Active chemical compounds of traditional Chinese medicine Herba Leonuri: implications for cardiovascular diseases

Novel insights into the protective effects of leonurine against acute kidney injury: Inhibition of ER stress-associated ferroptosis via regulating ATF4/CHOP/ACSL4 pathway

Acute kidney injury (AKI) is a common and serious global health problem with high risks of mortality and the development of chronic kidney diseases. Leonurine is a unique bioactive component from Leonurus japonicus Houtt. and exerts antioxidant, antiapoptotic or anti-inflammatory properties. This study aimed to explore the benefits of leonurine on AKI and the possible mechanisms involved, with a particular foc on the regulation of ferroptosis and endoplasmic reticulum (ER) stress. Our results showed that leonurine exhibited prominent protective effects against AKI, as evidenced by the amelioration of histopathological alterations and reduction of renal dysfunction. In addition, leonurine significantly suppressed ferroptosis in AKI both in vivo and in vitro by effectively restoring ultrastructural abnormalities in mitochondria, decreasing ASCL4 and 4-HNE levels, scavenging reactive oxygen species (ROS), as well as increasing GPX4 and GSH levels. In parallel, leonurine also markedly mitigated ER stress via down-regulating PERK, eIF-2α, ATF4, CHOP and CHAC1. Further studies suggested that ER stress was closely involved in erastin-induced ferroptosis, and leonurine protected tubular epithelial cells in vitro by inhibiting ER stress-associated ferroptosis via regulating ATF4/CHOP/ASCL4 signalling pathway. Mechanistically, ATF4 silencing in vitro regulated CHOP and ACSL4 expressions, ultimately weakening both ER stress and ferroptosis. Notably, analyses of single-cell RNA sequencing data revealed that ATF4, CHOP and ASCL4 in renal tubular cells were all abnormally upregulated in patients with AKI compared to healthy controls, suggesting their contributions to the pathogenesis of AKI. Altogether, these findings suggest that leonurine alleviates AKI by inhibiting ER stress-associated ferroptosis via regulating ATF4/CHOP/ASCL4 signalling pathway, thus providing novel mechanisms for AKI treatment.

A new mechanism of therapeutic effect of stachydrine on heart failure by inhibiting myocardial ferroptosis

Ferroptosis is a novel form of programmed cell death caused by iron-dependent lipid peroxidation and excessive production of ROS. Its morphology is characterized by mitochondrial atrophy, increased mitochondrial membrane density, mitochondrial cristae degeneration and rupture, and unchanged nuclear morphology. Here, we investigated whether a bioactive constituent extracted from the Chinese herb Leonurus japonicus Houtt. (Yimucao), stachydrine, could improve cardiac function by inhibiting myocardial ferroptosis. We found significant morphological features of ferroptosis in a TAC-induced mouse model of heart failure, in which increased lipid peroxidation in cardiac tissue was accompanied by abnormalities in cystine metabolism as well as iron metabolism. The contractile function of adult mouse cardiomyocytes was severely reduced after the occurrence of erastin-induced ferroptosis. We found that in heart failure mice and erastin-induced cardiomyocyte ferroptosis models, stachydrine significantly improved myocardial function, improving mitochondrial morphological features of ferroptosis and associated signaling pathway alterations, including lipid peroxidation levels, cystine metabolism, and iron metabolism. The results of studies on stachydrine provides new inspirations for the treatment of cardiac ferroptosis and chronic heart failure.

Leonurine pretreatment protects the heart from myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion (I/R), an important complication of reperfusion therapy for myocardial infarction, is characterized by hyperactive oxidative stress and inflammatory response. Leonurine (4-guanidino-n-butyl syringate, SCM-198), an alkaloid extracted from Herbaleonuri, was previously found to be highly cardioprotective both in vitro and in vivo. Our current study aimed to investigate the effect of SCM-198 preconditioning on myocardial I/R injury in vitro and in vivo, respectively, as well as to decipher the mechanism involved. Rats were pretreated with SCM-198 before subjected to 45 min of myocardial ischemia, which was followed by 24 h of reperfusion. Primary neonatal rat cardiac ventricular myocytes (NRCMs) were exposed to hypoxia (95% N2 + 5% CO2) for 12 h, and then to 12 h reoxygenation so as to mimic I/R. The enzymatic measurements demonstrated that SCM-198 reduced the release of infarction-related enzymes, and the hemodynamic and echocardiography measurements showed that SCM-198 restored cardiac functions, which suggested that SCM-198 could significantly reduce infarct size, maintaining cardiomyocyte morphology, and that SCM-198 pretreatment could significantly reduce cardiomyocytes apoptosis. Moreover, we demonstrated that SCM-198 could exert a cardioprotective effect by reducing reactive oxygen species (ROS) level and Akt phosphorylation while reducing the phosphorylation of p38 and JNK. In addition, the upregulation of p-Akt, Bcl-2/Bax induced by SCM-198 treatment were blocked by PI3K inhibitor LY294002, and the total protein level of Akt was not affected by SCM-198 pretreatment. Our experimental results indicated that SCM-198 could have a cardioprotective effect on I/R injury, which confirmed the utility of SCM-198 preconditioning as a strategy to prevent I/R injury.

Leonurine improves bovine oocyte maturation and subsequent embryonic development by reducing oxidative stress and improving mitochondrial function

It is acknowledged that excessive reactive oxygen species (ROS) level attributes greatly to the compromised developmental potential of oocytes matured in vitro. Although agents were applied to alleviate ROS levels, results were varied because of the distinct antioxidative activity and cell toxicity. Leonurine (LEO), extracted from the natural Chinese herb motherwort, is considered to be a potent free radical scavenger. Yet, it is undetermined whether LEO is benefit for oocyte development during in vitro maturation (IVM). In the present study, the effect of LEO on the quality of bovine oocyte as well as the underlying mechanism was investigated. We found that maturation rate (P < 0.01), subsequent blastocyst formation rate (P < 0.05), and the total blastocyst cell number (P < 0.05) after parthenogenetic activation were significantly increased in the group treated with 20 μM LEO. Moreover, a dramatic decline in ROS (P < 0.01), decreased lipid content (P < 0.01), elevated MMP level (P < 0.05), increased ATP content (P < 0.05), and reduced mitochondrial temperature (P < 0.01) were observed in oocytes treated with LEO. Furthermore, the expression level of anti-apoptotic protein BCL2 was significantly higher in LEO treated oocytes (P < 0.01), and the ratio of BAX/BCL2 was obvious decreased (P < 0.01). Finally, we found that LC3B intensity was significantly reduced (P < 0.05) while the rate of EdU positive nuclei was markedly increased (P < 0.05) in embryos derived from LEO-treated oocytes. Our results demonstrate that LEO exhibits a potent protective role in the acquisition of oocyte development capacity against oxidative stress during IVM, and provides a new solution for optimizing the in vitro culture system of bovine embryos.

Stachytine Hydrochloride Improves Cardiac Function in Mice with ISO-Induced Heart Failure by Inhibiting the α-1,6-Fucosylation on N-Glycosylation of β1AR

Background: Cardiovascular diseases have become a major public health problem that seriously threatens human health. The cumulative effects of various cardiovascular events will eventually develop into chronic heart insufficiency and even heart failure, and the β1 adrenergic receptor signal pathway plays an important role in this process. Stachytine hydrochloride is the main active ingredient of Yimucao, which is a traditional Chinese medicine used to treat gynecological diseases. Modern studies have found that stachytine hydrochloride has a good cardioprotective effect, but it is still unclear whether stachytine hydrochloride has an effect on the β1 adrenergic receptor signal pathway. The purpose of this study is to explore the effect of stachytine hydrochloride on the β1 adrenergic receptor signal pathway.

Method: In this study, a continuous infusion of isoproterenol (40 mg/kg/day) was administered to mice and ventricular myocytes explored the potential mechanism of stachytine hydrochloride (12 mg/kg/day) on the β1 adrenergic receptor signal pathway in the heart. Evaluate changes in cardiac morphology and function by echocardiography, cardiac hemodynamics, and histological methods, and detect molecular changes by Western blot and immunofluorescence. Treat primary cultured adult mouse or neonatal rat ventricular myocytes with or without isoproterenol (0.1 μMol), PNGase F (10^–2 units/ml), and stachytine hydrochloride (10 μMol) at different time points. Detect α-1,6-fucosylation on N-glycosylation, calcium transient, contraction, and relaxation function and related signals.

Results: Stachytine hydrochloride reduces cardiac remodeling and modulates hemodynamic parameters during chronic β1 adrenergic receptor activation in vivo. The N-glycosylation of β1 adrenergic receptors decreased after continuous isoproterenol stimulation, while stachytine hydrochloride can increase the N-glycosylation of β1AR in the heart of mice with isoproterenol-induced heart failure. Decreased N-glycosylation of β1 adrenergic receptors will downregulate the cAMP/PKA signal pathway and inhibit myocardial excitation and contraction coupling. Stachytine hydrochloride significantly reduced isoproterenol-induced cardiac N-linked glycoproteins with α-1,6-fucosylation.

Conclusion: Our results show that stachytine hydrochloride inhibits the synthesis of α-1,6-fucosylation on the N-terminal sugar chain by reducing α-1,6-fucosyltransferase (FUT8) and α-1,3-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase A (MGAT4a), upregulating the N-glycosylation level on β1 adrenergic receptors, and maintaining cAMP/PKA signal pathway activation.

Leonurine protects against influenza A virus infection-induced pneumonia in mice

Influenza A virus (H1N1), a swine-origin influenza A virus, causes seasonal epidemics that result in severe illnesses and deaths. Leonurine has been reported to function as an anti-inflammatory agent with protective effects on nervous, urinary and cardiovascular systems. However, the therapeutic effects of leonurine on the pneumonia caused by H1N1 infection remain unclear. Hematoxylin and eosin staining was performed to evaluate the lung injuries of mice infected by H1N1. The amount of immune cells was analyzed by flow cytometry. Enzyme-linked immunosorbent assay was used to evaluate the alteration of multiple cytokines in lung tissues. Real-time quantitative polymerase chain reaction assay was performed to investigate the ribonucleic acid (RNA) levels of certain genes. The protein levels in toll-like receptor 4/nuclear factor kappa-light-chain-enhancer of activated B cells (TLR4/NF-κB) signaling were estimated by western blot assay. Leonurine treatment significantly inhibited the mortality caused by H1N1 infection. Leonurine treatment (60 mg/kg) alleviated the lung injuries caused by virus infection. The inflammatory cell accumulation and cytokine expression were inhibited by the leonurine administration. Leonurine inhibited the mRNA expression of pro-inflammatory cytokines in the lung homogenates at day 5 postinfection. Leonurine regulated the TLR4/NF-κB signaling in the lung homogenates of H1N1-infected mice at day 5 postinfection. Leonurine protects against H1N1 infection-induced pneumonia in mice.

Leonurine, a potential drug for the treatment of cardiovascular system and central nervous system diseases

Leonurus japonicus Houtt., a traditional Chinese herbal medicine, is often used as a gynecological medicine with the effect of promoting blood circulation, regulating menstruation, clearing heat, and detoxificating. As the most important alkaloid in L. japonicus, leonurine has a wide range of biological activities, such as antioxidation, anti-inflammation, and anti-apoptosis. Cardiovascular system and central nervous system diseases are arrogant killers that threaten human lives and health around the world, but many drugs for treating them have certain side effects. This paper reviews the potential therapeutic effects of leonurine on cardiovascular system and central nervous system diseases, summarizes the previous research progress, and focuses on its therapeutic effect in various diseases. Although leonurine plays a prominent role in the treatment of cardiovascular system and central nervous system diseases, there are still some shortages, such as low bioavailability, weak transmembrane ability, and poor fat solubility. Therefore, the structure modification of leonurine may solve these problems and provide reference value for the development of new drugs. At present, leonurine is in clinical trial, and it is hoped that our summary will help to provide guidance for its future research on the basic science and clinical application.

Breast Cancer Resistance Protein and Multidrug Resistance Protein 2 Mediate the Disposition of Leonurine-10-O-β-glucuronide

Background:

Leonurine (Leo), a promising antilipemic agent that has been approved for clinical trials, is extensively metabolized into bioactive Leonurine-10-O-β-glucuronide (L-10-G) vivo.

Objective:

To explore the effects of breast cancer resistance protein (Bcrp) and multidrug resistance protein 2 (Mrp2) on the disposition of L-10-G.

Methods:

The pharmacokinetics, tissue distribution and intestinal perfusion of Leo were studied by using efflux transporter gene knockout mouse models. The enzyme kinetics via liver and intestinal microsomes were also examined.

Results:

After intravenous injection with Leo, the AUC0-∞ values of L-10-G in Bcrp1-/- and Mrp2-/- mice were 1.55-fold and 16.80-fold higher, respectively, than those in wild-type FVB mice (P < 0.05). After oral administration, the AUC0-∞ value of L-10-G showed a 2.82-fold increase in Mrp2-/- mice compared with wild-type FVB mice (P < 0.05). After gavage with Leo for 10 and 25 min, the bile accumulation of L-10-G in Mrp2-/- mice was 3-fold and 22-fold lower, respectively, than that in wild-type FVB mice (P < 0.05). Besides, the intestinal excreted amount of L-10-G showed 2.22-fold and 2.68-fold decrease in Bcrp1-/- and Mrp2-/- mice, respectively, compared with that in wild-type FVB mice (P < 0.05). The clearance of L-10-G decreased in liver microsomes and increased in intestinal microsomes of Bcrp1-/- and Mrp2-/- mice compared to the wild-type FVB mice (P < 0.05).

Conclusion:

Both Bcrp and Mrp2 are involved in the disposition of L-10-G, and Mrp2 exhibits a superior influence.

Effects of stem bark aqueous extract of Fagara tessmannii Engl (Rutaceae) on cardiovascular risks related to monosodium glutamate-induced obesity in rat: In vivo and in vitro assessments

ETHNOPHARMACOLOGICAL RELEVANCE

Fagara tessmannii is a shrub of the African rainforests in South-West, Centre, South and East provinces in Cameroon. It is used in traditional medicine for the treatment of tumors, swellings, inflammation, gonorrhoea, schistosomiasis, antifungal, heart diseases and as anti-hypertensive.

AIM OF THE STUDY

We investigated the potential effects of F. tessmannii on cardiovascular risk related to monosodium glutamate-induced obesity.

MATERIALS AND METHODS

Monosodium glutamate (MSG, 4 mg/g/day) was injected subcutaneously to newborn Wistar rats for the four consecutive first days of their life and on the 6th, 8th and 10th day after birth. After 21 weeks, obese rats were treated orally with F. tessmannii (100 or 200 mg/kg/day), orlistat (10 mg/kg/day) or telmisartan (10 mg/kg/day) for 6 weeks. Body weight, obesity, body mass index (BMI), Lee index, insulin sensitivity and glucose tolerance, blood pressure, lipid profile as a Coronary Risk Index (CRI), and reactivity of isolated thoracic aorta were evaluated.

RESULTS

In addition to significantly decrease body weight (17.60% and 20.34%), BMI, Lee's index, retroperitoneal fat, total adiposity, and coronary risk indicators, F. tessmannii has significantly decreased insulin resistance and hyperglycemia and high blood pressure observed in MSG-obese rats. The high contractility to phenylephrine as well as the hypersensitivity to sodium nitroprusside (a nitric oxide-donor), observed in MSG aortic rings were significantly reduced by the F. tessmannii extract. Enhanced serum Na⁺ and Cl^- levels and decreased K⁺ observed in obese rats were also significantly reversed after F. tessmannii treatment.

CONCLUSIONS

F. tessmannii fights against obesity and associated cardiovascular risks by modulating production and vascular responsiveness to vasoactive factors, monitoring premature aging. F. tessmannii promotes the loss of ectopic fat and other fatty tissues, the sensitivity of the peripherical tissues to insulin, the energy expenditure and the renovascular decompression and regulates ions movement which prevents hypertension.

Stachydrine hydrochloride suppresses phenylephrine-induced pathological cardiac hypertrophy by inhibiting the calcineurin/nuclear factor of activated T-cell signalling pathway

The calcineurin (CaN)/nuclear factor of activated T-cell (NFAT) signalling pathway plays an important role in pathological cardiac hypertrophy. Here, we investigated the potential effects of stachydrine hydrochloride, a bioactive constituent extracted from the Chinese herb Leonurus japonicus Houtt. (Yimucao), on pathological cardiac hypertrophy during chronic α1-adrenergic receptor (α1-AR) activation and the underlying mechanisms. First, by transcriptome analysis, we determined that pathological hypertrophy models could be prepared after phenylephrine stimulation. In primary cultured neonatal rat ventricular myocytes, stachydrine hydrochloride reduced phenylephrine-induced cardiomyocyte surface area and the mRNA expression of cardiac hypertrophy biomarkers (atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), and β-myosin heavy chain/α-myosin heavy chain (β-MHC/α-MHC)). In addition, phenylephrine stimulation potently induced activation of the CaN/NFAT pathway. Interestingly, stachydrine hydrochloride inhibited CaN activation and reduced NFATc3 nuclear translocation in phenylephrine-stimulated neonatal rat ventricular myocytes. In mice treated with phenylephrine, stachydrine hydrochloride treatment decreased cardiac hypertrophy and regulated heart function. Collectively, our data show that stachydrine hydrochloride decreases cardiac hypertrophy in phenylephrine-stimulated hearts by inhibiting the CaN/NFAT pathway, which might contribute to alleviation of pathological cardiac hypertrophy and cardiac dysfunction by stachydrine hydrochloride after phenylephrine stimulation This also indicated that governing of CaN/NFAT pathway might serve as a preventive or therapeutic strategy for pathological cardiac hypertrophy.

Leonurine improves in vitro porcine embryo development competence by reducing reactive oxygen species production and protecting mitochondrial function

Leonurine (LEO) is pseudoalkaloid that has been isolated from motherwort. It has been found to have various biological activities, including an antioxidant capacity. This study aimed to confirm whether LEO could be used in porcine in vitro culture (IVC) medium for its antioxidant effect and related molecular mechanisms. The results showed that embryos in IVC medium supplemented with 40 μM LEO had an increased blastocyst formation rate, total cell number, and proliferation capacity and a low apoptosis rate. LEO supplementation decreased reactive oxygen species levels and increased glutathione levels. Moreover, LEO-treated embryos exhibited improved intracellular mitochondrial membrane potential and reduced autophagy. In addition, pluripotency related gene was up-regulated while apoptosis and autophagy related genes were down-regulated with LEO supplementation. These results suggest that LEO has a beneficial effect on pre-implantation embryo development by reducing oxidative stress and enhancing mitochondrial function.

Impact of natural products on the cholesterol transporter ABCA1

ETHNOPHARMACOLOGICAL RELEVANCE

In different countries and areas of the world, traditional medicine has been and is still used for the treatment of various disorders, including chest pain or liver complaints, of which we now know that they can be linked with altered lipid and cholesterol homeostasis. As ATP-binding cassette transporter A1 (ABCA1) plays an essential role in cholesterol metabolism, its modulation may be one of the molecular mechanisms responsible for the experienced benefit of traditional recipes. Intense research activity has been dedicated to the identification of natural products from traditional medicine that regulate ABCA1 expression.

AIMS OF THE REVIEW

This review surveys natural products, originating from ethnopharmacologically used plants, fungi or marine sources, which influence ABCA1 expression, providing a reference for future study.

MATERIALS AND METHODS

Information on regulation of ABCA1 expression by natural compounds from traditional medicine was extracted from ancient and modern books, materia medica, and electronic databases (PubMed, Google Scholar, Science Direct, and ResearchGate).

RESULTS

More than 60 natural compounds from traditional medicine, especially traditional Chinese medicine (TCM), are reported to regulate ABCA1 expression in different in vitro and in vivo models (such as cholesterol efflux and atherosclerotic animal models). These active compounds belong to the classes of polyketides, terpenoids, phenylpropanoids, tannins, alkaloids, steroids, amino acids and others. Several compounds appear very promising in vivo, which need to be further investigated in animal models of diseases related to ABCA1 or in clinical studies.

CONCLUSION

Natural products from traditional medicine constitute a large promising pool for compounds that regulate ABCA1 expression, and thus may prevent/treat diseases related to cholesterol metabolism, like atherosclerosis or Alzheimer's disease. In many cases, the molecular mechanisms of these natural products remain to be investigated.

Protective Effect of Stachydrine Against Cerebral Ischemia-Reperfusion Injury by Reducing Inflammation and Apoptosis Through P65 and JAK2/STAT3 Signaling Pathway

Stachydrine, a constituent of Leonurus japonicus Houtt which also called Japanese motherwort has been shown to improve vascular microcirculation and ameliorate endothelial dysfunction. This study investigated the neuroprotective effect of stachydrine. Male Sprague-Dawley (SD) rats were randomly divided into sham, control, and stachydrine groups. The neurological deficit score was evaluated and the infarct size of the brain was measured using 2,3,5-triphenyltetra-zolium (TTC) chloride staining assay, and the pathological changes in the brain tissues were examined by HE staining. Nissl and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL) staining were performed to assess the numbers of Nissl bodies and the levels of apoptosis in the neurons. The activities of superoxide dismutase (SOD) and the levels of malondialdehyde (MDA) were also measured. The release of inflammatory factors IL-1β and TNF-α were detected by Enzyme-linked immunosorbent assay (ELISA). Compared with the control group, the stachydrine group showed a significant prevention of neurological deficit, as indicated by the reduced infarct volume in the brain. Moreover, the stachydrine treatment reduced the activities of SOD, the levels of MDA and decreased the amount of IL-1β, and TNF-α, indicating that it could function to decrease the level of inflammation, thus reducing brain damage. The ischemic stroke model of PC12 cells was prepared via oxygen-glucose deprivation (OGD) protocol for 6 h. The expression of P65 and JAK2/STAT3 signaling pathway related proteins was measured by western blot. The treatment group was found to have the survival rate of PC12 cells improved and the release of inflammatory factors reduced when compared with the OGD group. This study demonstrated that stachydrine could improve nerve function by inhibiting the phosphorylation of P65/JAK2 and STAT3.

Inhibition of PI3K/Akt/NF-κB signaling with leonurine for ameliorating the progression of osteoarthritis: In vitro and in vivo studies

Osteoarthritis (OA) is characterized as the degeneration and destruction of articular cartilage. In recent decades, leonurine (LN), the main active component in medical and edible dual purpose plant Herba Leonuri, has been shown associated with potent anti-inflammatory effects in several diseases. In the current study, we examined the protective effects of LN in the inhibition of OA development as well as its underlying mechanism both in vitro and in vivo experiments. In vitro, interleukin-1 beta (IL-1β) induced over-production of prostaglandin E2, nitric oxide, inducible nitric oxide synthase, cyclooxygenase-2, interleukin-6 and tumor necrosis factor alpha were all inhibited significantly by the pretreatment of LN at a dose-dependent manner (5, 10, and 20 µM). Moreover, the expression of thrombospondin motifs 5 (ADAMTS5) and metalloproteinase 13 (MMP13) was downregulated by LN. All these changes led to the IL-1β induced degradation of extracellular matrix. Mechanistically, the LN suppressed IL-1β induced activation of the PI3K/Akt/NF-κB signaling pathway cascades. Meanwhile, it was also demonstrated in our molecular docking studies that LN had strong binding abilities to PI3K. In addition, LN was observed exerting protective effects in a surgical induced model of OA. To sum up, this study indicated LN could be applied as a promising therapeutic agent in the treatment of OA.

Discovery of Leonuri and therapeutical applications: From bench to bedside

Despite several advances in percutaneous coronary intervention and the discovery of new drugs, the incidence of myocardial infarction and deaths due to cardiovascular diseases (CVD) has not decreased markedly in China. The quality of life is affected seriously, which further results in great social and family burden. Many drugs, from the century-old aspirin to the newly FDA-approved Byvalson, have been proven to be effective in the treatment and prevention of CVD. As clinically reported, those life-saving drugs still have their side effects in regards to the narrow therapeutic indexes influenced by individual genetic variations. Herba Leonuri, also known as Chinese Motherwort, which are naturally present in plants and traditionally are used for the uterotonic action, postpartum blood stasis, breast pain as well as other gynecological disorders in China for thousands of years. Since the last two decades, our group has reported leonurine, a unique alkaloid found in Herba Leonuri, exhibits various bioactivities such as antioxidant, anti-apoptotic effects, free radical scavenging and anti-inflammatory effects, in addition to improving micro-circulation. These bioactivities are related to the underlying mechanisms of ischemic heart diseases and cardiac fibrosis. Pharmacological studies have proven leonurine to be effective in treating CVD in various ways, particularly ischemic heart diseases. Besides the cardio protective effects, which are similar in the central nervous system, more specifically, inhibited mitochondrial reactive oxygen species production together with the restored mitochondrial function and redox state were observed in middle cerebral artery occlusion rats by leonurine treatment, which strongly reveals its neuroprotective effects and carries a therapeutic potential for recovery and prevention of stroke. Based on their mode of action, we propose that leonurine can be developed as drugs to treat ischemic heart diseases. Taking advantage of the most recent findings in pharmacological research including the effects of low toxicity and good pharmacokinetics characteristics, leonurine has a very attractive prospect of clinical application. Our recent promising pharmacological results may be able to eradicate the barrier hindering its sale on market. In sum, from bench to bedside is no longer a long way for leonurine.

Phytochemistry and pharmacology of the genus Leonurus: The herb to benefit the mothers and more

Plants belonging to the genus Leonurus, also named motherwort, are traditionally used for anti-gynecological disorder in East Asia, and for sedative in Europe. Chemical investigation of the genus Leonurus not only enriched the natural products library, but also enlarged the pharmacological application of this traditional herb. In this review, we systematically summarized the structures of 259 compounds isolated from the genus Leonurus, featured with 147 labdane diterpenoids. The reported bioactivity studies up to 2017 are presented in the second part, with the main focus on the isolated compounds and also concerning the extracts. In addition to the traditional uterine contraction and sedative activity, recently the cardiovascular protection effect of leonurine has drawn most attention. Other than that, neuroprotection, anti-inflammation, anti-cancer, anti-platelet aggregation and many other activities have been assigned to various compounds from the genus Leonurus. Among 70 bioactivity references cited in this review, 57% of them were concentrated on two alkaloids (leonurine and stachydrine), whereas only 20% are about the 147 diterpenoids. Anti-inflammation is the major bioactivity discovered so far for the labdane diterpenoids from the genus Leonurus, whose further therapeutic potential still remains for exploration.

Anti-inflammatory Labdane Diterpenoids from Leonurus macranthus

Twenty new polyoxygenated labdane diterpenoids (1-20) were isolated from the aerial parts of Leonurus macranthus. Their structures were elucidated on the basis of spectroscopic and spectrometric data (1D and 2D NMR, IR, and HRESIMS). The absolute configurations of macranthin A (1) and 6-O-deacetylmacranthin A (2) were determined by single-crystal X-ray crystallographic analysis and a modified Mosher's method, respectively. Compounds 1-9, 12, 14, and 19 showed inhibition of nitric oxide production in lipopolysaccharide-activated BV-2 microglial cells with IC50 values of 10.0-63.7 μM.

Effects of stachydrine on norepinephrine-induced neonatal rat cardiac myocytes hypertrophy and intracellular calcium transients

Background

Leonurus heterophyllus sweet has been suggested to have cardioprotective effects against heart diseases, including ischemic diseases and ventricular remodeling. However, the active ingredients of the herb and the underlying mechanisms are poorly understood. The aim of the present study was to investigate the effects of stachydrine (STA), a major constituent of Leonurus heterophyllus sweet, on norepinephrine (NE) induced hypertrophy and the changes of calcium transients in neonatal rat cardiomyocytes.

Methods

Ventricular myocytes from 1-day-old Wistar rats were isolated and cultured in DMEM/F12 with 1 μmol/L norepinephrine in the presence or absence of 10 μmol/L STA for 72 h. Cardiomyocytes hypertrophy was evaluated by cell surface area, total protein/DNA content, β/α-MHC mRNA ratio. While calcium handling function was evaluated by Ca²⁺-transient amplitude and decay, SERCA2a activity and expression, PLN expression and phosphorylation. β1-adrenergic receptor system activation was evaluated by the content of cAMP and the activation of PKA.

Results

NE treatment increases the cell surface area, protein synthesis, the expression level of β-MHC and β/α-MHC ratio. These effects were attenuated by STA. NE-induced hypertrophy was associated with increased Ca²⁺-transient amplitude, accelerated decay of the Ca²⁺-transient, increased phospholamban expression, hyper-phosphorylation at both the serine-16 and threonine-17 residues, increased intracellular cAMP level, and PKA overactivation. All of which were significantly inhibited by STA.

Conclusion

These data suggest that STA attenuates norepinephrine-induced cardiomyocyte hypertrophy and has potential protective effects against β-adrenergic receptor induced Ca²⁺ mishandling.

Heterologous expression of AtMYB12 in kale (Brassica oleracea var. acephala) leads to high flavonol accumulation

Overexpression of Arabidopsis AtMYB12 transcription factor greatly increases the total phenolic and flavonol content in transgenic kale leaves. Flavonoids are a diverse group of plant secondary metabolites exhibiting a number of health-promoting effects. There has been a growing interest to develop biotechnological methods for the enhanced production of flavonoids in crop plants. AtMYB12 is an Arabidopsis transcription factor which specifically activates flavonol synthesis and its overexpression has led to increased flavonol accumulation in several transgenic plants. In the present study, AtMYB12 was overexpressed in a commercial cultivar of kale and the transgenic plants were tested both in in vitro and in semi-field conditions in cages under natural light. Using this method, a severalfold increase in both total phenolics content and flavonol accumulation was achieved. This study provides a reliable and efficient transformation protocol for kale and suggests the potential of this flavonol-enriched vegetable for the production of kaempferol.

Synthesis of Carbohydrate-based Natural Products from Leonurus japonicus and their Biological Evaluation as Anti-oxidants

Natural products are important materials that have found a wide variety of uses, especially in medicine. Traditional Chinese medicine (TCM) has especially taken advantage of natural products and compounds found in Leonurus, a species of herb used extensively in TCM to treat various ailments. Herein we describe the synthesis of three natural products from Leonurus japonicus and our investigation of their hepatoprotective properties.

Simultaneous determination and pharmacokinetic study of stachydrine and leonurine in rat plasma after oral administration of Herba Leonuri extract by LC-MS/MS

A simple, sensitive and specific method was developed for simultaneous determination of stachydrine and leonurine in rat plasma using diphenhydramine as an internal standard (IS). The separation was performed on an Agilent ZORBAX Eclipse XDB-C(18) column (150mm×4.6mm, i.d., 5μm) at a flow rate of 0.6mL/min, and the mixture of methanol-water containing 0.1% formic acid was used as the mobile phase. The lower limits of quantitation (LLOQs) in rat plasma were 0.895 and 0.287ng/mL for stachydrine and leonurine, respectively. Intra- and inter-day precisions were within 14.4% and accuracies were not more than 3.0%. After single oral administration of 14.5g/kg Herba Leonuri extract, C(max) of stachydrine and leonurine in rat plasma were respectively 1608±267 and 43.3±8.2ng/mL, while T(max) values were respectively 0.75±0.27 and 0.83±0.26h. The results demonstrated that the present LC-MS/MS method was sensitive enough for pharmacokinetic study of stachydrine and leonurine following oral administration of Herba Leonuri extract.

Leonurine (SCM-198) attenuates myocardial fibrotic response via inhibition of NADPH oxidase 4

In our previous studies, we have reported that leonurine, a plant phenolic alkaloid in Herba leonuri, exerted cardioprotective properties in a number of preclinical experiments. Herein, we investigated the roles and the possible mechanisms of leonurine for reducing fibrotic responses in angiotensin II (Ang II)-stimulated primary neonatal rat cardiac fibroblasts and post-myocardial infarction (MI) rats. In in vitro experiments performed in neonatal rat cardiac fibroblasts, leonurine (10-20 μM) pretreatment attenuated Ang II-induced activation of extracellular signal-regulated kinase 1/2, production of intracellular reactive oxygen species (ROS), expression and activity of matrix metalloproteinase (MMP)-2/9, and expression of α-smooth muscle actin and types I and III collagen. A small interfering RNA-mediated knockdown strategy for NADPH oxidase 4 (Nox4) revealed that Nox4 was required for Ang II-induced activation of cardiac fibroblasts. In vivo studies using a post-MI model in rats indicated that administration of leonurine inhibited myocardial fibrosis while reducing cardiac Nox4 expression, ROS production, NF-κB activation, and plasma MMP-2 activity. In conclusion, our results provide the first evidence that leonurine could prevent cardiac fibrosis and the activation of cardiac fibroblasts partly through modulation of a Nox4-ROS pathway.