Enhancement of phenylephrine-induced contraction in the isolated rat aorta with endothelium by H2O-extract from an Oriental medicinal plant Leonuri herba

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.

Leonurine, a Potential Agent of Traditional Chinese Medicine: Recent Updates and Future Perspectives

Herba Leonuri, also named Chinese Motherwort, has been extensively investigated as an effective agent on the uterus system. Our group has been studying the natural products of Herba Leonuri for several years, and during this period, many biological activities of the drug were recognized. Leonurine (4-guanidino- N-butyl-syringate) is an alkaloid present in Herba Leonuri. Recently, growing evidence has highlighted the therapeutic potential of leonurine in multiple diseases, especially cardiovascular. In this review, we discuss the biological activities of leonurine, as well as recent advances involving this alkaloid.

Rationalizing ethnopharmacological uses of Alternanthera sessilis: A folk medicinal plant of Pakistan to manage diarrhea, asthma and hypertension

ETHNOPHARMACOLOGICAL RELEVANCE

Tribal herbal practitioners of Pakistan use Alternanthera sessilis (Amaranthaceae) to treat diarrhea, asthma and hypertension.

OBJECTIVE

The current study was conducted to provide mechanistic basis for anti-spasmodic, anti- asthmatic and anti-hypertensive use of Alternanthera sessilis.

MATERIALS AND METHODS

The crude ethanolic extract of Alternanthera sessilis (As.Cr) and its fractions were tested in- vitro on isolated rabbit tissue preparations (i.e., jejunum, trachea, and aorta) and in-vivo in ketamin-diazepam anaesthetized normotensive rats.The responses were recorded using isotonic and isometric transducers coupled with Power Lab data acquisition system.

RESULTS

On isolated rabbit jejunum preparations, As.Cr exerted concentration-dependent (0.01-1.0mg/ml) spasmolytic effect and caused relaxation of K(+)(80mM)-induced spastic contractions. Furthermore, there was non-parallel shift in Ca(++)concentration response curves (CRCs) towards right at tissue bath concentrations of 0.1 and 0.3mg/ml. On isolated rabbit trachea, it relaxed carbachol (1μM)- and K(+()80mM)-induced contractions at respective tissue bath concentrations of 5.0 and 1.0mg/ml. On isolated rabbit aorta, it also demonstrated relaxant effect on phenylephrine (1μM)- and K(+()80mM)-induced contractions at tissue bath concentrations of 5.0 and 3.0mg/ml respectively. These findings were found to be comparable with verapamil, a reference Ca(++)channel blocker (CCB). The solvent-solvents fractionation revealed domination of spasmolytic effects in dichloromethane fraction as compared to aqueous fraction. Intravenous administration of As.Cr decreased mean arterial blood pressure, systolic blood pressure and diastolic blood pressure of ketamine-diazepam anaesthetized normotensive albino rats dose-dependently, at dose range of 1-10mg/kg.

CONCLUSION

Our results reflected presence of Ca(++) channel blocking (CCB) activity in As.Cr, thus rationalizing medicinal use of Alternanthera sessilis in diarrhea, asthma and hypertension.

Application of Bioactive Natural Materials-based Products on Five Women's Diseases

Women's health has been threatened by various diseases mainly including heart disease, breast cancer, osteoporosis, depression, and autoimmune disease. But development of medication for these diseases has been restricted by high development costs and low success rates. Herein the attempt to develop valid bioactive materials from a traditional natural material has been made. Resveratrol has been reported to be effective in treatment of breast cancer and heart disease. Goji berry has received attention as a natural based therapeutic material to treat a diabetes, cardiovascular disease, and osteoporosis. Leonurus family has been reported to be effective particularly in pregnant women due to high contents of vitamin as well as stimulation of uterine contraction. Annona family has effects such as anti-anxiety, anticonvulsant and recently it is proposed to be as a therapeutic material to cure depression based on its strong antidepressant effect. Shiraia bambusicola has been utilized to cure angiogenesis-related disease from ancient China and furthermore recently it was proved to be effective in rheumatoid arthritis. Getting an understanding of utilization of these traditional natural materials not only enhances the interest in development of therapeutic materials for preventing and treating various women's diseases, but also makes it possible to develop novel therapeutic materials.

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.

Leonurine protects against tumor necrosis factor-α-mediated inflammation in human umbilical vein endothelial cells

OBJECTIVE

Leonurine, a bioactive alkaloid compound in Herba leonuri, has various pharmacological activities, including antioxidant and anti-apoptotic capacities. This study was conducted to test the hypothesis that leonurine was able to attenuate tumor necrosis factor (TNF)-α-induced human umbilical vein endothelial cells (HUVEC) activation and the underlying molecular mechanisms.

METHODS

Mitogen-activated protein kinases (MAPK) activation, nuclear factor-κB (NF-κB) activation, and inflammatory mediators expression were detected by Western blot or enzyme-liked immunosorbent assay, intracellular reactive oxygen species (ROS) and NF-κB p65 translocation were measured by immunofluorescence, endothelial cell-monocyte interaction was detected by microscope.

RESULTS

Leonurine inhibited U937 cells adhesion to TNF-α-activated HUVEC in a concentration dependent manner. Treatment with leonurine blocked TNF-α-induced mRNA and protein expression of adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1), cyclooxygenase-2, and monocyte chemoattractant protein-1 in endothelial cells. In addition, leonurine attenuated TNF-α-induced intracellular ROS production in HUVEC. Furthermore, leonurine also suppressed the TNF-α-activated p38 phosphorylation and IκBα degradation. Subsequently, reduced NF-κB p65 phosphorylation, nuclear translocation, and DNA-binding activity were also observed.

CONCLUSIONS

Our results demonstrated for the first time that the anti-inflammatory properties of leonurine in endothelial cells, at least in part, through suppression of NF-κB activation, which may have a potential therapeutic use for inflammatory vascular diseases.

Cerebral protection of purified Herba Leonuri extract on middle cerebral artery occluded rats

AIM OF STUDY

Oxidative stress is involved in stroke. In particular, Chinese Herbal Medicine with antioxidant properties is believed to have potential therapeutic effect. In this study, neuroprotective effects of purified Herba Leonuri (pHL) were evaluated in Wistar rats undergone middle cerebral artery occlusion (MCAO).

MATERIALS AND METHODS

The rats were treated with their respective treatments for 2 weeks prior to the MCAO, continually treated for another 7 days after MCAO. During the post-surgery treatment period, neurological deficit score was measured. At the end of treatment, animals were sacrificed and samples were collected for analysis of infarct volume, apoptosis and antioxidant analysis.

RESULTS

Under the treatment of pHL, the infarct volume was reduced significantly from 20.75+/-0.03% to 15.19+/-0.02% (p<0.05). The neurological impairment was alleviated to 1.82 as compared to vehicle (2.43). Plasma antioxidant concentration was increased from 0.31+/-0.03 mM to 0.42+/-0.05 mM (p<0.05). DNA oxidative damage was reduced to 1.19+/-0.03 in stroke pHL treated group (p<0.05 as compared to vehicle group, 1.78+/-0.03). pHL could reduce the level of apoptosis and also the pro-apoptotic proteins, but increase the level of anti-apoptotic proteins.

CONCLUSION

pHL is believed to have promising therapeutic effect for stroke treatment through antioxidant mechanisms.

Anti-oxidative stress effects of Herba leonuri on ischemic rat hearts

Our current study was to test the hypothesis that the extract of Herba leonuri (HL) would have antioxidant and cardioprotective effects on ischemic myocardium. The extract of HL (400 mg/kg/day) was administered orally (daily) starting from 1 week before and continuing until 3 weeks after myocardial infarction (MI). Surviving rats were sacrificed at different time points to obtain left ventricles for biochemical assays. Our study demonstrates for the first time that HL does have antioxidant effects both in vitro and in vivo. The antioxidant effects of HL are exerted only under the condition of oxidative stress, by selectively preserving the activities of superoxide dismutase and glutathione peroxidase, as well as depressing the formation of malondialdehyde, especially in the acute phase of acute MI. Its effects of scavenging free radicals and inhibiting the formation of reactive oxygen species may play a key role in protecting the endogenous antioxidant system from oxidative stress in vivo.

Mesaconitine-induced relaxation in rat aorta: involvement of Ca2+ influx and nitric-oxide synthase in the endothelium

Aconiti tuber, roots of aconite (Aconitum japonicum), is an oriental herbal medicine used for centuries in Japan and China to improve the health of persons with a weak constitution and poor metabolism. We investigated the effects of mesaconitine, one of the aconite alkaloids in Aconiti tuber, on the contraction and free intracellular Ca2+ concentration ([Ca2+]i) level in isolated rat thoracic aorta. Mesaconitine at 30 microM inhibited 3 microM phenylephrine-induced contraction in the endothelium-intact, but not endothelium-denuded, aortic rings. The effect of mesaconitine was dependent on external Ca2+ concentrations. The relaxation induced by mesaconitine was abolished by N(omega)-nitro-L-arginine methyl ester (0.1 mM, an inhibitor of nitric-oxide synthase), as well as the relaxation induced by acetylcholine. Acetylcholine induced relaxation in two phases in our conditions; the initial phase was transient and external Ca2+ -independent, and the second phase was sustained and external Ca2+ -dependent. Treatment with 100 nM thapsigargin, which depleted intracellular Ca2+ stores, inhibited acetylcholine-induced, but not mesaconitine-induced, relaxation. Mesaconitine increased the [Ca2+]i level in endothelial cells by influx of Ca2+ from extracellular spaces. These findings suggest that mesaconitine-induced Ca2+ influx and activation of nitric-oxide synthase in endothelial cells and, thus, induced vasorelaxation in rat aorta.