Search Results (410)

Fluorescent markers play important roles in spectroscopic and microscopic research techniques and are broadly used in basic and applied sciences. We have obtained markers with fluorescent properties, two etheno derivatives of 2-aminopurine, as follows: 1,N²-etheno-2-aminopurine (1,N²-ε2APu, I) and N²,3-etheno-2-aminopurine (N²,3-ε2APu, II). In the present paper, we investigate their interaction with two key enzymes of purine metabolism, purine nucleoside phosphorylase (PNP), and xanthine oxidase (XO), using diffraction of X-rays on protein crystals, isothermal titration calorimetry, and fluorescence spectroscopy. Crystals were obtained and structures were solved for WT PNP and D204N-PNP mutant in a complex with N²,3-ε2APu (II). In the case of WT PNP—1,N²-ε2APu (I) complex, the electron density corresponding to the ligand could not be identified in the active site. Small electron density bobbles may indicate that the ligand binds to the active site of a small number of molecules. On the basis of spectroscopic studies in solution, we found that, in contrast to PNP, 1,N²-ε2APu (I) is the ligand with better affinity to XO. Enzymatic oxidation of (I) leads to a marked increase in fluorescence near 400 nm. Hence, we have developed a new method to determine XO activity in biological material, particularly suitable for milk analysis. Full article

Chaenomeles speciosa (Sweet) Nakai (C. speciosa) is a traditional Chinese herbal medicine that possesses not only abundant nutritional value but also significant medicinal properties. The extracts of C. speciosa fruits effectively reduce urate levels, but the specific chemical constituents responsible for this effect in C. speciosa fruits are still unknown. Therefore, this study aims to investigate and analyze the structure–activity relationships of these constituents to better understand their ability to lower uric acid. Activity-guided fractionation and purification processes were used to isolate compounds with xanthine oxidase (XO) inhibitory activity from C. speciosa fruits, resulting in three extracts: petroleum ether, ethyl acetate, and n-butanol. The ethyl acetate and n-butanol fractions showed strong activity and underwent further separation and purification using chromatographic techniques. Twenty-four compounds were isolated and identified, with nine showing potent activity, including chlorogenic acid, methyl chlorogenate, butyl chlorogenate, ethyl chlorogenate, cryptochlorogenic acid methyl ester, caffeic acid, p-coumaric acid, benzoic acid and protocatechuic acid. The docking analysis showed that these compounds interacted with amino acid residues in the active site of XO through hydrogen bonding and hydrophobic interactions. These findings suggest that these compounds help reduce uric acid in C. speciosa, supporting further investigation into their mechanism of action. Full article

Anthocyanins, typical polyphenol compounds in grape skin, have attracted increasing interest due to their health-promoting properties. In this body of work, five representative anthocyanins (Cy-3-O-glc, Dp-3-O-glc, Pn-3-O-glc, Mv-3-O-glc, and Pt-3-O-glc) were studied using the density functional theory (DFT) to elucidate structure–radical scavenging activity in the relationship and the reaction path underlying the radical-trapping process. Based on thermodynamic parameters involved in HAT, SET-PT, and SPLET mechanisms, along with the structural attributes, it was found that the C4′ hydroxyl group mainly contributes to the radical scavenging activities of the investigated compounds. Pt-3-O-glc exhibits a good antioxidant capacity among the five compounds. The preferred radical scavenging mechanisms vary in different phases. For the Pt-3-O-glc compound, the calculations indicate the thermodynamically favoured product is benzodioxole, rather than o-quinone, displaying considerably reduced energy in double HAT mechanisms. Additionally, the thermodynamic and kinetic calculations indicate that the reaction of ^•OH into the 4′-OH site of Pt-3-O-glc has a lower energy barrier (7.6 kcal/mol), a higher rate constant (5.72 × 10⁹ M⁻¹ s⁻¹), and exhibits potent ^•OH radical scavenging properties. Molecular docking results have shown the strong affinity of the studied anthocyanins with the pro-oxidant enzyme xanthine oxidase, displaying their significant role in inhibiting ROS formation. Full article

Terpenes are plant secondary metabolites known for their anti-inflammatory and antioxidant activities. According to ethnobotanical knowledge, Rhododendron luteum Sweet was used in traditional medicine against inflammation. The present study was conducted to determine the triterpene profile and antioxidant and anti-inflammatory activity of supercritical CO₂ (SC-CO₂) extracts of Rhododendron luteum Sweet flower (RLF). An LC-APCI-MS/MS analysis showed the presence of eight pentacyclic triterpenes and one phytosterol in the extracts obtained with pure CO₂ as well as CO₂ with the addition of aqueous ethanol as a co-solvent. Among the compounds detected, oleanolic/ursolic acid, β-sitosterol and 3β-taraxerol were the most abundant. The extract obtained with pure SC-CO₂ was additionally subjected to HS-SPME-GC-FID-MS, which revealed more than 100 volatiles, mainly eugenol, β-phenylethanol, dodecane, β-caryophyllene, estragole and (Z)- and (E)-cinnamyl alcohol, followed by δ-cadinene. The extracts demonstrated significant hyaluronidase inhibition and exhibited varying modes of lipoxygenase and xanthine oxidase inhibitory activities. The studies of RLF have shown that their SC-CO₂ extracts can be a rich source of triterpenes with anti-inflammatory potential. Full article

Xanthine oxidase (XOD) is a key enzyme that promotes the oxidation of xanthine/hypoxanthine to form uric acid, and the accumulation of uric acid leads to hyperuricaemia. The prevalence of gout caused by hyperuricaemia is increasing year by year. TAOZHI (TZ) can be used for the treatment of rheumatic arthralgia due to qi stagnation and blood stasis and contains a large number of polyphenolic components. The aim of this study was to investigate the relationship between chromatograms and XOD inhibition of 21 batches of TZ total polyphenol extract samples. Chemometric methods such as grey correlation analysis, bivariate correlation analysis, and partial least squares regression were used to identify the active ingredient groups in the total polyphenol extracts of TZ, which were validated using molecular docking techniques. The total polyphenol content contained in the 21 batches did not differ significantly, and all batches showed inhibitory effects on XOD. Spectroeffect correlation analysis showed that the inhibitory effect of TZ on XOD activity was the result of the synergistic effect of multiple components, and the active component groups screened to inhibit XOD were F2 (4-O-Caffeoylquinic acid), F4, and F10 (naringenin). The molecular docking results showed that the binding energies of all nine dockings were lower than −7.5 kcal/mol, and the binding modes included hydrogen bonding, hydrophobic forces, salt bridges, and π-staking, and the small molecules might exert their pharmacological effects by binding to XOD through the residue sites of the amino acids, such as threonine, arginine, and leucine. This study provides some theoretical basis for the development and utilisation of TZ total polyphenols. Full article

Electrogenerated hydrophilic carbon (EHC) nanomaterials emerge as a highly attractive option for mimicking the activity of the superoxide dismutase enzyme (SOD) due to their exceptional water solubility and electron-transfer reversibility. Motivated by these properties, the EHC nanomaterials were utilized to assess the effect of ionic strength on the SOD-like activity. Superoxide anion radicals (O₂^•−) were generated using the hypoxanthine–xanthine oxidase system, with nitro blue tetrazolium chloride serving as the detecting system. A significant boost in the SOD-like activity was found via the addition of an electrolyte to the as-prepared nanomaterial solution. The effect of the electrolyte cation (Na⁺ and K⁺), as well as its counterion (Cl⁻, CH₃COO⁻, and H₂PO₄⁻/HPO₄²⁻) were analyzed. Based on these studies, a new formulation for the preparation of the carbon-based nanomaterial was established. It was demonstrated that the SOD-like activity follows an enzyme-type catalytic activity rather than the stoichiometric scavenging of the superoxide anion radical. It was concluded that 12.71 µg/mL of the EHC nanomaterial exhibits catalytic activity comparable to 15.46 µg/mL of the native Cu/Zn-SOD enzyme. This study provides a starting point for the development of a new nanotool to fight the oxidative stress associated with pathophysiological conditions where SOD activity is depleted. Full article

Erectile dysfunction (ED) is a prevalent condition affecting men’s sexual health, with oxidative stress (OS) having recently been identified as a significant contributing causative factor. This narrative review aims to elucidate the role of OS in the pathophysiology of ED, focusing on impact, mechanisms, and potential therapeutic interventions. Key findings indicate that OS disrupts endothelial function and nitric oxide (NO) signaling, crucial for erectile function. Various sources of reactive oxygen species (ROS) and their detrimental effects on penile tissue are discussed, including aging, diabetes mellitus, hypertension, hyperlipidemia, smoking, obesity, alcohol consumption, psychological stress, hyperhomocysteinemia, chronic kidney disease, and sickle cell disease. Major sources of ROS, such as NADPH oxidase, xanthine oxidase, uncoupled endothelial NO synthase (eNOS), and mitochondrial electron transport, are identified. NO is scavenged by these ROS, leading to endothelial dysfunction characterized by reduced NO availability, impaired vasodilation, increased vascular tone, and inflammation. This ultimately results in ED due to decreased blood flow to penile tissue and the inability to achieve or maintain an erection. Furthermore, ROS impact the transmission of nitrergic neurotransmitters by causing the death of nitrergic neurons and reducing the signaling of neuronal NO synthase (nNOS), exacerbating ED. Therapeutic approaches targeting OS, including antioxidants and lifestyle modifications, show promise in ameliorating ED symptoms. The review underscores the need for further research to develop effective treatments, emphasizing the interplay between OS and vascular health in ED. Integrating pharmacological and non-pharmacological strategies could enhance clinical outcomes for ED patients, advocating for OS management in ED treatment protocols to improve patient quality of life. Full article

Plantaginis semen is the dried ripe seed of Plantago asiatica L. or Plantago depressa Willd., which has a long history in alleviating hyperuricemia (HUA) and chronic kidney diseases. While the major chemical ingredients and mechanism remained to be illustrated. Therefore, this work aimed to elucidate the chemicals and working mechanisms of PS for HUA. UPLC-QE-Orbitrap-MS was applied to identify the main components of PS in vitro and in vivo. RNA sequencing (RNA-seq) was conducted to explore the gene expression profile, and the genes involved were further confirmed by real-time quantitative PCR (RT-qPCR). A total of 39 components were identified from PS, and 13 of them were detected in the rat serum after treating the rat with PS. The kidney tissue injury and serum uric acid (UA), xanthine oxidase (XOD), and cytokine levels were reversed by PS. Meanwhile, renal urate anion transporter 1 (Urat1) and glucose transporter 9 (Glut9) levels were reversed with PS treatment. RNA-seq analysis showed that the PPAR signaling pathway; glycine, serine, and threonine metabolism signaling pathway; and fatty acid metabolism signaling pathway were significantly modified by PS treatment. Further, the gene expression of Slc7a8, Pck1, Mgll, and Bhmt were significantly elevated, and Fkbp5 was downregulated, consistent with RNA-seq results. The PPAR signaling pathway involved Pparα, Pparγ, Lpl, Plin5, Atgl, and Hsl were elevated by PS treatment. URAT1 and PPARα proteins levels were confirmed by Western blotting. In conclusion, this study elucidates the chemical profile and working mechanisms of PS for prevention and therapy of HUA and provides a promising traditional Chinese medicine agency for HUA prophylaxis. Full article

Fabiana punensis S. C. Arroyo is a subshrub or shrub that is indigenous to the arid and semiarid region of northern Argentina and is known to possess several medicinal properties. The objective of this study was to optimize the extraction conditions so as to maximize the yield of bioactive total phenolic compound (TPC) and flavonoids (F) of F. punensis’ aerial parts by using non-conventional extraction methods, namely ultrasound-assisted extraction, UAE, and microwave-assisted extraction, MAE, and to compare the biological activities and toxicity of optimized extracts vs. conventional extracts, i.e., those gained by maceration. Response Surface Methodology (RSM) was used to apply factorial designs to optimize the parameters of extraction: solid-to-liquid ratio, extraction time, ultrasound amplitude, and microwave power. The experimental values for TPC and F and antioxidant activity under the optimal extraction conditions were not significantly different from the predicted values, demonstrating the accuracy of the mathematical models. Similar HPLC-DAD patterns were found between conventional and UAE- and MAE-optimized extracts. The main constituents of the extracts correspond to phenolic compounds (flavonoids and phenolic acids) and apigenin was identified. All extracts showed high scavenger capacity on ABTS^•+, O₂^•− and H₂O₂, enabling the inhibition of the pro-inflammatory enzymes xanthine oxidase (XO) and lipoxygenase (LOX). They also showed an antimutagenic effect in Salmonella Typhimurium assay and cytotoxic/anti-proliferative activity on human melanoma cells (SKMEL-28). Toxicological evaluation indicates its safety. The results of this work are important in the development of efficient and sustainable methods for obtaining bioactive compounds from F. punensis for the prevention of chronic degenerative diseases associated with oxidative stress, inflammation, and DNA damage. Full article

Hyperuricemia (HUA), or elevated uric acid in the blood, has become more prevalent in recent years. Polyphenols, which are known to have good inhibitory activity on xanthine oxidoreductase (XOR), are effective in uric acid reduction. In this review, we address the structure–activity relationship of flavonoids that inhibit XOR activity from two perspectives: the key residues of XOR and the structural properties of flavonoids. Flavonoids’ inhibitory effect is enhanced by their hydroxyl, methoxy, and planar structures, whereas glycosylation dramatically reduces their activity. The flavonoid structure–activity relationship informed subsequent discussions of the changes that occur in polyphenols’ XOR inhibitory activity during their extraction, processing, gastrointestinal digestion, absorption, and interactions. Furthermore, gastrointestinal digestion and heat treatment during processing can boost the inhibition of XOR. Polyphenols with comparable structures may have a synergistic effect, and their synergy with allopurinol thus provides a promising future research direction. Full article

Edible flowers are a potential source of bioactive ingredients and are also an area of scientific research. Particularly noteworthy are Cyani flos, which have a wide range of uses in herbal medicine. The below study aimed to investigate the influence of selected soluble fiber fractions on the selected properties of physical and biochemical powders obtained during spray drying a water extract of Cyani flos. The drying efficiency for the obtained powders was over 60%. The obtained powders were characterized by low moisture content (≤4.99%) and water activity (≤0.22). The increase in the addition of pectin by the amount of 2–8% in the wall material resulted in a decrease in hygroscopicity, water solubility, and protection of flavonoids and anthocyanins both before and after digestion in the tested powders in comparison to the sample with only inulin as a carrier. Additionally, it was noted that all samples were characterized by high bioaccessibility when determining antioxidant properties and xanthine oxidase inhibition. Full article

Molybdenum (Mo) is an essential element for human life, acting as a cofactor in various enzymes crucial for metabolic homeostasis. This review provides a comprehensive insight into the latest advances in research on molybdenum-containing enzymes and their clinical significance. One of these enzymes is xanthine oxidase (XO), which plays a pivotal role in purine catabolism, generating reactive oxygen species (ROS) capable of inducing oxidative stress and subsequent organ dysfunction. Elevated XO activity is associated with liver pathologies such as non-alcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC). Aldehyde oxidases (AOs) are also molybdenum-containing enzymes that, similar to XO, participate in drug metabolism, with notable roles in the oxidation of various substrates. However, beneath its apparent efficacy, AOs’ inhibition may impact drug effectiveness and contribute to liver damage induced by hepatotoxins. Another notable molybdenum-enzyme is sulfite oxidase (SOX), which catalyzes the conversion of sulfite to sulfate, crucial for the degradation of sulfur-containing amino acids. Recent research highlights SOX’s potential as a diagnostic marker for HCC, offering promising sensitivity and specificity in distinguishing cancerous lesions. The newest member of molybdenum-containing enzymes is mitochondrial amidoxime-reducing component (mARC), involved in drug metabolism and detoxification reactions. Emerging evidence suggests its involvement in liver pathologies such as HCC and NAFLD, indicating its potential as a therapeutic target. Overall, understanding the roles of molybdenum-containing enzymes in human physiology and disease pathology is essential for advancing diagnostic and therapeutic strategies for various health conditions, particularly those related to liver dysfunction. Further research into the molecular mechanisms underlying these enzymes’ functions could lead to novel treatments and improved patient outcomes. Full article

Although patients with hyperuricemia and gout often have dyslipidemia, the effects of febuxostat, a xanthine oxidase inhibitor, on their lipid profiles are unclear. Thus, we performed a sub-analysis of the randomized PRIZE study in which the effects of febuxostat on carotid atherosclerosis were investigated in patients with hyperuricemia. The participants were randomized to the febuxostat or control group. The primary endpoint of this sub-analysis was changes in the patients’ non-high-density lipoprotein cholesterol (HDL-C) levels from baseline to 6-month follow-up. Correlations between the changes in lipid profiles and cardiometabolic parameters were also evaluated. In total, 456 patients were included. From baseline to 6 months, non-HDL-C levels were significantly reduced in the febuxostat group (−5.9 mg/dL, 95% confidence interval [CI]: −9.1 to −2.8 mg/dL, p < 0.001), but not in the control group (−1.3 mg/dL, 95% CI: −4.4 to 1.8, p = 0.348). The reduction in non-HDL-C levels was more pronounced in women and correlated with changes in serum uric acid and estimated glomerular filtration rate levels only in the febuxostat group. In patients with hyperuricemia, febuxostat treatment was associated with reduced non-HDL-C levels from baseline to the 6-month follow-up compared to the control treatment, suggesting that the lipid-lowering effect of febuxostat should be considered when targeting dyslipidemia. Full article

There is a growing interest in the discovery of novel xanthine oxidase inhibitors for gout prevention and treatment with fewer side effects. This study aimed to identify the xanthine oxidase (XO) inhibitory potential and drug-likeness of the metabolites present in the methanolic leaf extract of Anastatica (A.) hierochuntica L. using in vitro and in silico models. The extract-derived metabolites were identified by liquid-chromatography–quadrupole-time-of-flight-mass-spectrometry (LC-QTOF-MS). Molecular docking predicted the XO inhibitory activity of the identified metabolites and validated the best scored in vitro XO inhibitory activities for experimental verification, as well as predictions of their anticancer, pharmacokinetic, and toxic properties; oral bioavailability; and endocrine disruption using SwissADMET, PASS, ProTox-II, and Endocrine Disruptome web servers. A total of 12 metabolites, with a majority of flavonoids, were identified. Rutin, quercetin, and luteolin flavonoids demonstrated the highest ranked docking scores of −12.39, −11.15, and −10.43, respectively, while the half-maximal inhibitory concentration (IC₅₀) values of these metabolites against XO activity were 11.35 µM, 11.1 µM, and 21.58 µM, respectively. In addition, SwissADMET generated data related to the physicochemical properties and drug-likeness of the metabolites. Similarly, the PASS, ProTox-II, and Endocrine Disruptome prediction models stated the safe and potential use of these natural compounds. However, in vivo studies are necessary to support the development of the prominent and promising therapeutic use of A. hierochuntica methanolic-leaf-extract-derived metabolites as XO inhibitors for the prevention and treatment of hyperuricemic and gout patients. Furthermore, the predicted findings of the present study open a new paradigm for these extract-derived metabolites by revealing novel oncogenic targets for the potential treatment of human malignancies. Full article

Cordyceps militaris, well known for its therapeutic potential in managing type-2 diabetes through the inhibition of α-amylase and α-glucosidase enzymes, was the central focus of this research, which investigated the influence of various cultivation substrates on its enzymatic inhibitory properties and bioactive compound content. Previous studies have primarily focused on the general pharmacological benefits of C. militaris but have not thoroughly explored how different substrates affect its bioactive profile and enzyme inhibitory activities. This study aimed to evaluate the impact of substrate selection on the enzyme inhibition activities and the levels of bioactive compounds such as cordycepin and adenosine in C. militaris, demonstrating that substrate selection markedly affects both these enzymes’ inhibition activities and bioactive compound levels. Particularly, C. militaris fruiting bodies grown on Brihaspa atrostigmella showed the highest concentrations of cordycepin (2.932 mg/g) and adenosine (1.062 mg/g). This substrate also exhibited the most potent α-glucosidase inhibition with an IC₅₀ value of 336.4 ± 16.0 µg/mL and the most effective α-amylase inhibition with an IC₅₀ value of 504.6 ± 4.2 µg/mL. Conversely, C. militaris cultivated on the solid residues of Gryllus bimaculatus displayed the strongest xanthine oxidase (XOD) inhibition, with the lowest IC₅₀ value of 415.7 ± 11.2 µg/mL. These findings highlight the critical role of substrate choice in enhancing the medicinal properties of C. militaris, suggesting that optimized cultivation can enhance the bioactive properties for more effective natural therapies for diabetes and other metabolic disorders. This study not only extends the understanding of C. militaris’ pharmacological potential but also illustrates its applicability in developing customized treatment options. Full article