Pinoresinol rescues developmental phenotypes of Arabidopsis phenylpropanoid mutants overexpressing FERULATE 5-HYDROXYLASE.

Most phenylpropanoid pathway flux is directed toward the production of monolignols, but this pathway also generates multiple bioactive metabolites. The monolignols coniferyl and sinapyl alcohol polymerize to form guaiacyl (G) and syringyl (S) units in lignin, components that are characteristic of plant secondary cell walls. Lignin negatively impacts the saccharification potential of lignocellulosic biomass. Although manipulation of its content and composition through genetic engineering has reduced biomass recalcitrance, in some cases, these genetic manipulations lead to impaired growth. The reduced-growth phenotype is often attributed to poor water transport due to xylem collapse in low-lignin mutants, but alternative models suggest that it could be caused by the hyper- or hypoaccumulation of phenylpropanoid intermediates. In Arabidopsis thaliana, overexpression of FERULATE 5-HYDROXYLASE (F5H) shifts the normal G/S lignin ratio to nearly pure S lignin and does not result in substantial changes to plant growth. In contrast, when we overexpressed F5H in the low-lignin mutants cinnamyl dehydrogenase c and d (cadc cadd), cinnamoyl-CoA reductase 1, and reduced epidermal fluorescence 3, plant growth was severely compromised. In addition, cadc cadd plants overexpressing F5H exhibited defects in lateral root development. Exogenous coniferyl alcohol (CA) and its dimeric coupling product, pinoresinol, rescue these phenotypes. These data suggest that mutations in the phenylpropanoid pathway limit the biosynthesis of pinoresinol, and this effect is exacerbated by overexpression of F5H, which further draws down cellular pools of its precursor, CA. Overall, these genetic manipulations appear to restrict the synthesis of pinoresinol or a downstream metabolite that is necessary for plant growth.

Integrative analysis of the metabolome and transcriptome provides insights into the mechanisms of lignan biosynthesis in Herpetospermum pedunculosum (Cucurbitaceae).

BACKGROUND: Herpetospermum pedunculosum (Ser.) C. B. Clarke is a traditional Chinese herbal medicine that heavily relies on the lignans found in its dried ripe seeds (Herpetospermum caudigerum), which have antioxidant and hepatoprotective functions. However, little is known regarding the lignan biosynthesis in H. pedunculosum. In this study, we used metabolomic (non-targeted UHPLC-MS/MS) and transcriptome (RNA-Seq) analyses to identify key metabolites and genes (both structural and regulatory) associated with lignan production during the green mature (GM) and yellow mature (YM) stages of H. pedunculosum. RESULTS: The contents of 26 lignan-related metabolites and the expression of 30 genes involved in the lignan pathway differed considerably between the GM and YM stages; most of them were more highly expressed in YM than in GM. UPLC-Q-TOF/MS confirmed that three Herpetospermum-specific lignans (including herpetrione, herpetotriol, and herpetin) were found in YM, but were not detected in GM. In addition, we proposed a lignan biosynthesis pathway for H. pedunculosum based on the fundamental principles of chemistry and biosynthesis. An integrated study of the transcriptome and metabolome identified several transcription factors, including HpGAF1, HpHSFB3, and HpWOX1, that were highly correlated with the metabolism of lignan compounds during seed ripening. Furthermore, functional validation assays revealed that the enzyme 4-Coumarate: CoA ligase (4CL) catalyzes the synthesis of hydroxycinnamate CoA esters. CONCLUSION: These results will deepen our understanding of seed lignan biosynthesis and establish a theoretical basis for molecular breeding of H. pedunculosum.

The conversion of monolignans to sesquilignans and dilignans is closely correlated to the regulation of Arctium lappa seed germination.

MAIN CONCLUSION: The secondary metabolic conversion of monolignans to sesquilignans/dilignans was closely related to seed germination and seedling establishment in Arctium lappa. Arctium lappa plants are used as a kind of traditional Chinese medicines for nearly 1500 years, and so far, only a few studies have put focus on the key secondary metabolic changes during seed germination and seedling establishment. In the current study, a combined approach was used to investigate the correlation among secondary metabolites, plant hormone signaling, and transcriptional profiles at the early critical stages of A. lappa seed germination and seedling establishment. Of 50 metabolites in methonolic extracts of A. lappa samples, 35 metabolites were identified with LC-MS/MS and 15 metabolites were identified with GC-MS. Their qualitative properties were examined according to the predicted chemical structures. The quantitative analysis was performed for deciphering their metabolic profiles, discovering that the secondary metabolic conversion from monolignans to sesquilignans/dilignans was closely correlated to the initiation of A. lappa seed germination and seedling establishment. Furthermore, the critical transcriptional changes in primary metabolisms, translational regulation at different cellular compartments, and multiple plant hormone signaling pathways were revealed. In addition, the combined approach provides unprecedented insights into key regulatory mechanisms in both gene transcription and secondary metabolites besides many known primary metabolites during seed germination of an important traditional Chinese medicinal plant species. The results not only provide new insights to understand the regulation of key medicinal components of 'ARCTII FRUCTUS', arctiin and arctigenin at the stages of seed germination and seedling establishment, but also potentially spur the development of seed-based cultivation in A. lappa plants.

Enterolignans: from natural origins to cardiometabolic significance, including chemistry, dietary sources, bioavailability, and activity.

The enterolignans, enterolactone and enterodiol, the main metabolites produced from plant lignans by the gut microbiota, have enhanced bioavailability and activity compared to their precursors, with beneficial effects on metabolic and cardiovascular health. Although extensively studied, the biosynthesis, cardiometabolic effects, and other therapeutic implications of mammalian lignans are still incompletely understood. The aim of this review is to provide a comprehensive overview of these phytoestrogen metabolites based on up-to-date information reported in studies from a wide range of disciplines. Established and novel synthetic strategies are described, as are the various lignan precursors, their dietary sources, and a proposed metabolic pathway for their conversion to enterolignans. The methodologies used for enterolignan analysis and the available data on pharmacokinetics and bioavailability are summarized and their cardiometabolic bioactivity is explored in detail. The special focus given to research on the health benefits of microbial-derived lignan metabolites underscores the critical role of lignan-rich diets in promoting cardiovascular health.

Plasmid-free production of the plant lignan pinoresinol in growing Escherichia coli cells.

BACKGROUND: The high-value aryl tetralin lignan (+)-pinoresinol is the main precursor of many plant lignans including (-)-podophyllotoxin, which is used for the synthesis of chemotherapeutics. As (-)-podophyllotoxin is traditionally isolated from endangered and therefore limited natural sources, there is a particular need for biotechnological production. Recently, we developed a reconstituted biosynthetic pathway from (+)-pinoresinol to (-)-deoxypodophyllotoxin, the direct precursor of (-)-podophyllotoxin, in the recombinant host Escherichia coli. However, the use of the expensive substrate (+)-pinoresinol limits its application from the economic viewpoint. In addition, the simultaneous expression of multiple heterologous genes from different plasmids for a multi-enzyme cascade can be challenging and limits large-scale use. RESULTS: In this study, recombinant plasmid-free E. coli strains for the multi-step synthesis of pinoresinol from ferulic acid were constructed. To this end, a simple and versatile plasmid toolbox for CRISPR/Cas9-assisted chromosomal integration has been developed, which allows the easy transfer of genes from the pET vector series into the E. coli chromosome. Two versions of the developed toolbox enable the efficient integration of either one or two genes into intergenic high expression loci in both E. coli K-12 and B strains. After evaluation of this toolbox using the fluorescent reporter mCherry, genes from Petroselinum crispum and Zea mays for the synthesis of the monolignol coniferyl alcohol were integrated into different E. coli strains. The product titers achieved with plasmid-free E. coli W3110(T7) were comparable to those of the plasmid-based expression system. For the subsequent oxidative coupling of coniferyl alcohol to pinoresinol, a laccase from Corynebacterium glutamicum was selected. Testing of different culture media as well as optimization of gene copy number and copper availability for laccase activity resulted in the synthesis of 100 mg/L pinoresinol using growing E. coli cells. CONCLUSIONS: For efficient and simple transfer of genes from pET vectors into the E. coli chromosome, an easy-to-handle molecular toolbox was developed and successfully tested on several E. coli strains. By combining heterologous and endogenous enzymes of the host, a plasmid-free recombinant E. coli growing cell system has been established that enables the synthesis of the key lignan pinoresinol.

An Improved Assessment Method to Estimate (Poly)phenol Intake in Adults with Chronic Pancreatitis.

BACKGROUND: Insights into (poly)phenol exposure represent a modifiable factor that may modulate inflammation in chronic pancreatitis (CP), yet intake is poorly characterized and methods for assessment are underdeveloped. AIMS: The aims are to develop and test a method for estimating (poly)phenol intake from a 90-day food frequency questionnaire (FFQ) using the Phenol-Explorer database and determine associations with dietary patterns in CP patients versus controls via analysis of previously collected cross-sectional data. METHODS: Fifty-two CP patients and 48 controls were recruited from an ambulatory clinic at a large, academic institution. To assess the feasibility of the proposed methodology for estimating dietary (poly)phenol exposure, a retrospective analysis of FFQ data was completed. Mann-Whitney U tests were used to compare (poly)phenol intake by group; Spearman correlations and multivariable-adjusted log-linear associations were used to compare (poly)phenol intakes with dietary scores within the sample. RESULTS: Estimation of (poly)phenol intake from FFQs was feasible and produced estimates within a range of intake previously reported. Total (poly)phenol intake was significantly lower in CP vs controls (463 vs. 567mg/1000kcal; p = 0.041). In adjusted analyses, higher total (poly)phenol intake was associated with higher HEI-2015 (r = 0.34, p < 0.001), aMED (r = 0.22, p = 0.007), EDIH (r = 0.29, p < 0.001), and EDIP scores (r = 0.35, p < 0.001), representing higher overall diet quality and lower insulinemic and anti-inflammatory dietary potentials, respectively. CONCLUSIONS: Using enhanced methods to derive total (poly)phenol intake from an FFQ is feasible. Those with CP have lower total (poly)phenol intake and less favorable dietary pattern indices, thus supporting future tailored dietary intervention studies in this population.

Specialized metabolites degradation by microorganisms.

Secondary metabolites are specialized metabolic products synthesized by plants, insects, and bacteria, some of which exhibit significant physiological activities against other organisms. Plants containing bioactive secondary metabolites have been used in traditional medicine for centuries. In developed countries, one-fourth of medicines directly contain plant-derived compounds or indirectly contain them via semi-synthesis. These compounds have contributed considerably to the development of not only medicine but also molecular biology. Moreover, the biosynthesis of these physiologically active secondary metabolites has attracted substantial interest and has been extensively studied. However, in many cases, the degradation mechanisms of these secondary metabolites remain unclear. In this review, some unique microbial degradation pathways for lignans and C-glycosides are explored.

Minor Lignans with Inhibitory Activity against LPS-induced NO Production from Schisandra chinensis.

Phytochemical investigation into the fruits of Schisandra chinensis led to the isolation of seven new minor lignans, schisanchignans A-G (1-7), including one benzofuran type (1), three aryltetralin type (2-4) and three tetrahydrofuran type (5-7). Their structures were established by comprehensive spectroscopic analyses, and the absolute configurations were determined by electronic circular dichroism technique including quantum chemical calculation method. Of note, this is the first report of nor-benzofuran and aryltetralin types of lignans from S. chinensis. Compounds 1, 3 and 4 exhibited mild inhibitory activity against the lipopolysaccharide-induced production of nitric oxide in murine RAW264.7 cells.

Alkaloids and Lignans from the Aerial Parts of Rauvolfia tetraphylla Inhibit NO Production in LPS-activated RAW 264.7 Cells.

Three previously undescribed compounds named rauvolphyllas A-C (1-3), along with thirteen known compounds, 18ß-hydroxy-3-epi-α-yohimbine (4), yohimbine (5), α-yohimbine (6), 17-epi-α-yohimbine (7), (E)-vallesiachotamine (8), (Z)-vallesiachotamine (9), 16S-E-isositsirikine (10), Nb -methylisoajimaline (11), Nb -methylajimaline (12), ajimaline (13), (+)-lyoniresinol 3α-O-ß-D-glucopyranoside (14), (+)-isolarisiresinol 3α-O-ß-D-glucopyranoside (15), and (-)-lyoniresinol 3α-O-ß-D-glucopyranoside (16) were isolated from the aerial parts of Rauvolfia tetraphylla L. Their chemical structures were elucidated based on the extensive spectroscopic interpretation of HR-ESI-MS, 1D and 2D NMR spectra. The absolute configurations of 2 and 3 were determined by experimental ECD spectra. Compounds 5, 6, 7, and 11-13 exhibited nitric oxide production inhibition activity in LPS-activated RAW 264.7 cells with the IC50 values of 79.10, 44.34, 51.28, 33.54, 37.67, and 28.56 µM, respectively, compared to that of the positive control, dexamethasone, which showed IC50 value of 13.66 µM. The other isolates were inactive with IC50 values over 100 µM.

Isolation of Novel Compounds from Lepidium sativum Seeds and Evaluation of Their Potential Anti-tumor Activity.

Four undescribed compounds including a pair of enantiomers of a dihydroarylnaphthalene lignan [(±)-1], an arylnaphthalene lignan (2), and an indoleacetic acid ester (3), together with four known compounds (4－7), were isolated from the seeds of Lepidium sativum. Their structures were identified by HRMS and NMR spectroscopic data, and the absolute configuration of these compounds were assigned by ECD data in combination with quantum chemical calculations. Compound (-)-1 had weak inhibitory activity against HeLa cell line with an IC50 value of 60.23 ± 3.51 µM, and compound (+)-1 presented moderate inhibitory effect against HeLa cell line with an IC50 value of 19.99 ± 1.00 µM (IC50 value of the positive control was 0.40 ±0.02 µM).

Hepatoprotective Lignan Glycosides from the Leaves and Stems of Symplocos cochinchinensis (Lour.) S. Moore.

This study investigates Symplocos cochinchinensis (Lour.) S. Moore leaves and stems, commonly known as Symplocos, a plant indigenous to Asia renowned for its traditional use in holistic medicine. A comprehensive phytochemical analysis of S. cochinchinensis led to the isolation of two new lignans, namely symplolignans A and B (1 and 2) along with eleven known lignan glucosides: nortrachelogenin 4-O-ß-D-glucopyranoside (3), nortracheloside (4), matairesinol 4-O-ß-D-glucopyranoside (5), lariciresinol 4'-O-ß-D-glucopyranoside (6), balanophonin 4-O-ß-D-glucopyranoside (7), dehydrodiconiferyl alcohol 4-O-ß-D-glucopyranoside (8), dehydrodiconiferyl alcohol γ'-O-ß-D-glucopyranoside (9), 3-(ß-D-glucopyranosyloxymethyl)-2-(4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl)-7-methoxy-(2R,3S)-dihydrobenzofura (10), and pinoresinol 4'-O-ß-D-glucopyranoside (11). Their chemical structures were elucidated using 1D- and 2D-NMR, mass spectrometry, and their spectroscopic data were compared with those reported in literatures. Furthermore, all compounds were evaluated for their hepatoprotective effects using the Resazurin reduction assay in HepG2 hepatocellular carcinoma cells. Compounds 1, 5, 7, and 8 exhibited notable hepatoprotective efficacy, with cell viability ranging from 105.0±2.6 to 109.2±3.3 at a concentration of 10 µM. This research highlights the therapeutic potential of these compounds and enhanced to the understanding of lignans and neolignans in liver cell proliferation.

Simultaneous separation and determination of seven biphenyl cyclooctene lignans in Schisandra chinensis and its preparations by micellar electrokinetic chromatography with dual organic solvent system.

INTRODUCTION: Gomisin is a natural dibenzo cyclooctene lignan, which is mainly derived from the family Magnoliaceae. It has anti-inflammatory, antioxidant, anti-tumor, anti-aging, and hypoglycemic effects. Gomisins play important roles as medicines, nutraceuticals, food additives, and cosmetics. OBJECTIVE: The objective of this study is to establish a micellar electrokinetic chromatography (MEKC) method for simultaneous separation and determination of seven biphenyl cyclooctene lignans (Gomisin D, E, G, H, J, N, and O) in Schisandra chinensis and its preparations. METHODS: The method was optimized by studying the effects of the main parameters on the separation. The method has been validated and successfully applied to the determination of seven Gomisins in S. chinensis and its preparations. RESULTS: In the separation system, the running buffer was composed of 20 mM Na2HPO4, 8.0 mM sodium dodecyl sulfate (SDS), 11% (v/v) methanol, and 6.0% (v/v) ethanol. A diode array detector was used with a detection wavelength of 230 nm, a separation voltage of 17 kV, and an operating temperature of 25°C. Under this condition, the seven analytes were separated at baseline within 20 min, and a good linear relationship was obtained with correlation coefficient ranging from 0.9919 to 0.9992. The limit of detection (LOD, S/N = 3) and the limit of quantification (LOQ, S/N = 10) ranged from 0.8 to 0.9 µg/mL and from 2.6 to 3.0 µg/mL, respectively. The recovery rate was between 99.1% and 102.5%. CONCLUSION: The experimental results indicated that this method is suitable for the separation and determination of seven Schisandra biphenyl cyclooctene lignan compounds in real samples. At the same time, it provides an effective reference for the quality control of S. chinensis and its preparations.

Bioactive neolignan, iridoid and flavonoid glycosides from the leaves of Vaccinium bracteatum.

Two neolignan glycosides including a new one (1), along with seven iridoid glycosides (3 - 9) and nine flavonoid glycosides (10 - 18), were isolated from the leaves of Vaccinium bracteatum. Their structures were established mainly on the basis of 1D/2D NMR and ESIMS analyses, as well as comparison to known compounds in the literature. The structure of 1 with absolute stereochemistry was also confirmed by chemical degradation and ECD calculation. Selective compounds showed antiradical activity against ABTS and/or DPPH. Moreover, several isolates also suppressed the production of ROS in RAW264.7 cells and exerted neuroprotective effect toward PC12 cells.

Dibenzocyclooctadiene Lignans from Schisandra chinensis with Anti-Inflammatory Effects.

Schisandra chinensis (Schisandraceae) is a medicinal plant widely used in traditional Chinese medicine. Under the name Wu Wei Zi, it is used to treat many diseases, especially as a stimulant, adaptogen, and hepatoprotective. Dibenzocyclooctadiene lignans are the main compounds responsible for the effect of S. chinensis. As a part of ongoing studies to identify and evaluate anti-inflammatory natural compounds, we isolated a series of dibenzocyclooctadiene lignans and evaluated their biological activity. Furthermore, we isolated new sesquiterpene 7,7-dimethyl-11-methylidenespiro[5.5]undec-2-ene-3-carboxylic acid. Selected dibenzocyclooctadiene lignans were tested to assess their anti-inflammatory potential in LPS-stimulated monocytes by monitoring their anti-NF-κB activity, antioxidant activity in CAA assay, and their effect on gap junction intercellular communication in WB-ras cells. Some S. chinensis lignans showed antioxidant activity in CAA mode and affected the gap junction intercellular communication. The anti-inflammatory activity was proven for (-)-gomisin N, (+)-γ-schisandrin, rubrisandrin A, and (-)-gomisin J.

An Unprecedented 4,8-Cycloeudesmane, Further New Sesquiterpenoids, a Triterpene, Steroids, and a Lignan from the Resin of Commiphora myrrha and Their Anti-Inflammatory Activity In Vitro.

Myrrh has a long tradition in the treatment of inflammatory diseases. However, many of its (active) constituents are still unknown. In the present study, secondary metabolites were isolated from an ethanolic extract by various separation methods (liquid-liquid partition, silica and RP18 flash chromatography, CPC, and preparative HPLC), their structures were elucidated with NMR spectroscopy and mass spectrometry, and the selected compounds were tested for their effect on LPS-induced NO production by RAW 264.7 murine macrophages. Among the isolated substances are 17 sesquiterpenes (1-17) including the first 4,8-cycloeudesmane (1), a triterpene (38), two phytosterols (39, 40) and one lignan (43), which were previously unknown as natural products. Numerous compounds are described for the first time for the genus Commiphora. Eight of the eleven compounds tested (1, 29, 31, 32, 34-37) showed a statistically significant, concentration-dependent weak to moderate anti-inflammatory effect on NO production in the LPS-stimulated RAW 264.7 macrophages in vitro. For the reference substance, furanoeudesma-1,3-diene, an IC50 of 46.0 µM was determined. These sesquiterpenes might therefore be part of the multi-target molecular principles behind the efficacy of myrrh in inflammatory diseases.

Polyphenols of the Inuleae-Inulinae and Their Biological Activities: A Review.

Polyphenols are ubiquitous plant metabolites that demonstrate biological activities essential to plant-environment interactions. They are of interest to plant food consumers, as well as to the food, pharmaceutical and cosmetic industry. The class of the plant metabolites comprises both widespread (chlorogenic acids, luteolin, quercetin) and unique compounds of diverse chemical structures but of the common biosynthetic origin. Polyphenols next to sesquiterpenoids are regarded as the major class of the Inuleae-Inulinae metabolites responsible for the pharmacological activity of medicinal plants from the subtribe (Blumea spp., Dittrichia spp., Inula spp., Pulicaria spp. and others). Recent decades have brought a rapid development of molecular and analytical techniques which resulted in better understanding of the taxonomic relationships within the Inuleae tribe and in a plethora of data concerning the chemical constituents of the Inuleae-Inulinae. The current taxonomical classification has introduced changes in the well-established botanical names and rearranged the genera based on molecular plant genetic studies. The newly created chemical data together with the earlier phytochemical studies may provide some complementary information on biochemical relationships within the subtribe. Moreover, they may at least partly explain pharmacological activities of the plant preparations traditionally used in therapy. The current review aimed to systematize the knowledge on the polyphenols of the Inulae-Inulinae.

Anti-inflammatory effect of lignans from flaxseed after fermentation by lactiplantibacillus plantarum SCB0151 in vitro.

Lignan, a beneficial constituent of Flaxseed (Linum usitatissimum L.) showed great interest in researchers because of its multiple functional properties. Nonetheless, a challenge arises due to the glycosidic structure of lignans, which the gut epithelium cannot readily absorb. Therefore, we screened 18 strains of Lactiplantibacillus plantarum, Lacticaseibacillus casei, Lactobacillus acidophilus, Lacticaseibacillus rhamnosus, Pediococcus pentosaceus, Pediococcus acidilactici, and Enterococcus durans to remove glycosides from flaxseed lignan extract enzymatically. Among our findings, Lactiplantibacillus plantarum SCB0151 showed the highest activity of ß-glucosidase (8.91 ± 0.04 U/mL) and higher transformed efficiency of Secoisolariciresinol (SECO) (8.21 ± 0.13%). The conversion rate of Secoisolariciresinol diglucoside (SDG) and the generation rate of SECO was 58.30 ± 3.78% and 32.13 ± 2.78%, respectively, under the optimized conditions. According to the LC-HRMSMS analysis, SECO (68.55 ± 6.57 µM), Ferulic acid (FA) (32.12 ± 2.50 µM), and Coumaric acid (CA) (79.60 ± 6.21 µM) were identified in the biotransformation products (TP) of flaxseed lignan extract. Results revealed that the TP exhibited a more pronounced anti-inflammatory effect than the flaxseed lignan extract. SECO, FA, and CA demonstrated a more inhibitory effect on NO than that of SDG. The expression of iNOS and COX-2 was significantly suppressed by TP treatment in LPS-induced Raw264.7 cells. The secretion of IL-6, IL-2, and IL-1ß decreased by 87.09 ± 0.99%, 45.40 ± 0.87%, and 53.18 ± 0.83%, respectively, at 60 µg/mL of TP treatment. Given these data, the bioavailability of flaxseed lignan extract and its anti-inflammatory effect were significantly enhanced by Lactiplantibacillus plantarum SCB0151, which provided a novel approach to commercializing flaxseed lignan extract for functional food.

Tissue-specific transcriptome and metabolome analyses reveal candidate genes for lignan biosynthesis in the medicinal plant Schisandra sphenanthera.

Schisandra sphenanthera is an extremely important medicinal plant, and its main medicinal component is bioactive lignans. The S. sphenanthera fruit is preferred by the majority of consumers, and the root, stem, and leaf are not fully used. To better understand the lignan metabolic pathway, transcriptome and metabolome analyses were performed on the four major tissues of S. sphenanthera. A total of 167,972,229 transcripts and 91,215,760 unigenes with an average length of 752 bp were identified. Tissue-specific gene analysis revealed that the root had the highest abundance of unique unigenes (9703), and the leaves had the lowest (189). Transcription factor analysis showed that MYB-, bHLH- and ERF-transcription factors, which played important roles in the regulation of secondary metabolism, showed rich expression patterns and may be involved in the regulation of processes involved in lignan metabolism. In different tissues, lignans were preferentially enriched in fruit and roots by gene expression profiles related to lignan metabolism and relative lignan compound content. Furthermore, schisandrin B is an important compound in S. sphenanthera. According to weighted gene co-expression network analysis, PAL1, C4H-2, CAD1, CYB8, OMT27, OMT57, MYB18, bHLH3, and bHLH5 can be related to the accumulation of lignans in S. sphenanthera fruit, CCR5, SDH4, CYP8, CYP20, and ERF7 can be related to the accumulation of lignans in S. sphenanthera roots. In this study, transcriptome sequencing and targeted metabolic analysis of lignans will lay a foundation for the further study of their biosynthetic genes.

Two O-Methyltransferases from Phylogenetically Unrelated Cow Parsley (Anthriscus sylvestris) and Hinoki-Asunaro (Thujopsis dolabrata var. hondae) as a Signature of Lineage-Specific Evolution in Lignan Biosynthesis.

O-Methyltransferases (OMTs) play important roles in antitumor lignan biosynthesis. To date, six OMTs catalyzing the methylation of dibenzylbutyrolactone lignans as biosynthetic precursors of antitumor lignans have been identified. However, there is still no systematic understanding of the diversity and regularity of the biosynthetic mechanisms among various plant lineages. Herein, we report the characterization of two OMTs from Anthriscus sylvestris and Thujopsis dolabrata var. hondae [designated as AsSecoNorYatein (SNY) OMT and TdSNYOMT] together with the six known OMTs to evaluate their diversity and regularity. Although A. sylvestris 5-O-methylthujaplicatin (SecoNorYatein) and 4-O-demethylyatein (NorYatein) OMT (AsSNYOMT) and TdSNYOMT accept 5-O-methylthujaplicatin and 4-O-demethylyatein as substrates, phylogenetic analysis indicated that these two OMTs shared low amino acid sequence identity, 33.8%, indicating a signature of parallel evolution. The OMTs and the six previously identified OMTs were found to be diverse in terms of their substrate specificity, regioselectivity and amino acid sequence identity, indicating independent evolution in each plant species. Meanwhile, two-entropy analysis detected four amino acid residues as being specifically acquired by dibenzylbutyrolactone lignan OMTs. Site-directed mutation of AsSNYOMT indicated that two of them contributed specifically to 5-O-methylthujaplicatin methylation. The results provide a new example of parallel evolution and the diversity and regularity of OMTs in plant secondary (specialized) metabolism.

Anthriscus sylvestris Deoxypodophyllotoxin Synthase Involved in the Podophyllotoxin Biosynthesis.

Tetrahydrofuran ring formation from dibenzylbutyrolactone lignans is a key step in the biosynthesis of aryltetralin lignans including deoxypodophyllotoxin and podophyllotoxin. Previously, Fe(II)- and 2-oxoglutarate-dependent dioxygenase (2-ODD) from Podophyllum hexandrum (Himalayan mayapple, Berberidaceae) was found to catalyze the cyclization of a dibenzylbutyrolactone lignan, yatein, to give deoxypodophyllotoxin and designated as deoxypodophyllotoxin synthase (DPS). Recently, we reported that the biosynthesis of deoxypodophyllotoxin and podophyllotoxin evolved in a lineage-specific manner in phylogenetically unrelated plant species such as P. hexandrum and Anthriscus sylvestris (cow parsley, Apiaceae). Therefore, a comprehensive understanding of the characteristics of DPSs that catalyze the cyclization of yatein to deoxypodophyllotoxin in various plant species is important. However, for plant species other than P. hexandrum, the isolation of the DPS enzyme gene and the type of the enzyme, e.g. whether it is 2-ODD or another type of enzyme such as cytochrome P-450, have not been reported. In this study, we report the identification and characterization of A. sylvestris DPS (AsDPS). Phylogenetic analysis showed that AsDPS belonged to the 2-ODD superfamily and shared moderate amino acid sequence identity (40.8%) with P. hexandrum deoxypodophyllotoxin synthase (PhDPS). Recombinant protein assay indicated that AsDPS and PhDPS differ in terms of the selectivity of substrate enantiomers. Protein modeling using AlphaFold2 and site-directed mutagenesis indicated that the Tyr305 residue of AsDPS probably contributes to substrate recognition. This study advances our understanding of the podophyllotoxin biosynthetic pathway in A. sylvestris and provides new insight into 2-ODD involved in plant secondary (specialized) metabolism.