Vasorelaxant and hypotensive effects of an ethanolic extract of Nymphaea pubescens and its main compound quercetin 3-methyl ether 3'-O-ß-xylopyranoside.

Aim: Nymphaea plants were traditionally used to treat diseases associated with endothelial dysfunction. The present study investigated the effects of an ethanolic extract of Nymphaea pubescens Willd. (commonly named water lily, WL) and its main compound 1 (quercetin 3-methyl ether 3'-O-ß-xylopyranoside) on vascular function in rats. Materials and methods: The vasorelaxant effects of the WL extract and its main compound 1 and their underlying mechanisms of action were evaluated on isolated mesenteric arteries from Wistar rats. Blood pressure and heart rate were measured in anesthetized rats after infusion (i.v) of vehicle, WL extract, and compound 1 (at 0.01, 0.025, 0.05, 0.1, 0.5, and 1 mg/kg). Nifedipine was used as a positive control. Results: Both WL extract and compound 1 induced vasorelaxant effects (with EC50 of 0.08 ± 0.01 mg/mL and 42.8 ± 6.3 µM, respectively) that were reduced by endothelium removal. A significant decrease in these relaxations was observed with L-NAME but not with apamin-charybdotoxin or indomethacin. In the endothelium-denuded condition, WL extract-induced relaxation was enhanced by 4-aminopyridine and glibenclamide, while iberiotoxin and ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one) had no effect. In contrast, compound 1-induced relaxation was not changed by any of these inhibitors. Both WL extract and compound 1 enhanced sodium nitroprusside-induced relaxation and inhibited receptor-operated Ca2+ channels. Only the WL extract was able to reduce PE-induced contraction (p < 0.001). As compared to the vehicle, the infusion of WL extract and compound 1 lowered systolic and diastolic blood pressure. Interestingly, the hypotensive effect of the compound was similar to that of nifedipine. The rebound tachycardia found at the highest dose of nifedipine was not observed with the WL extract or compound 1 (p < 0.05). Conclusion and discussion: Our study demonstrated a vasorelaxant effect of the WL extract and its main compound quercetin 3-methyl ether 3'-O-ß-xylopyranoside, relying on the potentiation of the NO-cGMP pathway and calcium inhibitory effects. These vasorelaxant effects were associated with a potent hypotensive effect, providing pharmacological evidence for the traditional use of this plant.

Reduction of lauric acid content in virgin coconut oil improved plasma lipid profile in high-fat diet-induced hypercholesterolemic mice.

Virgin coconut oil (VCO) is claimed to have various health benefits, but favorable effects of its major component (∼50%), lauric acid, are controversial. Therefore, we aimed to reduce lauric acid content (∼30%) in VCO and evaluate its effect compared to VCO and medium-chain triglycerides (MCT), on food intake, bodyweight (BW), lipid profiles, and hepatic histology. Female C57BL/6 mice were treated with different diets for 3 months: control (normal diet), high-fat diet (HF), HF + VCO, HF + MCT, HF + low lauric acid VCO (LLA), and normal diet + LLA (C + LLA). LLA was prepared by enzymatic interesterification of VCO with methyl octanoate (methyl caprylate) and methyl decanoate (methyl caprate). Plasma and liver lipids, including total cholesterol (TC), high-density lipoprotein (HDL), and triglyceride, were measured by colorimetric assay, and hepatic fat accumulation was examined by oil-red-O staining. HF mice exhibited high plasma and liver TC and low-density lipoprotein (LDL). VCO or MCT treatment lowered liver TC and LDL, whereas LLA increased plasma HDL and markedly improved TC:HDL ratio. The HF-induced hepatic fat accumulation was attenuated by all treatments, of which VCO was the most effective. Control mice administered with LLA demonstrated lower liver TC and LDL, but higher plasma TC and HDL compared to controls. Lowest BW gain and food intake were found in mice treated with LLA. In conclusion, VCO, MCT, and LLA ameliorated hepatic histopathology caused by HF. VCO and MCT improved liver lipid profiles, whereas LLA has more beneficial effect on plasma lipids via a better TC:HDL ratio and showed promise for BW control.

Phosphodiesterase 5 and Arginase Inhibitory Activities of the Extracts from Some Members of Nelumbonaceae and Nymphaeaceae Families.

The objectives of this study were (1) to investigate the effect of extracts from some plants in the families Nelumbonaceae and Nymphaeaceae on phosphodiesterase 5 (PDE5) and arginase, which have been used in erectile dysfunction treatment, and (2) to isolate and identify the compounds responsible for such activities. The characterization and quantitative analysis of flavonoid constituents in the active extracts were performed by HPLC. Thirty-seven ethanolic extracts from different parts of plants in the genus Nymphaea and Victoria of Nymphaeaceae and genus Nelumbo of Nelumbonaceae were screened for PDE5 and arginase inhibitory activities. The ethanolic extracts of the receptacles and pollens of Nelumbo nucifera Gaertn., petals of Nymphaea cyanea Roxb. ex G.Don, Nymphaea stellata Willd., and Victoria amazonica (Poepp.) Sowerby and the petals and receptacles of Nymphaea pubescens Willd. showed IC50 values on PDE5 of less than 25 µg/mL while none of the extracts showed effects on arginase. The most active extract, N. pubescens petal extract, was fractionated to isolate and identify the PDE5 inhibitors. The results showed that six flavonoid constituents including quercetin 3'-O-ß-xylopyranoside (1), quercetin 3-methyl ether 3'-O-ß-xylopyranoside (2), quercetin (3), 3-O-methylquercetin (4), kaempferol (5) and 3-O-methylkaempferol (6) inhibited PDE5 with IC50 values at the micromolar level.

The new quinazoline derivative (N2-methyl-N4-[(thiophen-2-yl)methyl]quinazoline-2,4-diamine) vasodilates isolated mesenteric arteries through endothelium-independent mechanisms and has acute hypotensive effects in Wistar rats.

During the screening of new N2,N4-disubstituted quinazoline 2,4-diamines as phosphodiesterase-5 inhibitors and pulmonary artery vasodilators, one N2-methyl-N4-[(thiophen-2-yl)methyl]quinazoline-2,4-diamine (compound 8) presented a greater selectivity for systemic than pulmonary vasculature. The present study aimed to characterize its vasorelaxant and hypotensive effects in Wistar rats. Vasorelaxant effects of compound 8 and underlying mechanisms were evaluated on isolated mesenteric arteries. Acute hypotensive effect was evaluated in anesthetized rats. Additionally, cell viability and cytochrome P450 (CYP) activities were studied in rat isolated hepatocytes. Nifedipine was used as a comparator. Compound 8 induced a strong vasorelaxant effect, similar to nifedipine. This was unaffected by endothelium removal but was decreased by inhibitors of guanylate cyclase (ODQ) and KCa channel (iberiotoxin). Compound 8 enhanced sodium nitroprusside-induced relaxation, but inhibited vasoconstriction evoked by α1-adrenergic receptor activation and extracellular Ca2+ influx via receptor-operated Ca2+ channels. Acute intravenous infusion of compound 8 (0.05 and 0.1 mg/kg) produced hypotension. It showed similar potency to nifedipine for lowering diastolic and mean arterial blood pressure, but less so for the effect on systolic blood pressure. Compound 8 had no effect on hepatocyte viability and CYP activities except at high concentration (10 µM) at which a weak inhibitory effect on CYP1A and 3A was observed. In conclusion, this study identified a N2-methyl-N4-[(thiophen-2-yl)methyl]quinazoline-2,4-diamine with a potent vasodilator effect on resistance vessels, leading to an acute hypotensive effect and a low risk of liver toxicity or drug-drug interactions. These vascular effects were mediated mainly through sGC/cGMP pathway, opening of KCa channels, and inhibition of calcium entry.

Computational design, synthesis and biological evaluation of PDE5 inhibitors based on N2,N4-diaminoquinazoline and N2,N6-diaminopurine scaffolds.

We report the synthesis, and characterization of twenty-nine new inhibitors of PDE5. Structure-based design was employed to modify to our previously reported 2,4-diaminoquinazoline series. Modification include scaffold hopping to 2,6-diaminopurine core as well as incorporation of ionizable groups to improve both activity and solubility. The prospective binding mode of the compounds was determined using 3D ligand-based similarity methods to inhibitors of known binding mode, combined with a PDE5 docking and molecular dynamics based-protocol, each of which pointed to the same binding mode. Chemical modifications were then designed to both increase potency and solubility as well as validate the binding mode prediction. Compounds containing a quinazoline core displayed IC50s ranging from 0.10 to 9.39 µM while those consisting of a purine scaffold ranging from 0.29 to 43.16 µM. We identified 25 with a PDE5 IC50 of 0.15 µM, and much improved solubility (1.77 mg/mL) over the starting lead. Furthermore, it was found that the predicted binding mode was consistent with the observed SAR validating our computationally driven approach.

Quinazoline-based human phosphodiesterase 5 inhibitors exhibited a selective vasorelaxant effect on rat isolated pulmonary arteries involving NO-sGC-cGMP pathway and calcium inhibitory effects.

Phosphodiesterase 5 (PDE5) inhibitors are an attractive option among the currently available therapies in the management of pulmonary arterial hypertension (PAH). Good selectivity for PDE5 is associated with reduced side effects and greater vasorelaxant effect on pulmonary arteries (PA). This study investigated the vasorelaxant effects of a series of quinazoline-based PDE5 inhibitors and their precise mechanisms action using rat isolated PA and aorta, as compared to sildenafil. Their effects on rat hepatocytes (viability and CYP activities) were also evaluated. Compounds 5 and 11 displayed lower human PDE5 IC50 of the analogs studied here and induced a greater relaxant effect on PA (EC50 0.94 ± 0.30 and 1.03 ± 0.23 µM, respectively). As compared to sildenafil (EC50 = 0.05 ± 0.02 µM on PA), the relaxant effect of 5 and 11 on PA was lower but their selectivity for PA compared to aorta was higher. The effects of 5 and 11 were reduced by NG-nitro-L-arginine methyl ester, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one, but not by indomethacin or potassium channels blockers. They also enhanced the relaxant effect of sodium nitroprusside, and inhibited extracellular Ca2+ influx and intracellular Ca2+release. Compounds 5 and 11 did not reduce hepatocyte viability except at concentration > 10 µM, inhibited CYP3A at 10 µM, like sildenafil, but did not induce CYP1A. In conclusion, this study identified 2 quinazoline analogues with good PDE5 inhibitory activity and good selectivity for the pulmonary vasculature. Their relaxant effect involves both the potentiation of nitric oxide-sGC-cGMP pathway and calcium inhibition. These compounds are potential leads for developing new drugs for PAH.

Isolation of Intrapulmonary Artery and Smooth Muscle Cells to Investigate Vascular Responses.

The intrapulmonary artery (IPA) and vascular smooth muscle cells (VSMCs) isolated from rat lungs can be used to study the underlying mechanisms of vasoconstriction and vasorelaxation. After isolating the IPA and VSMCs, the characteristics of vascular responses in physiological and pathological conditions can be assessed in the absence of extrinsic factors such as nerve signals, hormones, cytokines, etc. Thus, the IPA and VSMCs serve as excellent models for studying vascular physiology/pathophysiology, along with various experimental investigations, such as modulation by pharmacological agents, patch-clamp electrophysiological analysis, calcium imaging, etc. Here, we have used a technique for isolating the IPA to investigate vascular responses in an organ bath setup. IPA segments were mounted on the organ bath chamber via intraluminal wires and stimulated by various pharmacological agents. The changes in IPA vascular tone (i.e., vasoconstriction and vasorelaxation), were recorded using an isometric force transducer and physiological data analysis software program. We implemented several experimental protocols, which can be adapted to investigate the mechanisms of vasorelaxation/vasoconstriction for studying the pharmacological activities of phytochemical or synthetic drugs. The protocols can also be used to evaluate drugs' roles in modulating various diseases, including pulmonary arterial hypertension. The IPA model allows us to investigate the concentration-response curve, which is crucial in assessing drugs' pharmacodynamic parameters.

Anti-hypotensive effect of "Yahom Navakot" in rats with orthostatic hypotension.

Background and aim: Yahom Navakot (YN), is a Thai traditional medicine, consisting of 54 plants, for treating fainting and dizziness. Thus, YN might relieve orthostatic hypotension (OH) symptoms, but its therapeutic action is unclear. Therefore, this study evaluated YN in OH rats, using a head-up tilt test (HUT). Experimental procedure: Rats were anesthetized, and OH induced via a 90oHUT, before and after administering vehicle, a YN powder suspension (10, 100 mg/kg), a YN aqueous extract (100 mg/kg), and midodrine (5 mg/kg). The systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP), pulse pressure (PP) and heart rate (HR) were determined via the carotid artery. Plasma noradrenaline (NA) was evaluated. YN-induced vasoconstriction of isolated rat aorta rings was determined using organ bath technique. Results and conclusion: Baseline BP increased with the 100 mg/kg YN powder suspension, the YN aqueous extract or midodrine, while HR decreased, compared with vehicle and control. 90oHUT rapidly reduced SBP, DPB and MAP, but increased HR, for control and vehicle-treated groups, but BP was steady with the 100 mg/kg YN powder suspension, the YN aqueous extract or midodrine. The 90oHUT-increase in HR was most pronounced with the 100 mg/kg YN powder suspension (the traditional formulation). This accords with increased plasma NA. YN also induced vasoconstriction in rat aorta via α1-receptor activation. Thus, the anti-hypotensive action of YN involved a stimulating effect on the heart and blood vessels via sympathetic activation. The results support the traditional use of YN and demonstrated the effectiveness of YN for OH prevention.

Development, Characterization, and Stability Evaluation of the Anti-Cellulite Emgel Containing Herbal Extracts and Essential Oils.

Recently, the herbal compress was successfully developed and applied for cellulite treatment. The aim of this study was to formulate a more convenient dosage form of herbal application from the original formula. In addition, we aimed to characterize and evaluate the stability of the developed dosage form. A gelled emulsion, or an "emgel," incorporated with 0.1 wt% tea and coffee extracts (1:1 ratio) plus 5 wt% essential oils (mixed oil) was prepared. The caffeine content in the finished product obtained from tea and coffee extracts analyzed by HPLC was 48.1 ± 2.3 µg/g. The bio-active marker monoterpenes of mixed oil characterized by headspace GCMS were camphene 50.8 ± 1.8 µg/mg, camphor 251.0 ± 3.2 µg/mg, 3-carene 46.7 ± 1.8 µg/mg, α-citral 75.0 ± 2.1 µg/mg, ß-citral 65.6 ± 1.3 µg/mg, limonene 36.8 ± 6.7 µg/mg, myrcene 53.3 ± 4.5 µg/mg, α-pinene 85.2 ± 0.6 µg/mg, ß-pinene 88.4 ± 1.1 µg/mg, and terpinene-4-ol 104.3 ± 2.6 µg/mg. The stability study was carried out over a period of 3 months at 4, 25, and 50 °C. The caffeine content showed no significant changes and passed the acceptance criteria of ≥80% at all tested temperatures. However, monoterpenes showed their stability for only 2 months at 50 °C. Therefore, the shelf-life of the emgel was, consequently, calculated to be 31 months using the Q10 method. Thus, the anti-cellulite emgel was successfully formulated. The characterization methods and stability evaluation for caffeine and monoterpenes in an emgel matrix were also successfully developed and validated.

Efficacy of an Anti-Cellulite Herbal Emgel: A Randomized Clinical Trial.

Cellulite describes unsightly skin overlying subcutaneous fat around thighs and buttocks of post-pubescent females. A herbal 'emgel' containing volatile oils and extracts of A traditional Thai herbal compress was tested in a double-blind, placebo-controlled trial with 18 women aged 20-50 year with severe cellulite. Appearance of cellulite (primary outcome), thigh circumferences, skin firmness, and cutaneous blood flow (secondary outcomes) were assessed at baseline, 2, 4, 8 and 12 weeks with a 2-week follow-up. Herbal emgel applied onto the thigh skin twice daily reduced cellulite severity scores in every time point. The score was reduced from 13.4 ± 0.3 (baseline) to 12.1 ± 0.3 (week 2) and 9.9 ± 0.6 (week 12). All secondary outcomes improved with both placebo and herbal emgels suggesting that ingredients in the base-formulation might be responsible. Querying of participants, analysis of their diaries, and physical monthly inspections found no adverse events. The herbal emgel safely improved the appearance of cellulite, while the base emgel may play a role for other endpoints. Further studies on the active constituents and their mechanism of action are needed to further explore these factors.

Dried mulberry fruit ameliorates cardiovascular and liver histopathological changes in high-fat diet-induced hyperlipidemic mice.

BACKGROUND AND AIM: Metabolic disease encompasses most contemporary non-communicable diseases, especially cardiovascular and fatty liver disease. Mulberry fruits of Morus alba L. are a favoured food and a traditional medicine. While they are anti-atherosclerotic and reduce hyperlipidemic risk factors, studies need wider scope that include ameliorating cardiovascular and liver pathologies if they are to become clinically effective treatments. Therefore, the present study sought to show that freshly dried mulberry fruits (dMF) might counteract the metabolic/cardiovascular pathologies in mice made hyperlipidemic by high-fat diet (HF). EXPERIMENTAL PROCEDURE: C57BL/6J mice were fed for 3 months with either: i) control diet, ii) HF, iii) HF+100 mg/kg dMF, or iv) HF+300 mg/kg dMF. Body weight gain, food intake, visceral fat accumulation, fasting blood glucose, plasma lipids, and aortic, heart, and liver histopathologies were evaluated. Adipocyte lipid accumulation, autophagy, and bile acid binding were also investigated. RESULTS AND CONCLUSION: HF increased food intake, body weight, visceral fat, plasma total cholesterol (TC) and low-density lipoprotein (LDL), TC/HDL ratio, blood glucose, aortic collagen, arterial and cardiac wall thickness, and liver lipid. Both dMF doses prevented hyperphagia, body weight gain, and visceral fat accumulation, lowered blood glucose, plasma TG and unfavourable TC/HDL and elevated plasma HDL beyond baseline. Arterial and cardiac wall hypertrophy, aortic collagen fibre accumulation and liver lipid deposition ameliorated in dMF-fed mice. Clinical trials on dMF are worthwhile but outcomes should be holistic commensurate with the constellation of disease risks. Here, dMF should supplement the switch to nutrient-rich from current energy-dense diets that are progressively crippling national health systems.

Characterization of Metabolites in Plasma, Urine and Feces of Healthy Participants after Taking Brahmi Essence for Twelve Weeks Using LC-ESI-QTOF-MS Metabolomic Approach.

Brahmi essence, developed from Bacopa monnieri (L.) Wettst. standardized extract and mulberry juice, was proven to improve the memory speed of healthy participants aged 55-80 years old, following a 12-week dietary program. However, the metabolites have not yet been reported. Our objective was to characterize the altered metabolites in the plasma, urine, and feces of healthy volunteers after consumption of Brahmi essence for 12 weeks, using the LC-MS metabolomics approach. The altered metabolites were selected from OPLS-DA S-plots; 15 metabolites in the plasma, 7 in the urine, and 17 in the feces samples were tentatively identified by comparison with an online database and literature. The metabolites in the plasma samples were in the classes of amino acids, acylcarnitine, and phospholipids. Benzeneactamide-4-O-sulphate and 3-hydroxyhippuric acid were found in urine samples. The metabolites in the class of amino acids, together with jujubogenin and pseudojujubogenin, were identified in the fecal samples. The aminoacyl-tRNA, aromatic amino acids, and branched-chain amino acid biosynthetic pathways were mainly related to the identified metabolites in all three samples. It could be implied that those metabolites and their pathways might be linked with the effect of Brahmi essence on memory speed.

Effects of Essential Oils and Some Constituents from Ingredients of Anti-Cellulite Herbal Compress on 3T3-L1 Adipocytes and Rat Aortae.

Cellulite is associated with a complex array of adipocytes under the skin and vascular system. A herbal compress that was previously developed was proven to have an anti-cellulite effect in healthy volunteers within 2 weeks of treatment. However, its mechanism and ingredients responsible for reducing cellulite were not known. The purpose of this study was to investigate the activity of eight essential oils in, and two water extracts from, the ingredients of the herbal compress together with nine monoterpenoid constituents on the 3T3-L1 adipocytes. The vasodilatory effect on rat aortae was also studied. The adipocytes were induced by dexamethasone, 3-isobutyl-1-methylxanthine and insulin. At all concentrations tested, all essential oils, water extracts and their monoterpenoid constituents significantly inhibited lipid accumulation activity (p < 0.05) and decreased the amount of triglycerides when compared to untreated cells (p < 0.01). In addition, our results showed that the mixed oil distilled from the herbal compress mixed ingredients could relax the isolated rat aorta (EC50 = 14.74 ± 2.65 µg/mL). In conclusion, all essential oils, extracts and chemical constituents tested showed effects on adipogenesis inhibition and lipolysis induction on the cultured adipocytes with the mixed oil demonstrating vasorelaxation activity, all of which might be the mechanisms of the anti-cellulite effects of the herbal compress.

Extract of Aquilaria crassna leaves and mangiferin are vasodilators while showing no cytotoxicity.

The leaves of Aquilaria spp. promote "physiological balance", and are "cardiotonic and provide blood nourishment". In Asia, these leaves are increasingly consumed as tea and claimed to provide benefits to cardiovascular function, albeit without any scientific proof. Therefore, this study sought to evaluate the action of Aquilaria crassna leaf aqueous extract (AE) on vascular function and vascular smooth muscle cytotoxicity. AE and a main constituent, mangiferin were investigated for their vasorelaxation of rat mesenteric arteries and aortae in vitro. Acute cytotoxicity of AE (0.1-1000 µg/ml) and mangiferin (0.1-100 µM) on rat enzymatically isolated vascular smooth muscle cells was assayed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide. AE dilated rat mesenteric arteries (EC50∼107 µg/ml, Emax∼95%) more than aorta (EC50∼265 µg/ml, Emax∼76%, p < 0.05). AE-induced vasodilation in mesenteric artery was reduced by endothelial removal (EC50∼202 µg/ml, p < 0.05), incubation with endothelial nitric oxide synthase (eNOS) (100 µM, L-NAME) (EC50∼309 µg/ml, p < 0.05), and partly reduced by L-type Ca2+ channel blockade at higher concentrations. Likewise, mangiferin (1-100 µM) dilated the mesenteric artery more potently than the aorta. However, its maximum relaxation was less than with AE (41% in the mesenteric artery and <10% in the aorta). Isolated vascular smooth muscle cells incubated in AE or mangiferin for 1 h showed no cytotoxicity. Thus, AE is a vasorelaxant while being free of acute cytotoxicity towards vascular smooth muscle, thus potentially ameliorating human vascular dysfunction.

Vasodilatory Effects and Mechanisms of Action of Bacopa monnieri Active Compounds on Rat Mesenteric Arteries.

B. monnieri extract (BME) is an abundant source of bioactive compounds, including saponins and flavonoids known to produce vasodilation. However, it is unclear which components are the more effective vasodilators. The aim of this research was to investigate the vasorelaxant effects and mechanisms of action of saponins and flavonoids on rat isolated mesenteric arteries using the organ bath technique. The vasorelaxant mechanisms, including endothelial nitric oxide synthase (eNOS) pathway and calcium flux were examined. Saponins (bacoside A and bacopaside I), and flavonoids (luteolin and apigenin) at 0.1-100 µM caused vasorelaxation in a concentration-dependent manner. Luteolin and apigenin produced vasorelaxation in endothelial intact vessels with more efficacy (Emax 99.4 ± 0.7 and 95.3 ± 2.6%) and potency (EC50 4.35 ± 1.31 and 8.93 ± 3.33 µM) than bacoside A and bacopaside I (Emax 83.6 ± 2.9 and 79.9 ± 8.2%; EC50 10.8 ± 5.9 and 14.6 ± 5.4 µM). Pretreatment of endothelial intact rings, with L-NAME (100 µM); an eNOS inhibitor, or removal of the endothelium reduced the relaxant effects of all compounds. In K+-depolarised vessels suspended in Ca2+-free solution, these active compounds inhibited CaCl2-induced contraction in endothelial denuded arterial rings. Moreover, the active compounds attenuated transient contractions induced by 10 µM phenylephrine in Ca2+-free medium containing EGTA (1 mM). Thus, relaxant effects occurred in both endothelial intact and denuded vessels which signify actions through both endothelium and vascular smooth muscle cells. In conclusion, the flavonoids have about twice the potency of saponins as vasodilators. However, in the BME, there is ~20 × the amount of vaso-reactive saponins and thus are more effective.

Elucidation of Vasodilation Response and Structure Activity Relationships of N²,N4-Disubstituted Quinazoline 2,4-Diamines in a Rat Pulmonary Artery Model.

Pulmonary arterial hypertension (PAH) is a rare and progressive disease arising from various etiologies and pathogenesis. PAH decreases life expectancy due to pulmonary vascular remodeling, elevation of mean pulmonary arterial pressure, and ultimately progresses to heart failure. While clinical treatments are available to reduce the associated symptoms, a complete cure has yet to be found. Phosphodiesterase-5 (PDE-5) inhibition has been identified as a possible intervention point in PAH treatment. The functional vasodilation response to N²,N4-diamino quinazoline analogues with differing PDE-5 inhibitory activities and varying physicochemical properties were assessed in both endothelium-intact and denuded rat pulmonary arteries to gain greater insight into their mode of action. All analogues produced vasorelaxant effects with EC50s ranging from 0.58 ± 0.22 µM to ˃30 µM. It was observed that vasodilation response in intact vessels was highly correlated with that of denuded vessels. The ~10% drop in activity is consistent with a loss of the nitric oxide mediated cyclic guanosine monophosphate (NO/cGMP) pathway in the latter case. A moderate correlation between the vasodilation response and PDE-5 inhibitory activity in the intact vessels was observed. Experimental protocol using the alpha-adrenergic (α1) receptor agonist, phenylephrine (PE), was undertaken to assess whether quinazoline derivatives showed competitive behavior similar to the α1 receptor blocker, prazosin, itself a quinazoline derivative, or to the PDE-5 inhibitor, sildenafil. Competitive experiments with the α1-adrenergic receptor agonist point to quinazoline derivatives under investigation here act via PDE-5 inhibition and not the former. The pre-incubation of pulmonary arterial rings with quinazoline test compounds (10 µM) reduced the contractile response to PE around 40⁻60%. The most promising compound (9) possessed ~32 folds higher selectivity in terms of vasodilation to its mammalian A549 cell cytotoxicity. This study provides experi0 0mental basis for PDE-5 inhibition as the mode of action for vasodilation by N²,N4-diamino quinazoline analogues along with their safety studies that may be beneficial in the treatment of various cardiovascular pathologies.

Design, synthesis and evaluation of N2,N4-diaminoquinazoline based inhibitors of phosphodiesterase type 5.

We describe the design, synthesis and evaluation of a series of N2,N4-diaminoquinazoline analogs as PDE5 inhibitors. Twenty compounds were prepared and these were assessed in terms of their PDE5 and PDE6 activity, ex-vivo vasodilation response, mammalian cytotoxicity and aqueous solubility. Molecular docking was used to determine the binding mode of the series and this was demonstrated to be consistent with the observed SAR. Compound 15 was the most active PDE5 inhibitor (IC50 = 0.072 ±â€¯0.008 µM) and exhibited 4.6-fold selectivity over PDE6. Ex-vivo assessment of 15 and 22 in a rat pulmonary artery vasodilation model demonstrated EC50s of 1.63 ±â€¯0.72 µM and 2.28 ±â€¯0.74 µM respectively.

Eulophia macrobulbon extract relaxes rat isolated pulmonary artery and protects against monocrotaline-induced pulmonary arterial hypertension.

BACKGROUND: Extract of the wild orchid, Eulophia macrobulbon (EM) inhibits phosphodiesterase5 (PDE5) suggesting it could preferentially dilate the pulmonary vasculature. PURPOSE AND STUDY DESIGN: To pharmacologically characterize the vascular actions of EM ethanolic extract and its active compound, 1-(4'-hydroxybenzyl)-4,8-dimethoxyphenanthrene-2,7-diol using isolated pulmonary arteries (PA) from rats having pulmonary arterial hypertension (PAH) induced by monocrotaline (MCT). PA were fixed and prepared for histology. RESULTS: EM extract relaxed PA (EC50 = 0.17  mg/ml, Emax ∼ 94%) but less so for aorta (EC50 = 0.51 mg/ml, Emax ∼ 62%), suggesting some selectivity towards the pulmonary circulation. PA vasorelaxation was reduced by endothelial removal or NG-nitro-L-arginine methyl ester, but unaffected by indomethacin, apamin +charybdotoxin, 4-aminopyridine, glibenclamide, iberiotoxin, or 1H - [1,2,4]oxadiazolo[4,3-a]quinoxalin -1- one. Sodium nitroprusside-induced relaxation was enhanced by EM extract, probably via PDE5 inhibition. EM extract reduced contractions evoked by extracellular Ca2+application, and inhibited intracellular Ca2+release activated by phenylephrine. The phenanthrene relaxed PA independently of the endothelium. MCT thickened walls and decreased lumens of PA, and hypertrophied right ventricular myocytes, effects ameliorated by 3 weeks of oral sildenafil (20  mg/kg) or EM extract (15, 450 or 1000  mg/kg). CONCLUSION: PAH is improved by EM extract acting through PA relaxation mediated through endothelial NO, reduced Ca2+-mobilization, and reduced PA wall thickness and right ventricular hypertrophy.

Cellulite Reduction by Modified Thai Herbal Compresses; A Randomized Double-Blind Trial.

Cellulite remains an obstinate clinical and cosmetic problem. In this study, we adapted the Thai traditional noninvasive treatment formulated with 5 additional herbals to improve blood flow, edema, and lipolysis, thereby augmenting cellulite treatment. This was a double-blind, randomized placebo-controlled paired trial. Twenty-one women (20-55 years) having cellulite (grade ≥2) were treated with steamed placebo or herbal compresses randomly assigned to one or other thigh twice weekly for 8 weeks with 2 weeks washout. Cellulite reduction was assessed from standardized photographs by 3 blinded evaluators at baseline and every 2 weeks; also assessed were thigh circumferences and cutaneous skin-fold thicknesses, trial diaries, and participant feedback. After 8 weeks, herbal compress treatment reduced Nürnberger-Müller cellulite scores from 12.6 ± 2.0 to 9.9 ± 2.4 compared with 12.5 ± 2.1 to 12.1 ± 2.0 (means ± SEM) for contralateral placebo-treated thighs ( P < .0001; effect size [ES] = 1.16, confidence interval [CI] = 0.48-1.83). Thigh circumferences diminished by 2.2 ± 0.9 cm (herbal) and 1.4 ± 0.7 cm (placebo) (ES = 0.96, CI = 0.30-1.61) and correspondingly skin-folds by 5.6 ± 2.2 and 2.4 ± 1.3 mm (ES = 1.72, CI = 0.99-2.45). No adverse actions were reported, and there were no dropouts, no missing data, and 100% adherence. Herbal compresses were efficacious against cellulite and thigh sizes. The herbal formula might be adapted to other delivery options, and rationally added herbals may increase effectiveness of traditional therapies and more sustainable actions.

Vasorelaxant and Hypotensive Effects of an Ethanolic Extract of Eulophia macrobulbon and Its Main Compound 1-(4'-Hydroxybenzyl)-4,8-Dimethoxyphenanthrene-2,7-Diol.

Background: Ethnopharmacological studies demonstrated the potential for Eulophia species to treat inflammation, cancer, and cardio-metabolic diseases. The aim of the study was to investigate the vasorelaxant effect of ethanolic Eulophia macrobulbon (EM) extract and its main phenanthrene on rat isolated mesenteric artery and to investigate the hypotensive effect of EM. Methods: The vasorelaxant effects of EM extract or phenanthrene and the underlying mechanisms were evaluated on second-order mesenteric arteries from Sprague Dawley rats. In addition, the acute hypotensive effect was evaluated in anesthetized rats infused with cumulative concentrations of the EM extract. Results: Both EM extract (10-4-1 mg/ml) and phenanthrene (10-7-10-4 M) relaxed endothelium-intact arteries, an effect that was partly reduced by endothelium removal (p < 0.001). A significant decrease in the relaxant effect of the extract and the phenanthrene was observed with L-NAME and apamin/charybdotoxin in endothelium-intact vessels, and with iberiotoxin in denuded vessels. SNP (sodium nitroprusside)-induced relaxation was significantly enhanced by EM extract and phenanthrene. By contrast, ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one), 4-aminopyridine and glibenclamide (endothelium-denuded vessels) and indomethacin (endothelium-intact vessels) had no effect. In calcium-free solution, both the EM extract and phenanthrene inhibited extracellular Ca2+-induced contraction in high KCl and phenylephrine (PE) pre-contracted rings. They also inhibited the intracellular Ca2+ release sensitive to PE. The acute infusion of EM extract (20 and 70 mg/kg) induced an immediate and transient dose-dependent hypotensive effect. Conclusion: The ethanolic extract of EM tubers and its main active compound, 1-(4'-hydroxybenzyl)-4,8-dimethoxyphenanthrene-2,7-diol (phenanthrene) induced vasorelaxant effects on rat resistance vessels, through pleiotropic effects including endothelium-dependent effects (NOS activation, enhanced EDH production) and endothelium-independent effects (opening of KCa channels, inhibition of Ca2+ channels, inhibition of intracellular Ca2+ release and PDE inhibition).