Jwu-Lai Yeh

The new generation dihydropyridine type calcium blockers, bearing 4-phenyl oxypropanolamine, display α-/β-Adrenoceptor antagonist and long-Acting antihypertensive activities

A new series of dihydropyridine derivatives, bearing oxypropanolamine moiety on phenyl ring at the 4-position of the dihydropyridine base, were prepared. Oxypropanolamine was synthesized by replacing the phenolic OH of vanillin or other compounds, having a phenyl aldehyde group, with epichlorohydrin, followed by cleavaging the obtained epoxide compounds with tert-butylamine, n-butylamine or 2-methoxy-1-oxyethylamino benzene (guaiacoxyethylamine), respectively. Obtained various oxypropanolamine compounds, still remaining a phenyl aldehyde moiety, were then performed by Hantzsch condensation reaction with methylacetoacetate or ethylacetoacetate, respectively, to give our new series of dihydropyridine linked with the 4-phenyl ring. These compounds were evaluated for inotropic, chronotropic, and aorta contractility that associated with calcium channel and adrenoceptor antagonist activities. Dihydropyridine derivatives that with oxypropanolamine side chain on their 4-phenyl ring associated α-/β-adrenoceptor blocking activities created a new family of calcium entry and the third generation β-adrenoceptor blockers. Optimizing this research to obtain more potent α-/β-adrenoceptor blocking and long-acting antihypertensive oxypropanolamine on the 4-phenyl ring of dihydropyridine series compounds was thus accomplished and classified as third generation dihydropyridine type calcium channel blockers, in comparison with previous short-acting type nifedipine and long-acting type amlodipine. We concluded that compounds 1a, 1b and 1g showed not only markedly high calcium-antagonistic activity but also the highest antihypertensive effect; compounds 1b, 1c, 1f, 1g, 1i and 1j induced sustained antihypertensive effects are major and attributed to their calcium entry and α-adrenoceptor blocking activities in the blood vessel due to their introduction of 2-methoxy, 1-oxyethylamino benzene moiety in the side chain on the 4-phenyl ring of dihydropyridine. Bradycardiac effects of all the compounds 1a–1j resulted from calcium entry and β-adrenoceptor blocking, which attenuate the sympathetic activation-associated reflex tachycardia in the heart. We selected compound 1b as candidate compound for further pharmacological and pre-clinical evaluation studies.

The xanthine derivative KMUP-1 inhibits models of pulmonary artery hypertension via increased NO and cGMP-dependent inhibition of RhoA/Rho kinase

Background and purpose:  KMUP‐1 is known to increase cGMP, enhance endothelial nitric oxide synthase (eNOS) and suppress Rho kinase (ROCK) expression in smooth muscle. Here, we investigated the mechanism of action of KMUP‐1 on acute and chronic pulmonary artery hypertension (PAH) in rats.

Capsinolol: the first β‐adrenoceptor blocker with an associated calcitonin gene‐related peptide releasing activity in the heart

1 The β‐adrenoceptor blocking and calcitonin gene‐related peptide (CGRP)‐releasing properties of capsinolol (N‐[4‐(2‐hydroxy‐3 (isopropylamino) propoxy)‐3‐methoxybenzyl] ‐nonanamide), derived from nonivamide, were investigated under in vivo and in vitro conditions. 2 Capsinolol (0.1, 0.5, 1.0 mg kg−1, i.v.), as well as (±)‐propranolol, produced a dose‐dependent bradycardia response and a temporary pressor action in urethane‐anaesthetized normotensive Wistar rats. These cardiovascular effects were different from the vagus reflex and parasympathetic efferent effects shown by capsaicin (0.1 mg kg−1, i.v.) in the rat. 3 Capsinolol (1.0 mg kg−1) inhibited the tachycardia effects induced by (−)−isoprenaline, but had no blocking effect on the arterial pressor responses induced by (−)−phenylephrine. The findings suggest that capsinolol possesses β‐adrenoceptor blocking activity, but it has no α‐adrenoceptor blocking activity. 4 In guinea‐pig isolated tissues, capsinolol (10−8 to 10−6 m) antagonized (−)−isoprenaline‐induced positive chronotropic and inotropic effects of the atria and tracheal relaxation responses in a concentration‐dependent manner. The parallel shift to the right of the concentration‐response curve of (−)−isoprenaline suggests capsinolol is a β‐adrenoceptor competitive antagonist. 5 Capsinolol (10−5 to 10−4 m) exhibited a positive cardiotonic effect that was not inhibited by (±)‐propranolol and reserpine, but was inhibited by capsazepine (10−6 m) and CGRP8–37 (10−6 m). This effect was independent of intrinsic sympathomimetic effects. 6 An immunoassay of released CGRP from guinea‐pig isolated perfused heart indicated that capsinolol increases the release of CGRP and thus produces positive cardiotonic effects. 7 In conclusion, capsinolol is a non‐selective β‐adrenoceptor antagonist with capsaicin‐like cardiotonic properties unrelated to traditional intrinsic sympathomimetic effects. It is suggested that capsinolol causes CGRP release from cardiac sensory neurones via a non‐adrenergic mechanism and then activates CGRP receptors on cardiac muscle.

Inhibition of Proinflammatory Tumor Necrosis Factor-α-Induced Inducible Nitric-Oxide Synthase by Xanthine-Based 7-[2-[4-(2-Chlorobenzene)piperazinyl]ethyl]-1,3-dimethylxanthine (KMUP-1) and 7-[2-[4-(4-Nitrobenzene)piperazinyl]ethyl]-1, 3-dimethylxanthine (KMUP-3) in Rat Trachea: The Involvement of Soluble Guanylate Cyclase and Protein Kinase G

In the study of anti-proinflammation by 7-[2-[4-(2-chlorobenzene)piperazinyl] ethyl]-1,3-dimethylxanthine (KMUP-1) and 7-[2-[4-(4-nitrobenzene)piperazinyl]ethyl]-1,3-dimethylxanthine (KMUP-3), exposure of rat tracheal smooth muscle cells (TSMCs) to tumor necrosis factor-α (TNF-α), a proinflammatory cytokine, increased the expression of inducible nitric-oxide synthase (iNOS) and NO production and decreased the expression of soluble guanylate cyclase α1 (sGCα1), soluble guanylate cyclase β1 (sGCβ1), protein kinase G (PKG), and the release of cGMP in TSMCs. The cell-permeable cGMP analog 8-Br-cGMP, xanthine-based KMUP-1 and KMUP-3, and the phosphodiesterase 5 inhibitor zaprinast all inhibited TNF-α-induced increases of iNOS expression and NO levels and reversed TNF-α-induced decreases of sGCα1, sGCβ1, and PKG expression. These results imply that cGMP enhancers could have anti-proinflammatory potential in TSMCs. TNF-α also increased protein kinase A (PKA) expression and cAMP levels, cyclooxygenase-2 (COX-2) expression, and activated productions of prostaglandin (PG) E2 and 6-keto-PGF1α (stable PGI2 metabolite). Dexamethasone and N-[2-(cyclohexyloxyl)-4-nitrophenyl]-methane sulfonamide (NS-398; a selective COX-2 inhibitor) attenuated TNF-α-induced expression of COX-2 and activated productions PGE2 and PGI2. However, KMUP-1 and KMUP-3 did not affect COX-2 activities and did not further enhance cAMP levels in the presence of TNF-α. It is suggested that TNF-α-induced increases of PKA expression and cAMP levels are mediated by releasing PGE2 and PGI2, the activation products of COX-2. In conclusion, xanthine-based KMUP-1 and KMUP-3 inhibit TNF-α-induced expression of iNOS in TSMCs, involving the sGC/cGMP/PKG expression pathway but without the involvement of COX-2.

KMUP‐1 attenuates isoprenaline‐induced cardiac hypertrophy in rats through NO/cGMP/PKG and ERK1/2/calcineurin A pathways

Background and purpose:  To determine whether KMUP‐1, a novel xanthine‐based derivative, attenuates isoprenaline (ISO)‐induced cardiac hypertrophy in rats, and if so, whether the anti‐hypertrophic effect is mediated by the nitric oxide (NO) pathway.

Inhibition of human prostate cancer cells proliferation by a selective alpha1-adrenoceptor antagonist labedipinedilol-A involves cell cycle arrest and apoptosis

In this research, we conducted an in vitro analysis to evaluate the prostate cancer cells response to labedipinedilol-A in order to determine the effect of this selective alpha(1)-adrenoceptor antagonist to suppress prostate cancer cell growth by affecting cell proliferation and apoptosis. Here, we report that treatment of androgen-sensitive (LNCaP) and androgen-insensitive (PC-3) prostate cancer cells with labedipinedilol-A inhibited cell proliferation in concentration-dependent and time-dependent manners. Moreover, norepinephrine-stimulated proliferation of both cell lines are markedly inhibited by labedipinedilol-A. The probable involvement of alpha(1)-adrenoceptors in this cellular response is suggested. Labedipinedilol-A-induced growth inhibition was associated with G(0)/G(1) arrest, and G(2)/M arrest depending upon concentrations. Cell cycle blockade was associated with reduced amounts of cyclin D1/2, cyclin E, Cdk2, Cdk4, and Cdk6 and increased levels of the Cdk inhibitory proteins (Cip1/p21 and Kip1/p27). In addition, labedipinedilol-A also induced apoptosis in PC-3 cells, as determined by using Hoechst 33342 staining, DNA fragmentation, and Annexin V staining assay. Furthermore, labedipinedilol-A triggered the mitochondrial apoptotic pathway, as indicated by increasing the expression of Bax, but decreasing the level of Bcl-2, resulting in mitochondrial membrane potential loss, cytochrome c release, and activation of caspase-9 and -3. We further investigated the role of MAPK cascades in the anti-proliferative and apoptosis effects of labedipinedilol-A, and confirmed that labedipinedilol-A could activate JNK1/2 but not p38 in both cell lines. Unlike JNK1/2, however, labedipinedilol-A treatment resulted in down-regulation of phospho-ERK1/2 expression. We concluded that labedipinedilol-A possessed the growth-suppressive and apoptotic effects on LNCaP and PC-3 cells by its alpha(1)-adrenoceptor blockade, and the apoptotic effects of labedipinedilol-A primarily through caspases and MAPKs mediated pathways.

Lercanidipine inhibits vascular smooth muscle cell proliferation and neointimal formation via reducing intracellular reactive oxygen species and inactivating Ras-ERK1/2 signaling.

Lercanidipine, a calcium channel antagonist, is currently employed in the treatment of essential hypertension and angina pectoris. The purpose of this study was to elucidate the anti-proliferative effect of lercanidipine and to investigate the molecular role of this agent. Both in vitro studies and in a balloon injury rat carotid artery model were employed to study the effect of lercanidipine on smooth muscle cell proliferation. Lercanidipine-inhibited rat vascular smooth muscle cell (VSMC) proliferation and migration in a dose-dependent manner following stimulation of VSMC cultures with 10% fetal bovine serum (FBS) and 20 ng/ml platelet-derived growth factor (PDGF)-BB. FBS- and PDGF-BB-stimulated intracellular Ras, MEK1/2, ERK1/2, proliferative cell nuclear antigen (PCNA), and Akt activations were significantly inhibited by lercanidipine; however, lercanidipine did not affect FBS- and PDGF-BB-induced STAT3 phosphorylation. Lercanidipine also inhibited PDGF-receptor beta chain phosphorylation and reactive oxygen species (ROS) production induced by PDGF-BB. Lercanidipine blocked the FBS-inducible progression through the G(0)/G(1) to the S-phase of the cell cycle in synchronized cells. In vivo, 14 days after balloon injury, treatment with 3 and 10 mg/kg lercanidipine resulted in significant inhibition of the neointima/media ratio. Suppression of neointima formation by lercanidipine was dependent on its influence on ERK1/2 phosphorylation. These results demonstrate that lercanidipine can suppress the proliferation of VSMCs via inhibiting cellular ROS, Ras-MEK1/2-ERK1/2, and PI3K-Akt pathways, and suggesting that it may have therapeutic relevance in the prevention of human restenosis.

Vanidipinedilol : A vanilloid-based β-adrenoceptor blocker displaying Calcium entry blocking and vasorelaxant activities

Calcium channel and beta-adrenoceptor blockade have proved highly useful in antihypertensive therapy. Studies of the mechanisms of action of vanidipinedilol that combine these effects within a single molecule are described here. Intravenous injection of vanidipinedilol (0.1, 0.25, 0.5, 1.0, and 2.0 mg/kg) produced dose-dependent hypotensive and bradycardic responses, significantly different from nifedipine-induced (0.5 mg/kg, i.v.) hypotensive and reflex tachycardic effects in pentobarbital-anesthetized Wistar rats. A single oral administration of vanidipinedilol at doses of 10, 25, and 50 mg/kg dose-dependently reduced blood pressure with a decrease in heart rate in conscious spontaneously hypertensive rats (SHRs). In the isolated Wistar rat atrium, vanidipinedilol (10(-7), 10(-6), and 10(-5) M) competitively antagonized the (-)isoproterenol-induced positive chronotropic and inotropic effects and inhibited the increase in heart rate induced by Ca2+ (3.0-9.0 mM) in a concentration-dependent manner. The parallel shift to the right of the concentration-response curve of (-)isoproterenol and CaCl2 suggested that vanidipinedilol possessed beta-adrenoceptor-blocking and calcium entry-blocking activities. On tracheal strips of reserpinized guinea pig, cumulative doses of vanidipinedilol (10(-10) to 3x10(-6) M) produced dose-dependent relaxant responses. Preincubating the preparation with ICI 118,551 (10(-10), 10(-9), 10(-8) M), a beta2-adrenoceptor antagonist, shifted the vanidipinedilol concentration-relaxation curve significantly to a region of higher concentrations. These results implied that vanidipinedilol had a partial beta2-agonist activity. In the isolated thoracic aorta of rat, vanidipinedilol had a potent effect inhibiting high-K+-induced contractions. KCI-induced intracellular calcium changes of blood vessel smooth muscle cell (A7r5 cell lines) determined by laser cytometry also was decreased after administration of vanidipinedilol (10(-8), 10(-7), 10(-6) M). Furthermore, the binding characteristics of vanidipinedilol and various antagonists were evaluated in [3H]CGP-12177 binding to ventricle and lung and [3H]nitrendipine binding to cerebral cortex membranes in rats. The order of potency of beta1- and beta2-adrenoceptor antagonist activity against [3H]CGP-12177 binding was (-)propranolol (pKi, 8.59 for beta1 and 8.09 for beta2) > vanidipinedilol (pKi, 7.09 for beta1 and 6.64 for beta2) > atenolol (pKi, 6.58 for beta1 and 5.12 for beta2). The order of potency of calcium channel antagonist activity against [3H]nitrendipine binding was nifedipine (pKi, 9.36) > vanidipinedilol (pKi, 8.07). The ratio of beta1-adrenergic-blocking/calcium entry-blocking selectivity is 0.1 and indicated that vanidipinedilol revealed more in calcium entry-blocking than in beta-adrenergic-blocking activities. It has been suggested that vanidipinedilol-induced smooth muscle relaxation may involve decreased entry of Ca2+ and partial beta2-agonist activities. In conclusion, vanidipinedilol is a nonselective beta-adrenoceptor antagonist with calcium channel blocking and partial beta2-agonist associated vasorelaxant and tracheal relaxant activities. Particularly, the vasodilator effects of vanidipinedilol are attributed to a synergism of its calcium entry blocking and partial beta2-agonist activities in the blood vessel. A sustained bradycardic effect results from beta-adrenoceptor blocking and calcium entry blocking, which blunts the sympathetic activation-associated reflex tachycardia in the heart.

Baicalein, an active component of Scutellaria baicalensis Georgi, prevents lysophosphatidylcholine-induced cardiac injury by reducing reactive oxygen species production, calcium overload and apoptosis via MAPK pathways.

BackgroundLysophosphatidylcholine (lysoPC), a metabolite from membrane phospholipids, accumulates in the ischemic myocardium and plays an important role in the development of myocardial dysfunction ventricular arrhythmia. In this study, we investigated if baicalein, a major component of Huang Qui, can protect against lysoPC-induced cytotoxicity in rat H9c2 embryonic cardiomyocytes.MethodsCell viability was detected by the MTT assay; ROS levels were assessed using DCFH-DA; and intracellular free calcium concentrations were assayed by spectrofluorophotometer. Cell apoptosis and necrosis were evaluated by the flow cytometry assay and Hoechst staining. Mitogen-Activated Protein Kinases (MAPKs), which included the ERK, JNK, and p38, and the apoptotic mechanisms including Bcl-2/Bax, caspase-3, caspase-9 and cytochrome c pathways were examined by Western blot analysis. The activation of MAPKs was examined by enzyme-linked immunosorbent assay.ResultsWe found that lysoPC induced death and apoptosis of H9c2 cells in a dose-dependent manner. Baicalein could prevent lysoPC-induced cell death, production of reactive oxygen species (ROS), and increase of intracellular calcium concentration in H9c2 cardiomyoctes. In addition, baicalein also inhibited lysoPC-induced apoptosis, with associated decreased pro-apoptotic Bax protein, increased anti-apoptotic Bcl-2 protein, resulting in an increase in the Bcl-2/Bax ratio. Finally, baicalein attenuated lysoPC-induced the expression of cytochrome c, casapase-3, casapase-9, and the phosphorylations of ERK1/2, JNK, and p38. LysoPC-induced ERK1/2, JNK, and p38 activations were inhibited by baicalein.ConclusionsBaicalein protects cardiomyocytes from lysoPC-induced apoptosis by reducing ROS production, inhibition of calcium overload, and deactivations of MAPK signaling pathways.

Eugenolol and glyceryl-isoeugenol suppress LPS-induced iNOS expression by down-regulating NF-kappaB AND AP-1 through inhibition of MAPKS and AKT/IkappaBalpha signaling pathways in macrophages.

Eugenol and isoeugenol, two components of clover oil, have been reported to possess several biomedical properties, such as anti-inflammatory, antimicrobial and antioxidant effects. This study aims to examine the anti-inflammatory effects of eugenol, isoeugenol and four of their derivatives on expression of inducible nitric oxide synthase (iNOS) activated by lipopolysaccharide (LPS) in mouse macrophages (RAW 264.7), and to investigate molecular mechanisms underlying these effects. We found that two derivatives, eugenolol and glyceryl-isoeugenol, had potent inhibitory effects on LPS-induced upregulation of nitrite levels, iNOS protein and iNOS mRNA. In addition, they both suppressed the release of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) induced by LPS. Moreover, they both attenuated the DNA binding of NF-κB and AP-1, phosphorylation of inhibitory κBα (IκBα), and nuclear translocation of p65 protein induced by LPS. Finally, we demonstrated that glyceryl-isoeugenol suppressed the phosphorylation of ERK1/2, JNK and p38 MAPK, whereas eugenolol suppressed the phosphorylation of ERK1/2 and p38 MAPK. Taken together, these results suggest that that eugenolol and glyceryl-isoeugenol suppress LPS-induced iNOS expression by down-regulating NF-κB and AP-1 through inhibition of MAPKs and Akt/IκBα signaling pathways. Thus, this study implies that eugenolol and glyceryl-isoeugenol may provide therapeutic benefits for inflammatory diseases.