Letter: Isolation and synthesis of pinoresinol diglucoside, a major antihypertensive principle of Tu-Chung(Eucommia ulmoides, Oliver)

Preparation techniques, structural features, and bioactivities of Eucommia ulmoides polysaccharides: A review

Eucommia ulmoides Oliv. (tu-chung), as a famous nature medical and edible plant, has the effect of tonifying liver and kidney, strengthening the function of the muscles and bones, and miscarriage prevention. Accumulating evidence has demonstrated that the polysaccharides from Eucommia ulmoides Oliv. (EUPs) are a kind of vital and representative biologically active macromolecules and have various health-promoting biological activities in vivo and in vitro, such as antioxidant activity, immunomodulatory activity, hypolipidemic and hypoglycemic activities, anti-inflammatory activities, anti-tumor activity, and among others. The review aims to comprehensively and systematically collate the recent research progress on extraction and purification methods, structural characteristics, biological activities, mechanism of action, structural modification, and toxicity of EUPs to support their therapeutic potential and health-care functions. New valuable insights for future research with EUPs were also proposed in the areas of structural characterization and pharmacological activities to promoting the development of therapeutic agents and functional foods.

Quanduzhong capsules for the treatment of grade 1 hypertension patients with low-to-moderate risk: A multicenter, randomized, double-blind, placebo-controlled clinical trial

Background: Duzhong [DZ (Eucommia ulmoides Oliv.)] is regarded as a traditional Chinese medicine with a history dating back more than 2000 years. This herb is considered a nourishing herb in China and is commonly used as a tonic to strengthen muscles and bones, nourish the kidneys and liver, and soothe miscarriages. Moreover, there is evidence that DZ is capable of regulating blood pressure (BP), and several compounds isolated from DZ have been shown to have a BP-lowering effect. Quanduzhong capsules contain an extract of DZ [Eucommia ulmoides Oliv. (Eucommiaceae; Eucommiae cortex)] that is effective in treating hypertension. This multicenter, randomized, double-blind, placebo-controlled clinical trial sought to evaluate the clinical efficacy of Quanduzhong capsules in the treatment of low-to-moderate risk grade 1 hypertension patients. Materials and methods: A total of 60 patients from 3 centers with documented low-to-moderate risk grade 1 hypertension were randomly assigned in a 1:1 ratio to the test group or the control group. After a 1 week lead-in period using sham Quanduzhong capsules, all patients who met the entry criteria (29 cases in the test group and 29 cases in the control group) entered the 4 week test period. The test group took Quanduzhong capsules, and the control group continued to take sham Quanduzhong capsules. The primary endpoints [24-h mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) determined via 24-h ambulatory blood pressure monitoring (ABPM); office SBP and DBP] and secondary endpoints [mean arterial pressure; mean pulse; daytime mean SBP and DBP; nocturnal mean SBP and DBP; SBP and DBP load; area under the blood pressure (BP) curve; morning peak BP; early morning SBP and DBP; smoothness index of SBP and DBP; 24 h BP mean coefficient of variation (CV); percentage of patients with circadian restoration in ABPM; home BP; quality of life evaluated by WHO Quality of Life-BREF questionnaire; grading and quantitative evaluation of hypertension symptoms; values of plasmatic renin activity, angiotensin II, aldosterone, β-2 microglobulin and homocysteine] were assessed following the treatment. Drug-related adverse events and adverse drug reactions were also compared. Results: After a 4 week test period, a significant difference in the DBP CV between the two groups was observed (-2.49 ± 4.32 vs. 0.76 ± 4.3; p < .05). Moreover, the mean office SBP change was -7.62 ± 9.32 mmHg, and the mean DBP change was -4.66 ± 6.03 (p < .05). Among the three subjects with abnormal homocysteine levels in the test group, homocysteine levels decreased by 6.23 ± 9.15 μmol/L after treatment. No differences were observed between the two groups in any other indicators. After 4 weeks of treatment, there were no significant differences between the groups in terms of safety indicators (p > .05). No abnormal vital signs (except BP) or severe liver or renal function impairment were observed during the treatment periods; in addition, adverse events and drug reactions were mild. Conclusion: Treatment with Quanduzhong capsules reduced office SBP and DBP as well as DBP CV determined by 24-h ambulatory BP monitoring in patients with grade 1 hypertension at low-to-moderate risk. Clinical Trial Registration: https://www.chictr.org.cn/showproj.aspx?proj=32531, identifier ChiCTR1900021699.

Pinoresinol diglucoside ameliorates H/R-induced injury of cardiomyocytes by regulating miR-142-3p and HIF1AN

This study is aimed to investigate the effect of pinoresinol diglucoside (PDG) in ameliorating myocardial ischemia-reperfusion injury (MIRI). Hypoxia/reperfusion (H/R)-induced H9c2 cardiomyocytes were used to establish an in-vitro ischemia-reperfusion injury model of cardiomyocytes. Cells were treated with 1 μmol/L of PDG. Reactive oxygen species (ROS) level was detected by a 2',7'-dichlorofluorescein-diacetate assay. The release of lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) was examined by enzyme-linked immunosorbent assay. The viability and apoptosis of H9c2 cells were probed by MTT assay and flow cytometry. Besides this, Western blot and quantitative real-time PCR were used to detect microRNA-142-3p (miR-142-3p) and hypoxia-inducible factor 1 subunit alpha inhibitor (HIF1AN) expression levels. The binding sequence between miR-142-3p and HIF1AN 3'-untranslated region was validated by a dual-luciferase reporter gene assay. PDG treatment significantly reduced the level of ROS, LDH, and CK-MB, promoted viability, and inhibited the apoptosis of H9c2 cells. PDG treatment promoted miR-142-3p expression and inhibited HIF1AN expression in H9c2 cells. MiR-142-3p overexpression enhanced the effects of PDG on ROS, LDH, CK-MB levels, cell viability, and apoptosis in H9c2 cardiomyocytes, while overexpression of HIF1AN reversed the above effects. PDG ameliorates H/R-induced injury of cardiomyocytes by regulating miR-142-3p and HIF1AN.

Lignans as Pharmacological Agents in Disorders Related to Oxidative Stress and Inflammation: Chemical Synthesis Approaches and Biological Activities

Plant lignans exhibit a wide range of biological activities, which makes them the research objects of potential use as therapeutic agents. They provide diverse naturally-occurring pharmacophores and are available for production by chemical synthesis. A large amount of accumulated data indicates that lignans of different structural groups are apt to demonstrate both anti-inflammatory and antioxidant effects, in many cases, simultaneously. In this review, we summarize the comprehensive knowledge about lignan use as a bioactive agent in disorders associated with oxidative stress and inflammation, pharmacological effects in vitro and in vivo, molecular mechanisms underlying these effects, and chemical synthesis approaches. This article provides an up-to-date overview of the current data in this area, available in PubMed, Scopus, and Web of Science databases, screened from 2000 to 2022.

Traditional application and modern pharmacological research of Eucommia ulmoides Oliv

As a Traditional Chinese Medicine, Eucommia ulmoides Oliv. has been used for the treatment of various diseases since ancient times, involving lumbar pain, knee pain, osteoporosis, hepatoprotection, paralysis, intestinal haemorrhoids, vaginal bleeding, abortion, spermatorrhoea, foot fungus, anti-aging etc. With the developing discovery of E. ulmoides extracts and its active components in various pharmacological activities, E. ulmoides has gained more and more attention. Up to now, E. ulmoides has been revealed to show remarkable therapeutic effects on hypertension, hyperglycemia, diabetes, obesity, osteoporosis, Parkinson's disease, Alzheimer's disease, sexual dysfunction. E. ulmoides has also been reported to possess antioxidant, anti-inflammatory, neuroprotective, anti-fatigue, anti-aging, anti-cancer and immunoregulation activities etc. Along these lines, this review summarizes the traditional application and modern pharmacological research of E. ulmoides, providing novel insights of E. ulmoides in the treatment of various diseases.

Pinoresinol diglucoside (PDG) attenuates cardiac hypertrophy via AKT/mTOR/NF-κB signaling in pressure overload-induced rats

ETHNOPHARMACOLOGICAL RELEVANCE

Pinoresinol diglucoside (PDG), the active compound extracted from Eucommia ulmoides, Styrax sp. and Forsythia suspensa, plays the roles in regulating hypertension, inflammation and oxidative stress.

AIMS

Considering that hypertension and inflammation has been proved to contribute to cardiac remodeling, we tested the effects of PDG on cardiac hypertrophy (CM).

METHODS

Male Sprague Dawley (SD) rats were used to construct hypertrophic rats by partial abdominal aortic constriction (AAC)-surgery. PDG solution (2 mg/ml) was used to treat AAC-induced rats by intraperitoneal injection at low dose (L-PDG, 2.5 mg/kg per day), medium dose (M-PDG, 5 mg/kg per day), and high dose (H-PDG, 7.5 mg/kg per day) for 3 weeks post AAC-surgery. CM was evaluated by the ratio of left ventricular weight to body weight ratio (LVW/BW), left ventricular wall thickness by H&E staining, and collagen content deposit by Masson's staining. Further, isoproterenol (ISO) and phenylephrine (PE) were used to produce cellular models of CM in neonatal rat ventricular cardiomyocytes (NRVMs). PDG pre-treated NRVMs 2 h at low dose (L-PDG, 2.5 μg/ml), medium dose (M-PDG, 5 μg/ml), and high dose (H-PDG, 7.5 μg/ml) for 24 h with or without PE- and ISO-stimulation. CM was evaluated by the expressions of hypertrophic biomarkers. Next, the hypertrophic biomarkers and pro-inflammatory cytokines were measured using quantitative real-time PCR (qRT-PCR), the expressions of protein kinase B (AKT)/mammalian target of rapamycin (mTOR)/transcription factor nuclear factor-kappa B (NF-kB) signaling pathway were determined by Western blotting.

RESULTS

PDG treatment prevented cardiac histomorphology damages, decreased upregulations of hypertrophic biomarkers, and prevented fibrosis and inflammation after pressure overload resulting from AAC-surgery. Consistently, PDG remarkably inhibited the changes of cardiomyocyte hypertrophic biomarkers and inflammatory responses in cellular models of CM. Interestingly, PDG administration inhibited the activation of AKT/mTOR/NF-kB signaling pathway both in vivo and in vitro.

CONCLUSIONS

PDG prevents AAC-induced CM in vivo, PE- and ISO-induced CM in vitro. The AKT/mTOR/NF-kB signaling pathway could be the potential therapeutic target involved in the protection of PDG. These findings provide novel evidence that PDG might be a promising therapeutic strategy for CM.

Update of Genetic Linkage Map and QTL Analysis for Growth Traits in Eucommia ulmoides Oliver

Eucommia ulmoides (Tu-chung) is an economically and ecologically important tree species which has attracted worldwide attention due to its application in pharmacology, landscaping, wind sheltering and sand fixation. Molecular marker technologies can elucidate the genetic mechanism and substantially improve the breeding efficiency of E. ulmoides. The current research updated the original linkage map, and quantitative trait loci (QTL) analysis was performed on tree growth traits measured over 10 consecutive years in an E. ulmoides F1 population (“Xiaoye” × “Qinzhong No.1”). In total, 452 polymorphic markers were scored from 365 simple sequence repeat (SSR) primers, with an average of 1.24 polymorphic markers per primer combination. The integrated map was 1913.29 cM (centimorgan) long, covering 94.10% of the estimated genome and with an average marker density of 2.20 cM. A total of 869 markers were mapped into 19 major independent linkage groups. Growth-related traits measured over 10 consecutive years showed a significant correlation, and 89 hypothetical QTLs were forecasted and divided into 27 distinct loci. Three traits for tree height, ground diameter and crown diameter detected 25 QTLs (13 loci), 32 QTLs (17 loci) and 15 QTLs (10 loci), respectively. Based on BLASTX search results in the NCBI database, six candidate genes were obtained. It is important to explore the growth-related genetic mechanism and lay the foundation for the genetic improvement of E. ulmoides at the molecular level.

Transcriptome analysis of terpenoid biosynthetic genes and simple sequence repeat marker screening in Eucommia ulmoides

Trans-polyisoprene rubber is produced in the tissues of leaves, bark, and fruit of Eucommia ulmoides and is considered an important energy source. Transcript profiles of two tissues from E. ulmoides cv. Qinzhong No. 3, leaf and fruit, were analysed using the Illumina HiSeq 2000 system. In total, 104 million clean reads were obtained and assembled into 58,863 unigenes. Through gene functional classification, 28,091 unigenes (47.72%) were annotated and 65 unigenes have been hypothesized to encode proteins involved in terpenoid biosynthesis. In addition, 10,041 unigenes were detected as differentially expressed unigenes, and 29 of them were putatively related to terpenoid biosynthesis. The synthesis of trans-polyisoprene rubbers in E. ulmoides was hypothesised to be dominated by the mevalonate pathway. Farnesyl diphosphate synthase 2 (FPPS2) was considered a key component in the biosynthesis of trans-polyprenyl diphosphate. Rubber elongation factor 3 (REF3) might be involved in stabilising the membrane of rubber particles in E. ulmoides. To date, 351 simple sequence repeats (SSRs) were validated as polymorphisms from eight E. ulmoides plants (two parent plants and six F₁ individuals), and these could act as molecular markers for genetic map density increase and breeding improvement of E. ulmoides.

Tracing the mass flow from glucose and phenylalanine to pinoresinol and its glycosides in Phomopsis sp. XP-8 using stable isotope assisted TOF-MS

Phomopsis sp. XP-8, an endophytic fungus from the bark of Tu-Chung (Eucommia ulmoides Oliv) showed capability to biosynthesize pinoresinol (Pin) and pinoresinol diglucoside (PDG) from glucose (glu) and phenylalanine (Phe). To verify the mass flow in the biosynthesis pathway, [¹³C₆]-labeled glu and [¹³C₆]-labeled Phe were separately fed to the strain as sole substrates and [¹³C₆]-labeled products were detected by ultra-high-performance liquid chromatography-quadrupole time of flight mass spectrometry. As results, [¹³C₆]-labeled Phe was incorporated into [¹³C₆]-cinnamylic acid (Ca) and p-coumaric acid (p-Co), and [¹³C₁₂]-labeled Pin, which revealed that the Pin benzene ring came from Phe via the phenylpropane pathway. [¹³C₆]-Labeled Ca and p-Co, [¹³C₁₂]-labeled Pin, [¹³C₁₈]-labeled pinoresinol monoglucoside (PMG), and [¹³C₁₈]-labeled PDG products were found when [¹³C₆]-labeled glu was used, demonstrating that the benzene ring and glucoside of PDG originated from glu. It was also determined that PMG was not the direct precursor of PDG in the biosynthetic pathway. The study identified the occurrence of phenylalanine- lignan biosynthesis pathway in fungi at the level of mass flow.

Insights into Lignan Composition and Biosynthesis in Stinging Nettle (Urtica dioica L.)

Stinging nettle (Urtica dioica L.) has been used as herbal medicine to treat various ailments since ancient times. The biological activity of nettle is chiefly attributed to a large group of phenylpropanoid dimers, namely lignans. Despite the pharmacological importance of nettle lignans, there are no studies addressing lignan biosynthesis in this plant. We herein identified 14 genes encoding dirigent proteins (UdDIRs) and 3 pinoresinol-lariciresinol reductase genes (UdPLRs) in nettle, which are two gene families known to be associated with lignan biosynthesis. Expression profiling of these genes on different organs/tissues revealed a specific expression pattern. Particularly, UdDIR7, 12 and 13 displayed a remarkable high expression in the top internode, fibre tissues of bottom internodes and roots, respectively. The relatively high expression of UdPLR1 and UdPLR2 in the young internodes, core tissue of bottom internode and roots is consistent with the high accumulation of lariciresinol and secoisolariciresinol in these tissues. Lignan quantification showed a high abundance of pinoresinol in roots and pinoresinol diglucosides in young internodes and leaves. This study sheds light on lignan composition and biosynthesis in nettle, providing a good basis for further functional analysis of DIRs and PLRs and, ultimately, engineering lignan metabolism in planta and in cell cultures.

Ethnobotany, Phytochemistry and Pharmacological Properties of Eucommia ulmoides: A Review

Eucommia ulmoides Oliver, a single species of Eucommia genus belonging to the Eucommiaceae family, is an endemic in China and has been used in traditional Chinese medicine for nearly two thousand years. Records from different historical periods highlight E. ulmoides and its officinal botanical parts, usefulness in adaptation to disease and its central role in Chinese medicine theory. There are also historical collection documents for minorities in China. Tearing the leaves, bark and fruit produces strands of latex; a description of E. ulmoides’s morphological features is recorded in this paper. This review summarizes 204 natural compounds isolated from this plant, which are divided into seven categories: lignans, iridoids, flavonoids, phenols, steroids, terpenes and others. These components possess wide-ranging pharmacological efficacies, such as antihypertensive, antihyperglycemic, antihyperlipidemia, anti-oxidative, anti-osteoporosis, antitumor, immunomodulatory and neuroprotective activities. This review aims to provide a reference for extensive researches of E. ulmoides crude drugs, especially for quality control, biosynthesis and structure modification of active ingredients and pharmacological mechanism.

Comparison of pinoresinol diglucoside production by Phomopsis sp. XP-8 in different media and the characterisation and product profiles of the cultivation in mung bean

BACKGROUND

Phomopsis sp. XP-8 is an endophytic fungus with the ability to produce pinoresinol diglucoside (PDG) in vitro and thus has potential application in biosynthesis of PDG independent of plants. In order to enhance the production of PDG, 18 different natural materials were tested in solid-state cultivation of Phomopsis sp. XP-8.

RESULTS

Most of the tested natural materials promoted the production of PDG. A supplement derived from mung beans produced the highest PDG yield and better fungal growth than the other materials. Also, pinoresinol monoglucoside, pinoresinol and other substrates (phenylalanine, p-coumaric acid, cinnamic acid, caffeic acid, and ferulic acid) were obtained after fermentation on mung beans. Furthermore, PDG production was much higher when mung beans were incorporated into solid state agar versus a liquid medium. The highest pinoresinol diglucoside production (72.1 mg kg(-1) in fresh culture) was obtained in 9 days using a solid state culture of Phomopsis sp. XP-8 on a mung bean grain medium containing 100 g kg(-1) glucose. Mung bean water-soluble polysaccharide was identified as a major promoter of PDG production by Phomopsis sp. XP-8.

CONCLUSION

Mung bean, especially its water-soluble polysaccharide fraction, was an efficient natural material to promote PDG production by Phomopsis sp. XP-8. © 2015 Society of Chemical Industry.

Health-Promoting Properties of Eucommia ulmoides: A Review

Eucommia ulmoides (EU) (also known as “Du Zhong” in Chinese language) is a plant containing various kinds of chemical constituents such as lignans, iridoids, phenolics, steroids, flavonoids, and other compounds. These constituents of EU possess various medicinal properties and have been used in Chinese Traditional Medicine (TCM) as a folk drink and functional food for several thousand years. EU has several pharmacological properties such as antioxidant, anti-inflammatory, antiallergic, antimicrobial, anticancer, antiaging, cardioprotective, and neuroprotective properties. Hence, it has been widely used solely or in combination with other compounds to treat cardiovascular and cerebrovascular diseases, sexual dysfunction, cancer, metabolic syndrome, and neurological diseases. This review paper summarizes the various active ingredients contained in EU and their health-promoting properties, thus serving as a reference material for the application of EU.

Deep Eutectic Solvents Modified Molecular Imprinted Polymers for Optimized Purification of Chlorogenic Acid from Honeysuckle

Deep eutectic solvents (DES) were synthesized with choline chloride (ChCl), and DES modified molecular imprinted polymers (DES-MIPs), DES modified non-imprinted polymers (DES-NIPs, without template), MIPs and NIPs were prepared in an identical procedure. Fourier transform infrared spectrometer (FT-IR) and field emission scanning electron microscopy (FE-SEM) were used to characterize the obtained polymers. Rebinding experiment and solid-phase extraction (SPE) were used to prove the high selectivity adsorption properties of the polymers. Box-Behnken design (BBD) with three factors was used to optimize the extraction condition of chlorogenic acid (CA) from honeysuckles. The optimum extraction conditions were found to be ultrasonic time optimized (20 min), the volume fraction of ethanol (60%) and ratio of liquid to material (15 mL g(-1)). Under these conditions, the mean extraction yield of CA was 12.57 mg g(-1), which was in good agreement with the predicted BBD model value. Purification of hawthorn extract was achieved by SPE process, and SPE recoveries of CA were 72.56, 64.79, 69.34 and 60.08% by DES-MIPs, DES-NIPs, MIPs and NIPs, respectively. The results showed DES-MIPs had potential for promising functional adsorption material for the purification of bioactive compounds.

Bioconversion of Pinoresinol Diglucoside and Pinoresinol from Substrates in the Phenylpropanoid Pathway by Resting Cells of Phomopsis sp.XP-8

Pinoresinol diglucoside (PDG) and pinoresinol (Pin) are normally produced by plant cells via the phenylpropanoid pathway. This study reveals the existence of a related pathway in Phomopsis sp. XP-8, a PDG-producing fungal strain isolated from the bark of the Tu-chung tree (Eucommiaulmoides Oliv.). After addition of 0.15 g/L glucose to Phomopsis sp. XP-8, PDG and Pin formed when phenylalanine, tyrosine, leucine, cinnamic acid, and p-coumaric acid were used as the substrates respectively. No PDG formed in the absence of glucose, but Pin was detected after addition of all these substrates except leucine. In all systems in the presence of glucose, production of PDG and/or Pin and the accumulation of phenylalanine, cinnamic acid, or p-coumaric acid correlated directly with added substrate in a time- and substrate concentration- dependent manner. After analysis of products produced after addition of each substrate, the mass flow sequence for PDG and Pin biosynthesis was defined as: glucose to phenylalanine, phenylalanine to cinnamic acid, then to p-coumaric acid, and finally to Pin or PDG. During the bioconversion, the activities of four key enzymes in the phenylpropanoid pathway were also determined and correlated with accumulation of their corresponding products. PDG production by Phomopsis sp. exhibits greater efficiency and cost effectiveness than the currently-used plant-based system and will pave the way for large scale production of PDG and/or Pin for medical applications.

UPLC-MS/MS determination and gender-related pharmacokinetic study of five active ingredients in rat plasma after oral administration of Eucommia cortex extract

ETHNOPHARMACOLOGICAL RELEVANCE

Eucommiae cortex (EC), the bark of Eucommia ulmoides Oliv., has been traditionally used to treat many diseases in China for more than 2000 years. The pharmacological effects are primarily attributed to the presence of lignans, iridoids and phenolics, which are main active ingredients in EC.

AIM OF THE STUDY

First, to investigate the active ingredients that can be absorbed into the rat plasma according to which ingredients exhibit significant correlation of drug concentration-time curve. Second, to establish an efficient ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of ingredients absorbed in rat plasma. Finally, to investigate gender effect on the pharmacokinetics of the ingredients absorbed in male and female rats plasma after oral administration with EC extract.

MATERIALS AND METHODS

18 ingredients from EC were detected by UPLC-MS/MS, 9 out of 18 ingredients were absorbed into rat plasma. And 5 ingredients exhibit significant correlation of drug concentration-time curve. They were pinoresinol di-O-β-d-glucopyranoside (PDG), geniposide (GE), geniposidic acid (GA), aucubin (AN) and chlorogenic acid (CA). The analytes were extracted from rat plasma via a simple protein precipitation procedure and osalmid was used as the internal standard. Chromatographic separation was achieved on a Waters ACQUITY HSS T3 column (2.1mm×100mm, 1.8μm) using a gradient elution program with acetonitrile and 0.1% formic acid water as the mobile phase, with a flow rate of 0.3mLmin(-1). The detection was performed on a triple-quadrupole tandem mass spectrometer by multiple reactions monitoring (MRM) mode in a positive ion mode via electrospray ionization (ESI). The transition monitored were /z 683.00[M+H](+)→235.10 for PDG, / z 389.00[M+H](+)→208.80 for GE, m/z 375.00[M+H](+)→194.79 for GA, m/z 364.00[M+NH4](+)→148.81 for AN, m/z 355.10[M+H](+)→162.84 for CA and m/z 230.03[M+H](+)→120.77 for internal standard.

RESULTS

The developed method showed good linearity over a wide concentration range, the lower limits of quantification and higher accuracy and precision for determination of the 5 analytes. Then the method was applied to study the pharmacokinetics in rats, and the results indicated that there were significant differences in pharmacokinetic parameters of the analytes between the male and female rats, and absorptions of these analytes in male group were all significantly higher than those in female group.

CONCLUSION

This study established an efficient, sensitive and selective UPLC-MS/MS method for simultaneous determination of the five ingredients in rat plasma, and it could be successfully applied to the comparative pharmacokinetic studies in male and female rats after oral administration with EC extract.

Soluble epoxide hydrolase inhibitory and anti-inflammatory components from the leaves of Eucommia ulmoides Oliver (duzhong)

Eucommia ulmoides leaves have been used as a functional food and drink in China. The purpose of this study was to identify the bioactive constituents with soluble epoxide hydrolase (sEH) inhibitory activity and anti-inflammatory properties. Twenty-seven known compounds (1-27) were isolated from the leaves of E. ulmoides Oliver, and their structures were identified by NMR and ESIMS analysis; three of these, 2,5-dimethoxy-3-glucopyranosyl cinnamic alcohol (11), foliasalacioside E2 (26), and icariside F2 (27), were obtained from this plant for the first time. Compounds 1-7 exhibited soluble epoxide hydrolase (sEH) inhibitory activity at 100 μM; among them, quercetin (1) and kaempferol (5) displayed potential activities with IC50 values of 22.5 ± 0.9 and 31.3 ± 2.6 μM, respectively, with noncompetitive inhibition mode. Nuclear factor kappa B (NF-κB) inhibitory activity of the isolated compounds was evaluated by the NF-κB liciferase assay in HepG2 cells. Compounds 1, 9, 20, and 27 displayed potent NF-κB inhibitory effects, with IC50 values of 15.14 ± 2.29, 15.23 ± 2.34, 16.88 ± 2.17, and 16.25 ± 2.19 μM, respectively, whereas other compounds showed weak inhibition of NF-κB transcriptional activity ranging from 17.54 to 92.6 μM. A structure-activity relationship of flavonoids 1-9 was also discussed. The results obtained in this work might contribute to the understanding of pharmacological activities of E. ulmoides leaves and further investigation on its potential application values for food and drug.

Eucommia ulmoides Oliv.: ethnopharmacology, phytochemistry and pharmacology of an important traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Eucommia ulmoides Oliv. (Family Eucommiaceae), also known as Dù-zhòng (Chinese: ), Tuchong (in Japanese), is the sole species of the genus Eucommia. The leaf, stem, and bark as well as staminate flower of Eucommia ulmoides have been traditionally used to cure many diseases in China, Japan, Korea, among others. The aim of this review is to comprehensively outline the botanical description, ethnopharmacology, phytochemistry, biological activities, and toxicology of Eucommia ulmoides and to discuss possible trends for further study of Eucommia ulmoides.

MATERIALS AND METHODS

Information on Eucommia ulmoides was gathered via the internet (using Pub Med, Elsevier, Baidu Scholar, Google Scholar, Medline Plus, ACS, CNKI, and Web of Science) and from books in local libraries.

RESULTS

One-hundred twelve compounds of Eucommia ulmoides, including the main active constituents, lignans and iridoids, have been isolated and identified. In vitro and in vivo studies indicated that monomer compounds and extracts from Eucommia ulmoides possess wide-ranging pharmacological actions, especially in treating hypertension, hyperlipemia, diabetes, obesity, sexual dysfunction, osteoporosis, Alzheimer's disease, aging, lupus-like syndrome, and immunoregulation.

CONCLUSIONS

Eucommia ulmoides has been used as a source of traditional medicine and as a beneficial health food. Phytochemical and pharmacological studies of Eucommia ulmoides have received much interest, and extracts and active compounds continue to be isolated and proven to exert various effects. Further toxicity and clinical studies are warranted to establish more detailed data on crude extracts and pure compounds, enabling more convenient preparations for patients. Therefore, this review on the ethnopharmacology, phytochemistry, biological activities, and toxicity of Eucommia ulmoides will provide helpful data for further studies as well as the commercial exploitation of this traditional medicine.

Investigation into the mechanism of Eucommia ulmoides Oliv. based on a systems pharmacology approach

ETHNOPHARMACOLOGY RELEVANCE

Though Traditional Chinese Medicine (TCM) has long been playing a significant role in the maintenance of health for people in Asia as well as many other places, the mechanism of its action still remains ambiguous for most of the plants used in TCM, such as Eucommia ulmoides Oliv., a kind of herb that is widely used to help regulate hypertension and the immune system nowadays. However, its functioning mechanism is still unknown. Thus it is necessary to exploit the mechanism of Eucommia ulmoides Oliv.

METHODS

A systems pharmacology approach combining drug-likeness evaluation, oral bioavailability prediction, multiple drug targets prediction as well as network pharmacology techniques has been used.

RESULTS

This comprehensive systematic approach helps successfully to identify 41 candidate compounds contained in Eucommia ulmoides Oliv. while 39 potential targets hit by these ingredients and helps to uncover the synergistic mechanism of action on a systematic level.

CONCLUSIONS

Our work successfully explains the mechanism of the efficiency of Eucommia ulmoides Oliv. for the treatment of hypertension and enhancing immune. These results not only provide a new insight for the understanding of the chemical and pharmacological basis of Eucommia ulmoides Oliv., but also provide an efficient way for drug discovery from herbal medicine.

Can rye intake decrease risk of human breast cancer?

BACKGROUND

Rye contains more fibre and bioactive compounds than other cereals used for bread production. The fibre and compounds of the fibre complex could provide protection against breast cancer (BC).

OBJECTIVE

To review the evidence and theoretical background for a role of rye and some of its components in the prevention of BC.

DESIGN

A short review based to a great extent on the work by scientists in the Nordic countries.

RESULTS

Some of the possible mechanisms by which the fibre complex could reduce BC risk are presented. The fibre through its effect on fermentation increases esterification of bile acids reducing toxicity of the free bile acids and is involved in the production of butyrate with potential anticancer effects including BC. The fibre reduces the enterohepatic circulation of the oestrogens leading to lower plasma oestrogen concentrations. The fibre complex contains bioactive compounds such as lignans and alkylresorcinols that are antioxidative and potentially anticarcinogenic. In addition, vitamins, minerals, and phytic acid in rye may provide protection against BC.

CONCLUSION

Rye products made from wholegrain rye flour are likely to contribute to reduced BC risk.

Development and validation of an ultra high-performance liquid chromatographic method for the determination of a diastereomeric impurity in (+)-pinoresinol diglucoside chemical reference substance

(+)-Pinoresinol 4,4'-di-O-beta-D-glucopyranoside ((+)-PDG) is one of the major lignans with various pharmacological activities which could be isolated from Duzhong and other plant species. In this study, a diastereomeric impurity, (-)-pinoresinol 4,4'-di-O-beta-D-glucopyranoside ((-)-PDG), the main impurity was identified in (+)-PDG chemical reference substance (CRS) and a reliable chromatographic method for rapid purity determination of (+)-PDG CRS was firstly developed. The optimal chromatographic condition was found to be using ACN/1,4-dioxane-water (2.5:6:91.5, v/v/v) as mobile phase on a Waters Acquity UPLC HSS T3 column (2.1 mm x 100 mm, 1.8 microm) with column temperature of 37 degrees C. The method was validated and applied to determine the chromatographic purity of five (+)-PDG CRS samples. The content of (-)-PDG in four commercial (+)-PDG CRS was 8.47-20.30%, whereas no (-)-PDG was detected in our in-house prepared (+)-PDG CRS in which purity was confirmed to be 99.80%. The above results confirmed that this method is fast and highly efficient for purity determination of the (+)-PDG CRS.

Antihypertensive effect of Eucommia ulmoides Oliv. extracts in spontaneously hypertensive rats

AIM OF THE STUDY

To investigate the antihypertensive fractions of Eucommia ulmoides Oliv. and their underlying mechanisms in spontaneously hypertensive rats (SHRs).

MATERIALS AND METHODS

In vivo study, Eucommia ulmoides lignans (EuL) and Eucommia ulmoides iridoids (EuI) were administrated to Sprague-Dawley (SD) rats and SHRs, and their blood pressures were measured. Plasma level of nitric oxide (NO) was measured by colorimetric method, and renin activity (RA) and plasma concentration of angiotensin II (Ang II) were measured by radioimmunoassay. In vitro study, rat mesenteric artery was treated with EuL and the vessel relaxation responses were determined.

RESULTS

EuL could lower blood pressures of both SD rats and SHR dose-dependently by either intravenous (i.v.) or intragastric (i.g.) administration, but EuI failed to affect blood pressure in the two kinds of rats. Meanwhile, no synergistic effect was observed with the combination of EuL and EuI. The plasma level of NO in SHR treated with EuL 300 mg/kg twice a day was markedly increased. Both plasma RA and Ang II level were decreased with long-term oral treatment of EuL 150 and 300 mg/kg twice a day. In perfusion experiment, EuL relaxed mesenteric artery quickly and dose-dependently and the effect on the artery with and without endothelium was the same.

CONCLUSIONS

EuL may be the effective fraction to lowering blood pressure and its antihypertensive effect is probably associated with regulating NO and renin-angiotensin system (RAS) and directly relaxing artery.

Selective cytotoxic effects on human cancer cell lines of phenolic-rich ethyl-acetate fraction from Rhus verniciflua Stokes

Rhus verniciflua Stokes (RVS) is a plant with a long history of medicinal use in Eastern Asia. RVS has been widely used to treat gastritis, stomach cancer and atherosclerosis. The cytotoxic effects of different solvent fractions from an RVS ethanol extract were measured in 11 human cancer cell lines. The study showed that the ethyl-acetate (EtOAC) fraction was the most cytotoxic. This fraction contains a number of phenolic compounds, and this phenolic-rich EtOAC fraction was particularly effective against gastric and breast cancer cells. A purified phenolic-rich EtOAC fraction (PPEF) had a stronger apoptotic effect on these cells. Liquid chromatography-mass spectrometry (LC-MS) analysis showed that the PPEF contained gallic acid, protocatechuic acid, fisetin, sulfuretin, butein and 8 unknown compounds. There were only small amounts of flavonoids: fisetin, sulfuretin and butein. The results showed that PPEF induces apoptosis only in gastric and breast cancer cell lines, but not in lung, colon or liver cancer cell lines. Therefore, PPEF may have a significant potential as an organ-specific anti-cancer agent.

Pinoresinol-4,4'-di-O-beta-D-glucoside from Valeriana officinalis root stimulates calcium mobilization and chemotactic migration of mouse embryo fibroblasts

Lignans are major constituents of plant extracts and have important pharmacological effects on mammalian cells. Here we showed that pinoresinol-4,4'-di-O-beta-D-glucoside (PDG) from Valeriana officinalis induced calcium mobilization and cell migration through the activation of lysophosphatidic acid (LPA) receptor subtypes. Stimulation of mouse embryo fibroblast (MEF) cells with 10 microM PDG resulted in strong stimulation of MEF cell migration and the EC(50) was about 2 microM. Pretreatment with pertussis toxin (PTX), an inhibitor of G(i) protein, completely blocked PDG-induced cell migration demonstrating that PDG evokes MEF cell migration through the activation of the G(i)-coupled receptor. Furthermore, pretreatment of MEF cells with Ki16425 (10 microM), which is a selective antagonist for LPA(1) and LPA(3) receptors, completely blocked PDG-induced cell migration. Likewise, PDG strongly induced calcium mobilization, which was also blocked by Ki16425 in a dose-dependent manner. Prior occupation of the LPA receptor with LPA itself completely blocked PDG-induced calcium mobilization. Finally, PDG-induced MEF cell migration was attenuated by pretreatment with a phosphatidylinositol 3-kinase (PI3K) inhibitor such as LY294002. Cells lacking downstream mediator of PI3K such as Akt1 and Akt2 (DKO cells) showed loss of PDG-induced migration. Re-expression of Akt1 (but not Akt2) completely restored PDG-induced DKO cell migration. Given these results, we conclude that PDG is a strong inducer of cell migration. We suggest that the pharmacological action of PDG may occur through the activation of an LPA receptor whereby activation of PI3K/Akt signaling pathway mediates PDG-induced MEF cell migration.

Degradation of the neolignan, burchellin in the hemolymph of the bloodsucking insect Rhodnius prolixus

The neolignan, burchellin, a natural compound that reduces urine excretion in larvae of the bloodsucking bug, Rhodnius prolixus, a vector of Chagas' disease, is rapidly degraded in the hemolymph of the insect. The main product that accumulates in this tissue has been shown to be piperonyl alcohol. Other catabolites have been identified by GC-MS analysis.

Enantioselective dehydroxylation of enterodiol and enterolactone precursors by human intestinal bacteria

During the course of experiments on the transformation of lignans to phytoestrogenic substances, such as enterodiol (END) and enterolactone (ENL), a previously isolated bacterium, Eubacterium (E.) sp. strain SDG-2, capable of phenolic p-dehydroxylation in the biotransformation of secoisolariciresinol diglucoside to END and ENL, was concluded to be Eggerthella (Eg.) lenta (Eg. sp. SDG-2) on the basis of 16S rRNA gene sequence analysis. The bacterium could transform (+)-dihydroxyenterodiol (DHEND, 3a) to (+)-END (1a), but not for (-)-DHEND (3b) to (-)-END (1b) under anaerobic conditions. By incubation of a mixture of (+)- and (-)-dihydroxyenterolactone (DHENL, 4a and 4b) with Eg. sp. SDG-2, only (-)-DHENL (4b) was converted to (-)-ENL (2b), selectively. On the other hand, we isolated a different bacterium, strain ARC-1, capable of dehydroxylating (-)-DHEND (3b) to (-)-END (1b) from human feces. Strain ARC-1 could transform not only (-)-DHEND (3b) to (-)-END (1b), but also (+)-DHENL (4a) to (+)-ENL (2b). However, the bacterium could not transform (+)-DHEND (3a) and (-)-DHENL (4b). Both bacterial strains demonstrated different enantioselective dehydroxylation.

Effect of Eucommia ulmoides on systolic blood pressure in the spontaneous hypertensive rat

Experiments were conducted to establish the safety and efficacy of Eucommia ulmoides (Du-Zhong) extract in the treatment of hypertension. Pilot experiments using rats demonstrated that E. ulmoides extract was safe to the saturation limits of the compound. The maximum tolerated dose (MTD) was 1200 mg/kg when administered by gastric gavage at a concentration of 1200 mg/ml. Also, rats given 200 mg/kg, 600 mg/kg or 1200 mg/kg doses of E. ulmoides extract daily for 28 days demonstrated no evidence of acute toxicity as determined by clinical appearance, histopathology and serum chemistry evaluation. Lastly, spontaneous hypertensive rats (SHRs) were administered E. ulmoides extract daily for 22 days. Systolic blood pressure (BP) was measured on treatment days 1, 8, 15 and 22 at 0, 1, 2 and 3 hours post-treatment. Beginning on day 8, E. ulmoides extract administered at the mid or high dosages lowered BP in male, but not female, rats. BP declined at a rate of approximately 10 mmHg per hour. The mid dosage of 600 mg/kg was found to be the minimum effective dose. In conclusion, E. ulmoides extract was non-toxic and effective in reducing systolic BP in the SHR.

Biotransformation of pinoresinol diglucoside to mammalian lignans by human intestinal microflora, and isolation of Enterococcus faecalis strain PDG-1 responsible for the transformation of (+)-pinoresinol to (+)-lariciresinol

By anaerobic incubation of pinoresinol diglucoside (1) from the bark of Eucommia ulmoides with a fecal suspension of humans, eleven metabolites were formed, and their structures were identified as (+)-pinoresinol (2), (+)-lariciresinol (3), 3'-demethyl-(+)-lariciresinol (4), (-)-secoisolariciresinol (5), (-)-3-(3", 4"-dihydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butane-1, 4-diol (6), 2-(3', 4'-dihydroxybenzyl)-3-(3", 4"-dihydroxybenzyl)butane-1, 4-diol (7), 3-(3"-hydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butane-1, 4-diol (8), 2-(3', 4'-dihydroxybenzyl)-3-(3"-hydroxybenzyl)butane-1, 4-diol (9), (-)-enterodiol (10), (-)-(2R, 3R)-3-(3", 4"-dihydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butyrolactone (11), (-)-(2R, 3R)-2-(3', 4'-dihydroxybenzyl)-3-(3", 4"-dihydroxybenzyl)butyrolactone (12), (-)-(2R, 3R)-3-(3"-hydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butyrolactone (13), 2-(3', 4'-dihydroxybenzyl)-3-(3"-hydroxybenzyl)butyrolactone (14), 2-(3'-hydroxybenzyl)-3-(3", 4"-dihydroxybenzyl)butyrolactone (15) and (-)-(2R, 3R)-enterolactone (16) by various spectroscopic means, including two dimensional (2D)-NMR, mass spectrometry and circular dichroism. A possible metabolic pathway was proposed on the basis of their structures and time course experiments monitored by thin-layer chromatography. Furthermore, a bacterial strain responsible for the transformation of (+)-pinoresinol to (+)-lariciresinol was isolated from a human fecal suspension and identified as Enterococcus faecalis strain PDG-1.

Lignans isolated from valerian: identification and characterization of a new olivil derivative with partial agonistic activity at A(1) adenosine receptors

A methanolic extract of the roots of Valeriana officinalis (valerian) was investigated for its lignan content. In addition to the lignans 8'-hydroxypinoresinol (1) and pinoresinol-4-O-beta-D-glucoside (2), which had already been isolated from valerian in an earlier study, the 7,9'-monoepoxylignans massoniresinol-4'-O-beta-D-glucoside (3), 4'-O-beta-D-glucosyl-9-O-(6' '-deoxysaccharosyl)olivil (4), and berchemol-4'-O-beta-D-glucoside (5) and the 7,9':7',9-diepoxylignans pinoresinol-4,4'-di-beta-O-D-glucoside (6), 8-hydroxypinoresinol-4'-O-beta-D-glucoside (7), and 8'-hydroxypinoresinol-4'-O-beta-D-glucoside (8) were identified. While lignans 3, 6, 7, and 8 had already been isolated from other plants, lignans 4 and 5 are new natural products. The lignans were investigated in radioligand binding assays at various receptors of the central nervous system, including GABA(A), benzodiazepine, 5-HT(1A), and adenosine A(1) and A(2A) receptors, to investigate their potential contribution to the pharmacological activity of valerian. The novel olivil derivative 4 proved to be a partial agonist at rat and human A(1) adenosine receptors exhibiting A(1) affinity and activity in low micromolar to submicromolar concentrations. Lignan 4 is the first nonnucleoside adenosine receptor agonist not structurally related to adenosine.