Exploring Asphodelus microcarpus as a source of xanthine oxidase inhibitors: Insights from in silico and in vitro studies.

Xanthine oxidase (XO) plays a critical role in purine catabolism, catalyzing the conversion of hypoxanthine to xanthine and xanthine to uric acid, contributing to superoxide anion production. This process is implicated in various human diseases, particularly gout. Traditional XO inhibitors, such as allopurinol and febuxostat, while effective, may present side effects. Our study focuses on Asphodelus microcarpus, a plant renowned for traditional anti-inflammatory uses. Recent investigations into its phenolic-rich flowers, notably abundant in luteolin derivatives, reveal its potential as a natural source of XO inhibitors. In the present research, XO inhibition by an ethanolic flowers extract from A. microcarpus is reported. In silico docking studies have highlighted luteolin derivatives as potential XO inhibitors, and molecular dynamics support that luteolin 7-O-glucoside has the highest binding stability compared to other compounds and controls. In vitro studies confirm that luteolin 7-O-glucoside inhibits XO more effectively than the standard inhibitor allopurinol, with an IC50 value of 4.8 µg/mL compared to 11.5 µg/mL, respectively. These findings underscore the potential therapeutic significance of A. microcarpus in managing conditions related to XO activity. The research contributes valuable insights into the health-promoting properties of A. microcarpus and its potential application in natural medicine, presenting a promising avenue for further exploration in disease management.

Phytochemical Composition and Biological Activity.

Phytochemicals are bioactive plant compounds that provide humans with health benefits, representing a valuable source of novel bioactive molecules [...].

Design of 3-Phenylcoumarins and 3-Thienylcoumarins as Potent Xanthine Oxidase Inhibitors: Synthesis, Biological Evaluation, and Docking Studies.

Coumarin scaffold has proven to be promising in the development of bioactive agents, such as xanthine oxidase (XO) inhibitors. Novel hydroxylated 3-arylcoumarins were designed, synthesized, and evaluated for their XO inhibition and antioxidant properties. 3-(3'-Bromophenyl)-5,7-dihydroxycoumarin (compound 11) proved to be the most potent XO inhibitor, with an IC50 of 91 nM, being 162 times better than allopurinol, one of the reference controls. Kinetic analysis of compound 11 and compound 5 [3-(4'-bromothien-2'-yl)-5,7-dihydroxycoumarin], the second-best compound within the series (IC50 of 280 nM), has been performed, and both compounds showed a mixed-type inhibition. Both compounds present good antioxidant activity (ability to scavenge ABTS radical) and are able to reduce reactive oxygen species (ROS) levels in H2 O2 -treated cells. In addition, they proved to be non-cytotoxic in a Caco-2 cells viability assay. Molecular docking studies have been carried out to correlate the compounds' theoretical and experimental binding affinity to the XO binding pocket.

Promising inhibition of diabetes-related enzymes and antioxidant properties of Ptilostemon casabonae leaves extract.

Type 2 diabetes (T2D) is a progressive metabolic disorder of glucose metabolism. One of the therapeutic approaches for the treatment of T2D is reducing postprandial hyperglycaemia through inhibition of the digestive enzymes α-glucosidase and α-amylase. In this context, aimed at identifying natural products endowed with anti-T2D potential, we focused on Ptilostemon casabonae (L.) Greuter, a species belonging to Asteraceae family. Enzymatic inhibition, antioxidant activity, phenolic composition and cellular assays were performed. This study revealed that the P. casabonae hydroalcoholic extract exerts a potent inhibitory activity against α-glucosidase. This activity is supported by an antioxidant effect, preventing ROS formation in a stressed cellular system. HPLC-PDA-MS/MS analysis, revealed a complex polyphenolic fraction. Among the tested pure compounds, 1,5-dicaffeoylquinic acid, apigenin and rutin displayed good α-glucosidase inhibitory activity. Our study suggested new potential of P. casabonae encouraging us to further testing the possible therapeutic potential of this extract.

Inhibitory Effect of Quercetin on Oxidative Endogen Enzymes: A Focus on Putative Binding Modes.

Oxidative stress is defined as an imbalance between the production of free radicals and reactive oxygen species (ROS) and the ability of the body to neutralize them by anti-oxidant defense systems. Cells can produce ROS during physiological processes, but excessive ROS can lead to non-specific and irreversible damage to biological molecules, such as DNA, lipids, and proteins. Mitochondria mainly produce endogenous ROS during both physiological and pathological conditions. Enzymes like nicotinamide adenine dinucleotide phosphate oxidase (NOX), xanthine oxidase (XO), lipoxygenase (LOX), myeloperoxidase (MPO), and monoamine oxidase (MAO) contribute to this process. The body has enzymatic and non-enzymatic defense systems to neutralize ROS. The intake of bioactive phenols, like quercetin (Que), can protect against pro-oxidative damage by quenching ROS through a non-enzymatic system. In this study, we evaluate the ability of Que to target endogenous oxidant enzymes involved in ROS production and explore the mechanisms of action underlying its anti-oxidant properties. Que can act as a free radical scavenger by donating electrons through the negative charges in its phenolic and ketone groups. Additionally, it can effectively inhibit the activity of several endogenous oxidative enzymes by binding them with high affinity and specificity. Que had the best molecular docking results with XO, followed by MAO-A, 5-LOX, NOX, and MPO. Que's binding to these enzymes was confirmed by subsequent molecular dynamics, revealing different stability phases depending on the enzyme bound. The 500 ns simulation showed a net evolution of binding for NOX and MPO. These findings suggest that Que has potential as a natural therapy for diseases related to oxidative stress.

Comparison of Different Green Extraction Techniques Used for the Extraction of Targeted Flavonoids from Edible Feijoa (Acca sellowiana (O.Berg) Burret) Flowers.

This study aimed to investigate the effect of four green extraction techniques (ultrasound-assisted extraction, UAE; supercritical fluid extraction, SFE; subcritical water extraction, SWE; and extraction using deep eutectic solvents, DES) on the extraction of targeted flavonoids from edible feijoa flowers. The bioactive components in the obtained extracts were quantified by High-Performance Liquid Chromatography-Photodiode Array Detector (HPLC-PDA). Moreover, total polyphenol content and antioxidant activity by DPPH•, ABTS•+, FRAP, and CUPRAC assays were investigated. UAE generally gave the highest yields for isoquercitrin and quercetin content (18.36-25.33 and 10.86-16.13 µg/g), while DES extraction with choline chloride:lactic acid (1:2) and H2O content of 50% gave the highest yield of chrysanthemin (90.81 µg/g). The highest yield of flavone (12.69 mg/g) was obtained with supercritical CO2 at 300 bar. Finally, UAE gave the highest total polyphenol content (ca. 64 mg GAE/g) and antioxidant activity at 70 °C during 30 min with 40% (0.84 mmol TEAC/g and 2.25 mmol Fe2+/g, for ABTS•+ and CUPRAC, respectively) and 60% ethanol-water solution (0.49 mmol TEAC/g and 2.09 mmol Fe2+/g, for DPPH• and FRAP, respectively). The eco-friendly extraction techniques resulted in selective methods capable of extracting targeted bioactive compounds from edible feijoa flowers.

Template Entrance Channel as Possible Allosteric Inhibition and Resistance Site for Quinolines Tricyclic Derivatives in RNA Dependent RNA Polymerase of Bovine Viral Diarrhea Virus.

The development of potent non-nucleoside inhibitors (NNIs) could be an alternate strategy to combating infectious bovine viral diarrhea virus (BVDV), other than the traditional vaccination. RNA-dependent RNA polymerase (RdRp) is an essential enzyme for viral replication; therefore, it is one of the primary targets for countermeasures against infectious diseases. The reported NNIs, belonging to the classes of quinolines (2h: imidazo[4,5-g]quinolines and 5m: pyrido[2,3-g] quinoxalines), displayed activity in cell-based and enzyme-based assays. Nevertheless, the RdRp binding site and microscopic mechanistic action are still elusive, and can be explored at a molecular level. Here, we employed a varied computational arsenal, including conventional and accelerated methods, to identify quinoline compounds' most likely binding sites. Our study revealed A392 and I261 as the mutations that can render RdRp resistant against quinoline compounds. In particular, for ligand 2h, mutation of A392E is the most probable mutation. The loop L1 and linker of the fingertip is recognized as a pivotal structural determinant for the stability and escape of quinoline compounds. Overall, this work demonstrates that the quinoline inhibitors bind at the template entrance channel, which is governed by conformational dynamics of interactions with loops and linker residues, and reveals structural and mechanistic insights into inhibition phenomena, for the discovery of improved antivirals.

Hydroxylated Coumarin-Based Thiosemicarbazones as Dual Antityrosinase and Antioxidant Agents.

The design of novel antityrosinase agents appears extremely important in medical and industrial sectors because an irregular production of melanin is related to the insurgence of several skin-related disorders (e.g., melanoma) and the browning process of fruits and vegetables. Because melanogenesis also involves a nonenzymatic oxidative process, developing dual antioxidant and antityrosinase agents is advantageous. In this work, we evaluated the antioxidant and tyrosinase inhibition ability of two new bishydroxylated and two new monohydroxylated derivatives of (1E)-2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)hydrazine-1-carbothioamide (T1) using different experimental and computational approaches. The study was also carried out on another monohydroxylated derivative of T1 for comparison. Interestingly, these molecules have more potent tyrosinase-inhibitory properties than the reference compound, kojic acid. Moreover, the antioxidant activity appears to be influenced according to the number and substitution pattern of the hydroxyl groups. The safety of the compounds without (T1), with one (T3), and with two (T6) hydroxyl groups, has also been assessed by studying their cytotoxicity on melanocytes. These results indicate that (1E)-2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)hydrazine-1-carbothioamide and its hydroxylated derivatives are promising molecules for further drug development studies.

Hydroxy-3-Phenylcoumarins as Multitarget Compounds for Skin Aging Diseases: Synthesis, Molecular Docking and Tyrosinase, Elastase, Collagenase and Hyaluronidase Inhibition, and Sun Protection Factor.

Skin aging is a progressive biological process of the human body, and it is not only time-dependent. Differently substituted 3-phenylcoumarins proved to efficiently inhibit tyrosinase. In the current work, new substitution patterns have been explored, and the biological studies were extended to other important enzymes involved in the processes of skin aging, as elastase, collagenase and hyaluronidase. From the studied series, five compounds presented inhibitory activity against tyrosinase, one compound against elastase, eight compounds against collagenase and two compounds against hyaluronidase, being five compounds dual inhibitors. The 3-(4'-Bromophenyl)-5,7-dihydroxycoumarin (1) and 3-(3'-bromophenyl)-5,7-dihydroxycoumarin (2) presented the best profiles against tyrosinase (IC50 = 1.05 µM and 7.03 µM) and collagenase (IC50 = 123.4 µM and 110.4 µM); the 3-(4'-bromophenyl)-6,7-dihydroxycoumarin (4) presented a good inhibition against tyrosinase and hyaluronidase; the 3-(3'-bromophenyl)-6,7-dihydroxycoumarin (5) showed an effective tyrosinase and elastase inhibition; and 6,7-dihydroxy-3-(3'-hydroxyphenyl)coumarin (11) presented a dual profile inhibition against collagenase and hyaluronidase. Furthermore, considering the overall activities tested, compounds 1 and 2 proved to be the most promising anti-aging compounds. These compounds also showed to have a photo-protective effect, without being cytotoxic to human skin keratinocyte cells. To predict the binding site with the target enzymes, computational studies were also carried out.

Design, Synthesis, and in Vitro Evaluation of 4-(4-Hydroxyphenyl)piperazine-Based Compounds Targeting Tyrosinase.

Melanin biosynthesis is enzymatically regulated by tyrosinase (TYR, EC 1.14.18.1), which is efficiently inhibited by natural and synthetic phenols, demonstrating potential therapeutic application for the treatment of several human diseases. Herein we report the inhibitory effects of a series of (4-(4-hydroxyphenyl)piperazin-1-yl)arylmethanone derivatives, that were designed, synthesised and assayed against TYR from Agaricus bisporus (AbTYR). The best inhibitory activity was predominantly found for compounds bearing selected hydrophobic ortho-substituents on the aroyl moiety (IC50 values in the range of 1.5-4.6 µM). They proved to be more potent than the reference compound kojic acid (IC50 =17.8 µM) and displayed competitive mechanism of inhibition of diphenolase activity of AbTYR. Docking simulation predicted their binding mode into the catalytic cavities of AbTYR and the modelled human TYR. In addition, these compounds displayed antioxidant activity combined with no cytotoxicity in MTT tests. Notably, the best inhibitor affected tyrosinase activity in α-MSH-stimulated B16F10 cells, thus demonstrating anti-melanogenic activity.

Euphorbia characias Extract: Inhibition of Skin Aging-Related Enzymes and Nanoformulation.

Plant extracts have long served as important sources of bioactive compounds, and they are currently the focus of extensive research in the development of novel preventive and therapeutic strategies. However, their health benefits are often limited by low bioavailability. Nanoparticle delivery systems can represent a solution to such limitations. Euphorbia characias is a Mediterranean shrub known to have biological activities, such as inhibiting tyrosinase and showing a potential role as a skin-whitening agent. In this study, an ethanolic extract from E. characias leaves was tested for its inhibitory activity on skin-related enzymes, such as elastase, collagenase, and hyaluronidase, and for sun protection factors. Moreover, the extract was formulated in phospholipid vesicles to improve its local bioavailability and applicability. The vesicles were characterized by size, surface charge, storage stability, and entrapment efficiency. The nanoformulation was also evaluated for antioxidant activity and assayed for cytocompatibility and anti-tyrosinase activity in melanoma cells. Our findings demonstrated that the extract has a photo-protective effect and enzyme-inhibitory properties. E. characias nanoformulation was also cytocompatible and improved the extract's activity in the cells, suggesting a potential skin application for antimelanogenic treatments and confirming the key role of nanotechnological approaches to maximize plant extract's potentialities.

Structural Insight of New Butyrylcholinesterase Inhibitors Based on Benzylbenzofuran Scaffold.

In the present work, we use a merger of computational and biochemical techniques as a rational guideline for structural modification of benzofuran derivatives to find pertinent structural features for the butyrylcholinesterase inhibitory activity and selectivity. Previously, we revealed a series of 2-phenylbenzofuran compounds that displayed a selective inhibitory activity for BChE. Here, in an effort to discover novel selective BChE inhibitors with favorable physicochemical and pharmacokinetic profiles, 2-benzylbenzofurans were designed, synthesized, and evaluated as BChE inhibitors. The 2-phenylbenzofuran scaffold structure is modified by introducing one methylene spacer between the benzofuran core and the 2-phenyl ring with a hydroxyl substituent in the para or meta position. Either position 5 or 7 of the benzofuran scaffold was substituted with a bromine or chlorine atom. Further assessment of the selected list of compounds indicated that the substituent's nature and position determined their activity and selectivity. 5-bromo-2-(4-hydroxybenzyl)benzofuran 9B proved to be the most potent butyrylcholinesterase inhibitor (IC50 = 2.93 µM) of the studied series. Computational studies were carried out to correlate the theoretical and experimental binding affinity of the compounds to the BChE protein.

Biopolymer: A Sustainable Material for Food and Medical Applications.

Biopolymers are a leading class of functional material suitable for high-value applications and are of great interest to researchers and professionals across various disciplines. Interdisciplinary research is important to understand the basic and applied aspects of biopolymers to address several complex problems associated with good health and well-being. To reduce the environmental impact and dependence on fossil fuels, a lot of effort has gone into replacing synthetic polymers with biodegradable materials, especially those derived from natural resources. In this regard, many types of natural or biopolymers have been developed to meet the needs of ever-expanding applications. These biopolymers are currently used in food applications and are expanding their use in the pharmaceutical and medical industries due to their unique properties. This review focuses on the various uses of biopolymers in the food and medical industry and provides a future outlook for the biopolymer industry.

Quercetin and its derivates as antiviral potentials: A comprehensive review.

Quercetin, widely distributed in fruits and vegetables, is a flavonoid known for its antioxidant, antiviral, antimicrobial, and antiinflammatory properties. Several studies highlight the potential use of quercetin as an antiviral, due to its ability to inhibit the initial stages of virus infection, to be able to interact with proteases important for viral replication, and to reduce inflammation caused by infection. Quercetin could also be useful in combination with other drugs to potentially enhance the effects or synergistically interact with them, in order to reduce their side effects and related toxicity. Since there is no comprehensive compilation about antiviral activities of quercetin and derivates, the aim of this review is providing a summary of their antiviral activities on a set of human viral infections along with mechanisms of action. Thus, the following family of viruses are examined: Flaviviridae, Herpesviridae, Orthomyxoviridae, Coronaviridae, Hepadnaviridae, Retroviridae, Picornaviridae, Pneumoviridae, and Filoviridae.

Structural Characterisation and Assessment of the Novel Bacillus amyloliquefaciens RK3 Exopolysaccharide on the Improvement of Cognitive Function in Alzheimer's Disease Mice.

In this study Bacillus amyloliquefaciens RK3 was isolated from a sugar mill effluent-contaminated soil and utilised to generate a potential polysaccharide with anti-Alzheimer's activity. Traditional and molecular methods were used to validate the strain. The polysaccharide produced by B. amyloliquefaciens RK3 was purified, and the yield was estimated to be 10.35 gL-1. Following purification, the polysaccharide was structurally and chemically analysed. The structural analysis revealed the polysaccharide consists of α-d-mannopyranose (α-d-Manp) and ß-d-galactopyranose (ß-d-Galp) monosaccharide units connected through glycosidic linkages (i.e., ß-d-Galp(1→6)ß-d-Galp (1→6)ß-d-Galp(1→2)ß-d-Galp(1→2)[ß-d-Galp(1→6)]ß-d-Galp(1→2)α-d-Manp(1→6)α-d-Manp (1→6)α-d-Manp(1→6)α-d-Manp(1→6)α-d-Manp). The scanning electron microscopy and energy-dispersive X-ray spectroscopy imaging of polysaccharides emphasise their compactness and branching in the usual tubular heteropolysaccharide structure. The purified exopolysaccharide significantly impacted the plaques formed by the amyloid proteins during Alzheimer's disease. Further, the results also highlighted the potential applicability of exopolysaccharide in various industrial and pharmaceutical applications.

Euphorbia characias: Phytochemistry and Biological Activities.

The aim of this review is to summarize all the compounds identified and characterized from Euphorbia characias, along with the biological activities reported for this plant. Euphorbia is one of the greatest genera in the spurge family of Euphorbiaceae and includes different kinds of plants characterized by the presence of milky latex. Among them, the species Euphorbia characias L. is an evergreen perennial shrub widely distributed in Mediterranean countries. E. characias latex and extracts from different parts of the plant have been extensively studied, leading to the identification of several chemical components such as terpenoids, sterol hydrocarbons, saturated and unsaturated fatty acids, cerebrosides and phenolic and carboxylic acids. The biological properties range between antioxidant activities, antimicrobial, antiviral and pesticidal activities, wound-healing properties, anti-aging and hypoglycemic properties and inhibitory activities toward target enzymes related to different diseases, such as cholinesterases and xanthine oxidase. The information available in this review allows us to consider the plant E. characias as a potential source of compounds for biomedical research.

Evaluation of 4-(4-Fluorobenzyl)piperazin-1-yl]-Based Compounds as Competitive Tyrosinase Inhibitors Endowed with Antimelanogenic Effects.

There is a considerable attention for the development of inhibitors of tyrosinase (TYR) as therapeutic strategy for the treatment of hyperpigmentation disorders in humans. Continuing in our efforts to identify TYR inhibitors, we describe the design, synthesis and pharmacophore exploration of new small molecules structurally characterized by the presence of the 4-fluorobenzylpiperazine moiety as key pharmacophoric feature for the inhibition of TYR from Agaricus bisporus (AbTYR). Our investigations resulted in the discovery of the competitive inhibitor [4-(4-fluorobenzyl)piperazin-1-yl]-(3-chloro-2-nitro-phenyl)methanone 26 (IC50 =0.18 µM) that proved to be ∼100-fold more active than reference compound kojic acid (IC50 =17.76 µM). Notably, compound 26 exerted antimelanogenic effect on B16F10 cells in absence of cytotoxicity. Docking analysis suggested its binding mode into AbTYR and into modelled human TYR.

Washingtonia filifera seed extracts inhibit the islet amyloid polypeptide fibrils formations and α-amylase and α-glucosidase activity.

Washingtonia filifera seeds have revealed to possess antioxidant properties, butyrylcholinesterase and xanthine oxidase inhibition activities. The literature has indicated a relationship between Alzheimer's disease (AD) and type-2 diabetes (T2D). Keeping this in mind, we have now evaluated the inhibitory properties of W. filifera seed extracts on α-amylase, α-glucosidase enzyme activity and the Islet Amyloid Polypeptide (IAPP) fibrils formation. Three extracts from seeds of W. filifera were evaluated for their enzyme inhibitory effect and IC50 values were calculated for all the extracts. The inhibition mode was investigated by Lineweaver-Burk plot analysis and the inhibition of IAPP aggregate formation was monitored. W. filifera methanol seed extract appears as the most potent inhibitor of α-amylase, α-glucosidase, and for the IAPP fibril formation. Current findings indicate new potential of this extract that could be used for the identification or development of novel potential agents for T2D and AD.

Anti-Aging Potential of Extracts from Washingtonia filifera Seeds.

The aim of this study was to test the inhibitory effect of fruit extracts from Washingtonia filifera on skin aging-related enzymes. The pulp extracts did not exert a significant enzyme inhibition while seed extracts from W. filifera exhibit anti-elastase, anti-collagenase, and anti-tyrosinase activities. Tyrosinase was mildly inhibited while a stronger effect was observed with respect to elastase and collagenase inhibition. Alcoholic extracts provided better results than aqueous extracts. Among them, methanol extracts showed the prominent enzyme inhibitory activities being IC50 value for elastase and collagenase comparable and even better than the reference compound. The inhibition mode of the most active extracts was investigated by Lineweaver-Burk plot analysis. Seed extracts from W. filifera were also investigated for their photo-protective effect by Mansur equation and the antioxidant activity of W. filifera extract was evaluated in oxidative-stressed cells. To evaluate the safety of the extract, the effect on cell viability of human keratinocytes cells was analyzed. Methanol extract presented the best photo-protective effect and exerted an antioxidant activity in a cellular system with no cytotoxic effect. The overall results demonstrate that W. filifera extracts are promising sources of bioactive compounds that could be used in cosmetic and pharmaceutical preparation.

A new biological prospective for the 2-phenylbenzofurans as inhibitors of α-glucosidase and of the islet amyloid polypeptide formation.

In this study, we have investigated a series of hydroxylated 2-phenylbenzofurans compounds for their inhibitory activity against α-amylase and α-glucosidase activity. Inhibitors of carbohydrate degrading enzymes seem to have an important role as antidiabetic drugs. Diabetes mellitus is a wide-spread metabolic disease characterized by elevated levels of blood glucose. The most common is type 2 diabetes, which can lead to severe complications. Since the aggregates of islet amyloid polypeptide (IAPP) are common in diabetic patients, the effect of compounds to inhibit amyloid fibril formation was also determined. All the compounds assayed showed to be more active against α-glucosidase. Compound 16 showed the lowest IC50 value of the series, and it is found to be 167 times more active than acarbose, the reference compound. The enzymatic activity assays showed that compound 16 acts as a mixed-type inhibitor of α-glucosidase. Furthermore, compound 16 displayed effective inhibition of IAPP aggregation and it manifested no significant cytotoxicity. To predict the binding of compound 16 to IAPP and α-glucosidase protein complexes, molecular docking studies were performed. Altogether, our results support that the 2-phenylbenzofuran derivatives could represent a promising candidate for developing molecules able to modulate multiple targets involved in diabetes mellitus disorder.