pinene (which comprised > 80% of the total terpenes) were functionally characterized as a 1,8-cineole synthase and a β/α-pinene synthase. Our results provide novel insights into the genomic architecture of terpene yield and we provide candidate genes for breeding or engineering of crops for biofuels or the production of industrially valuable terpenes.

The Biochemistry, Toxicology, and Uses of the pharmacologically active phytochemicals: Alkaloids, Terpenes, Polyphenols, and Glycosides

Abstract: The research focused on the biochemistry and the medicinal uses of alkaloids, terpenes, polyphenols, and glycosides. Several parts of plants such as bark, root, leaf, stem, etc. are being used to revert abnormalities back to normal, prevent illnesses, or allay symptoms. These plant parts contain bioactive compounds such as terpenes, glycosides, polyphenols, and alkaloids. Alkaloids have a range of pharmacological activities such as antiasthma ( e.g. ephedrine), anticancer ( e.g. homoharringtonine), antimalarial ( e.g. quinine). Other alkaloids possess stimulant ( e.g. cocaine, caffeine, theobromine, nicotine) and psychotropic activities ( e.g. psilocin), and have been widely used as recreational drugs or in entheogenic rituals. Alkaloids can be toxic too ( e.g. tubocurarine, atropine). Although alkaloids act on diverse metabolic systems in humans and animals, they almost uniformly induce a bitter taste. The characteristics and number of the structures of phenol in polyphenols underlie the unique chemical, physical, and biological (metabolic, therapeutic, toxic, etc.) properties of specific members of the class; e.g. ellagitannin and tannic acid. Generally, foods often contain complex mixtures of polyphenols. Several polyphenolic extracts, such as from grape seeds, olive pulp, maritime pine bark, or grape skin, are sold as ingredients for functional foods, cosmetics, and dietary supplements. Terpenoids and terpenes are the primary components of the essential oils of most types of flowers plants. Essential oils are used widely as scents and fragrances in perfumery and also in traditional medicine, such as aromatherapy. Similarly, many plant glycosides are used as medicines Amygdalin and laetrile (a synthetic derivative) were investigated as potential drugs for cancer treatment and were promoted as alternative medicine; nevertheless, they are ineffective and dangerous. Pharmacologically active phytochemicals can have useful applications, as well as safety concerns.

RNA-Seq in the discovery of a sparsely expressed scent-determining monoterpene synthase in lavender (Lavandula)

Abstract: Using RNA-Seq, we cloned and characterized a unique monoterpene synthase responsible for the formation of a scent-determining S-linalool constituent of lavender oils from Lavandula × intermedia. Several species of Lavandula produce essential oils (EOs) consisting mainly of monoterpenes including linalool, one of the most abundant and scent-determining oil constituents. Although R-linalool dominates the EOs of lavenders, varying amounts (depending on the species) of the S-linalool enantiomer can also be found in these plants. Despite its relatively low abundance, S-linalool contributes a sweet, pleasant scent and is an important constituent of lavender EOs. While several terpene synthase genes including R-linalool synthase have been cloned from lavenders many important terpene synthases including S-linalool synthase have not been described from these plants. In this study, we employed RNA-Seq and other complementary sequencing data to clone and functionally characterize the sparsely expressed S-linalool synthase cDNA (LiS-LINS) from Lavandula × intermedia. Recombinant LiS-LINS catalyzed the conversion of the universal monoterpene precursor geranyl diphosphate to S-linalool as the sole product. Intriguingly, LiS-LINS exhibited very low (~ 30%) sequence similarity to other Lavandula terpene synthases, including R-linalool synthase. However, the predicted 3D structure of this protein, including the composition and arrangement of amino acids at the active site, is highly homologous to known terpene synthase proteins. LiS-LINS transcripts were detected in flowers, but were much less abundant than those corresponding to LiR-LINS, paralleling enantiomeric composition of linalool in L. × intermedia oils. These data indicate that production of S-linalool is at least partially controlled at the level of transcription from LiS-LINS. The cloned LiS-LINS cDNA may be used to enhance oil composition in lavenders and other plants through metabolic engineering.

Mevalonate Pathway Promiscuity Enables Noncanonical Terpene Production.

Abstract: Lepidoptera (butterflies and moths) make the six-carbon compounds homoisopentenyl pyrophosphate (HIPP) and homodimethylallyl pyrophosphate (HDMAPP) that are incorporated into 16, 17, and 18 carbon farnesyl pyrophosphate (FPP) analogues. In this work we heterologously expressed the lepidopteran modified mevalonate pathway, a propionyl-CoA ligase, and terpene cyclases in E. coli to produce several novel terpenes containing 16 carbons. Changing the terpene cyclase generated different novel terpene product profiles. To further validate the new compounds we confirmed 13C propionate was incorporated, and that the masses and fragmentation patterns were consistent with novel 16 carbon terpenes by GC-QTOF. On the basis of the available farnesyl pyrophosphate analogues lepidoptera produce, this approach should greatly expand the reachable biochemical space with applications in areas where terpenes have traditionally found uses.