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Integrative metabolome and transcriptome analyses reveal the differences in flavonoid and terpenoid synthesis between Glycyrrhiza uralensis (licorice) leaves and roots
Abstract
Licorice from Glycyrrhiza uralensis roots is used in foods and medicines. Although we are aware that licorice roots and leaves have distinct material compositions, the specific reasons for these differences remain unknown. Comparison of the metabolomes and transcriptomes between the leaves and roots revealed flavonoids and triterpenoid saponins were significantly different. Isoflavones were enriched in roots because of upregulation of genes encoding chalcone isomerase and flavone synthase, which are involved in isoflavone synthesis. Six triterpenoid saponins were significantly enriched only in the roots. The leaves did not accumulate glycyrrhetinic acid because of low expression levels of genes involved in its synthesis. A gene encoding a UDP glycosyltransferase, which likely catalyzes the key step in the transformation of glycyrrhetinic acid to glycyrrhizin, was screened. Our results provide information about the differences in flavonoid and triterpenoid synthesis between roots and leaves, and highlight targets for genetic engineering.
... changes in gene expression with the accumulation of stress-related metabolites [46]. Similarly, in Glycyrrhiza uralensis, integrated approaches have been employed to explore the biosynthesis of flavonoids and triterpenoids, highlighting key regulatory genes that contribute to the accumulation of bioactive compounds [47]. These methodologies have also been applied in crops like Zea mays [48], and other crops such as tea [7], watermelon [49], and Solanum nigrum L. [50], where researchers have investigated the interplay between genetic variation and metabolite profiles in response to environmental factors. ...
Safflower (Carthamus tinctorius L.) is a traditional Chinese medicinal herb renowned for its high flavonoid content and significant medicinal value. However, the dynamic changes in safflower petal flavonoid profiles across different flowering phases present a challenge in optimizing harvest timing and medicinal use. To enhance the utilization of safflower, this study conducted an integrated transcriptomic and metabolomic analysis of safflower petals at different flowering stages. Our findings revealed that certain flavonoids were more abundant during the fading stage, while others peaked during full bloom. Specifically, seven metabolites, including p-coumaric acid, naringenin chalcone, naringenin, dihydrokaempferol, apigenin, kaempferol, and quercetin, accumulated significantly during the fading stage. In contrast, dihydromyricetin and delphinidin levels were notably reduced. Furthermore, key genes in the flavonoid biosynthesis pathway, such as 4CL, DFR, and ANR, exhibited up-regulated expression with safflower’s flowering progression, whereas CHI, F3H, and FLS were down-regulated. Additionally, exposure to UV-B stress at full bloom led to an up-regulation of flavonoid content and altered the expression of key flavonoid biosynthetic genes over time. This study not only elucidates the regulatory mechanisms underlying flavonoid metabolism in safflower but also provides insights for maximizing its medicinal and industrial applications.
This study aimed to quantify four polycyclic aromatic hydrocarbons (PAH4) in licorice roots. A novel analytical method, referred to as “dispersive solid–liquid extraction,” was applied to detect the PAH4 in licorice roots by HPLC coupled with fluorescence detector (FLD). Extraction solvent, adsorbent type, and amount were optimized to improve the extraction efficiency and achieve satisfactory clean-up. The satisfactory linearity, limit of detection, limit of quantification, recovery, and precision of PAH4 were acquired. Benzo[a]anthracene, chrysene, and benzo[a]pyrene were detected in some licorice root samples, whereas benzo[b]fluoranthene was not detected in any sample. None of the samples contained PAH4 levels higher than the maximum limit (MLs) established by the European Commission and Korean Ministry of Food and Drug Safety. These results suggest that the dispersive solid–liquid extraction method combined with HPLC-FLD is effective for the analysis of PAH4 in licorice roots and can be applied to a wide range of herbal medicines.
Abiotic stressors such as extreme temperatures, drought, flood, light, salt, and heavy metals alter biological diversity and crop production worldwide. Therefore, it is important to know the mechanisms by which plants cope with stress conditions. Polyphenols, which are the largest group of plant-specialized metabolites, are generally recognized as molecules involved in stress protection in plants. This diverse group of metabolites contains various structures, from simple forms consisting of one aromatic ring to more complex ones consisting of large number of polymerized molecules. Consequently, all these molecules, depending on their structure, may show different roles in plant growth, development, and stress protection. In the present review, we aimed to summarize data on how different polyphenol structures influence their biological activity and their roles in abiotic stress responses. We focused our review on phenolic acids, flavonoids, stilbenoids, and lignans.
The aerial portion of a plant, namely the leaf, is inhabited by pathogenic and non-pathogenic microbes. The leaf's physical and chemical properties, combined with fluctuating and often challenging environmental factors, create surfaces that require a high degree of adaptation for microbial colonization. As a consequence, specific interactive processes have evolved to establish a plant leaf niche. Little is known about the impact of the host immune system on phyllosphere colonization by non-pathogenic microbes. These organisms can trigger plant basal defenses and benefit the host by priming for enhanced resistance to pathogens. In most disease resistance responses, microbial signals are recognized by extra- or intracellular receptors. The interactions tend to be species-specific and it is unclear how they shape leaf microbial communities. In natural habitats, microbe-microbe interactions are also important for shaping leaf communities. To protect resources, plant colonizers have developed direct antagonistic or host manipulation strategies to fight competitors. Phyllosphere-colonizing microbes respond to abiotic and biotic fluctuations and are therefore an important resource for adaptive and protective traits. Understanding the complex regulatory host-microbe-microbe networks is needed to transfer current knowledge to biotechnological applications such as plant-protective probiotics.
An unbalanced pigment distribution among the sepal and petal segments results in various colour patterns of orchid flowers. Here, we explored this type of mechanism of colour pattern formation in flowers of the Cattleya hybrid ‘KOVA’. Our study showed that pigment accumulation displayed obvious spatiotemporal specificity in the flowers and was likely regulated by three R2R3-MYB transcription factors. Before flowering, RcPAP1 was specifically expressed in the epichile to activate the anthocyanin biosynthesis pathway, which caused substantial cyanin accumulation and resulted in a purple-red colour. After flowering, the expression of RcPAP2 resulted in a low level of cyanin accumulation in the perianths and a pale pink colour, whereas RcPCP1 was expressed only in the hypochile, where it promoted α-carotene and lutein accumulation and resulted in a yellow colour. Additionally, we propose that the spatiotemporal expression of different combinations of AP3- and AGL6-like genes might participate in KOVA flower colour pattern formation.
All plants synthesize a diverse array of terpenoid metabolites. Some are common to all, but many are synthesized only in specific taxa and presumably evolved as adaptations to specific ecological conditions. While the basic terpenoid biosynthetic pathways are common in all plants, recent discoveries have revealed many variations in the way plants synthesized specific terpenes. A major theme is the much greater number of substrates that can be used by enzymes belonging to the terpene synthase (TPS) family. Other recent discoveries include non-TPS enzymes that catalyze the formation of terpenes, and novel transport mechanisms.
Inflammation represents an adaptive response generated by injuries or harmful stimuli. Natural remedies represent an interesting alternative to traditional therapies, involving several biochemical pathways. Besides, the valorization of agrochemical wastes nowadays seems to be a feasible way to reduce the health spending and improve the accessibility at bioactive natural compounds. In this context, the chemical composition of three Glycyrrhiza glabra L. (licorice) leaf extracts, obtained through maceration or ultrasound-assisted method (fresh and dried leaves) was investigated. A guided fractionation obtained three main components: pinocembrin, glabranin and licoflavanone. All the extracts showed similar antioxidant properties, evaluated by 2,2′-diphenyl-1-picrylhydrazyl (DPPH) or 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) Diammonium Salt (ABTS) assay, while, among the isolated compounds, licoflavanone exhibited the best antioxidant activity. The anti-inflammatory activity of the extracts and the purified compounds was investigated in lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophages. Extract C and licoflavanone showed a good anti-inflammatory activity without affecting cell viability, as they decreased nitrite levels even when used at 12.5 μg/mL (p < 0.005) and 50 μM concentration (p < 0.001), respectively. Interestingly, licoflavanone markedly decreased pro-inflammatory cytokines and cyclooxygenase 2/inducible nitric oxide synthase (COX-2/iNOS) expression levels (p < 0.001). A modulation of nuclear factor kappa B/mitogen-activated protein kinases (NF-kB/MAPK) pathway underlay such behavior, highlighting the potential of this natural compound as a new scaffold in anti-inflammatory drug research.
Licorice, the root and rhizome of Glycyrrhiza uralansis Fisch, is one of the most frequently used Traditional Chinese Medicines in rigorous clinical trials to remove toxins and sputum, and to relieve coughing. However, the aerial parts are not used so widely at present. It has been reported that the aerial parts have many bioactivities such as anti-microbial and anti-HIV activities. In this study, we aimed to discover the bioactive compounds from the leaves of G. uralensis. Four new compounds, licostilbene A-B (1–2) and licofuranol A-B (3–4), together with eight known flavonoids (5–12), were isolated and identified from the leaves of G. uralensis. Their structures were elucidated mainly by the interpretation of high-resolution electrospray mass spectrometry (HR-ESI-MS) and nuclear magnetic resonance (NMR) spectroscopic data. Compared with quercetin, which showed a 50% inhibitory concentration (IC50) value of 4.08 μg/mL, compounds 1–9 showed significant anti-inflammatory activities by inhibiting lipopolysaccharide (LPS)-induced nitric oxide (NO) production with IC50 values of 2.60, 2.15, 3.21, 3.25, 2.00, 3.45, 2.53, 3.13 and 3.17 μg/mL, respectively. The discovery of these active compounds is important for the prevention and treatment of inflammation.
Citrus-derived flavonoids play important roles in the regulation of physiological conditions of citrus plants, including color changes of flower and fruit, flavor development, and anti-stress physiology. Moreover, citrus flavonoids possess multiple health-promoting effects in humans, and they are important ingredients for nutraceuticals and functional foods. The biosynthesis of flavonoids in citrus plants is of special significance because it determines the chemical structures and bioaccumulation of these bioactive compounds in the plants, which consequently influences their physiological functions in both citrus plants and human body. This review systematically summarizes: 1) the biosynthesis pathway of citrus-derived flavonoids, 2) the biosynthesis location and distribution of flavonoids in citrus plants, 3) the factors affecting flavonoid biosynthesis, 4) the biological significance of flavonoid biosynthesis in citrus plants, and 5) the health-promoting properties of citrus-derived flavonoids. The collation of this information provides scientific guidance for the development of healthy citrus foods and other health-promoting products containing citrus flavonoids.
Chinese liquorice/licorice (Glycyrrhiza uralensis) is a leguminous plant species whose roots and rhizomes have been widely used as a herbal medicine and natural sweetener. Whole-genome sequencing is essential for gene discovery studies and molecular breeding in liquorice. Here, we report a draft assembly of the approximately 379-Mb whole-genome sequence of strain 308-19 of G. uralensis; this assembly contains 34 445 predicted protein-coding genes. Comparative analyses suggested well-conserved genomic components and collinearity of gene loci (synteny) between the genome of liquorice and those of other legumes such as Medicago and chickpea. We observed that three genes involved in isoflavonoid biosynthesis, namely, 2-hydroxyisoflavanone synthase (CYP93C), 2,7,4'-trihydroxyisoflavanone 4'-O-methyltransferase/isoflavone 4'-O-methyltransferase (HI4OMT) and isoflavone-7-O-methyltransferase (7-IOMT) formed a cluster on the scaffold of the liquorice genome and showed conserved microsynteny with Medicago and chickpea. Based on the liquorice genome annotation, we predicted genes in the P450 and UDP-dependent glycosyltransferase (UGT) superfamilies, some of which are involved in triterpenoid saponin biosynthesis, and characterised their gene expression with the reference genome sequence. The genome sequencing and its annotations provide an essential resource for liquorice improvement through molecular breeding and the discovery of useful genes for engineering bioactive components through synthetic biology approaches.
Flavones correspond to a flavonoid subgroup that is widely distributed in the plants, and which can be synthesized by different pathways, depending on whether they contain C- or O-glycosylation and hydroxylated B-ring. Flavones are emerging as very important specialized metabolites involved in plant signaling and defense, as well as key ingredients of the human diet, with significant health benefits. Here, we appraise flavone formation in plants, emphasizing the emerging theme that biosynthesis pathway determines flavone chemistry. Additionally, we briefly review the biological activities of flavones, both from the perspective of the functions that they play in biotic and abiotic plant interactions, as well as their roles as nutraceutical components of the human and animal diet.
Licorice (Gancao in Chinese) has been used worldwide as a botanical source in medicine and as a sweetening agent in food products for thousands of years. Triterpene saponins and flavonoids are its main ingredients that exhibit a variety of biological activities, including hepatoprotective, antiulcer, anti-inflammatory, antiviral and anticancer effects among others. This review attempts to summarize the current knowledge on the anticancer properties and mechanisms of the compounds isolated from licorice and obtain new insights for further research and development of licorice. A broad spectrum of in vitro and in vivo studies have recently demonstrated that the mixed extracts and purified compounds from licorice exhibit evident anticancer properties by inhibition of proliferation, induction of cell cycle arrest, apoptosis, autophagy, differentiation, suppression of metastasis, angiogenesis, and sensitization of chemotherapy or radiotherapy. A combined treatment of licorice compounds and clinical chemotherapy drugs remarkably enhances anticancer effects and reduces the side effects of chemotherapeutics. Furthermore, glycyrrhizic acid and glycyrrhetinic acid in licorice have been indicated to present obvious liver-targeting effects in targeted drug delivery systems for hepatocellular carcinoma treatment.
Plants synthesize and accumulate large amount of specialized (or secondary) metabolites also known as
natural products, which provide a rich source for modern pharmacy. In China, plants have been used in traditional medicine for thousands of years. Recent development of molecular biology, genomics and functional genomics as well as high-throughput analytical chemical technologies has greatly promoted the research on medicinal plants. In this article, we review recent advances in the elucidation of biosynthesis of specialized metabolites in medicinal plants, including phenylpropanoids, terpenoids and alkaloids. These natural products may share a common upstream pathway to form a limited numbers of common precursors, but are characteristic in distinct modifications leading to highly variable structures. Although this review is focused on
traditional Chinese medicine, other plants with a great medicinal interest or potential are also discussed. Understanding of their biosynthesis processes is critical for producing these highly value molecules at large scale and low cost in microbes and will benefit to not only human health but also plant resource conservation.
Licorice is a common herb which has been used in traditional Chinese medicine for centuries. More than 20 triterpenoids and nearly 300 flavonoids have been isolated from licorice. Recent studies have shown that these metabolites possess many pharmacological activities, such as antiviral, antimicrobial, anti-inflammatory, antitumor and other activities. This paper provides a summary of the antiviral and antimicrobial activities of licorice. The active components and the possible mechanisms for these activities are summarized in detail. This review will be helpful for the further studies of licorice for its potential therapeutic effects as an antiviral or an antimicrobial agent.
In the course of a continued investigation of the alkaloid constituents of the family Amaryllidaceae, 15 Amaryllidaceae alkaloids isolated from Crinum bulbispermum and C. moorei were tested for anti-inflammatory activity using cyclooxygenase assay (COX-1 and COX-2) and antibacterial activity against Bacillus subtilis, Staphylococus aureus, Escherichia coli and Klebsiella pneumoniae. The alkaloids showed only low inhibitory activity on COX-1 and COX-2. No bacterial growth inhibition was observed at the final concentration of 250μg ml-1 used in this study.
There has been increasing interest in the research on flavonoids from plant sources because of their versatile health benefits reported in various epidemiological studies. Since flavonoids are directly associated with human dietary ingredients and health, there is need to evaluate structure and function relationship. The bioavailability, metabolism, and biological activity of flavonoids depend upon the configuration, total number of hydroxyl groups, and substitution of functional groups about their nuclear structure. Fruits and vegetables are the main dietary sources of flavonoids for humans, along with tea and wine. Most recent researches have focused on the health aspects of flavonoids for humans. Many flavonoids are shown to have antioxidative activity, free radical scavenging capacity, coronary heart disease prevention, hepatoprotective, anti-inflammatory, and anticancer activities, while some flavonoids exhibit potential antiviral activities. In plant systems, flavonoids help in combating oxidative stress and act as growth regulators. For pharmaceutical purposes cost-effective bulk production of different types of flavonoids has been made possible with the help of microbial biotechnology. This review highlights the structural features of flavonoids, their beneficial roles in human health, and significance in plants as well as their microbial production.
Glycyrrhizin, a triterpenoid saponin derived from the underground parts of Glycyrrhiza plants (licorice), has several pharmacological activities and is also used worldwide as a natural sweetener. The biosynthesis of glycyrrhizin involves the initial cyclization of 2,3-oxidosqualene to the triterpene skeleton β-amyrin, followed by a series of oxidative reactions at positions C-11 and C-30, and glycosyl transfers to the C-3 hydroxyl group. We previously reported the identification of a cytochrome P450 monooxygenase (P450) gene encoding β-amyrin 11-oxidase (CYP88D6) as the initial P450 gene in glycyrrhizin biosynthesis. In this study, a second relevant P450 (CYP72A154) was identified and shown to be responsible for C-30 oxidation in the glycyrrhizin pathway. CYP72A154 expressed in an engineered yeast strain that endogenously produces 11-oxo-β-amyrin (a possible biosynthetic intermediate between β-amyrin and glycyrrhizin) catalyzed three sequential oxidation steps at C-30 of 11-oxo-β-amyrin supplied in situ to produce glycyrrhetinic acid, a glycyrrhizin aglycone. Furthermore, CYP72A63 of Medicago truncatula, which has high sequence similarity to CYP72A154, was able to catalyze C-30 oxidation of β-amyrin. These results reveal a function of CYP72A subfamily proteins as triterpene-oxidizing enzymes and provide a genetic tool for engineering the production of glycyrrhizin.
Glycyrrhiza uralensis is one of the most popular medicinal plants in the world and is also widely used in the flavoring of food and tobacco. Due to limited genomic and transcriptomic data, the biosynthetic pathway of glycyrrhizin, the major bioactive compound in G. uralensis, is currently unclear. Identification of candidate genes involved in the glycyrrhizin biosynthetic pathway will significantly contribute to the understanding of the biosynthetic and medicinal chemistry of this compound.
We used the 454 GS FLX platform and Titanium regents to produce a substantial expressed sequence tag (EST) dataset from the vegetative organs of G. uralensis. A total of 59,219 ESTs with an average read length of 409 bp were generated. 454 ESTs were combined with the 50,666 G. uralensis ESTs in GenBank. The combined ESTs were assembled into 27,229 unique sequences (11,694 contigs and 15,535 singletons). A total of 20,437 unique gene elements representing approximately 10,000 independent transcripts were annotated using BLAST searches (e-value <or= 1e-5) against the SwissProt, KEGG, TAIR, Nr and Nt databases. The assembled sequences were annotated with gene names and Gene Ontology (GO) terms. With respect to the genes related to glycyrrhizin metabolism, genes encoding 16 enzymes of the 18 total steps of the glycyrrhizin skeleton synthesis pathway were found. To identify novel genes that encode cytochrome P450 enzymes and glycosyltransferases, which are related to glycyrrhizin metabolism, a total of 125 and 172 unigenes were found to be homologous to cytochrome P450s and glycosyltransferases, respectively. The cytochrome P450 candidate genes were classified into 32 CYP families, while the glycosyltransferase candidate genes were classified into 45 categories by GO analysis. Finally, 3 cytochrome P450 enzymes and 6 glycosyltransferases were selected as the candidates most likely to be involved in glycyrrhizin biosynthesis through an organ-specific expression pattern analysis based on real-time PCR.
Using the 454 GS FLX platform and Titanium reagents, our study provides a high-quality EST database for G. uralensis. Based on the EST analysis, novel candidate genes related to the secondary metabolite pathway of glycyrrhizin, including novel genes encoding cytochrome P450s and glycosyltransferases, were found. With the assistance of organ-specific expression pattern analysis, 3 unigenes encoding cytochrome P450s and 6 unigenes encoding glycosyltransferases were selected as the candidates most likely to be involved in glycyrrhizin biosynthesis.
Studies were carried out on the effects of coumarin, ferulic acid and naringenin on soybean seed germination and on the growth of seed-borne fungi at concentrations of 50 and 100 mg.L-1. The compounds showed good inhibition of seed germination, especially at 50 mg.L-1, but little fungistatic activity. Possible mechanisms of action are discussed.Os compostos fenólicos são metabólitos secundários importantes na ecologia vegetal, especialmente em relações alelopáticas e interações com microorganismos, sendo sintetizados principalmente através da via do ácido chiquímico. Neste trabalho, os efeitos de cumarina, ácido ferúlico e naringenina sobre a germinação de sementes de soja e sobre o crescimento de fungos contaminantes foram investigados, nas concentrações de 50 e 100 mg.L-1. A germinação das sementes e o crescimento dos fungos foram estudados através de método do rolo de papel e do método do papel de filtro, respectivamente. Os compostos mostraram alta inibição da germinação das sementes, principalmente a 50 mg.L-1, porém baixa atividade fungistática. Possíveis mecanismos de ação são discutidos.
Two known saponins, licorice-saponin H2 and macedonoside A, were isolated from the stolons of Glycyrrhiza lepidota (American licorice) as major saponins. Since licorice-saponin H2 and macedonoside A are minor saponins isolated from the three glycyrrhizin-producing species (i.e. G. glabra, G. uralensis, G. inflata) and the three macedonoside C-producing species (i.e. G. macedonica, G. echinata, G. pallidiflora), respectively, the present study suggests that G. lepidota is an intermediate of both glycyrrhizin-producing and macedonoside C-producing species. The phylogenetic tree constructed from the nucleotide sequences of ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit gene (rbcL) of these seven Glycyrrhiza plants indicated that G. lepidota was separated from the other six Glycyrrhiza species, and this phylogenetic relationship was in accordance with their saponin compositions.
Licorice is known as a botanical source in medicine and a sweetening agent in food products. Commercial licorice is from the source of wild and cultivated G. uralensis. It was recognized that the material basis of wild and cultivated licorice is different. This study systematically investigated the difference between them by multidimensional analysis technology. The results showed that the content of starch grain, total dietary fibre (TDF), and 11 secondary metabolite components was significantly different in wild and cultivated licorice. principal component analysis (PCA) and orthogonal partial least square (OPLS-DA) analyses showed that the wild and cultivated licorice samples could be clearly separated based on the acquired data of microscopic, macromolecular substance and secondary metabolite analysis. The main markers were starch grain, isoliquiritin apioside, liquirtin apioside and TDF. Additionally, NIR spectroscpy combined with PLS-DA has demonstrated a suitable, fast and nondestructive methodology for authentication of wild and cultivated licorice.
Malonyl-CoA:flavonoid acyltransferases (MaT) modify isoflavones, but only a few have been characterized for activity and assigned to specific physiological processes. Legume roots exude isoflavone malonates into the rhizosphere, where they are hydrolyzed into isoflavone aglycones. Soybean GmMaT2 was highly expressed in seeds, root hairs, and nodules. GmMaT2 and GmMaT4 recombinant enzymes used isoflavone 7-O-glucosides as acceptors and malonyl-CoA as an acyl donor to generate isoflavone glucoside malonates. GmMaT2 had higher activity towards isoflavone glucosides than GmMaT4. Overexpression (OE) in hairy roots of GmMaT2 and 4 produced more malonyldaidzin, malonylgenistin, and malonylglycitin, and resulted in more nodules than control. However, only GmMaT2 knockdown (KD) hairy roots showed reduced levels of malonyldaidzin, malonylgenistin, and malonylglycitin, and likewise, reduced nodule numbers. These were consistent with the up-regulation of only GmMaT2 by rhizobial infection, and higher expression levels of early nodulation genes in GmMaT2- and 4-OE, but lower only in GmMaT2-KD roots compared to control roots. Higher malonyl isoflavonoid levels in transgenic hairy roots were associated with higher levels of isoflavones in root exudates and more nodules, and vice versa. We posit that GmMaT2 participates in soybean nodulation by catalyzing isoflavone malonylation and affecting malonyl isoflavone secretion for activation of Nod factor and nodulation
The objective of this study is to investigate the inhibition of Glycyrrhiza glabra extract, commonly known as licorice, as a green source of corrosion inhibitor against mild steel corrosion in 1 M HCl solution. The extract of Glycyrrhiza glabra has been used for mild steel inhibition in 1 M HCl solution. By means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) the corrosion inhibition performance and by atomic force microscopy (AFM) and contact angle test the surface characteristics were evaluated. The results of polarization test revealed that the Glycyrrhiza glabra leaves extract acted as mixed type inhibitor and retarded both anodic and cathodic reactions rates. Results revealed that by addition of Glycyrrhiza glabra leaves extract the corrosion current density of mild steel significantly decreased from 260 μA/cm2 for the sample without inhibitor to 40.2 μA/cm2 for the sample containing 800 ppm inhibitor. In addition, it was found that in the presence of Glycyrrhiza glabra leaves extract the hydrogen evolution mechanism did not change but the anodic dissolution mechanism of iron was affected in the presence of inhibitors. The EIS results showed that the increase of Glycyrrhiza glabra leaves extract concentration and immersion time resulted in the increase of corrosion inhibition efficiency. The maximum corrosion inhibition efficiency (about 88%) and surface coverage (about 72%) were obtained in the presence of 800 ppm Glycyrrhiza glabra leaves extract after 24 h immersion. Atomic force microscopy test results showed lower mild steel surface degradation in the HCl solution with 800 ppm Glycyrrhiza glabra leaves extract. Also, the decrease in surface hydrophilicity in the presence of Glycyrrhiza glabra leaves extract confirmed the adsorption of organic molecules of the inhibitors, such as Glycyrrhizin (GL), 18β-Glycyrrhetinic acid (GA), Liquritigenin (LTG), Licochalcone A (LCA), Licochalcone E (LCE), and Glabridin (GLD), on the active sites of mild steel. In addition, the modeling studies based on classical molecular dynamics (MD), Monte Carlo (MC) and quantum mechanics (QM) techniques evidenced that all corrosion inhibiting materials exist in Glycyrrhiza glabra adsorbed to steel surface, and thereby form a corrosion-protective film over the steel surface.
Liquiritin is one of flavone compounds derived from licorice, a common flavoring and sweetening agent in food products. This study investigated the effects and mechanisms of liquiritin in interleukin (IL)-1β-stimulated SW982 human synovial cells, which is a useful tool to study the inflammatory response of rheumatoid arthritis (RA). The SW982 cells were pretreated with various concentrations (0, 10 and 40 μM) of liquiritin, followed by IL-1β (10 ng/mL) stimulation. Liquiritin significantly inhibited protein and mRNA levels of inflammatory cytokines IL-6 and IL-8 in IL-1β-stimulated SW982 cells. Liquiritin suppressed IL-1β-induced phosphorylation of p38, c-jun N-terminal kinase (JNK), and adenosine monophosphate-activated protein kinase (AMPK), inhibited p-c-Jun activation and decreased p65 protein translocation into the nucleus induced by IL-1β. These results indicate that liquiritin exerts an anti-inflammatory effect via modulating JNK, p38, activator protein-1 (AP-1), AMPK and nuclear factor-κB (NF-κB) pathways in IL-1β-induced human synovial cells.
Strigolactones are a structurally diverse class of plant hormones that control many aspects of shoot and root growth. Strigolactones are also exuded by plants into the rhizosphere, where they promote symbiotic interactions with arbuscular mycorrhizal fungi and germination of root parasitic plants in the Orobanchaceae family. Therefore, understanding how strigolactones are made, transported, and perceived may lead to agricultural innovations as well as a deeper knowledge of how plants function. Substantial progress has been made in these areas over the past decade. In this review, we focus on the molecular mechanisms, core developmental roles, and evolutionary history of strigolactone signaling. We also propose potential translational applications of strigolactone research to agriculture. Expected final online publication date for the Annual Review of Plant Biology Volume 68 is April 29, 2017. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
The roots and rhizomes of licorice plants (genus Glycyrrhiza L.) are commercially employed, after processing, in confectionery production or as sweetening and flavouring agents in the food, tobacco and beer industries. G. glabra, G. inflata and G. uralensis are the most significant licorice species, often indistinctly used for different productions. Licorice properties are directly related to its chemical composition, which determines the commercial values and the quality of the derived products. In order to better understand the characteristics and properties of each species, a chemical characterization of three species of licorice (G. glabra, G. inflata, G. uralensis) is proposed, through an untargeted metabolomic approach and using high-resolution mass spectrometry. The statistical analysis reveals new possible markers for the analyzed species, and provides a reliable identification of a high number of metabolites, contributing to the characterization of Glycyrrhiza metabolome.
In plants, carotenoids are essential for photosynthesis and photoprotection. However, carotenoids are not the end products of the pathway; apocarotenoids are produced by carotenoid cleavage dioxygenases (CCDs) or non-enzymatic processes. Apocarotenoids are more soluble or volatile than carotenoids but they are not simply breakdown products, as there can be modifications post-cleavage and their functions include hormones, volatiles, and signals. Evidence is emerging for a class of apocarotenoids, here referred to as apocarotenoid signals (ACSs), that have regulatory roles throughout plant development beyond those ascribed to abscisic acid (ABA) and strigolactone (SL). In this context we review studies of carotenoid feedback regulation, chloroplast biogenesis, stress signaling, and leaf and root development providing evidence that apocarotenoids may fine-tune plant development and responses to environmental stimuli.
Licorice botanicals are produced from the roots of Glycyrrhiza species (Fabaceae), encompassing metabolites of both plant and rhizobial origin. The composition in both primary and secondary metabolites (1°/2°Ms) reflects the physiologic state of the plant at harvest. Interestingly, the relative abundance of 1°Ms vs 2°Ms in licorice extracts remains undetermined. A centrifugal partition chromatography (CPC) method was developed to purify liquiritin derivatives that represent major bioactive 2°Ms and to concentrate the polar 1°Ms from the crude extract of Glycyrrhiza uralensis. One objective was to determine the purity of the generated reference materials by orthogonal UHPLC-UV/LC-MS and qHNMR analyses. The other objectives were to evaluate the presence of 1°Ms in purified 2°Ms and define their mass balance in a crude botanical extract. Whereas most impurities could be assigned to well-known 1°Ms, p-hydroxybenzylmalonic acid, a new natural tyrosine analogue, was also identified. Additionally, in the most polar fraction, sucrose and proline represented 93% (w/w) of all qHNMR-quantified 1°Ms. Compared to the 2°Ms, accounting for 11.9% by UHPLC-UV, 1°Ms quantified by qHNMR defined an additional 74.8% of G. uralensis extract. The combined orthogonal methods enable the mass balance characterization of licorice extracts and highlight the relevance of 1°Ms, and accompanying metabolites, for botanical quality control.
Licorice is an herbal plant named for its unique sweet flavor. It is widely used in the food and tobacco industries as a sweetener. Licorice is also used in traditional Chinese medicine (TCM) and complementary medicine. Because the use of licorice has long been a part of TCM, the details of its therapeutic applications have been thoroughly established. In modern science, licorice is of interest because of its broad range of applications. Extracts of and compounds isolated from licorice have been well studied and biologically characterized. In this review, we discuss the nutraceutical and functional activities of licorice as well as those of the extracts of and the isolated compounds from licorice, including agents with anti-inflammatory activity, cell-protective abilities and chemopreventive effects. The side effects of licorice are also enumerated. A comparison of the activities of licorice described by modern science and TCM is also presented, revealing the correspondence of certain characteristics.
Terpenes are the largest class of small-molecule natural products on earth, and the most abundant by mass. Here, we summarize recent developments in elucidating the structure and function of the proteins involved in their biosynthesis. There are six main building blocks or modules (α, β, γ, δ, ε, and ζ) that make up the structures of these enzymes: the αα and αδ head-to-tail trans-prenyl transferases that produce trans-isoprenoid diphosphates from C(5) precursors; the ε head-to-head prenyl transferases that convert these diphosphates into the tri- and tetraterpene precursors of sterols, hopanoids, and carotenoids; the βγ di- and triterpene synthases; the ζ head-to-tail cis-prenyl transferases that produce the cis-isoprenoid diphosphates involved in bacterial cell wall biosynthesis; and finally the α, αβ, and αβγ terpene synthases that produce plant terpenes, with many of these modular enzymes having originated from ancestral α and β domain proteins. We also review progress in determining the structure and function of the two 4Fe-4S reductases involved in formation of the C(5) diphosphates in many bacteria, where again, highly modular structures are found.
Some plant terpenes such as sterols and carotenes are part of primary metabolism and found essentially in all plants. However, the majority of the terpenes found in plants are classified as 'secondary' compounds, those chemicals whose synthesis has evolved in plants as a result of selection for increased fitness via better adaptation to the local ecological niche of each species. Thousands of such terpenes have been found in the plant kingdom, but each species is capable of synthesizing only a small fraction of this total. In plants, a family of terpene synthases (TPSs) is responsible for the synthesis of the various terpene molecules from two isomeric 5-carbon precursor 'building blocks', leading to 5-carbon isoprene, 10-carbon monoterpenes, 15-carbon sesquiterpenes and 20-carbon diterpenes. The bryophyte Physcomitrella patens has a single TPS gene, copalyl synthase/kaurene synthase (CPS/KS), encoding a bifunctional enzyme producing ent-kaurene, which is a precursor of gibberellins. The genome of the lycophyte Selaginella moellendorffii contains 18 TPS genes, and the genomes of some model angiosperms and gymnosperms contain 40-152 TPS genes, not all of them functional and most of the functional ones having lost activity in either the CPS- or KS-type domains. TPS genes are generally divided into seven clades, with some plant lineages having a majority of their TPS genes in one or two clades, indicating lineage-specific expansion of specific types of genes. Evolutionary plasticity is evident in the TPS family, with closely related enzymes differing in their product profiles, subcellular localization, or the in planta substrates they use.
In order to reveal the chemical characteristics of Glycyrrhiza uralensis growing in Mongolia and to clarify whether it can be the source of Glycyrrhizae Radix used in Japan, eight major bioactive constituents in the underground parts of G. uralensis collected in Mongolia were quantitatively analyzed and compared with Glycyrrhizae Radix produced in China. Most of the 15 samples from eastern, southern and western parts of Mongolia contained 26.95-58.55 mg/g of glycyrrhizin, exceeding the criterion (25 mg/g) assigned in the Japanese Pharmacopoeia. The sample collected in Tamsagiyn hooly, Dornod province, in eastern Mongolia was of the highest content 58.55 mg/g. The contents of three flavanone constituents (liquiritin apioside, liquiritin and liquiritigenin) and three chalcones (isoliquiritin apioside, isoliquiritin and isoliquiritigenin) varied significantly according to collection places; the subtotal of the three flavanones ranged from 3.00 to 26.35 mg/g, and the subtotal of the three chalcones ranged from 1.13 to 10.50 mg/g. The content of glycyrrhizin and subtotal contents of flavanones and chalcones in the underground parts of G. uralensis from Mongolia were obviously lower than wild samples, but higher than cultivated samples derived from the same species produced in China. Glycycoumarin, a species-specific constituent of G. uralensis, was detected in all Mongolian samples. Its contents in samples from eastern Mongolia, Sergelen and Tamsagiyn hooly of Dornod province were very high and were compatible with Tohoku-kanzo derived from wild Chinese G. uralensis. The present study suggested that Mongolian G. uralensis could be a source of Glycyrrhizae Radix, mostly of Japanese Pharmacopoeia grade. However, the producing area should be taken into consideration to ensure relatively high quality. In addition, planned use and promotion of cultivation must be advocated to avoid confronting Mongolian Glycyrrhiza with the same threat as its congener in China. Our study sheds some light on selecting cultivation areas and superior strains, which are important tasks to promote cultivation.
The two most commonly used methods to analyze data from real-time, quantitative PCR experiments are absolute quantification and relative quantification. Absolute quantification determines the input copy number, usually by relating the PCR signal to a standard curve. Relative quantification relates the PCR signal of the target transcript in a treatment group to that of another sample such as an untreated control. The 2(-Delta Delta C(T)) method is a convenient way to analyze the relative changes in gene expression from real-time quantitative PCR experiments. The purpose of this report is to present the derivation, assumptions, and applications of the 2(-Delta Delta C(T)) method. In addition, we present the derivation and applications of two variations of the 2(-Delta Delta C(T)) method that may be useful in the analysis of real-time, quantitative PCR data.
As the largest class of natural products, terpenes have a variety of roles in mediating antagonistic and beneficial interactions among organisms. They defend many species of plants, animals and microorganisms against predators, pathogens and competitors, and they are involved in conveying messages to conspecifics and mutualists regarding the presence of food, mates and enemies. Despite the diversity of terpenes known, it is striking how phylogenetically distant organisms have come to use similar structures for common purposes. New natural roles undoubtedly remain to be discovered for this large class of compounds, given that such a small percentage of terpenes has been investigated so far.