Nitric Oxide Inhibition Research Articles

Inhibitory nitric oxide production and cytotoxic activities of phenolic compounds from Gnetum montanum Markgr

One new compound, styrene dimer-type listeanol-4-O-α-ʟ-rhamnopyranosyl-(1→4)-β-ᴅ-glucopyranoside (1), and four known compounds namely listeanol (2), isorhapotigenin (3), genetifolin E (4), gnetifolin K (5) were isolated from the methanolic extract from the aerial part of the Gnetum montanum Markgr. in Viet Nam. Their chemical structures were determined by modern spectroscopic methods (NMR and HR-ESI-MS) and comparison with those of published data. These compounds were evaluated for their anti-inflammatory and cytotoxic activities. Among them, compound 3 exhibited the NO inhibitory production on the RAW264.7 cell line, and inhibited the HepG2 cell line with respective IC50 values of 79.88 ± 5.51 (µg/mL) (L-NMMA 7.90 ± 0.63 µg/mL), and 63.48 ± 3.63 (µg/mL) (Ellipticine 0.40 ± 0.01 µg/mL).

Carboxymethylated Rhizoma alismatis polysaccharides reduces the risk of calcium oxalate stone formation by reducing cellular inflammation and oxidative stress.

This study aims to elucidate the mechanism and potential of Rhizoma alismatis polysaccharides (RAPs) in preventing oxidative damage to human renal proximal tubule epithelial cells. The experimental approach involved incubating HK-2 cells with 100nm calcium oxalate monohydrate for 24h to establish a cellular injury model. Protection was provided by RAPs with varying carboxyl group contents: 3.57%, 7.79%, 10.84%, and 15.33%. The safeguarding effect of RAPs was evaluated by analyzing relevant cellular biochemical indicators.Findings demonstrate that RAPs exhibit notable antioxidative properties. They effectively diminish the release of reactive oxygen species, lactate dehydrogenase, and malondialdehyde, a lipid oxidation byproduct. Moreover, RAPs enhance superoxide dismutase activity and mitochondrial membrane potential while attenuating the permeability of the mitochondrial permeability transition pore. Additionally, RAPs significantly reduce levels of inflammatory factors, including NLRP3, TNF-α, IL-6, and NO. This reduction corresponds to the inhibition of overproduced pro-inflammatory mediator nitric oxide and the caspase 3 enzyme, leading to a reduction in cellular apoptosis. RAPs also display the ability to suppress the expression of the HK-2 cell surface adhesion molecule CD44.The observed results collectively underscore the substantial anti-inflammatory and anti-apoptotic potential of all four RAPs. Moreover, their capacity to modulate the expression of cell surface adhesion molecules highlights their potential in inhibiting the formation of kidney stones. Notably, RAP3, boasting the highest carboxyl group content, emerges as the most potent agent in this regard.

Anti-Inflammatory and Antioxidant Properties of Crude Methanol Extracts from the Flowers and Peels of Khlong Seng Local Durian (Durio Zibethinus Murr.)

The agricultural byproduct, represented by durian peels during the season, needs to be converted into economic value within the local area. This study aimed to assess the pharmaceutical properties, specifically antioxidant and anti-inflammatory effects, of methanol extracts from both flowers and peels of the local durian in the district. Additionally, in vitro testing was conducted to evaluate the impact on cells and the inhibition of nitric oxide induced by LPS. Results indicated that the flowers’ extract exhibited a higher concentration of antioxidants compared to the peels. The FRAP assay, using Trolox and Fe(II) as standards, showed statistically significant differences (p-value < 0.05) with values of 427.40 ± 7.64 µmole TE/g extract and 3,568.47 ± 77.55 µmole Fe(II) equivalent/g extract, along with a DPPH scavenging of 85.19 % and an IC50 of 114.50 ± 7.27 µg/mL. Concerning the inhibition of LPS-induced nitric oxide content, the peels’ extract, excluding KS7, demonstrated a response. KS10 exhibited the highest statistically significant difference (p-value < 0.05) in inhibition at concentrations of 0.6, 0.8 and 10 µg/mL, while others showed inhibition at 1.0 µg/mL. The outcomes of this research suggest the potential to enhance the value of agricultural waste, contributing to both the development of durian agriculture and public health at the local level. HIGHLIGHTS Exploring the antioxidant and anti-inflammatory attributes of Khlong Seng Local durian peel and flower The flowers primarily exhibit antioxidant properties, while the peel demonstrates anti-inflammatory characteristics across all samples of durians aged between 50 - 60 years The discovery highlighted the potential of agricultural waste, showcasing its capacity to be transformed into alternative products, thereby enhancing income opportunities for local farmers GRAPHICAL ABSTRACT

Anti-inflammatory Effect of the Hydroethanolic Extract from Dacryodes kukachkana Leaves in Mice: Role of Macrophage Nitric Oxide

Aims: This study aimed to characterize and evaluate the effect of the hydroethanolic extract from D. kukachkana leaves (HEDkL) in mice models of acute inflammation and in isolated macrophages stimulated with carrageenan, along with possible adverse effects in the central nervous system. Study Design: After characterization of phenolic constituents, HEDkL was injected in the animals 60 min before the administration of inflammatory stimulis. The anti-inflammatory effect of HEDkL was evaluated in the models of paw edema, peritonitis and air pouch and in peritoneal macrophages stimulated with carrageenan in vitro. The per se effect of HEDkL was evaluated for behavioral alterations. Place and Duration of Study: Higher Institute of Biomedical Sciences and Animal Health Research Center, State University of Ceara; Physiopharmacology Laboratory, Federal University of Acre; between March 2021 and March 2023. Methodology: The characterization of phenolic compounds was performed by HPLC-DAD. Swiss mice (25 - 35 g) received HEDkL (25 - 200 mg/kg; per oral) 60 min before carrageenan. Macrophages were incubated with HEDkL (100 - 200 µg/mL) before being stimulated. The anti-inflammatory effect was assessed for edema, hypernociception, vascular permeability, leukocyte infiltrate, oxidative stress and inflammatory. Behavioral alterations (exploratory, anxiolytic, depressant activities) were evaluated in the animals treated with HEDkL (50 mg/kg). Results: The HPLC-DAD revealed the presence of ellagic acid, epicatechin and gallic acid. In the paw edema model, HEDkL (50 mg/kg) inhibited the edema late phase (2 - 5h) by 45% and the activity of the enzyme myeloperoxidase by 48%. In the peritonitis model, HEDkL (50 mg/kg) reduced leukocyte migration (45%), hypernociception (73%), total proteins (20%) and NO2-/NO3- (23%). In the air pouch model, HEDkL (50 mg/kg) reduced the migration of total leukocytes (76%) and neutrophils (88%). In vitro HEDkL (200 µg/mL) reduced by 31% the NO2-/NO3- in the supernatant of macrophages. HEDkL did not alter the animals exploratory, anxiolytic, or depressant behaviors. Conclusion: HEDkL containing flavonoids and phenols presents anti-inflammatory effect in vivo and in vitro involving nitric oxide inhibition, being devoid of behavioral alterations.

Discovery of structurally important cycloartane-type triterpenes from Dysoxylum binectariferum leaves and their anti-inflammatory activity

Seven undescribed cycloartane-type triterpenes (4–10) were isolated from the leaves of Dysoxylum binectariferum. The chemical structures and relative stereochemistry of all cycloartane triterpenes were determined by analysis of 1D and 2D NMR and ESI-HRMS spectroscopic data. Compound 4 was found to be a diastereoisomer of the previously discovered compound 2 (beddomeilactol). The compound 5 was identified as the methyl ester of compound 1 (beddomeilactone). The compounds 6 and 7 were found to be diastereoisomers with only a stereochemical change at C-4 and their absolute stereochemistry established by X-ray analysis. Compounds 6–8 and 10 were identified as 3,4-seco-cycloartane type triterpenes, while compound 9 was elucidated as nor-3,4-seco-cycloartane triterpene. Nitric oxide (NO) inhibition was used to assess the anti-inflammatory effects of all newly isolated natural products in LPS-induced RAW 264.7 cell line. It was found that compounds 1, 2, 6 and 8 showed good IC50 values of 14.98 ± 4.06, 38.50 ± 2.88, 36.95 ± 3.24, and 35.37 ± 4.51 µM respectively for NO production inhibition and were non-toxic to RAW 264.7 macrophages.

Exploring the therapeutic potential of pomegranate juice for uterine relaxation

ABSTRACT Background The effects of pomegranate juice (PJ) and its components on uterine smooth muscle are unknown. Hence, this study unequivocally demonstrates that pomegranate juice (PJ) significantly impacts myometrial function, providing crucial insights into its relaxant properties and their potential therapeutic applications for uterine-related disorders. Research design and methods Rat uterine smooth muscle horn strips were suspended in Krebs solution organ baths. Contractions were measured isometrically using a transducer (AD instrument Australia). The effects of PJ were evaluated on contractile activity elicited by potassium chloride (KCl 60 Mm) depolarization. Inhibitors of nitric oxide (L-NAME 3 X 10−4), guanylate cyclase (methylene blue 1 X 10−5), and Prostaglandin I2 (indomethacin 3 X 10−5), as well as Potassium Channels blockers, were determined. Results The juice at concentrations from 1.5–5 mg/ml significantly decreased the rat uterine horn contraction induced by KCl. The NO, cGMP, and PGI2 inhibitors did not block the relaxation response. Furthermore, the PGI2 inhibitor significantly enhanced the relaxation effects; K+ channel blockers had no inhibitory effects on the relaxation responses. Contrarily, GLIB improved considerably relaxation. Conclusion Research suggests pomegranate juice’s active ingredient may reduce uterine contractions and treat uterotonic disorders, potentially preventing preterm birth and dysmenorrhea. Further research is needed to determine its mechanism of action. Trial registration Code: AEC-013

In-vitro and In-vivo Studies of Anti-inflammatory Potential of Compounds Derived from Piper mullesua

The identification and development of new anti-inflammatory drugs continue to benefit greatly from the use of natural substances and their synthetic counterparts. Studies have been conducted on a compounds obtained from the Piper mullesua plant. The current work aims to use in-vitro and in-vivo experiments to investigate these substances’ anti-inflammatory properties. Our investigation’s findings showed that various substances had varying percentages of cell viability on RAW 264.7 cells. These substances were also tested for suppression of nitric oxide. Novel approaches to the creation of pharmaceuticals have demonstrated the potential of natural product derivatives. This study set out to investigate PM208-209’s potential anti-inflammatory properties. The impact of PM208-209 on inhibiting tumor necrosis factor-alpha (TNF-α) and IL-6 in LPS-induced RAW 264.7 cells was examined using enzyme-linked immunosorbent assay (ELISA). Additionally, PM208-209 demonstrated anti-inflammatory effects in mice, as evidenced by the suppression of vascular permeability and migration of leukocytes. The information gathered suggested that PM208-209 should be investigated further in terms of pharmacological research and could be regarded as a possible therapeutic anti-inflammatory option

Cyanide Insensitive Oxidase Confers Hydrogen Sulfide and Nitric Oxide Tolerance to Pseudomonas aeruginosa Aerobic Respiration.

Hydrogen sulfide (H2S) and nitric oxide (NO) are long-known inhibitors of terminal oxidases in the respiratory chain. Yet, they exert pivotal signaling roles in physiological processes, and in several bacterial pathogens have been reported to confer resistance against oxidative stress, host immune responses, and antibiotics. Pseudomonas aeruginosa, an opportunistic pathogen causing life-threatening infections that are difficult to eradicate, has a highly branched respiratory chain including four terminal oxidases of the haem-copper type (aa3, cbb3-1, cbb3-2, and bo3) and one oxidase of the bd-type (cyanide-insensitive oxidase, CIO). As Escherichia coli bd-type oxidases have been shown to be H2S-insensitive and to readily recover their activity from NO inhibition, here we tested the effect of H2S and NO on CIO by performing oxygraphic measurements on membrane preparations from P. aeruginosa PAO1 and isogenic mutants depleted of CIO only or all other terminal oxidases except CIO. We show that O2 consumption by CIO is unaltered even in the presence of high levels of H2S, and that CIO expression is enhanced and supports bacterial growth under such stressful conditions. In addition, we report that CIO is reversibly inhibited by NO, while activity recovery after NO exhaustion is full and fast, suggesting a protective role of CIO under NO stress conditions. As P. aeruginosa is exposed to H2S and NO during infection, the tolerance of CIO towards these stressors agrees with the proposed role of CIO in P. aeruginosa virulence.

Synergistic regulation of hydrogen sulfide and nitric oxide on biochemical components, exopolysaccharides, and nitrogen metabolism in nickel stressed rice field cyanobacteria.

The present study examined the regulatory mechanism of hydrogen sulfide (H2S) and nitric oxide (NO) in nickel (Ni) stressed cyanobacteria viz., Nostoc muscorum and Anabaena sp. by analyzing growth, photosynthetic pigments, biochemical components (protein and carbohydrate), exopolysaccharides (EPS), inorganic nitrogen content, and activity of enzymes comprised in nitrogen metabolism and Ni accumulation. The 1µM Ni substantially diminished growth by 18% and 22% in N. muscorum and Anabaena sp. respectively, along with declining the pigment contents (Chl a/Car ratio and phycobiliproteins), and biochemical components. It also exerted negative impacts on inorganic uptake of nitrate and nitrite contents; nitrate reductase and nitrite reductase; and ammonium assimilating enzymes (glutamine synthetase, glutamate synthase, and glutamate dehydrogenase exhibited a reverse trend) activities. Nonetheless, the adverse impact of Ni can be mitigated through the exogenous supplementation of NaHS [sodium hydrosulfide (8µM); H2S donor] and SNP [sodium nitroprusside (10µM); NO donor] which showed substantial improvement on growth, pigments, nitrogen metabolism, and EPS layer and noticeably occurred as a consequence of a substantial reduction in Ni accumulation content which minimized the toxicity effects. The accumulation of Ni on both the cyanobacterial cell surface (EPS layer) are confirmed by the SEM-EDX analysis. Further, the addition of NO scavenger (PTIO; 20µM) and inhibitor of NO (L-NAME; 100µM); and H2S scavenger (HT; 20µM) and H2S inhibitor (PAG; 50µM) reversed the positive responses of H2S and NO and damages were more prominent under Ni stress thereby, suggesting the downstream signaling of H2S on NO-mediated alleviation. Thus, this study concludes the crosstalk mechanism of H2S and NO in the mitigation of Ni-induced toxicity in rice field cyanobacteria.

The Roles of Potassium Channels and Nitric oxide in the Modulation of Apelin induced-relaxation in Isolated Diabetic Rat Aorta

Diabetes is associated with endothelial dysfunction, which impairs blood vesselscapacity to maintain vascular tone. Apelin is an adipocyte-produced relaxing factor that has endothelium-dependent and nitric oxide (NO)-mediated vasorelaxant effects. The current study investigated how streptozotocin (STZ)-induced type one diabetes modulates the mechanisms involved in aortic vascular response to apelin, focusing on the role of potassium channels and endothelial derived relaxing factors (EDRF). In this study, precontracted rat thoracic aortic segments were pre-incubated with the NO inhibitor, cyclooxygenase (COX) inhibitor and potassium channels blockers including: non-selective calcium-activated potassium channel, big conductance calcium-activated potassium channels (BKca), intermediate conductance calcium activated potassium channels (IKca), delayed inward rectifier potassium channels (Kir), adenosine triphosphates-sensitive potassium channels (KATP) and voltage sensitive potassium channels (Kv) blockers, then cumulative concentrations of apelin were applied to each group in both non-diabetic and diabetic conditions. The statistical analysis between diabetic and non-diabetic groups revealed that endothelial impairment induced by diabetes in rat thoracic aorta remarkably attenuated the vascular responses to apelin. An important new finding in this study was that almost all potassium channels blockers noticeably P<0.001 increased apelin efficacy with relatively no changes in the peptide potency. However, in diabetic aortic segments, the non-selective Kca, BKca blockers, NO inhibitor and COX inhibitor reversed vascular responses to apelin, but Kir, KATP and Kv blockers significantly reduced vascular responses to apelin in comparison to control rats. It is worth noting that diabetes did not only alter the peptide potency in these experimental groups but also significantly increased the maximum responses when Kca and BKca blockers preincubated. In conclusion, our findings shed light on the mechanisms behind diabetes-induced aortic artery hypo-reactivity to apelin which involve the inhibition of endothelial NO synthase activities and decreased contribution of Kca, BKca, IKca, Kv, Kir and KATP channels.

Ivermectin Exerts Anticonvulsant Effects Against Status Epilepticus Induced by Lithium-Pilocarpine in Rats via GABAA Receptor and Neuroinflammation Modulation: Possible Interaction of Opioidergic Pathways and KATP Channel with Nitrergic System.

Status epilepticus (SE) is a critical medical emergency marked by persistent or rapidly repeating seizures, posing a threat to life. Using the lithium-pilocarpine-induced SE model, we decide to evaluate the anti-seizure effects of ivermectin as a positive allosteric modulator of GABAA receptor and the underlying mechanisms involved. Lithium chloride was injected intraperitoneally at a dose of 127 mg/kg, followed by the administration of pilocarpine at a dose of 60 mg/kg after a 20-h interval in order to induce SE. Subsequently, the rats received varying amounts of ivermectin (0.3, 1, 3, 5, and 10 mg/kg, i.p.) 30 min before the onset of SE. To study the underlying molecular mechanisms, we had pharmacological interventions of diazepam (1 mg/kg), glibenclamide and nicorandil as ATP-sensitive potassium channel blocker and opener (both 1 mg/kg, i.p.), naltrexone and morphine, as opioid receptor antagonist and agonist (1 mg/kg and 0.5 mg/kg, i.p., respectively). In addition, three nitric oxide inhibitors, namely, L-NAME (10 mg/kg, i.p.), 7-NI (30 mg/kg, i.p.), and aminoguanidine (100 mg/kg, i.p.), were administered to the rats in the experiment. Finally, we use ELISA and western blotting, respectively, to examine the amounts of pro-inflammatory cytokines (TNF-α and IL-1β), nitrite, and GABAA receptors in the rat hippocampal tissue. The study found that ivermectin, at doses of 3, 5, and 10 mg/kg, exerts anti-seizure effects and decrease Racine's scale SE score. Interestingly glibenclamide and naltrexone reduced the anti-seizure effects of ivermectin, and from other hand diazepam, nicorandil, morphine, L-NAME, 7-NI, and aminoguanidine, enhance the effects when co-administrated with subeffective dose of ivermectin. Additionally, the study found that ivermectin decreased the elevated levels of TNF-α and IL-1β following SE, while increased the reduced expression of GABAA receptors. Overall, these findings suggest that ivermectin has anti-seizure effects in a SE seizure which may be mediated by the modulation of GABAergic, opioidergic, and nitrergic pathways and KATP channels.

Performance of nitric oxide in sepsis: a scoping review

Performance of nitric oxide in sepsis: a scoping review

Profiling the Phytochemicals of Orostachys margaritifolia: Biological Activities, LC-ESI/MS, and HPLC Analyses.

Orostachys margaritifolia Y. N. Lee (OMY) is an endemic Korean plant in the family Crassulaceae that is known to contain a variety of bioactive compounds. To assess the physiological activities of an OMY ethanol extract, ABTS+ and DPPH radical scavenging assays and a nitric oxide (NO) inhibition assay were conducted. The phytochemical makeup of the extract was profiled via liquid chromatography-mass spectrometry (LC-ESI/MS) and high-performance liquid chromatography with a photodiode array detector (HPLC/PDA). The OMY extract was found to have weaker ABTS+ and DPPH radical scavenging activities than the control group (green tea). In the NO inhibition assay, the OMY extract induced a significant increase in macrophage cell viability but showed a lower NO inhibitory activity than l-NAME, producing an IC50 value of 202.6 μg/mL. The LC-ESI/MS and HPLC/PDA analyses identified isoquercitrin and astragalin in the OMY extract, quantifying their contents at 3.74 mg/g and 3.19 mg/g, respectively. The study revealed possibilities for the utilization of OMY as a future source of drugs for alleviating inflammation and diseases related to reactive oxygen species.

Proximate composition, bioactive constituents, and therapeutic potentials of pasteurized Noni juice derived from <em>Morinda citrifolia</em> (L.) growing in Sri Lanka

Morinda citrifolia (L.), also known as Noni or Ahu in Sri Lanka, is infrequently consumed as a dietary supplement within the country due to its association with myths and perceived toxicity. Nonetheless, in Sri Lanka, limited scientific research has been undertaken in the past to explore the therapeutic potential of noni, with public awareness primarily focused on its exportdriven cultivation. The study focused on evaluating the proximate composition, bioactive constituents, and therapeutic potential of hydro-methanolic extracts from pasteurized noni fruit juice, employing an 80% methanol extraction method, filtration, and assessment through standard assays to elucidate its potentia health benefits. The juice showed noteworthy antioxidant potential through DPPH scavenging activity (57.90 ± 0.40 μg/mL) and ABTS scavenging activity (42.95 ± 1.33 μg/mL), as well as high nitric oxide inhibition activity (164.56 ± 3.22 μg/mL), suggesting its anti-inflammatory properties. The juice also displayed potential as an anti-diabetic agent by inhibiting alpha-amylase (27.68 ± 0.36 μg/mL) and alpha-glucosidase (25.67 ± 1.03 μg/mL). Furthermore, it exhibited potential in protecting against certain pathological processes through heat-induced hemolysis inhibition (36.08 ± 1.08 μg/mL), protein denaturation inhibition (56.14 ± 1.11 μg/mL), and proteinase inhibitory activity (38.04 ± 0.56 μg/mL). These findings support the potential use of pasteurized fruit juice as a functional food ingredient, offering benefits to both the food industry and consumers. Further research can be directed towards the development of Noni fruit-incorporated food products that possess desirable sensory attributes to mitigate any potential aversion associated with its taste and odor profiles.

Helicobacter pylori secretory Proteins-Induced oxidative stress and its role in NLRP3 inflammasome activation

Helicobacter pylori-associated stomach infection is a leading cause of gastric ulcer and related cancer. H. pylori modulates the functions of infiltrated immune cells to survive the killing by reactive oxygen and nitrogen species (ROS and RNS) produced by these cells. Uncontrolled immune responses further produce excess ROS and RNS which lead to mucosal damage. The persistent oxidative stress is a major cause of gastric cancer. H. pylori regulates nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs), nitric oxide synthase 2 (NOS2), and polyamines to control ROS and RNS release through lesser-known mechanisms. ROS and RNS produced by these pathways differentiate macrophages and T cells from protective to inflammatory phenotype. Pathogens-associated molecular patterns (PAMPs) induced ROS activates nuclear oligomerization domain (NOD), leucine rich repeats (LRR) and pyrin domain-containing protein 3 (NLRP3) inflammasome for the release of pro-inflammatory cytokines. This study evaluates the role of H. pylori secreted concentrated proteins (HPSCP) related oxidative stress role in NLRP3 inflammasome activation and macrophage differentiation. To perceive the role of ROS/RNS, THP-1 and AGS cells were treated with 10 μM diphenyleneiodonium (DPI), 50 μM salicyl hydroxamic acid (SHX), 5 μM Carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone (FCCP), which are specific inhibitors of NADPH oxidase (NOX), Myeloperoxidase (MPO), and mitochondrial oxidative phosphorylation respectively. Cells were also treated with 10 μM of NOS2 inhibitor l-NMMA and 10 μM of N-acetyl cysteine (NAC), a free radical scavenger·H2O2 (100 μM) treated and untreated cells were used as positive controls and negative control respectively. The expression of gp91phox (NOX2), NOS2, NLRP3, CD86 and CD163 was analyzed through fluorescent microscopy. THP-1 macrophages growth was unaffected whereas the gastric epithelial AGS cells proliferated in response to higher concentration of HPSCP. ROS and myeloperoxidase (MPO) level increased in THP-1 cells and nitric oxide (NO) and lipid peroxidation significantly decreased in AGS cells. gp91phox expression was unchanged, whereas NOS2 and NLRP3 downregulated in response to HPSCP, but increased after inhibition of NO, ROS and MPO in THP-1 cells. HPSCP upregulated the expression of M1 and M2 macrophage markers, CD86 and CD163 respectively, which was decreased after the inhibition of ROS.This study concludes that there are multiple pathways which are generating ROS during H. pylori infection which further regulates other cellular processes. NO is closely associated with MPO and inhibition of NLRP3 inflammasome. The low levels of NO and MPO regulates gastrointestinal tract homeostasis and overcomes the inflammatory response of NLRP3. The ROS also plays crucial role in macrophage polarization hence alter the immune responses duing H. pylori pathogenesis.

Anti-Inflammatory Properties of Oxygenated Isocoumarins and Xanthone from Thai Mangrove-Associated Endophytic Fungus Setosphaeria rostrata.

Chronic inflammation plays a crucial role in the development and progression of numerous chronic diseases. To search for anti-inflammatory metabolites from endophytic fungi isolated from plants growing in Thai mangrove areas, a chemical investigation of those fungi was performed. Five new oxygenated isocoumarins, setosphamarins A-E (1-5) were isolated from the EtOAc extract of an endophytic fungus Setosphaeria rostrata, along with four known isocoumarins and one xanthone. Their structures were determined by extensive spectroscopic analysis. The absolute configurations of the undescribed compounds were established by comparative analysis between experimental and calculated circular dichroism (ECD) spectroscopy. All the compounds were evaluated for their anti-inflammatory activity by monitoring nitric oxide inhibition in lipopolysaccharide-induced macrophage J774A.1 cells. Only a xanthone, ravenelin (9), showed potent activity, with an IC50 value of 6.27 μM, and detailed mechanistic study showed that it suppressed iNOS and COX-2 expression.

Vasorelaxant effects of ellagitannins isolated from Cuphea carthagenensis.

Cuphea carthagenensis (Jacq.) J. F. Macbr. is a popular plant in Brazilian folk medicine owing to its hypotensive and central nervous system depressant effects. This study aimed to validate the hypotensive effect of the plant's aqueous extract (AE) in rats and examine the vascular actions of three hydrolyzable tannins, oenothein B, woodfordin C, and eucalbanin B, isolated from AE. Systolic blood pressure in unanesthetized rats was determined using the non-invasive tail-cuff method. Oral treatment of normotensive rats with 0.5 and 1.0 g/kg/day AE induced a dose-related hypotensive effect after 1 week. In rat aortic rings pre-contracted with noradrenaline, all ellagitannins (20 - 180 µM) induced a concentration-related vasorelaxation. This effect was blocked by either removing the endothelium or pre-incubating with NG-nitro-l-arginine methyl ester (10 µM), an inhibitor of nitric oxide (NO) synthase. In KCl-depolarized rat portal vein preparations, the investigated compounds did not affect significantly the maximal contractile responses and pD2 values of the concentration-response curves to CaCl2. Our results demonstrated the hypotensive effect of C. carthagenensis AE in unanesthetized rats. All isolated ellagitannins induced vasorelaxation in vitro via activating NO synthesis/NO release from endothelial cells, without altering the Ca2+ influx in vascular smooth muscle preparations. Considering the low oral bioavailability of ellagitannins, the determined in vitro actions of these compounds are unlikely to account for the hypotensive effect of AE in vivo. It remains to be determined the role of the bioactive ellagitannin-derived metabolites in the hypotensive effect observed after oral treatment of unanesthetized rats with the plant extract.

Nitric Oxide Inhibitors from the Stem Bark of Biancaea decapetala: An In Vitro and In Silico Study

Nitric Oxide Inhibitors from the Stem Bark of Biancaea decapetala: An In Vitro and In Silico Study

Investigation of an aminothiazole-based scaffold as an anti-inflammatory agent: Potential application in the management of cytokine storm in SARS-CoV-19

Aminothiazole-based structures, including compounds like anakinra, nitazoxanide, amiphenazole, and tizoxanide, along with cytokine-blocking agents such as tocilizumab and siltuximab are currently under extensive investigation for their potential in managing severe COVID-19 by specifically targeting and inhibiting cytokines responsible for cytokine release syndrome (CRS). These targeted therapies have shown promising results in effectively mitigating the effects of severe COVID-19. Herein, we carried out a biological assessment of a novel aminothiazole-based derivative 5-(phenylthio)-4-(2-(trifluoromethyl) phenyl) thiazol-2-amine (X22) to gauge its potential as an anti-inflammatory agent. Utilizing in vitro assays, which included measuring nitric oxide (NO) inhibition and observing the production of LPS-induced pro-inflammatory cytokines (TNF-α and IL-6) in RAW 264.7 macrophages. Furthermore, the X22 was characterized by experimental FT-IR, NMR, and UV–visible spectral analysis. The optimized molecular geometry and vibrational wave numbers were calculated using the DFT and B3LYP/6–311++G (d,p) basis set. The vibrational assignments were calculated using VEDA's Potential Energy Distribution (PED) program. 1H and 13C NMR were calculated by the GIAO method. Additionally, compounds HOMO-LUMO and HF interactions were studied. Subsequently, the MEP map was traced to find the reactive sites of X22. In addition, Mulliken population analysis and thermodynamic properties with respect to various temperatures were also calculated. All the theoretical predictions were carried out by using the DFT-B3LYP method at the level of 6–311++G (d,p). Finally, the molecular docking interactions revealed that ligand (X22) binds to TNF-α and IL-6 via H-bonding with amino acids Tyr 151, Ser60, Gln61, and Arg179. These findings suggest that X22 could be a valuable therapeutic agent for mitigating the progression of severe SARS-CoV-2 infections.

Anti-Inflammatory Flavonoids from Agrimonia pilosa Ledeb: Focusing on Activity-Guided Isolation.

To elucidate the anti-inflammatory properties and constituents of Agrimonia pilosa Ledeb. (A. pilosa), a comprehensive investigation was conducted employing activity-guided isolation. The anti-inflammatory effects were evaluated through an in vitro nitric oxide (NO) assay on lipopolysaccharide (LPS)-treated RAW 264.7 macrophage cells. Seven bio-active compounds with anti-inflammatory properties were successfully isolated from the butanol fraction and identified as follows: quercetin-7-O-β-d-rhamnoside (1), apigenin-7-O-β-d-glucopyranoside (2), kaempferol-7-O-β-d-glucopyranoside (3), quercetin (4), kaempferol (5), apigenin (6), and apigenin-7-O-β-d-glucuronide-6″-butylester (7). All isolated compounds showed strong NO inhibitory activity with IC50 values ranging from 1.4 to 31 µM. Compound 6 demonstrated the most potent NO inhibition. Compound 7, a rare flavonoid, was discerned as a novel anti-inflammatory agent, ascertained through its inaugural demonstration of nitric oxide inhibition. Subsequently, a comprehensive structure-activity relationship (SAR) analysis was conducted employing eight flavonoids derived from A. pilosa. The outcomes elucidated that flavones exhibit superior NO inhibitory effects compared to flavonols, and the aglycone form manifests greater potency in NO inhibition than the glycone counterpart. These results highlight A. pilosa as a promising source of effective anti-inflammatory agents and indicate its potential as a health-beneficial dietary supplement and therapeutic material.