Search Results (183)

G-protein-coupled receptors (GPCRs) are vital transmembrane proteins that regulate a wide range of physiological processes by transmitting extracellular signals into intracellular responses. Among them, the β2-adrenergic receptor (β2-AR) plays a central role in bronchodilation, smooth muscle relaxation, and cardiovascular modulation, making it a key therapeutic target for diseases such as asthma, chronic obstructive pulmonary disease (COPD), and hypertension. This study explores the potential of natural bioactive compounds like ephedrine, quercetin, catechin, and resveratrol as alternative ligands for β2-AR through molecular docking analysis. Using AutoDock 4.6, these compounds were docked with the binding site of the β2-AR (PDB ID: 2RH1), and their binding affinities and interaction map were evaluated. Results showed that all compounds exhibited favorable binding energies and stable interactions with key receptor residues, with quercetin demonstrating the highest affinity. The findings suggest that these natural compounds may serve as promising leads for the development of safer, plant-derived modulators of β2-AR, supporting the role of computational approaches in natural product-based drug discovery. However, as docking cannot determine functional activity, these findings should be interpreted as preliminary and require experimental validation. Full article

G-protein-coupled receptors (GPCRs) are a group of various membrane proteins that mediate essential physiological processes by translating extracellular signals into intracellular responses. The β2-Adrenergic Receptor (β2-AR), a key GPCR, plays a critical role in smooth muscle relaxation, bronchodilation, and cardiovascular function, making it an important therapeutic target for diseases such as asthma and hypertension. Diketopiperazines (DPKs), as cyclic peptides, have shown promise as scaffolds for inhibiting protein interactions and modulating receptor activity, offering a potential alternative to traditional small-molecule inhibitors with reduced side effects. In this study, five DPK derivatives were selected from the PubChem database and evaluated for their binding affinity to the 3D structure of β2-AR (PDB ID = 2RH1) through molecular docking studies using AutoDock 4.6 and MGLTools. The binding energy and hydrogen bond formation of each compound were evaluated to determine their interaction efficiency. Among the compounds, tryptophan-proline diketopiperazine (compound 3) exhibited the highest binding affinity with a binding energy of −5.89 kcal/mol. This enhanced interaction is attributed to the aromatic nature of tryptophan, which promotes strong π-π stacking interactions, and the rigidity of proline, which optimally fits within the receptor’s binding pocket. Hydrophobic interactions further stabilized the complex. These findings highlight compound 3 as a promising β2-AR modulator, providing valuable insights for the design of peptide-based inhibitors targeting β2-AR-related pathologies. Full article

Background: Gastrointestinal endoscopy is crucial for diagnosing colorectal cancer and inflammatory bowel diseases, but its effectiveness can be impacted by peristalsis, poor bowel preparation, and inadequate withdrawal time. Conventional antispasmodics, though effective, may not be suitable for elderly patients or those with comorbidities. L-menthol, derived from peppermint oil, has emerged as a safer alternative. Through calcium channel blockade, L-menthol promotes GI smooth muscle relaxation. This study evaluated L-menthol’s efficacy and safety as a potential alternative to antispasmodic agents in endoscopy. Methods: Following PRISMA2020 guidelines and the Cochrane Handbook, we conducted a systematic review and meta-analysis of randomized controlled trials involving adults undergoing endoscopy, comparing L-menthol to placebo. The primary outcome was the adenoma detection rate, with secondary outcomes, including severity of peristalsis, safety, withdrawal time, and ease of examination. We searched five databases on 31 May 2023, with updates on 20 October 2024. Results: Fourteen studies were included. L-menthol reduced peristalsis during colonoscopy and upper endoscopy, achieving a suppression rate of 55.9% (560/1002 patients; odds ratio (OR) = 3.88, 95% confidence interval (95% CI): 2.13–7.07), which improved mucosal visualization. It improved ease of examination (OR = 2.53, 95% CI: 1.35–4.73), allowing endoscopists to perform procedures with less technical difficulty. However, L-menthol had no significant impact on the adenoma detection rate (OR = 1.06, 95% CI: 0.69–1.64), indicating no added benefit for lesion detection, and did not prolong withdrawal time (MD = 3.24 s, 95% CI: −101.05–107.53). Adverse event rates remained low and comparable to placebo (OR = 0.97, 95% CI: 0.74–1.27). Conclusions: L-menthol reduces peristalsis and enhances ease of examination without adverse events. Although its effect on the adenoma detection rate remains inconclusive, its antispasmodic properties make it a promising alternative for patients who cannot tolerate conventional agents. Full article

The genus Marrubium (Lamiaceae) is widely used in traditional medicine. While some representatives of the genus have been well investigated, the biological activity of others remains largely unknown. The aim of the current study was to assess the in vitro antioxidant potential and the effect on the reactivity of isolated rat gastric smooth muscles (SM) of aqueous extracts of Marrubium friwaldskyanum inflorescences, stems and leaves, and Marrubium peregrinum as a whole herb. The antioxidant activity was analyzed through multiple spectrophotometric and fluorometric assays. The effect on SM reactivity was determined by the treatment of excised gastric muscles of 10 male Whistar rats with the plant extracts alone or successive to 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide, ketanserin, verapamil, and acetylcholine. According to the obtained results, the M. friwaldskyanum leaf extract exhibited the greatest antioxidant potential, followed by the M. peregrinum one. The SM reactivity analysis revealed that the treatment with all four extracts induced a dose-dependent contractile response with predominant cholinergic character. However, activation of serotoninergic and/or dopaminergic pathways was also observed. Furthermore, when applied after verapamil, the extracts showed a SM relaxant effect. The discovered biological activity will serve as a basis for future analyses through which the therapeutic effect of the plants will be investigated. Full article

Background/Objectives: Haloxylon griffithii is a medicinal plant possessing therapeutic effects in disorders associated with the gastrointestinal (GIT) system. This research aims to study the pharmacological activity of Haloxylon griffithii in a multidimensional manner, involving phytochemistry screening and in vitro and in vivo experiments. Methods: The whole dried plant was extracted with 80% methanol and further fractionation using solvents of increasing polarity. GC-MS analysis was performed on the crude extract to discover volatile compounds. The spasmolytic/spasmogenic effect was assessed in isolated rabbit jejunum using spontaneous and K⁺-induced contractions, as well as contractions induced by increasing concentrations of calcium ions in depolarized tissue. Antidiarrheal activity was evaluated in Swiss albino rats/mice (n = 6/group) using castor oil-induced diarrhea and peristaltic index models. In silico ADMET screening was conducted via SwissADME and pkCSM. Results: The GC-MS profiling of H. griffithii revealed the presence of 59 phytochemicals and a rare azulene derivative and constituents, including α-santonin and hexadecanoic acid esters, with favorable pharmacokinetic profiles, as predicted using SwissADME and pkCSM computational tools. The in vitro and in vivo experiments revealed the significant calcium channel blocking activity in non-polar fractions (n-hexane and ethyl acetate), while the polar extracts (ethanolic, aqueous) exhibited cholinergic effects, indicating a dual mode of action. Conclusions: This was a first-time demonstration of both antidiarrheal and smooth muscle-relaxant activity in H. griffithii, supported by GC-MS profiling and pharmacological assay. The findings lend scientific credibility to the traditional use of the plant in community healthcare, while also reinforcing the need for further pharmacological and clinical studies to explore its potential in drug development. Full article

Indomethacin, ibuprofen, and acetylsalicylic acid (ASA) are non-steroidal anti-inflammatory drugs (NSAIDs) that inhibit prostaglandin (PG) synthesis. Previous studies in airway smooth muscle demonstrated that chronic exposure to testosterone (TES, 40 nM) enhances the relaxation induced by salbutamol and theophylline due to K⁺ channel increment, without modifying cyclooxygenase expression. This study examines how indomethacin, ibuprofen, and ASA affect K⁺ currents and the relaxation response to these bronchodilators. In organ baths, tracheas from young male guinea pigs chronically (48 h) treated with 40 nM TES showed increased relaxation to salbutamol and theophylline, which was completely abolished by indomethacin. Patch-clamp recordings revealed that TES increased salbutamol- and theophylline-induced K⁺ currents, and only indomethacin fully inhibited this potentiation; ibuprofen and ASA had partial effects. The involved currents included voltage-dependent K⁺ (K_V) and high-conductance Ca²⁺-activated K⁺ (BK_Ca) channels. Our results demonstrate that indomethacin exerts a dual action, inhibiting K⁺ channel activity and PG synthesis, unlike ibuprofen and ASA. This dual mechanism explains its stronger inhibitory effect on TES-enhanced ASM relaxation. These findings suggest that indomethacin may counteract the protective effects of TES, which promotes anti-inflammatory and smooth muscle-relaxing states. Therefore, it is advisable to exercise caution when prescribing indomethacin to young males with asthma, as the protective role of TES may diminish, potentially resulting in an exacerbation of asthma symptoms. Full article

Retinoic acid (RA), a vitamin A derivative, has been shown to prevent the development of neurological disorders by ensuring the integrity of the physiological structure of the neurovascular unit and regulating the physiological cell’s function. After an ischemia event, RA reduces the effects of blood–brain barrier disruption by blocking the apoptotic signaling pathway. However, the effect of RA on smooth muscle cells (SMCs), which are crucial to maintaining blood perfusion, has never been investigated. This study aimed to evaluate the effect of RA on the vasoactive response of middle cerebral artery SMCs in normal and ischemic contexts (O₂ and glucose deprivation, OGD). For this purpose, SMCs cultures were incubated with RA, and the vasoactive response was evaluated in both conditions (OGD and non-OGD). To simulate OGD, co-cultures of neurons and astrocytes were made and incubated with RA to analyze the effect of the secretome released by these cells on SMCs contractility. In non-OGD conditions, RA induced rapid relaxation of SMCs and, in the long term (24 h), promoted cell contraction. In OGD conditions, SMCs contractility patterns were different when pre-incubated with RA. In these conditions, NA loses its contractility effect, and SNP seems to revert its relaxant effect. However, SMCs pre-incubated with 5 uM RA show the vasorelaxant pattern typical of SNP, despite the OGD condition. These effects demonstrate an effect of RA on the vasoactive profile of SMCs, with therapeutic potential in OGD conditions. Full article

Obstructive airway diseases, including asthma and chronic obstructive pulmonary disease (COPD), evoke significant global health concerns manifested by airway inflammation and obstruction. Despite their differing origins, shared pathophysiological features and responses to therapeutic interventions highlight common molecular mechanisms. Standard treatments include inhaled bronchodilators, with combination therapies offering enhanced symptom control. Cyclic AMP (cAMP) plays a crucial role in airway relaxation. Phosphodiesterase (PDE) decreases cAMP levels, thereby attenuating the relaxation of airway smooth muscle, making it a promising therapeutic target. The balance between cAMP production and degradation is essential for regulating airway tone and function. PDE inhibitors for the treatment of obstructive airway diseases have suffered challenges, with adverse side effects of prospective inhibitors causing clinical failures. Efforts to develop PDE inhibitors with an improved safety profile could prove to be beneficial as an add-on treatment for severe asthma and COPD. The recent FDA approval of Ensifentrine, a dual PDE3/4 inhibitor, can significantly advance COPD management by improving bronchodilation, reducing inflammation, and lowering exacerbation rates with favorable safety outcomes. Full article

Background/Objectives: Phosphodiesterase 5 (PDE5) inhibitors, sildenafil, vardenafil, and tadalafil, activate the cyclic guanosine monophosphate pathway resulting in vascular smooth muscle relaxation. They have been tested for a broad variety of conditions from cancer to Alzheimer’s disease with a positive impact. The known mechanism of action of these drugs could not explain such a plethora of effects. We studied the influence of PDE5 inhibitors on lipid bilayers as a possible application point of their action. Methods: To monitor the membrane changes induced by PDE5 inhibitors, the differential scanning microcalorimetry and the molecular dynamics simulation were used. Results: We found that sildenafil, vardenafil, and tadalafil change elastic properties of model membranes: PDE5 inhibitors disorder thin membranes and order thick membranes. Moreover, PDE inhibitors were able to induce lipid interdigitation. To address the biological aspect of the findings, we performed molecular dynamics on smooth muscle cell’s lipid raft treated with PDE5 inhibitors and revealed the increased density of the lipids. Furthermore, we showed that the lipid condensation in the PDE inhibitors presence increases nitric oxide permeability. Conclusions: The obtained results may be of biological relevance as lipid raft thickening might have an impact on membrane protein function. Moreover, improved nitric oxide flow through membrane may partially explain therapeutic action of these drugs. The presented results are useful for finding novel implications for PDE inhibitors. Full article

Background/Objectives: Mebeverine hydrochloride (MBH) is an antispasmodic agent used to regulate bowel movements and relax intestinal smooth muscle, but its application is limited by specific side effects; therefore, this study investigates the effects of previously synthesized MBH-loaded silver nanoparticles (AgNPs) on smooth muscle contractile activity and their anti-inflammatory potential as an alternative delivery system. Methods: The interactions of AgNPs with cholinergic inhibitors, selective antagonists, Ca²⁺ blockers, and key neurotransmitters were analyzed. In vitro, albumin denaturation suppression and ex vivo assays evaluated the anti-inflammatory effects of AgNPs-MBH, validated using a DFT in silico approach. To comprehensively assess the systemic impact and IBS treatment potential of AgNPs-MBH, we also examined in vitro their antimicrobial activity and hepatic cell responses, as the liver is a key organ in evaluating the overall safety and efficacy of nanoparticles. Additionally, the drug-release capabilities of Ag NPs were established. Results: Our findings indicate that AgNPs with MBH do not affect blocked cholinergic receptors, but their effects are more pronounced and distinct in amplitude and character than MBH. MBH-loaded AgNPs showed a lower anti-inflammatory effect than MBH but were still better than diclofenac. They also affected hepatic cell morphology and proliferation, suggesting potential for enhanced therapeutic efficacy. Drug-loaded AgNPs are considered not bactericidal. Conclusions: Based on our results, drug-loaded AgNPs might be a promising medication delivery system for MBH and a useful treatment option for IBS. Future in vivo and preclinical experiments will contribute to the establishment of drug-loaded AgNPs in IBS treatment. Full article

Schiff bases synthesized in our laboratory have demonstrated pain-relieving effects through both peripheral and central nervous system pathways. Considering that centrally acting analgesics often affect the muscle tone of the gastrointestinal tract (GIT) and related deep internal organs, this study was conducted to examine potential relaxant effects on blood vessels and GIT smooth muscles. The possible relaxant effects of Schiff bases (SB1 and SB2) on isolated rabbit aortic strips were evaluated. The experiments involved assessing their impact on contractions induced by 80 mM potassium chloride (KCL) and 1 µM norepinephrine (NE). Norepinephrine concentration response curves (N. ECRCs) were constructed in the absence and presence of three different concentrations of SB1 and SB2, using N. ECRCs as a negative control. Terazosin served as a standard α1 receptor blocker. Docking studies were employed to validate the mechanism of action for SB1 and SB2. The study outcomes suggest that SB1 is more potent than SB2, demonstrating lower EC₅₀ values for NE-induced contractions in intact (5.50 × 10⁻⁵ ± 2.23 M) and denuded (5.81 × 10⁻⁵ ± 3.80 M) aortae. For NE-induced contractions, SB1 showed percent relaxation values of 48% and 41% in intact and denuded aortae, respectively. In comparison, SB2 exhibited values of 82.5% and 74%, showing that SB1 is more efficacious than SB2. The rightward shift of N. ECRCs for both SB1 and SB2 confirms their inhibition of α1 receptors. Additive effects of SB1 and SB2 were seen in the presence of verapamil (p < 0.0001). Docking analysis revealed that the compounds can properly bind to the target receptor Gq 1D (P25100). Findings show that both Schiff base SB1 and SB2 produce significant (p < 0.05) vasorelaxation via the α1 receptor blocking mechanism. Full article

Cardiovascular disease remains a leading cause of morbidity and mortality worldwide, requiring both pharmacological and lifestyle-based preventive strategies. Artichoke (Cynara cardunculus L. var. scolymus) has gained attention for its health benefits, including choleretic and lipid-lowering activities. However, its cardiovascular effects remain underdiscussed. This paper provides a critical review of the current literature on the cardiovascular effects of artichoke, with a focus on its underlying mechanisms of action and clinical efficacy. Experimental studies assessing artichoke’s effects on endothelial function, vascular smooth muscle relaxation, and modulation of the renin–angiotensin–aldosterone axis were assessed. Additionally, clinical studies, systematic reviews, and meta-analyses investigating its antihypertensive effects were reviewed. Artichoke and its bioactive components, particularly flavonoids and caffeoylquinic acids, enhance endothelial-dependent and -independent vasorelaxation and inhibit angiotensin-converting enzyme activity. Although clinical studies indicate improvements in flow-mediated dilation, they report only modest reductions in blood pressure, with high variability in formulations, dosages, and patient populations. While artichoke supplementation may support blood pressure regulation and endothelial health, current evidence suggests it should be considered an adjunct rather than a replacement for conventional antihypertensive therapy. Standardized formulations and well-controlled clinical studies will be required to clarify its therapeutic role. Full article

The dried root of Sanguisorba officinalis L. (commonly known as Diyu) has been studied for its various pharmacological effects, including its antibacterial, antitumor, antioxidant, and anti-inflammatory activities. In the present study, primary cultured vascular endothelial cells (HUVECs) and isolated phenylephrine-precontracted rat thoracic aortic rings were examined to investigate the possible mechanism of a butanol extract of Diyu (BSO) in its vascular relaxant effect. HUVECs treated with BSO produced a significantly higher amount of nitric oxide (NO) compared to the control. However, its production was inhibited by pretreatment with N^G-nitro-L-arginine methylester (L-NAME) or wortmannin. BSO also increased the phosphorylation levels of endothelial nitric oxide synthase (eNOS) and Akt. In the aortic ring, BSO relaxed PE-precontracted rat thoracic aortic rings in a concentration-dependent manner. The absence of the vascular endothelium significantly attenuated BSO-induced vasorelaxation. The non-selective NOS inhibitor, L-NAME, and the selective inhibitor of soluble guanylyl cyclase (sGC), 1H-[1,2,4]-oxadiazolo-[4,3-α]-quinoxalin-1-one (ODQ), dramatically inhibited the BSO-induced relaxation effect of the endothelium-intact aortic ring. Ca²⁺-free buffer and intracellular Ca²⁺ homeostasis regulators (TG, Gd³⁺, and 2–APB) inhibited BSO-induced vasorelaxation. In Ca²⁺-free Krebs solution, BSO markedly reduced PE-induced contraction. Vasodilation induced by BSO was significantly inhibited by wortmannin, an inhibitor of Akt. Pretreatment with the non-selective inhibitor of Ca²⁺-activated K⁺ channels (K_Ca), tetraethylammonium (TEA), significantly attenuated the BSO-induced vasorelaxant effect. Furthermore, BSO decreased the systolic blood pressure and heart rate in a concentration-dependent manner in rats. In conclusion, BSO induces vasorelaxation via endothelium-dependent signaling, primarily through the activation of the PI3K-Akt-eNOS-NO signaling pathway in endothelial cells, and the activation of the NO-sGC-cGMP-K⁺ channels pathway in vascular smooth muscle cells. Additionally, store-operated Ca²⁺ entry (SOCE)-eNOS pathways and the inhibition of Ca²⁺ mobilization from intracellular stores contribute to BSO-induced vasorelaxation. Full article

Arterial and venous graft spasm can occur during harvesting or immediately after coronary artery bypass grafting (CABG), leading to increased perioperative morbidity and affecting graft patency rates. Bypass grafts harvested from diabetic patients are particularly prone to spasm. This study aimed to elucidate the functional characteristics of human bypass grafts for the internal mammary artery (IMA) and saphenous vein (SV), from both diabetic and non-diabetic patients, and to determine how diabetes affected their responses to spasmogenic and relaxant agents. SV and IMA graft rings isolated from diabetic and non-diabetic patients during CABG were placed in an isolated organ bath system. Contractions to potassium chloride (10–100 mM) and phenylephrine (10⁻⁸–10⁻⁴ M) were evaluated, and relaxation responses to acetylcholine (10⁻⁹–10⁻⁴ M) and sodium nitroprusside (10⁻⁸–10⁻⁴ M) were assessed to evaluate endothelial and smooth muscle function, respectively. We observed increased responses to phenylephrine, an alpha-1 adrenoceptor agonist, in both IMAs and SVs, as well as an increased responses to potassium chloride, a non-receptor agonist, in SVs in diabetic patients compared to non-diabetic patients. We did not observe any deterioration in endothelium-dependent relaxations in either SV or IMA grafts under diabetic conditions. This study is the first to demonstrate that diabetes exacerbates potassium chloride-induced contractions in human SV grafts. Understanding the differences in potassium chloride-induced contraction profiles between arterial and venous grafts is essential in optimizing graft spasm management and improving the patency rates of bypass grafts. Full article

Background: Lower urinary tract symptoms (LUTS) due to prostate hyperplasia are the most frequent urological symptoms in elderly men. Current pharmacological treatments for LUTS and benign prostatic hyperplasia (BPH) are widely used in clinical practice; however, adverse effects associated with these drugs have been reported for sexual dysfunction and orthostatic hypotension. Prunella vulgaris (PV) is a medicinal herb that has a long history of use. This study aimed to address this gap by investigating the relaxant activity of PV extract (PVE) on rat prostate smooth muscle ex vivo and evaluating intravesical cystometry for its potential. Methods and Results: Ten male Sprague Dawley (SD) rats were used to study the relaxant efficacy of PVE and its constituents in isometric contraction ex vivo. Thirty-six SD rats were randomly assigned to six groups of six animals (n = 6) and administered testosterone propionate (TP; 3 mg/kg) daily for 4 weeks to induce BPH. Groups of BPH rats were treated with or without PVE (30, 60, or 90 mg/kg) via oral gavage. At the end of the experiments, the animals were subjected to intravesical pressure under urethane anesthesia. After successful cystometric recording, rats were euthanized with carbon dioxide. Prostate and bladder tissues were harvested and processed for histological and biochemical analysis. The results demonstrated that PVE exerted relaxant effects on prostatic smooth muscle in a concentration-dependent manner, mediated by nitric oxide and potassium channels, without antagonizing adrenergic receptors. Additionally, intravesical cystometry in SD rats treated with oral gavage of PVE for 4 weeks showed a significant improvement in voiding abnormalities. Conclusions: These findings suggest the potential of PV and its compounds as a therapeutic strategy to improve LUTS associated with BPH. Full article