Vasorelaxant and antiproliferative effects of berberine

Advance of studies on anti-atherosclerosis mechanism of berberine

Coptis Chinensis is a traditional Chinese medicine herb that has the effect of clearing heat and drying dampness, purging fire to eliminate toxin. Berberine is the main alkaloid of Coptis Chinensis, and, recent researches showed that berberine had the effect of anti-atherosclerosis. This paper reviewed the anti-atherosclerosis mechanism of berberine, which may be related to regulating lipids, anti-inflammation, decompression, reducing blood sugar, and inhibiting vascular smooth muscle cell proliferation.

Cardiovascular and metabolic effects of Berberine

Berberine (BBR) is a natural alkaloid isolated from the Coptis Chinensis. While this plant has been used in Ayurvedic and Chinese medicine for more than 2500 years, interest in its effects in metabolic and cardiovascular disease has been growing in the Western world in the last decade. Many papers have been published in these years reporting beneficial effects in carbohydrate and lipid metabolism, endothelial function and the cardiovascular system. In this review, we report a detailed analysis of the scientific literature regarding this topic, describing the effects and the underlying mechanisms of BBR on carbohydrate and lipid metabolism, endothelial function and the cardiovascular system.

A systematic review of the anticancer properties of berberine, a natural product from Chinese herbs

Natural products represent a rich reservoir of potential small chemical molecules exhibiting antiproliferation and anticancer properties. An example is berberine, a protoberberine alkaloid widely distributed in medical plants used in traditional Chinese prescriptions. Recent advances have shown that berberine exerts anticancer activities both in vitro and in vivo through different mechanisms. Berberine shows inhibitory effects on the proliferation and reproduction of certain tumorigenic microorganisms and viruses, such as Heliobacter pylori and hepatitis B virus. Transcriptional regulation of some oncogene and carcinogenesis-related gene expression and interaction with both DNA and RNA are also well documented. Besides, berberine is a broad spectrum enzyme inhibitor, which affects N-acetyltransferase, cyclooxygenase-2, and topoisomerase activities and gene/protein expression. These actions, together with the regulation of reactive oxygen species production, mitochondrial transmembrane potential, and nuclear factor-kappaB activation might underlie its antiproliferative and proapoptotic effects. More importantly, the suppression of tumor growth and metastasis, the beneficial application in combined medication, and the improvement of multidrug resistance both in vivo and in vitro clearly show its potential as an alternative medicine for tumor chemotherapy.

In vitro antifungal activity of the berberine and its synergism with fluconazole

Berberine with and without fluconazole was tested by an agar disk diffusion assay in which clinical isolates of Candida albicans were applied onto yeast extract-peptone-dextrose agar plate. Berberine, which had no intrinsic antifungal activity at the concentration tested, exerted a powerful antifungal activity in combination of fluzonazole. Combinations of berberine and fluconazole were also tested by the checkerboard assay to determine whether they had favorable or unfavorable antifungal interactions. The MIC of fluconazole was 1.9 microg/ml when the drug was tested alone and decreased to 0.48 microg/ml in the presence of berberine concentrations of 1.9 microg/ml. However, berberine at concentrations of >1.9 microg/ml combined with a fluconazole supra-MIC (i.e., >1.9 microg/ml) eliminated the residual turbidity in the incubation wells. This endpoint fitted to the definition of MIC-0 (optically clear wells) and reflected the absence of a trailing effect, which is the result of a residual growth at fluconazole concentrations greater than the MIC.

Berberine-induced decline in circulating CD31+/CD42- microparticles is associated with improvement of endothelial function in humans

Elevated circulating endothelial microparticles (EMPs) are associated with endothelial dysfunction. This study is to investigate whether berberine-induced fall in circulating EMPs facilitates improvement of endothelial function in healthy subjects. Fourteen healthy subjects received 1-month berberine therapy (1.2 g/d) and 11 healthy subjects served as control. Circulating EMPs were measured by flow cytometric analysis before and after therapy. Brachial artery endothelium-dependent and -independent function was assessed by flow-mediated vasodilation (FMD) and sublinqual nitroglyceride-mediated vasodilation (NMD). In vitro, human umbilical vein endothelial cells (HUVECs) were stimulated by EMPs (10(6)/ml) with or without the presence of berberine (10 microM). Intracellular endothelial nitric oxide synthase (eNOS) protein expression was detected by flow cytometry. After berberine therapy, circulating CD31(+)/CD42(-) microparticles were reduced, which was in parallel with the improvement of flow-mediated vasodilation while nitroglyceride-mediated vasodilation kept unchanged. A robust relationship was found between drop of circulating CD31(+)/CD42(-) microparticles and increased flow-mediated vasodilation. The EMPs in vitro led to diminished eNOS protein expression in HUVECs and this EMP-mediated detrimental effect was markedly inhibited by berberine. Berberine-induced decline in circulating CD31(+)/CD42(-) microparticles contributes to upregulation of endothelial function in healthy subjects. Deceasing EMPs may be a novel therapeutic target for the improvement of endothelial dysfunction in humans.

Berberine prevents hyperglycemia-induced endothelial injury and enhances vasodilatation via adenosine monophosphate-activated protein kinase and endothelial nitric oxide synthase

AIMS

Endothelial dysfunction is a key event that links obesity, diabetes, hypertension, and cardiovascular diseases. The aim of the present study was to examine the protective effect of the alkaloid drug berberine against hyperglycemia-induced cellular injury and endothelial dysfunction.

METHODS AND RESULTS

In both cultured endothelial cells and blood vessels isolated from rat aorta, berberine concentration dependently enhanced phosphorylation of endothelial nitric oxide synthase (eNOS) at Ser1177 and promoted the association of eNOS with heat shock protein 90 (HSP90), leading to an increased production of nitric oxide. Furthermore, berberine attenuated high glucose-induced generation of reactive oxygen species, cellular apoptosis, nuclear factor-kappaB activation, and expression of adhesion molecules, thus suppressing monocyte attachment to endothelial cells. In mouse aortic rings, berberine elicited endothelium-dependent vasodilatations and alleviated high glucose-mediated endothelial dysfunction. All these beneficial effects of berberine on the endothelium were abolished by either pharmacological inhibition of adenosine monophosphate-activated protein kinase (AMPK) or adenovirus-mediated overexpression of a dominant negative version of AMPK.

CONCLUSION

Berberine protects against endothelial injury and enhances the endothelium-dependent vasodilatation, which is mediated in part through activation of the AMPK signalling cascade. Berberine or its derivatives may be useful for the treatment and/or prevention of endothelial dysfunction associated with diabetes and cardiovascular disease.

Clinical outcomes of diabetic foot management with Circulat

Major and minor lower-extremity amputation is a common complication among diabetics. Various sources indicate diabetic foot ulcer prevalence at between 2.2% and 15% in diabetics. This study evaluates the efficacy and tolerance of a standardized plant extract combination, Circulat, developed for the prevention and treatment of severe manifestations of type 2 diabetes, such as necrotic damage of the foot. Thus, a retrospective cohort study was carried out in 174 patients treated with Circulat with diabetic foot grades D1-D3, according to The University of Texas Wound Classification System, in 50 medical centers, from 2004 to 2007. Circulat obtained 50.57% complete cure of diabetic foot, significant improvement in 37.9% and prevented amputation in 88.5% of the study's total population. The treatment was well tolerated. Four patients (2.3%) had slight gastrointestinal unrest which did not warrant suspension of treatment.

Pharmacological and therapeutic effects of Berberis vulgaris and its active constituent, berberine

Barberry (Berberis vulgaris L. family Berberidaceae) is well known in Iran and various parts of this plant including its root, bark, leaf and fruit have been used as folk medicine. The two decades of research has demonstrated different pharmacological and therapeutic effects of B. vulgaris and its isoquinoline alkaloids (particularly berberine). Studies carried out on the chemical composition of the plant show that the most important constituents of this plant are isoquinoline alkaloids such as berberine, berbamine and palmatine. Berberine represents one of the most studied among the naturally occurring protoberberine alkaloids. In addition to B. vulgaris (barberry), berberine is present in many other plants and is used for the treatment of different diseases. This article reviews the traditional uses and pharmacological effects of total extract and the most active ingredient of B. vulgaris (berberine).

Berberine inhibits platelet-derived growth factor-induced growth and migration partly through an AMPK-dependent pathway in vascular smooth muscle cells

Platelet-derived growth factor (PDGF) is released from vascular smooth muscle cells (VSMCs), endothelial cells, or macrophages after percutaneous coronary intervention and is related with neointimal proliferation and restenosis. Berberine is a well-known component of the Chinese herb medicine Huanglian (Coptis chinensis), and is capable of inhibiting growth and endogenous PDGF synthesis in VSMCs after in vitro mechanical injury. We analyzed the effects of berberine on VSMC growth, migration, and signaling events after exogenous PDGF stimulation in vitro in order to mimic a post-angioplasty PDGF shedding condition. Pretreatment of VSMCs with berberine inhibited PDGF-induced proliferation. Berberine significantly suppressed PDGF-stimulated Cyclin D1/D3 and Cyclin-dependent kinase (Cdk) gene expression. Moreover, berberine increased the activity of AMP-activated protein kinase (AMPK), which led to phosphorylation activation of p53 and increased protein levels of the Cdk inhibitor p21(Cip1). Compound C, an AMPK inhibitor, partly but significantly attenuated berberine-elicited growth inhibition. In addition, stimulation of VSMCs with PDGF led to a transient increase in GTP-bound, active form of Ras, Cdc42 and Rac1, as well as VSMC migration. However, pretreatment with berberine significantly inhibited PDGF-induced Ras, Cdc42 and Rac1 activation and cell migration. Co-treatment with farnesyl pyrophosphate and geranylgeranyl pyrophosphate drastically reversed berberine-mediated anti-proliferative and migratory effects in VSMCs. Based on these findings, we conclude that berberine inhibited PDGF-induced VSMC growth via activation of AMPK/p53/p21(Cip1) signaling while inactivating Ras/Rac1/Cyclin D/Cdks and suppressing PDGF-stimulated migration via inhibition of Rac1 and Cdc42. These observations offer a molecular explanation for the anti-proliferative and anti-migratory properties of berberine.

Berberine-induced mobilization of circulating endothelial progenitor cells improves human small artery elasticity

Berberine (BR) has been proved to promote endothelial function. However, the exact mechanisms underlying the effect of BR on endothelial function are not completely clear. It has been demonstrated that endothelial progenitor cells (EPCs) contribute to improvement of endothelial function and C2 small artery elasticity index is a surrogate parameter for the clinical evaluation of endothelial function. We hypothesized that BR-induced mobilization of circulating EPCs is associated with BR-related improvement of endothelial function. To address this assumption, 15 healthy volunteers were recruited and received BR 0.4 g three times per day for 30 days. The number of circulating CD34/KDR double-positive cells as well as C1 large and C2 small artery elasticity indices were evaluated before and after BR therapy. The number of CD34/KDR double-positive EPCs increased significantly after BR treatment (0.030+/-0.020% vs 0.017+/-0.010%, P<0.01). After 30-day BR therapy C2 increased significantly (6.21+/-2.80 ml per mm Hg x 100 vs 4.06+/-2.67 ml per mm Hg x 100, P<0.01) and C1 remained unchanged (10.79+/-3.27 ml per mm Hg x 10 vs 10.06+/-2.08 ml per mm Hg x 10, P>0.05). The increment of CD34/KDR double-positive EPCs was positively correlated with the increment of C2 (r=0.68, P<0.01). We concluded that BR-induced mobilization of circulating EPCs contributes to improvement of small artery elasticity in healthy persons.

Berberine inhibits cytosolic phospholipase A2 and protects against LPS-induced lung injury and lethality independent of the alpha2-adrenergic receptor in mice

Acute lung injury is still a significant clinical problem having a high mortality rate despite significant advances in antimicrobial therapy and supportive care made in the past few years. Our previous study demonstrated that berberine (Ber) remarkably decreased mortality and attenuated the lung injury in mice challenged with LPS, but the mechanism behind this remains unclear. Here, we report that pretreatment with Ber significantly reduced pulmonary edema, neutrophil infiltration, and histopathological alterations; inhibited protein expression and phosphorylation of cytosolic phospholipase A2; and decreased thromboxane A2 release induced by LPS. Yohimbine, an alpha2-adrenergic receptor antagonist, did not antagonize these actions of Ber. Furthermore, pretreatment with Ber decreased TNF-alpha production and mortality in mice challenged with LPS, which were enhanced by yohimbine, and Ber combined with yohimbine also improved survival rate in mice subjected to cecal ligation and puncture. Taken together, these observations indicate that Ber attenuates LPS-induced lung injury by inhibiting TNF-alpha production and cytosolic phospholipase A2 expression and activation in an alpha2-adrenoceptor-independent manner. Berberine combined with yohimbine might provide an effective therapeutic approach to acute lung injury during sepsis.

Relaxant action mechanism of berberine identified as the active principle of Argemone ochroleuca Sweet in guinea-pig tracheal smooth muscle

In this study we investigated the relaxant effect of the aerial parts of Argemone ochroleuca (Papaveraceae), which is used in Mexican traditional medicine for the treatment of various respiratory diseases such as cough, bronchitis and asthma. The alkaloid berberine was identified as one of the active relaxant principles (EC50 = 118.50 +/-3.91 microM) in the dichloromethane extract of A. ochroleuca (EC50 = 78.03 +/- 2.15 microg mL(-1) with 95.12 +/- 3.56% of relaxation). Berberine concentration-dependently relaxed the carbachol-induced precontractions but not histamine- or KCl-induced precontraction. The relaxant effect of berberine was unaffected by the presence of propranolol (3 microM), glibenclamide (10 microM) or ODQ (10microM). However, 2', 5'-dideoxyadenosine (10 microM) blocked the log concentration-response curves of berberine. On the other hand, berberine produced a leftward shift of the log concentration-response curves of isoproterenol, forskolin and nitroprusside. Additionally, berberine produced a parallel rightward shift of the concentration-response curve of carbachol in a competitive manner with a pA2 of 3.87 +/- 0.045. The above results suggest that the relaxant effect of berberine on tracheal muscle is due to its antagonistic effect on muscarinic acetylcholine receptors.

Mitochondrially targeted effects of berberine [Natural Yellow 18, 5,6-dihydro-9,10-dimethoxybenzo(g)-1,3-benzodioxolo(5,6-a) quinolizinium] on K1735-M2 mouse melanoma cells: comparison with direct effects on isolated mitochondrial fractions

Berberine [Natural Yellow 18, 5,6-dihydro-9,10-dimethoxybenzo(g)-1,3-benzodioxolo(5,6-a)quinolizinium] is an alkaloid present in plant extracts and has a history of use in traditional Chinese and Native American medicine. Because of its ability to arrest the cell cycle and cause apoptosis of several malignant cell lines, it has received attention as a potential anticancer therapeutic agent. Previous studies suggest that mitochondria may be an important target of berberine, but relatively little is known about the extent or molecular mechanisms of berberine-mitochondrial interactions. The objective of the present work was to investigate the interaction of berberine with mitochondria, both in situ and in isolated mitochondrial fractions. The data show that berberine is selectively accumulated by mitochondria, which is accompanied by arrest of cell proliferation, mitochondrial fragmentation and depolarization, oxidative stress, and a decrease in ATP levels. Electron microscopy of berberine-treated cells shows a reduction in mitochondria-like structures, accompanied by a decrease in mitochondrial DNA copy number. Isolated mitochondrial fractions treated with berberine had slower mitochondrial respiration, especially when complex I substrates were used, and increased complex I-dependent oxidative stress. It is also demonstrated for the first time that berberine stimulates the mitochondrial permeability transition. Direct effects on ATPase activity were not detected. The present work demonstrates a number of previously unknown alterations of mitochondrial physiology induced by berberine, a potential chemotherapeutic agent, although it also suggests that high doses of berberine should not be used without a proper toxicology assessment.

Inhibitory effects of Zoagumhwan water extract and berberine on angiotensin II-induced monocyte chemoattractant protein (MCP)-1 expression and monocyte adhesion to endothelial cells

Angiotensin II (Ang II), a potent vasoconstrictor, has been implicated in vascular inflammation through induction of reactive oxygen species (ROS) and pro-inflammatory genes. Among the chemokines, monocyte chemoattractant protein (MCP)-1 induced by Ang II acts as a central mediator of the inflammatory responses. In the present study, we found that the water extract of ZoaGumHwan (ZGH), a Korean herbal remedy, dose-dependently inhibited Ang II-induced U937 monocyte adhesion to human umbilical vein endothelial cells (HUVECs) and mRNA expression of MCP-1 in HUVECs and C-C chemokine receptor 2 (CCR-2) in U937 cells. In addition, ZGH water extract inhibited Ang II-induced generation of reactive oxygen species in HUVECs in a dose-dependent manner. Berberine, a major component of Coptis chinensis Franch, also showed similar effects on ROS production and MCP-1 expression induced by Ang II. These results suggest that Korean herbal remedy, ZGH, effectively protects against Ang II-induced endothelial inflammation.

Hypotensive effect and toxicology of the extract from Coscinium fenestratum (Gaertn.) Colebr

The water extract from Coscinium fenestratum (Gaertn.) Colebr. (CF extract) was tested for hypotensive and vasorelaxant effects. Acute and subchronic toxicity as well as motor activity of CF extract were also evaluated. The present study demonstrates that CF extract is effective in reducing blood pressure in anesthetized normotensive rats. This effect is shown to be dose-related and rapid in onset. The extract showed an endothelium-dependent and independent vasorelaxant activity in isolated aortic rings precontracted with phenylephrine (1 microM) and KCl (60 mM). The capacity of L-NAME (100 microM), an inhibitor of nitric oxide synthase, to reduce the vasorelaxant action of the extract indicates the involvement of nitric oxide. In the acute toxicity test, an oral dose of 5000 mg/kg of the CF extract did not produce mortality or significant changes of the general behavior of animals and gross appearance of internal organs of rats. Similarly, in the subchronic toxicity test, an oral dose of 2500 mg/kg/day of the CF extract given to rats for 90 days did not cause any significant change of any of the parameters observed when compared with those of the control animals. Moreover, the CF extract did not produce any effect on the central nervous system when spontaneous motor activity in rats was assessed. However, because some average hematological and blood chemistry values were found to be statistically different, further studies, including chronic toxicity test, should be done to confirm the safety of this plant when it is used over a long period of time.

Determination of berberine in human plasma by liquid chromatography-electrospray ionization-mass spectrometry

A liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method for the determination of berberine in human plasma using chlorobenzylidine as the internal standard (IS) has been developed and validated. The plasma samples were prepared by LLE and the analytes were chromatographically separated on a Hanbon Lichrospher 5-C18 HPLC column under gradient elution with a mobile phase consisted of acetonitrile and 10mm ammonium acetate buffer containing 0.1% formic acid. Berberine was determined with electrospray ionisation-mass spectrometry (ESI-MS). LC-ESI-MS was performed in the selected-ion monitoring (SIM) mode using target ions at M(+)m/z 336.1 for berberine and M(+)m/z 464.1 for the IS. Calibration curve was linear over the range of 0.020-3.0 ng/ml. The lower limit of quantification (LLOQ) was 0.020 ng/ml. The intra- and inter-run variability values were less than 6.7 and 7.7%, respectively. The method has been successfully applied to determine the plasma concentration of berberine in healthy Chinese volunteers.

Endothelium-independent vasorelaxant effect of lidocaine in rat aortic rings

In the present study, lidocaine relaxed, in a concentration-dependent manner, the contractions induced by either phenylephrine or a high concentration of KCl (60 mM) in endothelium-intact rat aortic rings. Mechanical removal of endothelium did not significantly modify lidocaine-induced vasorelaxation. In endothelium-denuded aortic rings depolarized by 60 mM KCl, lidocaine inhibited Ca2+-induced contraction. Lidocaine also reduced the transient contraction elicited by phenylephrine in Ca2+-free medium. Pretreatment of endothelium-denuded aorta nonspecific K+ with tetraethylammonium, a channel blocker, had no effect on the relaxant effect of lidocaine. These results indicate that lidocaine induces an endothelium-independent relaxation in rat aortic rings. The main mechanisms may include suppression in Ca2+ through the voltage-sensitive Ca2+ influx intracellular Ca2+ channels and inhibition of release in the vascular smooth muscle cells.

Characterization of the transportation of berberine inCoptidis rhizoma extract through rat primary cultured cortical neurons

The aim of this study was to investigate the transport behavior and efflux of berberine through the primary culture cortical neurons. High-performance liquid chromatography coupled with an UV-vis detector at 347 nm was applied. The mobile phase was 0.05 m potassium dihydrogen phosphate solution (containing 0.5% triethylamine, pH 3.0)-acetonitrile (73:27, v/v). Neurons were incubated with Coptidis rhizoma extract 6.5 microg/mL (containing 1.91 microg/mL berberine) and verapamil, KCN or cimetidine for 2 h, and then lysed in methanol to extract intracellular berberine. A 20 microL aliquot of sample was injected into the HPLC system to determine berberine concentration. The results showed that metabolic inhibitor KCN and P-glycoprotein inhibitor verapamil could increase berberine concentration within the neurons, indicating that efflux of berberine was energy-dependent and P-glycoprotein was likely to be involved. Moreover, the organic cation transporter inhibitor cimetidine could decrease berberine concentration within the neurons, suggesting that the organic cation transporter might be involved in the berberine transport process.

Pharmacokinetics of berberine and its main metabolites in conventional and pseudo germ-free rats determined by liquid chromatography/ion trap mass spectrometry

Berberine (Ber) and its main metabolites were identified and quantified using liquid chromatography/electrospray ionization/ion trap mass spectrometry. Rat plasma contained the main metabolites, berberrubine, thalifendine, demethyleneberberine, and jatrorrhizine, as free and glucuronide conjugates after p.o. Ber administration. Moreover, the original drug, the four main metabolites, and their glucuronide conjugates were all detected in liver tissues after 0.5 h and in bile samples 1 h after p.o. Ber administration. Therefore, the metabolic site seemed to be the liver, and the metabolites and conjugates were evidently excreted into the duodenum as bile. The pharmacokinetics of Ber and the four metabolites were determined in conventional and pseudo germ-free rats (treated with antibiotics) after p.o. administration with 40 mg/kg Ber. The AUC0-limt and mean transit time values of the metabolites significantly differed between conventional and pseudo germ-free rats. The amounts of metabolites were remarkably reduced in the pseudo germ-free rats, whereas levels of Ber did not obviously differ between the two groups. The intestinal flora did not exert significant metabolic activity against Ber and its metabolites, but it played a significant role in the enterohepatic circulation of metabolites. In this sense, the liver and intestinal bacteria participate in the metabolism and disposition of Ber in vivo.

Successful treatment of pediatric psoriasis with Indigo naturalis composite ointment

The treatment of psoriasis in children is still an intractable problem and demands a long-term therapy with prolonged efficacy that is free from serious adverse events. Many modes of therapy are currently in use but the disease is often resistant to treatment owing to the unacceptable toxicity that leads to poor compliance. Therefore, to develop an alternative treatment is indispensable. Traditional Chinese medicine has been documented for over 1000 years to provide various effective treatments for inflammatory skin diseases. Herein, we report an 8-year-old boy with recalcitrant pediatric psoriasis who, after multiple treatment failures with conventional antipsoriatic medications, showed remarkable clinical improvement with 8 weeks of topical treatment with Indigo naturalis composite ointment. Remission has lasted for over 2 years until now. Our patient's response suggests that topical Indigo naturalis composite ointment may provide a safe and effective alternative treatment for pediatric psoriasis.

Photochemical and phototoxic activity of berberine on murine fibroblast NIH-3T3 and Ehrlich ascites carcinoma cells

The present study demonstrates photoinduced generation of superoxide anion radical and singlet oxygen upon UVA irradiation of berberine chloride, and its cytotoxic/phototoxic effects on murine fibroblast non-cancer NIH-3T3 and Ehrlich ascites carcinoma (EAC) cells. The EPR spectra monitored upon photoexcitation of aerated solutions of berberine evidenced the efficient activation of molecular oxygen via Type I and II mechanisms, as the generation of superoxide anion radical and singlet oxygen was observed. The EAC cell line was more sensitive to the effect of non-photoactivated and photoactivated berberine than the NIH-3T3 cell line. UVA irradiation increased the sensitivity of EAC cells to berberine, while the sensitivity of NIH-3T3 cells to photoactivated berberine was not changed. Berberine significantly induced direct DNA strand breaks in tested cells, oxidative lesions were not detected, and the effect of irradiation of cells after berberine treatment did not affect the increase of DNA damage in EAC and NIH-3T3 cells. The DNA damage generated by a combination of berberine with UVA irradiation induced a significant blockage of EAC cells in the S and G(2)/M phases and the stopping/decrease of cell proliferation after 24h of influence. On the other hand, after 36h or 48h of berberine treatment, the DNA damage induced necrotic or apoptotic death of EAC cells. Whether these divergences are caused by differences in the properties of two non-isogenic cell lines or by different berberine uptake and cell localization will be analyzed in our further investigations.

Selective inhibition of vascular smooth muscle cell proliferation by coptisine isolated from Coptis rhizoma, one of the crude drugs composing Kampo medicines Unsei-in

Acceleration of vascular smooth muscle cell (VSMC) proliferation is closely linked to the pathogenesis of vascular diseases. We, therefore, focused on traditional Japanese herbal medicines (Kampo medicines) used to ameliorate the impairment of microcirculation or blood stasis and screened them for their ability to inhibit rat VSMC proliferation. Among them, Unsei-in was found to effectively suppress VSMC proliferation, and Coptis rhizome was the responsible constituent crude drug. The extract of Coptis rhizome inhibited VSMC proliferation with the GI(50) value of 4.4 microg/ml, which was much lower than those against the proliferation of 3Y1, dRLh-84, B16, and HeLa cells. The Coptis rhizome extract inhibited the progression of VSMC arrested at G(0)/G(1) phase from G(0)/G(1) to S phase, but not that of 3Y1 cells. Biological assay-guided fractionation revealed that an alkaloid of Coptis rhizome, coptisine, was the active ingredient in selectively preventing VSMC proliferation with GI(50) of 3.3 microM (1.2 microg/ml). When the structurally-related isoquinoline alkaloids of protoberberine class were studied for their inhibitory activities, berberine decreased the VSMC proliferation with GI(50) of 95.1 microM (35.4 microg/ml), about 30 times higher concentration than coptisine, while palmatine failed to show any activity. This study provides evidence that coptisine, an ingredient of Unsei-in, prevents VSMC proliferation selectively at lower concentrations compared with various cells or other structurally related alkaloids.

Effect of berberine on proliferation, biosynthesis of macromolecules, cell cycle and induction of intercalation with DNA, dsDNA damage and apoptosis in Ehrlich ascites carcinoma cells

Our primary aim was to study berberine, a potential anti-cancer drug, for its cytotoxic and antiproliferative activity in-vitro using Ehrlich ascites carcinoma (EAC) cells. Cytotoxicity was measured by the growth inhibition assay. We investigated the effect of berberine on the biosynthesis of macro-molecules (DNA, RNA, proteins), cell cycle effects and induction of dsDNA damage and apoptosis in berberine-treated EAC cells. Our results showed that berberine acts cytotoxically on EAC cells. The cytotoxicity was directly concentration and time dependent. The highest cytotoxic concentrations (100 and 50 microg mL(-1)) induced intercalation of berberine with DNA, formation of dsDNA breaks, inhibition of DNA synthesis and death of EAC cells. A concentration of 10 mug mL(-1) induced clear apoptotic cell death, which was followed by inhibition of protein synthesis.

Effects of neutral sulfate berberine on LPS-induced cardiomyocyte TNF-alpha secretion, abnormal calcium cycling, and cardiac dysfunction in rats

AIM

To evaluate the effect of neutral sulfate berberine on cardiac function, tumor necrosis factor alpha (TNF-alpha) release, and intracellular calcium concentration ([Ca(2+)]i) in cardiomyocytes exposed to lipopolysaccharide (LPS).

METHODS

Primary cultured rat cardiomyocytes were prepared from ventricles of 3-4-day old Sprague-Dawley rats. TNF-alpha concentrations in cell-conditioned media were measured by using a Quantikine enzyme-linked immunosorbent assay kit, and cardiomyocyte [Ca(2+)]i was measured by using Fura-2/AM. The isolated rat hearts were perfused in the Langendorff mode.

RESULTS

LPS at doses of 1, 5, 10, and 20 microg/mL markedly stimulated TNF-alpha secretion from cardiomyocytes, and neutral sulfate berberine inhibited LPS-induced TNF-alpha production. Intracellular calcium concentration was significantly decreased after LPS stimulation for 1 h, and increased 2 h after LPS treatment. Pretreatment with neutral sulfate berberine reversed the LPS-induced [Ca(2+)]i alterations, although neutral sulfate berberine did not inhibit a rapid increase in cardiomyocyte [Ca(2+)]i induced by LPS. Perfusion of isolated hearts with LPS (100 microg/mL) for 20 min resulted in significantly impaired cardiac performance at 120 min after LPS challenge: the maximal rate of left ventricular pressure rise and fall (+/-dp/dt(max)) decreased compared with the control. In contrast, +/-dp/dt(max) at 120 min in hearts perfused with neutral sulfate berberine (1 micromol/L) for 10 min followed by 20 min LPS (100 microg/mL) was greater than the corresponding value in the LPS group.

CONCLUSION

Neutral sulfate berberine inhibits LPS-stimulated myocardial TNF-alpha production, impairs calcium cycling, and improves LPS-induced contractile dysfunction in intact heart.

Berberine suppresses MEK/ERK-dependent Egr-1 signaling pathway and inhibits vascular smooth muscle cell regrowth after in vitro mechanical injury

Vascular smooth muscle cell (SMC) proliferation plays an important role in the pathogenesis of atherosclerosis and post-angioplasty restenosis. Berberine is a well-known component of the Chinese herb medicine Huanglian (Coptis chinensis), and is capable of inhibiting SMC contraction and proliferation, yet the exact mechanism is unknown. We therefore investigated the effect of berberine on SMC growth after mechanic injury in vitro. DNA synthesis and cell proliferation assay were performed to show that berberine inhibited serum-stimulated rat aortic SMC growth in a concentration-dependent manner. Mechanical injury with sterile pipette tip stimulated the regrowth of SMCs. Treatment with berberine prevented the regrowth and migration of SMCs into the denuded trauma zone. Western blot analysis showed that activation of the MEK1/2 (mitogen-activated protein kinase kinase 1/2), extracellular signal-regulated kinase (ERK), and up-regulation of early growth response gene (Egr-1), c-Fos and Cyclin D1 were observed sequentially after mechanic injury in vitro. Semi-quantitative reverse-transcription PCR assay further confirmed the increase of Egr-1, c-Fos, platelet-derived growth factor (PDGF) and Cyclin D1 expression in a transcriptional level. However, berberine significantly attenuated MEK/ERK activation and downstream target (Egr-1, c-Fos, Cyclin D1 and PDGF-A) expression after mechanic injury in vitro. Our study showed that berberine blocked injury-induced SMC regrowth by inactivation of ERK/Egr-1 signaling pathway thereby preventing early signaling induced by injury in vitro. The anti-proliferative properties of berberine may be useful in treating disorders due to inappropriate SMC growth.

Roles of nitric oxide in protective effect of berberine in ethanol-induced gastric ulcer mice

AIM

To investigate the protective effects of berberine on ethanol-induced gastric ulcer in mice.

METHODS

Gastric ulcers were induced by oral ingestion of ethanol. Nitric oxide (NO) content was measured, and mRNA expression of endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) were analyzed by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

The ulcer index (UI) at 1 h, 2 h, 3 h and 6 h after oral administration of ethanol was 23.8+/-1.4, 23.3+/-2.2, 22.3+/-1.2 and 20.8+/-1.1, respectively. The UI in the berberine-treated groups (5 mg/kg and 50 mg/kg) was less than the control group. The content of NO in the control group was 73.3+/-7.3 microL/L, 94.0+/-9.2 microL/L, 109.6+/-6.4 microL/L and 138.2+/-10.2 microL/L in gastric juice and 5.8+/-1.1 micromol/g protein, 8.3+/-1.1 micromol/g protein, 9.8+/-1.1 micromol/g protein and 11.9+/-1.2 micromol/g protein in gastric tissue at 1 h, 2 h, 3 h and 6 h, respectively, after the oral administration of ethanol. The content of NO in the berberine-treated groups (5 mg/kg and 50 mg/kg) was higher than the control group at 1 h after the oral administration of ethanol (P<0.05), and was lower at 6 h (P<0.05). Analysis by RT-PCR showed that expression of eNOS was inhibited but iNOS expression was enhanced by ethanol. However, the expression of eNOS could be enhanced and iNOS expression could be inhibited by berberine (P<0.01).

CONCLUSION

Berberine could significantly protect gastric mucosa from damage by ethanol. This effect may be related to the increased expression of eNOS mRNA and inhibited expression of iNOS mRNA.

Kinetic difference of berberine between hippocampus and plasma in rat after intravenous administration of Coptidis rhizoma extract

In order to investigate the pharmacokinetics of berberine in Coptidis rhizoma extract in rat hippocampus and plasma, a simple and accurate high-performance liquid chromatography method was employed in this study. Berberine was determined using a Hypersil C(18) column with an isocratic mobile phase of acetonitrile-0.05 M potassium dihydrogen phosphate (containing 0.5% triethylamine, pH 3.0) and with UV detection at 236 nm. The lower limit of quantification for berberine in both hippocampus and plasma was 24 ng/ml, and the lowest concentrations of berberine determined in rat hippocampus and plasma samples were 30.7 ng/ml at 48 h and 38.5 ng/ml at 4 h, respectively. The calibration curve for berberine was linear over the concentration range 24--6000 ng/ml. At this concentration range, the overall recoveries (90.6--94.2%) for berberine were determined and the accuracy of intra- and inter-day assays from rat samples were less than 7% RSD. Following intravenous administration of C. rhizoma extract at a dose of 10.2 mg/kg containing 3 mg/kg berberine, berberine in the plasma eliminated rapidly (t(1/2 beta)=1.13 h). However, berberine in the hippocampus increased rapidly (t(1/2 alpha)=0.215 h), peaked at 3.67 h with a concentration of 272 ng/g, and had a slow elimination rate (t(1/2 beta)=12.0 h), which suggests that berberine could have a direct action on neuron and accumulate in the hippocampus. This study first showed the pharmacokinetic characteristics of berberine in rat hippocampus and the kinetic characteristics of berberine are dissimilar in the hippocampus and plasma.

Diphasic Effects of Astragalus membranaceus BUNGE (Leguminosae) on Vascular Tone in Rat Thoracic Aorta

This study was designed to investigate the effects of the aqueous ethanol extract of Astragalus membranaceus BUNGE (Leguminosae) on rat thoracic aorta. Isometric tension was recorded in response to drugs in organ bath. In endothelium-intact aortic rings, A. membranaceus extract induced a significant dose-dependent relaxation of the rings precontracted by phenylephrine, which could be inhibited by preincubation with L-N(omega)-nitro-arginine methyl ester or methylthioninium chloride. In endothelium-denuded ones, the extract could dose-dependently relax the rings contracted by phenylephrine, not by KCl; and it could also attenuate contractile response to phenylephrine, not to caffeine or phorbol-12,13-diacetate in Ca(2+)-free medium; but it failed to affect the CaCl(2)-induced enhancement of contractile response to phenylephrine in Ca(2+)-free medium. These results indicate that nitric oxide signaling and Ca(2+)-handling pathway are involved in the A. membranaceus extract-induced vasodilatation.

Effects of berberine on angiotensin-converting enzyme and NO/cGMP system in vessels

The present study was designed to examine the relaxant and anticonstrictive effects of berberine in the isolated thoracic aorta in rats. Intravenous injection of berberine lowered the mean arterial pressure (MAP) of anesthesized rats in a dose-dependent manner. The angiotensin-converting enzyme (ACE) activities were inhibited significantly by the addition of berberine in a dose-dependent manner of which the IC50 value of berberine for ACE was 42 micrograms/ml (125 microM). In the endothelium-intact rings, angiotensin I-induced contraction was markedly attenuated by prior exposure of aortic rings to berberine. Treatment of the intact aortic rings with berberine (10 micrograms/ml) increased the NOx and cGMP productions relative to the vehicle-treated group. Berberine induced a dose-dependent relaxation in phenylephrine-precontracted aortic rings, but NG-nitro-L-arginine methyl ester (L-NAME)-pretreated intact aortic rings or functional removal of the endothelium attenuated the berberine-induced relaxation without an effect on maximum response. These results suggest that berberine has a hypotensive effect, at least in part, via the inhibition of ACE and direct release of NO/cGMP in the vascular tissues.

Nitric oxide, human diseases and the herbal products that affect the nitric oxide signalling pathway

1. Nitric oxide (NO) is formed enzymatically from l-arginine in the presence of nitric oxide synthase (NOS). Nitric oxide is generated constitutively in endothelial cells via sheer stress and blood-borne substances. Nitric oxide is also generated constitutively in neuronal cells and serves as a neurotransmitter and neuromodulator in non-adrenergic, non-cholinergic nerve endings. Furthermore, NO can also be formed via enzyme induction in many tissues in the presence of cytokines. 2. The ubiquitous presence of NO in the living body suggests that NO plays an important role in the maintenance of health. Being a free radical with vasodilatory properties, NO exerts dual effects on tissues and cells in various biological systems. At low concentrations, NO can dilate the blood vessels and improve the circulation, but at high concentrations it can cause circulatory shock and induce cell death. Thus, diseases can arise in the presence of the extreme ends of the physiological concentrations of NO. 3. The NO signalling pathway has, in recent years, become a target for new drug development. The high level of flavonoids, catechins, tannins and other polyphenolic compounds present in vegetables, fruits, soy, tea and even red wine (from grapes) is believed to contribute to their beneficial health effects. Some of these compounds induce NO formation from the endothelial cells to improve circulation and some suppress the induction of inducible NOS in inflammation and infection. 4. Many botanical medicinal herbs and drugs derived from these herbs have been shown to have effects on the NO signalling pathway. For example, the saponins from ginseng, ginsenosides, have been shown to relax blood vessels (probably contributing to the antifatigue and blood pressure-lowering effects of ginseng) and corpus cavernosum (thus, for the treatment of men suffering from erectile dysfunction; however, the legendary aphrodisiac effect of ginseng may be an overstatement). Many plant extracts or purified drugs derived from Chinese medicinal herbs with proposed actions on NO pathways are also reviewed.

Adverse herbal interactions causing hypotension

A 57-year-old man consulted an herbalist for epigastric discomfort. Four hours after he drank a decoction made from 14 herbs, he developed nausea, epigastric pain, and dizziness. He also had two loose bowel movements. On arrival at the hospital 4 hours later, his blood pressure was 77/46 mm Hg, and his pulse was 60 beats/min. He was given intravenous fluids. In the next 3 hours, his blood pressure gradually returned to his usual level of 100/65 mm Hg. His other gastrointestinal symptoms gradually subsided during the next 24 hours. His white cell count was 17.8 x 109/L but was normal on recheck. Complete cell counts, renal function and liver function tests, and electrocardiogram were otherwise normal. He was discharged home on day 2. Seven of the 14 herbs taken by this patient are known to have vasodilatory or blood pressure-lowering effects, and 3 of these herbs are used to manage hypertension. In traditional Chinese medicine, practitioners often use a combination of herbs in an attempt to improve the efficacy but reduce the adverse effects of treatment. The risk of adverse herbal interactions will also be higher.

Cardiovascular actions of berberine

Berberine, is an alkaloid from Hydrastis canadensis L., Chinese herb Huanglian, and many other plants. It is widely used in traditional Chinese medicine as an antimicrobial in the treatment of dysentery and infectious diarrhea. This manuscript describes cardiovascular effects of berberine and its derivatives, tetrahydroberberine and 8-oxoberberine. Berberine has positive inotropic, negative chronotropic, antiarrhythmic, and vasodilator properties. Both derivatives of berberine have antiarrhythmic activity. Some cardiovascular effects of berberine and its derivatives are attributed to the blockade of K+ channels (delayed rectifier and K(ATP)) and stimulation of Na+ -Ca(2+) exchanger. Berberine has been shown to prolong the duration of ventricular action potential. Its vasodilator activity has been attributed to multiple cellular mechanisms. The cardiovascular effects of berberine suggest its possible clinical usefulness in the treatment of arrhythmias and/or heart failure.

Effects of San'o-shashin-to and the constituent herbal medicines on theophylline-induced increase in arterial blood pressure of rats

San'o-shashin-to, composed of Scutellariae Radix, Coptidis Rhizoma and Rhei Rhizoma (volume ratio = 1:1:1), reduced an increase in arterial blood pressure of anesthetized rats induced by theophylline (5 mg/kg, i.v.). The hypotensive effect of San'o-shashin-to was produced in a dose dependent manner and was maximum at its 0.5 g/kg. Then the constituent herbal medicines were examined for their possible hypotensive effect. Scutellariae Radix of 0.2 g/kg slightly decreased in the blood presure. Rhei Rhizoma of 0.2 g/kg decreased in the blood pressure and the hypotensive effect was significantly produced even at the dose of 0.05 g/kg, while Coptidis Rhizoma had little effect. Among fractions of San'o-shashin-to separated by Diaion HP-20 column chromatography, the 50% methanol-eluted fraction had a large hypotensive effect. The 50% methanol-eluted fraction of Scutellariae Radix and Rhei Rhizoma were also effective and, especially, that of Rhei Rhizoma had a large hypotensive effect. In isometric tension study, Scutellariae Radix and Rhei Rhizoma (10-30 microg/ml) slightly exerted contractile and relaxant effects, respectively, on the phenylephrine-contracted endothelium-intact rat thoracic aorta. Coptidis Rhizoma (1-10 microg/ml) caused both endothelium-dependent and -independent relaxantion. These results suggest that the hypotensive effect of San'o-shashin-to is not mediated by the direct action on blood vessel but by other actions. Some components in Scutellariae Radix and Rhei Rhizoma, especially in the latter may play a main role in the hypotensive effect.