Seasonal Dynamics of Metabolites in Needles of Taxus wallichiana var. mairei

Seasonal Variation of Polyphenols and Pigments in Ginkgo (Ginkgo biloba L.) Leaves: Focus on 3',8″-Biflavones

Ginkgo (Ginkgo biloba L.) is a widely recognized medicinal plant, often grown as an ornamental species in parks around the world. Its leaves change color from green in spring to yellow in autumn. In this study, we collected ginkgo leaves at seven developmental stages from May to November and measured chlorophylls, carotenoids, flavonoids, and antioxidant activity. The total polyphenol content showed a significant increase from May to November, rising from 15.15 ± 0.14 mg GAE g-1 dw to 45.18 ± 0.42 mg GAE g-1 dw. The total flavonoid content reached its peak in August at 5.87 ± 0.18 mg GAE g-1 dw. In contrast, the highest concentrations of total polyphenolic acids (4.13 ± 0.16 mg CAE g-1 dw) and antioxidant activity (306.95 ± 3.47 µmol TE g-1) were recorded in May. We specifically focused on a less-studied group of dimeric flavonoids or biflavonoids-3',8″-biflavones. We identified five 3',8″-biflavones (amentoflavone, bilobetin, ginkgetin, isoginkgetin, and sciadopitysin) throughout all developmental stages. Sciadopitysin was the most abundant biflavonoid, with its concentration rising from 614.71 ± 5.49 µg g-1 dw in May to 2642.82 ± 47.47 µg g-1 dw in November. Alongside sciadopitysin, the content of other biflavonoids (excluding amentoflavone) generally increased over the same period. This trend is further highlighted by the total biflavonoid content, which grew from 1448.97 ± 6.63 µg g-1 dw in May to 6071.67 ± 97.15 µg g-1 dw in November. We observed a negative correlation between biflavonoid and chlorophyll content, which may indicate their involvement in leaf senescence. However, this hypothesis warrants further investigation.

Dynamics of flavonoid metabolites in coconut water based on metabolomics perspective

Coconut meat and coconut water have garnered significant attention for their richness in healthful flavonoids. However, the dynamics of flavonoid metabolites in coconut water during different developmental stages remain poorly understood. This study employed the metabolomics approach using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to investigate the changes in flavonoid metabolite profiles in coconut water from two varieties, 'Wenye No.5'(W5) and Hainan local coconut (CK), across six developmental stages. The results showed that a total of 123 flavonoid metabolites including chalcones, dihydroflavonoids, dihydroflavonols, flavonoids, flavonols, flavonoid carboglycosides, and flavanols were identified in the coconut water as compared to the control. The total flavonoid content in both types of coconut water exhibited a decreasing trend with developmental progression, but the total flavonoid content in CK was significantly higher than that in W5. The number of flavonoid metabolites that differed significantly between the W5 and CK groups at different developmental stages were 74, 74, 60, 92, 40 and 54, respectively. KEGG pathway analysis revealed 38 differential metabolites involved in key pathways for flavonoid biosynthesis and secondary metabolite biosynthesis. This study provides new insights into the dynamics of flavonoid metabolites in coconut water and highlights the potential for selecting and breeding high-quality coconuts with enhanced flavonoid content. The findings have implications for the development of coconut-based products with improved nutritional and functional properties.

3'-8″- Biflavones: A Review of Their Structural Diversity, Natural Occurrence, Role in Plants, Extraction and Identification

Dimeric forms of flavonoids, known as biflavonoids, are much less studied compared to monomeric forms. It is estimated that nearly 600 different natural biflavonoids have been described to date, containing various subtypes that can be subdivided according to the position of their combinations and the nature of the subunits. The group in which two monomers are linked by a 3'-8″-C atom includes the first isolated biflavonoid ginkgetin, derivatives of amentoflavone, and several other compounds. 3'-8″-biflavones recently attracted much attention as potential molecules with biological activity such as antiviral and antimicrobial activity and as effective molecules for the treatment of neurodegenerative and metabolic diseases and in cancer therapies. With the growing interest in them as pharmacologically active molecules, there is also increasing interest in finding new natural sources of 3'-8″-biflavones and optimizing methods for their extraction and identification. Herein, we have summarized the available data on the structural diversity, natural occurrence, role in plants, extraction, and identification of 3'-8″-biflavones.

Comparative Analysis of Polyphenolic Compounds in Different Amaranthus Species: Influence of Genotypes and Harvesting Year

Amaranth is a nutritionally valuable crop, as it contains phenolic acids and flavonoids, yielding diverse plant secondary metabolites (PSMs) like phytosterol, tocopherols, and carotenoids. This study explored the variations in the contents of seventeen polyphenolic compounds within the leaves of one hundred twenty Amaranthus accessions representing nine Amaranthus species. The investigation entailed the analysis of phenolic content across nine Amaranthus species, specifically A. hypochondriacus, A. cruentus, A. caudatus, A. tricolor, A. dubius, A. blitum, A. crispus, A. hybridus, and A. viridis, utilizing ultra performance liquid chromatography with photodiode array detection (UPLC-PDA). The results revealed significant differences in polyphenolic compounds among accessions in which rutin content was predominant in all Amaranthus species in both 2018 and 2019. Among the nine Amaranthus species, the rutin content ranged from 95.72 ± 199.17 μg g-1 (A. dubius) to 1485.09 ± 679.51 μg g-1 (A. viridis) in 2018 and from 821.59 ± 709.95 μg g-1 (A. tricolor) to 3166.52 ± 1317.38 μg g-1 (A. hypochondriacus) in 2019. Correlation analysis revealed, significant positive correlations between rutin and kaempferol-3-O-β-rutinoside (r = 0.93), benzoic acid and ferulic acid (r = 0.76), and benzoic acid and kaempferol-3-O-β-rutinoside (r = 0.76), whereas gallic acid showed consistently negative correlations with each of the 16 phenolic compounds. Wide variations were identified among accessions and between plants grown in the two years. The nine species and one hundred twenty Amaranthus accessions were clustered into six groups based on their seventeen phenolic compounds in each year. These findings contribute to expanding our understanding of the phytochemical traits of accessions within nine Amaranthus species, which serve as valuable resources for Amaranthus component breeding and functional material development.

Integrated bioinformatics and network pharmacology to explore the therapeutic target and molecular mechanisms of Taxus chinensis against non-small cell lung cancer

Taxus chinensis (TC) has tremendous therapeutic potential in alleviating non-small cell lung cancer (NSCLC), but the mechanism of action of TC remains unclear. Integrated bioinformatics and network pharmacology were employed in this study to explore the potential targets and molecular mechanism of TC against NSCLC. Data obtained from public databases were combined with appropriate bioinformatics tools to identify the common targets for TC and NSCLC. Common targets were uploaded to the Metascape database for gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathway analyses. A protein-protein interaction network was established, and topological analysis was performed to obtain hub genes. The expression of the hub genes in NSCLC tissues and their consequent effects on the prognosis of patients with NSCLC were confirmed using the Human Protein Atlas database and appropriate bioinformatics tools. Molecular docking was used to verify the binding affinity between the active ingredients and hub targets. We found 401 common targets that were significantly enriched in the cancer, MAPK signaling, and PI3K/Akt signaling pathways. Proto-oncogene tyrosine-protein kinase Src (SRC), mitogen-activated protein kinase 1, phosphoinositide-3-kinase, regulatory subunit 1 (PIK3R1), AKT serine/threonine kinase 1 (AKT1), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), and lymphocyte-specific protein tyrosine kinase were identified as the hub genes. Immunohistochemical results confirmed that the expression of SRC, mitogen-activated protein kinase 1, PIK3R1, AKT1, and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha was upregulated in the NSCLC tissues, while survival analysis revealed the expression of SRC, AKT1, PIK3R1, and lymphocyte-specific protein tyrosine kinase was closely related to the prognosis of patients with NSCLC. Molecular docking results confirmed all bioactive ingredients present in TC strongly bound to hub targets. We concluded that TC exhibits an anti-NSCLC role through multi-target combination and multi-pathway cooperation.

Mass spectrometry imaging and single-cell transcriptional profiling reveal the tissue-specific regulation of bioactive ingredient biosynthesis in Taxus leaves

Taxus leaves provide the raw industrial materials for taxol, a natural antineoplastic drug widely used in the treatment of various cancers. However, the precise distribution, biosynthesis, and transcriptional regulation of taxoids and other active components in Taxus leaves remain unknown. Matrix-assisted laser desorption/ionization-mass spectrometry imaging analysis was used to visualize various secondary metabolites in leaf sections of Taxus mairei, confirming the tissue-specific accumulation of different active metabolites. Single-cell sequencing was used to produce expression profiles of 8846 cells, with a median of 2352 genes per cell. Based on a series of cluster-specific markers, cells were grouped into 15 clusters, suggesting a high degree of cell heterogeneity in T. mairei leaves. Our data were used to create the first Taxus leaf metabolic single-cell atlas and to reveal spatial and temporal expression patterns of several secondary metabolic pathways. According to the cell-type annotation, most taxol biosynthesis genes are expressed mainly in leaf mesophyll cells; phenolic acid and flavonoid biosynthesis genes are highly expressed in leaf epidermal cells (including the stomatal complex and guard cells); and terpenoid and steroid biosynthesis genes are expressed specifically in leaf mesophyll cells. A number of novel and cell-specific transcription factors involved in secondary metabolite biosynthesis were identified, including MYB17, WRKY12, WRKY31, ERF13, GT_2, and bHLH46. Our research establishes the transcriptional landscape of major cell types in T. mairei leaves at a single-cell resolution and provides valuable resources for studying the basic principles of cell-type-specific regulation of secondary metabolism.

Quality evaluation of compounds in leaves of six Taxus species based on UPLC-MS/MS and chemometrics

Introduction: Taxus species are used as medicinal plants all over the world. The leaves of Taxus species are sustainable medicinal resources that are rich in taxoids and flavonoids. However, traditional identification methods cannot effectively identify Taxus species on the basis of leaces used as raw medicinal materials, because their appearance and morphological characteristics are almost the same, and the probability of error identification increases in accordance with the subjective consciousness of the experimenter. Moreover, although the leaves of different Taxus species have been widely used, their chemical components are similar and lack systematic comparative research. Such a situation is challenging for quality assessment. Materials and methods: In this study, ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry combined with chemometrics was applied for the simultaneous determination of eight taxoids, four flavanols, five flavonols, two dihydroflavones, and five biflavones in the leaves of six Taxus species, namely, T. mairei, T. chinensis, T. yunnanensis, T. wallichiana, T. cuspidata, and T. media. Chemometric methods, including hierarchical cluster analysis, principal component analysis, orthogonal partial least squares-discriminate analysis, random forest iterative modeling, and fisher linear discriminant analysis, were utilized to differentiate and evaluate the six Taxus species. Results: This proposed method exhibited good linearity (R ² = 0.9999-0.9972) with a lower quantification limits of 0.94-3.05 ng/mL for all analytes. The intra- and inter-day precisions were within 6.83%. Six compounds, namely, 7-xylosyl-10-deacetyltaxol, ginkgetin, rutin, aromadendrin, 10-deacetyl baccatin III, and epigallocatechin, were identified through chemometrics for the first time. These compounds can be used as important chemical markers to distinguish the above six Taxus species rapidly. Conclusion: This study established a method for determination of the leaves of six Taxus species, and revealing the differences in the chemical components of these six Taxus species.

Flavonoid Components, Distribution, and Biological Activities in Taxus: A review

Taxus, also known as "gold in plants" because of the famous agents with emphases on Taxol and Docetaxel, is a genus of the family Taxaceae, distributed almost around the world. The plants hold an important place in traditional medicine in China, and its products are used for treating treat dysuria, swelling and pain, diabetes, and irregular menstruation in women. In order to make a further study and better application of Taxus plants for the future, cited references from between 1958 and 2022 were collected from the Web of Science, the China National Knowledge Internet (CNKI), SciFinder, and Google Scholar, and the chemical structures, distribution, and bioactivity of flavonoids identified from Taxus samples were summed up in the research. So far, 59 flavonoids in total with different skeletons were identified from Taxus plants, presenting special characteristics of compound distribution. These compounds have been reported to display significant antibacterial, antiaging, anti-Alzheimer's, antidiabetes, anticancer, antidepressant, antileishmaniasis, anti-inflammatory, antinociceptive and antiallergic, antivirus, antilipase, neuronal protective, and hepatic-protective activities, as well as promotion of melanogenesis. Flavonoids represent a good example of the utilization of the Taxus species. In the future, further pharmacological and clinical experiments for flavonoids could be accomplished to promote the preparation of relative drugs.

ABA and SA Participate in the Regulation of Terpenoid Metabolic Flux Induced by Low-Temperature within Conyza blinii

Under dry-hot valley climates, Conyza blinii (also known as Jin Long Dan Cao), suffers from nocturnal low-temperature stress (LTS) during winter. Here, to investigate the biological significance of terpenoid metabolism during LTS adaptation, the growth state and terpenoid content of C. blinii under different LTS were detected, and analyzed with the changes in phytohormone. When subjected to LTS, the results demonstrated that the growth activity of C. blinii was severely suppressed, while the metabolism activity was smoothly stimulated. Meanwhile, the fluctuation in phytohormone content exhibited three different physiological stages, which are considered the stress response, signal amplification, and stress adaptation. Furthermore, drastic changes occurred in the distribution and accumulation of terpenoids, such as blinin (diterpenoids from MEP) accumulating specifically in leaves and oleanolic acid (triterpenoids from MVA) accumulating evenly and globally. The gene expression of MEP and MVA signal transduction pathways also changes under LTS. In addition, a pharmacological study showed that it may be the ABA-SA crosstalk driven by the LTS signal, that balances the metabolic flux in the MVA and MEP pathways in an individual manner. In summary, this study reveals the different standpoints of ABA and SA, and provides a research foundation for the optimization of the regulation of terpenoid metabolic flux within C. blinii.

Quality analysis of hawthorn leaves (the leaves of Crataegus pinnatifida Bge. var major N.E.Br) in different harvest time

INTRODUCTION

Harvest time plays an important role on the quality of medicinal plants. The leaves of Crataegus pinnatifida Bge. var major N.E.Br (hawthorn leaves) could be harvested in summer and autumn according to the Pharmacopoeia of the People's Republic of China (Pharmacopoeia). However, little is known about the difference of the chemical constituents in hawthorn leaves with the harvest seasonal variations.

OBJECTIVE

The chemical constituents of hawthorn leaves in different months were comprehensively analysed to determine the best harvest time.

METHODS

Initially, the chemical information of the hawthorn leaves were obtained by ultra-high-performance liquid chromatography and quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). Subsequently, principal component analysis (PCA) was applied to compare the chemical compositions of hawthorn leaves harvested in different months. Then, an absolute quantitation method was established using high-performance liquid chromatography-charged aerosol detector (HPLC-CAD) to determine the contents of five compounds and clarify the changes of these components with the harvest seasonal variations. Meanwhile, a semi-quantitative method by integrating HPLC-CAD with inverse gradient compensation was also established and verified.

RESULTS

Fifty-eight compounds were identified through UHPLC-Q-TOF-MS. PCA revealed that the harvest season of hawthorn leaves had a significant effect on the chemical compositions. The contents of five components were relatively high in autumn. Other four main components without reference standards were further analysed through the semi-quantitative method, which also showed a high content in autumn.

CONCLUSIONS

This work emphasised the effect of harvest time on the chemical constituents of hawthorn leaves and autumn is recommended to ensure the quality.

Seasonal variation influences flavonoid biosynthesis path and content, and antioxidant activity of metabolites in Tetrastigma hemsleyanum Diels & Gilg

Environmental conditions contribute to plant growth and metabolism. This study aimed to determine a suitable environment and climate for large-scale artificial cultivation of an endangered plant, Tetrastigma hemsleyanum, by investigating the seasonal variations influencing the flavonoid biosynthetic selectivity and antioxidant activity of its major metabolites. Under conditions of precipitation (2.0~6.6 mm), temperature (17.5~24.1°C), humidity (67.3~80.2%), and sunshine duration (3.4~5.8 h) from April to May, the total flavonoid content in T. hemsleyanum reached higher levels between 281.3 and 392.8 μg/g. In the second half of April, the production selectivity (PS) of isoorientin (IsoO), orientin (Or), rutin (Rut), isoquercitin (IsoQ), kaempferol-3-O-rutinoside (Km3rut), astragalin (Ast), quercetin (Qu), apigenin (Ap), and kaempferol (Km) were 0.30, 0.06, 0.07, 0.07, 0.00, 0.04, 0.38, 0.05, and 0.03, respectively. Naringenin was dehydrogenated or hydroxylated to initiate two parallel reaction pathways for flavonoid biosynthesis in T. hemsleyanum: path I subsequently generated flavone derivatives including apigenin, luteolin, orientin, and isoorientin, and path II subsequently generated flavonol derivatives including Km, Qu, IsoQ, Rut, Ast, and Km3rut. The reaction selectivity of path II (RPSII) from January 1 to September 30 was considerably higher than that of path I (RPSI), except for March 16-31. In addition, either the content or antioxidant activity of three major metabolites in T. hemsleyanum followed the order of phenolic compounds > polysaccharides > sterols, and exhibited dynamic correlations with environmental factors. Naringenin favored hydroxylation and derived six flavonol compounds from January to September, and favored dehydrogenation and derived three flavone compounds from October to December. In most months of a year, Km preferentially favored hydroxylation rather than glucosylation.

Accumulation Pattern of Flavonoids during Fruit Development of Lonicera maackii Determined by Metabolomics

Lonicera maackii (Caprifoliaceae) is a large, upright shrub with fruits that contain many bioactive compounds. Flavonoids are common active substances in L. maackii. However, there is a dearth of information about the accumulation of these flavonoids and their possible medicinal value. We used targeted metabolomics analysis based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to analyze five developmental stages of L. maackii fruit. A total of 438 metabolites were identified in the five developmental stages, including 81 flavonoids and derivatives. The 81 flavonoids included 25 flavones and derivatives, 35 flavonols and derivatives, two isoflavones, three cyanidins and derivatives, eight procyanidins, and eight flavanones. In addition, we outlined the putative flavonoid biosynthesis pathway and screened their upstream metabolites. More importantly, we analyzed the accumulation patterns of several typical flavones and flavonols. The results reported here improved our understanding of the dynamic changes in flavonoids during fruit development and contributed to making full use of the medicinal value of L. maackii fruit.

Limoniastrum guyonianum behavior under seasonal conditions fluctuations of Sabkha Aïn Maïder (Tunisia)

In Sabkha biotope, several environmental factors (i.e., salinity, drought, temperature, etc.) especially during dry season affect halophytes developments. To cope with these harmful conditions, halophytes use multiple mechanisms of adaptations. In this study, we focused on the effect of environmental condition changes over a year in the Sabkha of Aïn Maïder (Medenine - Tunisia) on the physiological and biochemical behavior of Limoniastrum guyonianum using a modeling approach. Our study showed that the model depicted well (R² > 0.75) the monthly fluctuations of the studied parameters in this habitat. During the dry period (June to September), the salinity of the soil increased remarkably (high level of EC and Na⁺ content), resulting in high Na⁺ content in the aerial parts followed by a nutrient deficiency in K⁺, Ca²⁺, and Mg²⁺. As a result of this disruption, L. guyonianum decreased its water potential to more negative values to maintain osmotic potential using inorganic osmolytes (i.e., Na⁺) and organic osmolytes (i.e., sugars: sucrose, fructose, glucose, and xylitol, and organic acids: citric and malic acids). In addition, CO₂ assimilation rate, stomatal conductance, transpiration rate, and photosynthetic pigments decreased significantly with increasing salinity. The phenolic compounds contents and the antioxidant activity increased significantly in the dry period as a result of increased levels of H₂O₂ and lipid peroxidation. This increase was highly correlated with soil salinity and air temperature. The maintenance of tissue hydration (i.e., moderate decrease of relative water content), the accumulation of sugars and organic acids, the enhancement of phenolic compounds amounts, and the increase of antioxidant activity during the dry period suggest that L. guyonianum possesses an efficient tolerance mechanism that allows the plant to withstand the seasonal fluctuations of climatic conditions in its natural biotope.

Genetic and Environmental Factors Jointly Impact Leaf Phenolic Profiles of Iris variegata L

A plant’s main mechanism to diminish the effects caused by high free radical levels generated during high irradiance is the synthesis of various secondary metabolites. In addition to interspecies differences, their concentrations may be influenced by genetic, ontogenic, morphogenetic or environmental factors. We investigated the influence of genetic (genotypes from different natural habitats) and environmental (contrasting light regimes as well as successive parts of the vegetation period) variability on the accumulation of 10 selected phenolic compounds (phenolic acids, flavonoids, and xanthones) in Iris variegata genotypes. Genotypes originated from either sun-exposed or shaded natural habitats were transplanted to two experimental light treatments (high light intensity with a higher R/FR ratio and low light intensity with a lower R/FR ratio). Significant impacts of both genetic and environmental seasonal variability (spring, summer and fall during the vegetation period) on phenolic compound profiles were detected. Their highest amounts were detected in spring. The magnitude of difference between light treatments (high vs. low light intensity) and the direction of this change varied depending on the secondary compound class. Phenotypic correlations among the 10 analyzed secondary metabolites differed across the experimental light treatments and their number decreased from spring to fall.

Omic analysis of the endangered Taxaceae species Pseudotaxus chienii revealed the differences in taxol biosynthesis pathway between Pseudotaxus and Taxus yunnanensis trees

BACKGROUND

Taxol is an efficient anticancer drug accumulated in Taxus species. Pseudotaxus chienii is an important member of Taxaceae, however, the level of six taxoids in P. chienii is largely unknown.

RESULTS

High accumulation of 10-DAB, taxol, and 7-E-PTX suggested that P. chienii is a good taxol-yielding species for large-scale cultivation. By the omics approaches, a total of 3,387 metabolites and 61,146 unigenes were detected and annotated. Compared with a representative Taxus tree (Taxus yunnanensis), most of the differentially accumulated metabolites and differential expressed genes were assigned into 10 primary and secondary metabolism pathways. Comparative analyses revealed the variations in the precursors and intermediate products of taxol biosynthesis between P. chienii and T. yunnanensis. Taxusin-like metabolites highly accumulated in P. chienii, suggesting a wider value of P. chienii in pharmaceutical industry.

CONCLUSIONS

In our study, the occurrence of taxoids in P. chienii was determined. The differential expression of key genes involved in the taxol biosynthesis pathway is the major cause of the differential accumulation of taxoids. Moreover, identification of a number of differentially expressed transcription factors provided more candidate regulators of taxol biosynthesis. Our study may help to reveal the differences between Pseudotaxus and Taxus trees, and promote resource utilization of the endangered and rarely studied P. chienii.

Comparative metabolomic analysis reveals the variations in taxoids and flavonoids among three Taxus species

BACKGROUND

Trees of the genus Taxus are highly valuable medicinal plants with multiple pharmacological effects on various cancer treatments. Paclitaxel from Taxus trees is an efficient and widely used anticancer drug, however, the accumulation of taxoids and other active ingredients can vary greatly among Taxus species. In our study, the metabolomes of three Taxus species have been investigated.

RESULTS

A total of 2246 metabolites assigned to various primary and secondary metabolic pathways were identified using an untargeted approach. Analysis of differentially accumulated metabolites identified 358 T. media-, 220 T. cuspidata-, and 169 T. mairei-specific accumulated metabolites, respectively. By searching the metabolite pool, 7 MEP pathway precursors, 11 intermediates, side chain products and derivatives of paclitaxel, and paclitaxel itself were detected. Most precursors, initiated intermediates were highly accumulated in T. mairei, and most intermediate products approaching the end point of taxol biosynthesis pathway were primarily accumulated in T. cuspidata and T. media. Our data suggested that there were higher-efficiency pathways to paclitaxel in T. cuspidata and T. media compared with in T. mairei. As an important class of active ingredients in Taxus trees, a majority of flavonoids were predominantly accumulated in T. mairei rather than T. media and T. cuspidata. The variations in several selected taxoids and flavonoids were confirmed using a targeted approach.

CONCLUSIONS

Systematic correlativity analysis identifies a number of metabolites associated with paclitaxel biosynthesis, suggesting a potential negative correlation between flavonoid metabolism and taxoid accumulation. Investigation of the variations in taxoids and other active ingredients will provide us with a deeper understanding of the interspecific differential accumulation of taxoids and an opportunity to accelerate the highest-yielding species breeding and resource utilization.

Metabolic Variations of Flavonoids in Leaves of T. media and T. mairei Obtained by UPLC-ESI-MS/MS

The needles of Taxus species contain a large number of bioactive compounds, such as flavonoids. In the present study, the total flavonoid content in leaves of Taxus media and Taxus mairei was 19.953 and 14.464 mg/g, respectively. A total of 197 flavonoid metabolites (70 flavones, 42 flavonols, 26 flavone C-glycosides, 20 flavanones, 15 anthocyanins, 13 isoflavones, 6 flavonolignans, and 5 proanthocyanidins) were identified for the first time by a widely targeted Ultra Performance Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry (UPLC-ESI-MS/MS) method within the two Taxus species, containing 160 common metabolites, with 37 unique metabolites merely determined in T. mairei or T. media. Moreover, 42 differential flavonoid metabolites were screened in the two Taxus species, which showed specific metabolic patterns in isoflavonoid biosynthesis, anthocyanin biosynthesis, and flavone and flavonol biosynthesis pathways. Compared to T. mairei, a more activated phenylpropanoid pathway was found in T. media, which could be responsible for the higher content of total flavonoids in T. media. Our results provide new insights into the diversity of flavonoid metabolites between T. mairei and T. media, and provide a theoretical basis for the sufficient utilization of Taxus species and the development of novel drugs.

Transcriptome analyses provide insights into the expression pattern and sequence similarity of several taxol biosynthesis-related genes in three Taxus species

BACKGROUND

Taxol is an efficient anticancer drug; however, the accumulation of taxoids can vary hugely among Taxus species. The mechanism underlying differential accumulation of taxoids is largely unknown. Thus, comparative analysis of the transcriptomes in three Taxus species, including T. media, T. mairei and T. cuspidata, was performed.

RESULTS

KEGG enrichment analysis revealed that the diterpenoid biosynthesis and cytochrome P450 pathways were significantly enriched in different comparisons. Differential expressions of these taxol biosynthesis related genes might be a potential explanation for the interspecific differential accumulation of taxol and its derivatives. Besides, the sequences of several MEP pathway-associated genes, such as DXS, DXR, MCT, CMK, MDS, HDS, HDR, IPPI, and GGPPS, were re-assembled based on independent transcriptomes from the three Taxus species. Phylogenetic analysis of these MEP pathway-associated enzymes also showed a high sequence similarity between T. media and T. cuspidata. Moreover, 48 JA-related transcription factor (TF) genes, including 10 MYBs, 5 ERFs, 4 RAPs, 3 VTCs, and 26 other TFs, were analyzed. Differential expression of these JA-related TF genes suggested distinct responses to exogenous JA applications in the three Taxus species.

CONCLUSIONS

Our results provide insights into the expression pattern and sequence similarity of several taxol biosynthesis-related genes in three Taxus species. The data give us an opportunity to reveal the mechanism underlying the variations in the taxoid contents and to select the highest-yielding Taxus species.

Fungicidal activity of 10-deacetylbacatin III against Phytophthora capsici via inhibiting lysine biosynthesis

10-deacetyl-bacatin III (10-DAB) is a natural plant-derived taxane diterpene, whose antimicrobial activity against phytopathogens remains unknown. In this study, we demonstrated the antimicrobial effect of 10-DAB on plant-pathogenic oomycetes. Our results revealed that 10-DAB exhibited significant antimicrobial activities against test oomycetes, especially against Phytophthora capsici, with a median effective concentration (EC₅₀) of 1.46 μg/mL, but had no effect on test fungi. Under 10-DAB treatment, mycelia of P. capsici were contorted with an increased number of top branches, and the production and germination of zoospores were inhibited and delayed, respectively. In addition, 10-DAB had favorable protective and curative activities with control efficacies of 63.90% and 74.81% at 200 μg/mL on detached pepper leaves. Furthermore, 10-DAB caused a significant decrease in soluble protein, lysine, and α, ε-diaminopimelic acid content of P. capsici, which suggested that 10-DAB inhibited the lysine biosynthesis. On the contrary, treatment with exogenous lysine effectively counteracted 10-DAB's inhibition activity on P. capsici. Moreover, relative expression of four key lysine biosynthesis-related genes of P. capsici were decreased upon 10-DAB treatment. Taken together, our findings suggest a lysine biosynthesis inhibiting-dependent antimicrobial activity of 10-DAB against P. capsici, which contributes to accelerating the application of 10-DAB for successful management of phytophthora blight disease in agricultural production.

Comparative metabolomics reveals the metabolic variations between two endangered Taxus species (T. fuana and T. yunnanensis) in the Himalayas

BACKGROUND

Plants of the genus Taxus have attracted much attention owing to the natural product taxol, a successful anti-cancer drug. T. fuana and T. yunnanensis are two endangered Taxus species mainly distributed in the Himalayas. In our study, an untargeted metabolomics approach integrated with a targeted UPLC-MS/MS method was applied to examine the metabolic variations between these two Taxus species growing in different environments.

RESULTS

The level of taxol in T. yunnanensis is much higher than that in T. fuana, indicating a higher economic value of T. yunnanensis for taxol production. A series of specific metabolites, including precursors, intermediates, competitors of taxol, were identified. All the identified intermediates are predominantly accumulated in T. yunnanensis than T. fuana, giving a reasonable explanation for the higher accumulation of taxol in T. yunnanensis. Taxusin and its analogues are highly accumulated in T. fuana, which may consume limited intermediates and block the metabolic flow towards taxol. The contents of total flavonoids and a majority of tested individual flavonoids are significantly accumulated in T. fuana than T. yunnanensis, indicating a stronger environmental adaptiveness of T. fuana.

CONCLUSIONS

Systemic metabolic profiling may provide valuable information for the comprehensive industrial utilization of the germplasm resources of these two endangered Taxus species growing in different environments.

Response of Plant Secondary Metabolites to Environmental Factors

Plant secondary metabolites (SMs) are not only a useful array of natural products but also an important part of plant defense system against pathogenic attacks and environmental stresses. With remarkable biological activities, plant SMs are increasingly used as medicine ingredients and food additives for therapeutic, aromatic and culinary purposes. Various genetic, ontogenic, morphogenetic and environmental factors can influence the biosynthesis and accumulation of SMs. According to the literature reports, for example, SMs accumulation is strongly dependent on a variety of environmental factors such as light, temperature, soil water, soil fertility and salinity, and for most plants, a change in an individual factor may alter the content of SMs even if other factors remain constant. Here, we review with emphasis how each of single factors to affect the accumulation of plant secondary metabolites, and conduct a comparative analysis of relevant natural products in the stressed and unstressed plants. Expectantly, this documentary review will outline a general picture of environmental factors responsible for fluctuation in plant SMs, provide a practical way to obtain consistent quality and high quantity of bioactive compounds in vegetation, and present some suggestions for future research and development.

Comparative proteomic analyses of two Taxus species (Taxus × media and Taxus mairei) reveals variations in the metabolisms associated with paclitaxel and other metabolites

Taxus species are well-known for paclitaxel, which exhibits antitumor activities and is used for treating various cancers. Although most Taxus species are widespread in many areas, few studies have characterized the variation in metabolism among different Taxus species. Using an integrated approach involving 'tandem mass tag' labeling and liquid chromatography-tandem mass spectrometry (HPLC-MS), proteomes of T. media and T. mairei were investigated and 4078 proteins were quantified. Screening and classification of differentially expressed proteins revealed many metabolism-associated proteins. In detail, four enzymes involved in the flavonoid biosynthesis pathway were predominantly expressed in T. mairei. Four enzymes associated with supplying precursors for paclitaxel biosynthesis and three cytochrome P450 taxoid oxygenases were preferentially expressed in T. media compared with T. mairei. Furthermore, variations in taxoid contents between T. media and T. mairei were determined using HPLC-MS analysis. Variations in flavonoid contents between T. media and T. mairei were determined by HPLC analysis. A number of differentially expressed proteins may provide an explanation for the variation in metabolisms of different Taxus species.

Diterpenoids of terrestrial origin

This review covers the isolation and chemistry of diterpenoids from terrestrial as opposed to marine sources and includes labdanes, clerodanes, abietanes, pimaranes, kauranes, cembranes and their cyclization products. The literature from January to December, 2016 is reviewed.