The impact of some natural phenolic compounds on carbonic anhydrase, acetylcholinesterase, butyrylcholinesterase, and α-glycosidase enzymes: An antidiabetic, anticholinergic, and antiepileptic study

Phytochemical characterization and multifaceted bioactivity assessment of essential oil from Ptychotis verticillata Duby: Anti-diabetic, anti-tyrosinase, and anti-inflammatory activity

The aim of this study is to explore the pharmacological properties of the essential oil derived from Ptychotis verticillata Duby (PVEO), a medicinal plant native to Morocco, focusing on its antidiabetic, anti-tyrosinase, and anti-inflammatory effects. Additionally, the study aims to characterize the phytochemical composition of PVEO and evaluate its potential as a natural therapeutic alternative for various health conditions. To achieve this, phytochemical analysis was conducted using gas chromatography-mass spectrometry (GC-MS). Furthermore, in vitro assessments were conducted to investigate PVEO's antidiabetic activity by inhibiting α-amylase, xanthine oxidase, and α-glucosidase. Tests were also undertaken to evaluate the anti-inflammatory effect of PVEO on RAW 264.7 cells stimulated by lipopolysaccharide (LPS), as well as its efficacy as an anti-tyrosinase agent and its lipoxygenase inhibition activity. The results of the phytochemical analysis revealed that PVEO is rich in terpene compounds, with percentages of 40.35 % γ-terpinene, 22.40 % carvacrol, and 19.77 % β-cymene. Moreover, in vitro evaluations demonstrated that PVEO exhibits significant inhibitory activity against α-amylase, xanthine oxidase, and α-glucosidase, indicating promising antidiabetic, and anti-gout potential. Furthermore, PVEO showed significant anti-tyrosinase activity, with an IC50 of 27.39 ± 0.44 μg/mL, and remarkable lipoxygenase inhibition (87.33 ± 2.6 %), suggesting its candidacy for dermatoprotection. Additionally, PVEO displayed a dose-dependent capacity to attenuate the production of NO and PGE2, two inflammatory mediators implicated in various pathologies, without compromising cellular viability. The findings of this study provide a solid foundation for future research on natural therapies and the development of new drugs, highlighting the therapeutic potential of PVEO in the treatment of gout, diabetes, pigmentation disorders, and inflammation.

Identification of cholinesterases inhibitors from flavonoids derivatives for possible treatment of Alzheimer's disease: In silico and in vitro approaches

Nowadays, one of the methods to prevent the progress of Alzheimer's disease (AD) is to prescribe compounds that inhibit the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Researchers are actively pursuing compounds, particularly of natural origin, that exhibit enhanced efficacy and reduced side effects. The inhibition of AChE and BChE using natural flavonoids represents a promising avenue for regulating AD. This study aims to identify alternative flavonoids capable of modulating AD by down-regulating AChE and BChE activity through a molecular docking approach. Molecular docking analysis identified Ginkgetin and Kolaflavanone as potent inhibitors of AChE and BChE, respectively, among the selected flavonoids. Asn87 and Ala127 involved in the interactions of AChE-Ginkgetin complex through conventional hydrogen bonds. While in the BChE-Kolaflavanone complex, Asn83, Ser79, Gln 47, and Ser287 are involved. In vitro analysis further corroborated the inhibitory potential, with Ginkgetin exhibiting an IC50 of 3.2 mM against AChE, and Kolaflavanone displaying an IC50 of 3.6 mM against BChE. These findings underscore the potential of Ginkgetin and Kolaflavanone as candidate inhibitors for the treatment of AD through the inhibition of AChE and BChE enzymes. Nevertheless, additional in vitro and in vivo studies are imperative to validate the efficacy of these compounds.

3D-QSAR-based pharmacophore modelling of quinazoline derivatives for the identification of acetylcholinesterase inhibitors through virtual screening, molecular docking, molecular dynamics and DFT studies

Alzheimer's disease (AD) is a progressive neurological disorder responsible for the cognitive dysfunction and cognitive impairment in the patients. Acetylcholinesterase inhibitors (AChEIs) are used to treat AD however, these only provided symptomatic relief and more efficient drug molecules are desired for the effective treatment of the disease. In this article, ligand-based drug-designing strategy was used to develop and validate a field-based 3D-QSAR pharmacophore model on quinazoline-based AChEIs reported in the literature. The validated pharmacophore model (AAAHR_1) was used as a prefilter to screen an ASINEX database via virtual screening workflow (VSW). The hits generated were subjected to MM-GBSA to identify potential AChEIs and top three scoring molecules (BAS 05264565, LEG 12727144 and SYN 22339886) were evaluated for thermodynamic stability at the target site using molecular dynamic simulations. Additionally, DFT study was performed to predict the reactivity of lead molecules towards acetylcholinesterase (AChE). Thus, by utilising various computational tools, three molecules were identified as potent AChEIs that can be developed as potential drug candidates for the treatment of AD.Communicated by Ramaswamy H. Sarma.

Flavonoids as dual-target inhibitors against α-glucosidase and α-amylase: a systematic review of in vitro studies

Diabetes mellitus remains a major global health issue, and great attention is directed at natural therapeutics. This systematic review aimed to assess the potential of flavonoids as antidiabetic agents by investigating their inhibitory effects on α-glucosidase and α-amylase, two key enzymes involved in starch digestion. Six scientific databases (PubMed, Virtual Health Library, EMBASE, SCOPUS, Web of Science, and WHO Global Index Medicus) were searched until August 21, 2022, for in vitro studies reporting IC50 values of purified flavonoids on α-amylase and α-glucosidase, along with corresponding data for acarbose as a positive control. A total of 339 eligible articles were analyzed, resulting in the retrieval of 1643 flavonoid structures. These structures were rigorously standardized and curated, yielding 974 unique compounds, among which 177 flavonoids exhibited inhibition of both α-glucosidase and α-amylase are presented. Quality assessment utilizing a modified CONSORT checklist and structure-activity relationship (SAR) analysis were performed, revealing crucial features for the simultaneous inhibition of flavonoids against both enzymes. Moreover, the review also addressed several limitations in the current research landscape and proposed potential solutions. The curated datasets are available online at https://github.com/MedChemUMP/FDIGA .

Acetylphenyl-substituted imidazolium salts: synthesis, characterization, in silico studies and inhibitory properties against some metabolic enzymes

Herein, we present how to synthesize thirteen new 1-(4-acetylphenyl)-3-alkylimidazolium salts by reacting 4-(1-H-imidazol-1-yl)acetophenone with a variety of benzyl halides that contain either electron-donating or electron-withdrawing groups. The structures of the new imidazolium salts were conformed using different spectroscopic methods (1H NMR, 13C NMR, 19F NMR, and FTIR) and elemental analysis techniques. Furthermore, these compounds' the carbonic anhydrase (hCAs) and acetylcholinesterase (AChE) enzyme inhibition activities were investigated. They showed a highly potent inhibition effect toward AChE and hCAs with Ki values in the range of 8.30 ± 1.71 to 120.77 ± 8.61 nM for AChE, 16.97 ± 2.04 to 84.45 ± 13.78 nM for hCA I, and 14.09 ± 2.99 to 69.33 ± 17.35 nM for hCA II, respectively. Most of the synthesized imidazolium salts appeared to be more potent than the standard inhibitor of tacrine (TAC) against AChE and Acetazolamide (AZA) against CA. In the meantime, to prospect for potential synthesized imidazolium salt inhibitor(s) against AChE and hCAs, molecular docking and an ADMET-based approach were exerted.

Hesperidin Attenuates Titanium Dioxide Nanoparticle-Induced Neurotoxicity in Rats by Regulating Nrf-2/TNF-α Signaling Pathway, the Suppression of Oxidative Stress, and Inflammation

Background: Titanium dioxide nanoparticles (TiO2NPs) are widely utilized and consumed mainly as food additives. Oxidative stress is considered to be the basic effect of TiO2NPs through biological interactions. Hesperidin (HSP) is a bioflavonoid (flavanone glycoside) with lipid-lowering, inflammation, oxidative stress suppression, antihypertensive, cancer-fighting, and antiedema effects. Objective: This study was to investigate the possible protective influences of HSP of subchronic oral TiO2NP exposure on the brains of rats, including neurotransmitters, oxidative stress/antioxidant parameters, inflammatory markers, and histological changes in the brains of adult male albino rats. Methodology: The experiment was executed on 80 albino rats. The animals were randomly divided into 4 equal groups. The first group served as a control; the second group was treated with oral doses of HSP (100 mg/kg Bw daily); the third group received TiO2NPs (200 mg/kg Bw orally daily); and the fourth group was treated with TiO2NPs and an oral dose of HSP daily for 8 weeks. Blood samples were obtained for biochemical analysis. Neurotransmitters, oxidative stress biomarker levels, and inflammatory markers were measured in brain homogenates. Histological examination of the brain was performed through H&E staining. Results: Coadministration of hesperidin with TiO2NPs orally for 8 weeks decreased the levels of MDA, TNF-α, AChE, and dopamine in brain homogenates, which were increased in the TiO2NP group. It increased the other oxidative biomarkers (SOD, CAT, and GPx) and Nrf-2 expression levels. Brain histological sections of the TiO2NP-treated group show degeneration, necrosis, congestion, and inflammatory cell infiltration that decreased markedly in the coadministration of hesperidin with the TiO2NP group. Conclusion: Hesperidin cotreatment offers significant protection against TiO2NP-induced oxidative stress and biochemical and histological alteration in the brain.

A byproduct from the Valles Calchaquíes vineyards (Argentina) rich in phenolic compounds: a tool against endemic Leishmania dissemination

Vineyard-derived pomace is a byproduct of the wine industry that can have a negative impact on the environment if it is only disposed of or used as a fertilizer. Owing to its polyphenol content, grape pomace is an alternative to biocontrol undesirable microorganisms. In the present study, we characterized the phenolic composition of red and white grape pomace from Valles Calchaquíes, Argentina, and explored its activity against Leishmania (Leishmania) amazonensis, an etiological agent of American tegumentary leishmaniasis, a neglected endemic disease in northern Argentina. Red and white pomace extracts similarly reduced Leishmania viability after a 48-h treatment, with the fractions containing a higher proportion of phenolic compounds being more active. Both extracts stimulated ATPase activity on the parasite plasma membranes, with white grape pomace having a stronger effect than red grape pomace. In addition, the extracts displayed fairly good anticholinesterase activity, which may have contributed to their anti-Leishmania activity. These results reinforce the potential applicability of grape pomace as an antimicrobial agent for the development of biopesticides.

Bioinformatics Tools for the Analysis of Active Compounds Identified in Ranunculaceae Species

The chemical compounds from extracts of three Ranunculaceae species, Aconitum toxicum Rchb., Anemone nemorosa L. and Helleborus odorus Waldst. & Kit. ex Willd., respectively, were isolated using the HPLC purification technique and analyzed from a bioinformatics point of view. The classes of compounds identified based on the proportion in the rhizomes/leaves/flowers used for microwave-assisted extraction and ultrasound-assisted extraction were alkaloids and phenols. Here, the quantifying of pharmacokinetics, pharmacogenomics and pharmacodynamics helps us to identify the actual biologically active compounds. Our results showed that (i) pharmacokinetically, the compounds show good absorption at the intestinal level and high permeability at the level of the central nervous system for alkaloids; (ii) regarding pharmacogenomics, alkaloids can influence tumor sensitivity and the effectiveness of some treatments; (iii) and pharmacodynamically, the compounds of these Ranunculaceae species bind to carbonic anhydrase and aldose reductase. The results obtained showed a high affinity of the compounds in the binding solution at the level of carbonic anhydrases. Carbonic anhydrase inhibitors extracted from natural sources can represent the path to new drugs useful both in the treatment of glaucoma, but also of some renal, neurological and even neoplastic diseases. The identification of natural compounds with the role of inhibitors can have a role in different types of pathologies, both associated with studied and known receptors such as carbonic anhydrase and aldose reductase, as well as new pathologies not yet addressed.

Natural products targeting inflammation-related metabolic disorders: A comprehensive review

Currently, the incidence of metabolic disorders is increasing, setting a challenge to global health. With major advancement in the diagnostic tools and clinical procedures, much has been known in the etiology of metabolic disorders and their corresponding pathophysiologies. In addition, the use of in vitro and in vivo experimental models prior to clinical studies has promoted numerous biomedical breakthroughs, including in the discovery and development of drug candidates to treat metabolic disorders. Indeed, chemicals isolated from natural products have been extensively studied as prospective drug candidates to manage diabetes, obesity, heart-related diseases, and cancer, partly due to their antioxidant and anti-inflammatory properties. Continuous efforts have been made in parallel to improve their bioactivity and bioavailability using selected drug delivery approaches. Here, we provide insights on recent progress in the role of inflammatory-mediated responses on the initiation of metabolic disorders, with particular reference to diabetes mellitus, obesity, heart-related diseases, and cancer. In addition, we discussed the prospective role of natural products in the management of diabetes, obesity, heart-related diseases, and cancers and provide lists of potential biological targets for high throughput screening in drug discovery and development. Lastly, we discussed findings observed in the preclinical and clinical studies prior to identifying suitable approaches on the phytochemical drug delivery systems that are potential to be used in the treatment of metabolic disorders.

Increased therapeutic effect of nanotized silibinin against glycation and diabetes: An in vitro and in silico-based approach

BACKGROUND

The global prevalence of diabetes has increased sharply, with the number of cases expected to rise from 424.9 million in 2017 to 628.6 million by 2045. Flavonoids are plant derived molecules with well-established antioxidant potential in addition to other therapeutic properties. Silibinin is a naturally occurring flavonoid with antioxidant and antidiabetic properties. However, its rapid metabolism and low bioavailability limit its therapeutic effects.

AIMS & OBJECTIVES

In this study, we have synthesized the nanoformulation of silibinin and compared its antiglycating and antidiabetic potential with the soluble form.

METHODOLOGY

The inhibitory effect was tested on carbohydrate-hydrolyzing enzymes as well as glycation of human serum albumin (HSA). The structural and biochemical changes in HSA were assessed by spectroscopic analyses and different assays.

KEY FINDINGS

The nanoforms were found to be better inhibitors of α-amylase and α-glucosidase compared to the bulk forms. Glycation of HSA in the presence of nano-silibinin resulted in the formation of lower level of early and advanced glycation products. This was also confirmed by spectroscopic studies and by estimating protein oxidation and free lysine residues. Molecular docking studies further supported the experimental outcomes. These results indicate that the nano form has significantly stronger antidiabetic and antiglycating effects than the bulk form. Nano-silibinin could therefore be recommended as a dietary supplement for diabetics to help control glycation and other associated complications.

Comprehensive Metabolite Profiling of Berdav Propolis Using LC-MS/MS: Determination of Antioxidant, Anticholinergic, Antiglaucoma, and Antidiabetic Effects

Propolis is a complex natural compound that honeybees obtain from plants and contributes to hive safety. It is rich in phenolic and flavonoid compounds, which contain antioxidant, antimicrobial, and anticancer properties. In this study, the chemical composition and antioxidant activities of propolis were investigated; ABTS^•+, DPPH^• and DMPD^•+ were prepared using radical scavenging antioxidant methods. The phenolic and flavonoid contents of propolis were 53 mg of gallic acid equivalent (GAE)/g and 170.164 mg of quercetin equivalent (QE)/g, respectively. The ferric ion (Fe³⁺) reduction, CUPRAC and FRAP reduction capacities were also studied. The antioxidant and reducing capacities of propolis were compared with those of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and Trolox reference standards. The half maximal inhibition concentration (IC₅₀) values of propolis for ABTS^•+, DPPH^• and DMPD^•+ scavenging activities were found to be 8.15, 20.55 and 86.64 μg/mL, respectively. Propolis extract demonstrated IC₅₀ values of 3.7, 3.4 and 19.6 μg/mL against α-glycosidase, acetylcholinesterase (AChE) and carbonic anhydrase II (hCA II) enzyme, respectively. These enzymes' inhibition was associated with diabetes, Alzheimer's disease (AD) and glaucoma. The reducing power, antioxidant activity and enzyme inhibition capacity of propolis extract were comparable to those demonstrated by the standards. Twenty-eight phenolic compounds, including acacetin, caffeic acid, p-coumaric acid, naringenin, chrysin, quinic acid, quercetin, and ferulic acid, were determined by LC-MS/MS to be major organic compounds in propolis. The polyphenolic antioxidant-rich content of the ethanol extract of propolis appears to be a natural product that can be used in the treatment of diabetes, AD, glaucoma, epilepsy, and cancerous diseases.

Biological Evaluation of Valeriana Extracts from Argentina with Potent Cholinesterase Inhibition for the Treatment of Neurodegenerative Disorders and Their Comorbidities-The Case of Valeriana carnosa Sm. (Caprifoliaceae) Studied in Mice

Alzheimer's disease (AD) is a neurodegenerative disorder whose pathophysiology includes the abnormal accumulation of proteins (e.g., β-amyloid), oxidative stress, and alterations in neurotransmitter levels, mainly acetylcholine. Here we present a comparative study of the effect of extracts obtained from endemic Argentinian species of valerians, namely V. carnosa Sm., V. clarionifolia Phil. and V. macrorhiza Poepp. ex DC from Patagonia and V. ferax (Griseb.) Höck and V. effusa Griseb., on different AD-related biological targets. Of these anxiolytic, sedative and sleep-inducing valerians, V. carnosa proved the most promising and was assayed in vivo. All valerians inhibited acetylcholinesterase (IC₅₀ between 1.08-12.69 mg/mL) and butyrylcholinesterase (IC₅₀ between 0.0019-1.46 mg/mL). They also inhibited the aggregation of β-amyloid peptide, were able to chelate Fe²⁺ ions, and exhibited a direct relationship between antioxidant capacity and phenolic content. Moreover, V. carnosa was able to inhibit human monoamine oxidase A (IC₅₀: 0.286 mg/mL (0.213-0.384)). A daily intake of aqueous V. carnosa extract by male Swiss mice (50 and 150 mg/kg/day) resulted in anxiolytic and antidepressant-like behavior and improved spatial memory. In addition, decreased AChE activity and oxidative stress markers were observed in treated mouse brains. Our studies contribute to the development of indigenous herbal medicines as therapeutic agents for AD.

Synthesis of Novel Bromophenol with Diaryl Methanes—Determination of Their Inhibition Effects on Carbonic Anhydrase and Acetylcholinesterase

In this work, nine new bromophenol derivatives were designed and synthesized. The alkylation reactions of (2-bromo-4,5-dimethoxyphenyl)methanol (7) with substituted benzenes 8–12 produced new diaryl methanes 13–17. Targeted bromophenol derivatives 18–21 were synthesized via the O-Me demethylation of diaryl methanes with BBr3. Moreover, the synthesized bromophenol compounds were tested with some metabolic enzymes such as acetylcholinesterase (AChE), carbonic anhydrase I (CA I), and II (CA II) isoenzymes. The novel synthesized bromophenol compounds showed Ki values that ranged from 2.53 ± 0.25 to 25.67 ± 4.58 nM against hCA I, from 1.63 ± 0.11 to 15.05 ± 1.07 nM against hCA II, and from 6.54 ± 1.03 to 24.86 ± 5.30 nM against AChE. The studied compounds in this work exhibited effective hCA isoenzyme and AChE enzyme inhibition effects. The results show that they can be used for the treatment of glaucoma, epilepsy, Parkinson’s as well as Alzheimer’s disease (AD) after some imperative pharmacological studies that would reveal their drug potential.

Phthalimide-tethered imidazolium salts: Synthesis, characterization, enzyme inhibitory properties, and in silico studies

A series of new imidazolium salts were prepared in good yield by the reaction between 1-alkylimidazole and a variety of alkyl halides. The structures of the compounds were identified by FT-IR, ¹ H NMR, and ¹³ C NMR spectroscopy, elemental analysis, and mass spectrometry. The crystal structure of 1b was determined by the single-crystal X-ray diffraction method. The phthalimide-tethered imidazolium salts exhibited inhibition abilities toward acetylcholinesterase (AChE) and human carbonic anhydrases (hCAs) I and II, with K_i values in the range of 24.63 ± 3.45 to 305.51 ± 35.98 nM for AChE, 33.56 ± 3.71 to 218.01 ± 25.21 nM for hCA I and 17.75 ± 0.96 to 308.67 ± 13.73 nM for hCA II. The results showed that the new imidazolium salts can play a key role in the treatment of Alzheimer's disease, epilepsy, glaucoma, and leukemia, which is related to their inhibition abilities of hCA I, hCA II, and AChE. Molecular docking and in silico absorption, distribution, metabolism, excretion and toxicity studies were used to look into how the imidazolium salts interacted with the specific protein targets. To better visualize and understand the binding positions and the influence of the imidazolium salts on hCA I, hCA II, and AChE conformations, each one was subjected to molecular docking simulations.

Preventive Effects of Mandarin Fruit Peel Hydroethanolic Extract, Hesperidin, and Quercetin on Acetaminophen-Induced Hepatonephrotoxicity in Wistar Rats

Acetaminophen, also known as N-acetyl-para-aminophenol (NAPAP), is a traditional antipyretic and analgesic that is used extensively around the world to treat colds and fevers. However, a NAPAP excess causes rapid, severe liver and kidney damage. The goal of the study was to examine the protective effects and determine the mechanisms of action of MPHE, hesperidin, and quercetin in NAPAP-induced hepatorenal damage in Wistar rats. Male Wistar rats received a 0.5 g/kg oral supplement of NAPAP every other day for a period of four weeks. During the same period of NAPAP supplementation, MPHE (50 mg/kg), quercetin (20 mg/kg), and hesperidin (20 mg/kg) were administered to rats receiving NAPAP. MPHE, quercetin, and hesperidin treatments significantly improved liver function in NAPAP-supplemented rats. The high serum levels of aminotransferases, alkaline phosphatase, lactate dehydrogenase, and γ-glutamyl transferase as well as total bilirubin were significantly reduced, while the levels of suppressed serum albumin were significantly increased, demonstrating this improvement. Treatments utilizing these natural substances significantly enhanced kidney function as seen by a considerable decline in the increased blood levels of urea, uric acid, and creatinine. Additionally, the injection of MPHE, hesperidin, and quercetin resulted in a decrease in the quantity of lipid peroxides while increasing the activities of superoxide dismutase, glutathione peroxidase, and glutathione-S-transferase in the liver and kidneys. The treatments markedly abated the NAPAP-induced liver and kidney histological perturbations and reduced the NAPAP-induced serum tumor necrosis factor-α level and liver and kidney proapoptotic protein 53 and caspase 3 expressions. Otherwise, serum interleukin-4 level significantly increased by treatments. The MPHE, hesperidin, and quercetin treatments resulted in marked decrease in liver and kidney histopathological scores including inflammation, necrosis, apoptosis, and congestion. In conclusion, the MPHE, quercetin, and hesperidin may induce hepatonephropreventive impacts in NAPAP-supplemented rats via enhancing the antioxidant defense system, anti-inflammatory activity, and antiapoptotic action.

The palladium-based complexes bearing 1,3-dibenzylbenzimidazolium with morpholine, triphenylphosphine, and pyridine derivate ligands: synthesis, characterization, structure and enzyme inhibitions

The palladium-based complexes bearing N-heterocyclic carbene (NHC) ligand have long attracted attention as active catalysts for many catalytic reactions. Recently, the biological activities of these complexes, which are stable to air and moisture, have also been wondered. With the aim, we report the synthesis of a series of (NHC)Pd(Br₂)(L) complexes (NHC: 1,3-dibenzylbenzimidazolium, L: morpholine, triphenylphosphine, pyridine, 3-chloropyridine, and 2-aminopyridine). All complexes were characterized by NMR (¹H and ¹³C), FTIR spectroscopic and elemental analysis techniques. In addition, the single crystal structures of the complex 3, 4, and 6 were determined through single crystal x-ray crystallographic method. Furthermore, the carbonic anhydrase I and II isoenzymes (hCAs) and acetylcholinesterase (AChE) inhibition effects of these palladium-based complexes bearing NHC ligand were investigated. They showed highly potent inhibition effect with K_i values are between 10.06 ± 1.49–68.56 ± 11.53 nM for hCA I isoenzyme, 7.74 ± 0.66 to 49.39 ± 6.50 nM for hCA II isoenzyme and 22.83 ± 3.21 to 64.09 ± 9.05 nM for AChE enzyme.

Update on new trend and progress of the mechanism of polysaccharides in the intervention of Alzheimer's disease, based on the new understanding of relevant theories: A review

Alzheimer's disease (AD), a neurodegenerative disease with insidious onset and progressive progression, is the main type of dementia. Currently, there is no specific cure for the disease. At the same time, a series of drug developments based on the classic theory, the Aβ cascade hypothesis, have not completed phase III clinical trials, challenging the hypothesis. Polysaccharides obtained from natural products can be used in the treatment of AD, which has attracted academic attention due to its advantages of multi-target, multi-channel, no or modest side effects. The TCM syndrome type of AD is mainly "qi and blood deficiency, kidney essence deficiency", and the medicine is mainly used to replenish qi and blood, kidney and bone marrow. Thus, there has been extensive and in-depth research on polysaccharides obtained from tonic Chinese herbal medicine in China. Based on this background, this paper evaluated the effects and mechanisms of natural polysaccharides on AD by combing and screening English and related literature in recent 5 years and summarized the extraction process and structure-activity relationship of polysaccharides.

Neuroprotective effects of carvacrol against cadmium-induced neurotoxicity in rats: role of oxidative stress, inflammation and apoptosis

Cadmium (Cd), is a heavy metal reported to be associated with oxidative stress and inflammation. In this paper, we investigated the possible protective effects of carvacrol against Cd-induced neurotoxicity in rats. Adult male Sprague Dawley rats were treated orally with Cd (25 mg/kg body weight) and with carvacrol (25 and 50 mg/kg body weight) for 7 days. Carvacrol decreased the levels of malondialdehyde (MDA), glial fibrillary acidic protein (GFAP) and monoamine oxidase (MAO), and significantly increased the levels of glutathione (GSH) and activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in brain tissue. Additionally, carvacrol alleviated the in levels of inflammation and apoptosis related proteins involving p38 mitogen-activated protein kinase (p38 MAPK), cyclooxygenase-2 (COX-2), nuclear factor kappa B (NF-κB), B-cell lymphoma-3 (Bcl-3), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), myeloperoxidase (MPO), prostaglandin E2 (PGE2), neuronal nitric oxide synthase (nNOS), inducible nitric oxide synthase (iNOS), cysteine aspartate specific protease-3 (caspase-3) and Bcl-2 associated X protein (Bax) in the Cd-induced neurotoxicity. Carvacrol also decreased the mRNA expression of matrix metalloproteinases (MMP9 and MMP13), as well as 8-hydroxy-2'-deoxyguanosine (8 - OHdG) level, a marker of oxidative DNA damage. Collectively, our findings indicated that carvacrol has a beneficial effect in ameliorating the Cd-induced neurotoxicity in the brain of rats.

Emerging trends in environmental and industrial applications of marine carbonic anhydrase: a review

Biocatalytic conversion of greenhouse gases such as carbon dioxide into commercial products is one of the promising key approaches to solve the problem of climate change. Microbial enzymes, including carbonic anhydrase, NAD-dependent formate dehydrogenase, ribulose bisphosphate carboxylase, and methane monooxygenase, have been exploited to convert atmospheric gases into industrial products. Carbonic anhydrases are Zn²⁺-dependent metalloenzymes that catalyze the reversible conversion of CO₂ into bicarbonate. They are widespread in bacteria, algae, plants, and higher organisms. In higher organisms, they regulate the physiological pH and contribute to CO₂ transport in the blood. In plants, algae, and photosynthetic bacteria carbonic anhydrases are involved in photosynthesis. Converting CO₂ into bicarbonate by carbonic anhydrases can solidify gaseous CO2, thereby reducing global warming due to the burning of fossil fuels. This review discusses the three-dimensional structures of carbonic anhydrases, their physiological role in marine life, their catalytic mechanism, the types of inhibitors, and their medicine and industry applications.

Investigation of Euphorbia nivulia-HAM for Enzyme Inhibition Potential in Relation to the Phenolic and Flavonoid Contents and Radical Scavenging Activity

Euphorbia nivulia-Ham (EN) is a neglected medicinal plant traditionally used for a number of pathologies, but it has not been explored scientifically. In the current study, its various fractions were assessed for their phenolic and flavonoid content, radical scavenging, as well as its enzyme inhibitory potential. The hydro-alcoholic crude extract (ENCr) was subjected to a fractionation scheme to obtain different fractions, namely n-hexane (ENHF), chloroform (ENCF), n-butanol (ENBF), and aqueous fraction (ENAF). The obtained results revealed that the highest phenolic and flavonoid content, maximum radical scavenging potential (91 ± 0.55%), urease inhibition (54.36 ± 1.47%), and α-glucosidase inhibition (97.84 ± 1.87%) were exhibited by ENCr, while the ENBF fraction exhibited the highest acetylcholinestrase inhibition (57.32 ± 0.43%). Contrary to these, hydro-alcoholic crude as well as the other fractions showed no significant butyrylcholinestrases (BChE) and carbonic anhydrase inhibition activity. Conclusively, it was found that EN possesses a significant radical scavenging and enzyme inhibitory potential. Thus, the study may be regarded a step forward towards evidence-based phyto-medicine.

New Pd(II) complexes of the bisthiocarbohydrazones derived from isatin and disubstituted salicylaldehydes: Synthesis, characterization, crystal structures and inhibitory properties against some metabolic enzymes

Pd(II) complexes (Pd1, Pd2, and Pd3) were synthesized for the first time using asymmetric isatin bisthiocarbohydrazone ligands and PdCl₂(PPh₃)₂. All complexes were characterized by a range of spectroscopic and analytical techniques. The molecular structures of Pd1 and Pd3 have been determined by single-crystal X-ray diffraction analysis. The complexes are diamagnetic and exhibit square planar geometry. The asymmetric isatin bisthiocarbohydrazone ligands coordinate to Pd(II) ion in a tridentate manner, through the phenolic oxygen, imine nitrogen and thiol sulfur, forming five- and six-membered chelate rings within their structures. The fourth coordination site in these complexes is occupied by PPh₃ (triphenylphosphine). The free ligands and their Pd(II) complexes were evaluated for their carbonic anhydrase I, II (hCAs) and acetylcholinesterase (AChE) inhibitor activities. They showed a highly potent inhibition effect on AChE and hCAs. K_i values are in the range of 9 ± 0.6 - 30 ± 5.4 nM for AChE, 7 ± 0.5 - 16 ± 2.2 nM for hCA I and 3 ± 0.3-24 ± 1.9 nM for hCA II isoenzyme. The results clearly demonstrated that the ligands and their Pd(II) complexes effectively inhibited the used enzymes.

A Brief Review of Phenolic Compounds Identified from Plants: Their Extraction, Analysis, and Biological Activity

Phenolic compounds are the most abundant secondary metabolites in plants, showing a wide range of distinct biological activities, have received more and more attention in recent years. This review aims to gather and systematize available information on the phenolic compounds from plants by discussing different types of phenolic compounds, extraction, and analysis methods, with an emphasis on their potential biological activities. The research direction and problems that should be paid attention to in the future are also put forward to provide some references for the further study of phenolic compounds.

Selenourea and thiourea derivatives of chiral and achiral enetetramines: Synthesis, characterization and enzyme inhibitory properties

A series of chiral and achiral cyclic seleno- and thiourea compounds bearing benzyl groups on N-atoms were prepared from enetetramines and appropriate Group VI elements in good yields. All the synthesized compounds were characterized by elemental analysis, FT-IR, ¹H NMR and ¹³C NMR spectroscopy, and the molecular and crystal structures of (R,R)-4b and (R,R)-5b were confirmed by the single-crystal X-ray diffraction method. These assayed for their activities against metabolic enzymes acetylcholinesterase, butyrylcholinesterase, and α-glycosidase. These selenourea and thiourea derivatives of chiral and achiral enetetramines effectively inhibit AChE and BChE with IC₅₀ values in the range of 3.32-11.36 and 1.47-9.73 µM, respectively. Also, these compounds inhibited α-glycosidase enzyme with IC₅₀ values varying between 1.37 and 8.53 µM. The results indicated that all the synthesized compounds exhibited excellent inhibitory activities against mentioned enzymes as compared with standard inhibitors. Representatively, the most potent compound against α-glycosidase enzyme, (S,S)-5b, was 12-times more potent than standard inhibitor acarbose; 7b and 8a as most potent compounds against cholinesterase enzymes, were around 5 and 13-times more potent than standard inhibitor tacrine against achethylcholinesterase (AChE) and butyrylcholinesterase (BChE), respectively.

Protective effects of chrysin against the neurotoxicity induced by aluminium: In vitro and in vivo studies

Chronic exposure to aluminium (Al) can contribute to the progression of several neurological and neurodegenerative diseases. Al is a metal that promotes oxidative damage leading to neuronal death in different brain regions with behavior, cognition, and memory deficits. Chrysin is a flavonoid found mainly in honey, passion fruit, and propolis with antioxidant, anti-inflammatory, and cytoprotective properties. In this study, we used an integrated approach of in vitro and in vivo studies to evaluate the antioxidant and neuroprotective effects of chrysin against the neurotoxicity elicited by aluminium chloride (AlCl₃). In in vitro studies, chrysin (5 μM) showed the ability to counteract the early oxidative stress elicited by tert-butyl hydroperoxide, an oxidant that mimics the lipid peroxidation and Fenton reaction in presence of AlCl₃ as well as the late necrotic death triggered by AlCl₃ in neuronal SH-SY5Y cells. In vivo studies in a mouse model of neurotoxicity induced by chronic exposure to AlCl₃ (100 mg/kg/day) for ninety days then corroborated the antioxidant and neuroprotective effect of chrysin (10, 30, and 100 mg/kg/day) using the oral route. In particular, chrysin reduced the cognitive impairment induced by AlCl₃ as well as normalized the acetylcholinesterase and butyrylcholinesterase activities in the hippocampus. In parallel, chrysin counteracted the oxidative damage, in terms of lipid peroxidation, protein carbonylation, catalase, and superoxide dismutase impairment, in the brain cortex and hippocampus. Lastly, necrotic cells frequency in the same brain regions was also decreased by chrysin. These results highlight the ability of chrysin to prevent the neurotoxic effects associated with chronic exposure to Al and suggest its potential use as a food supplement for brain health.

Modulatory effects of carvacrol against cadmium-induced hepatotoxicity and nephrotoxicity by molecular targeting regulation

AIM

Cadmium (Cd) is a toxic heavy metal that causes severe toxic effects on different tissues including liver and kidney. Therefore the research for alternatives to reduce the damage caused by Cd has substantial importance. This study was performed to examine the possible modulatory effects of carvacrol (CRV) against Cd-induced hepatorenal toxicities and the possible mechanisms underlying these effects.

MATERIALS AND METHODS

In the present study, 35 male Wistar rats were randomly divided into 5 groups. The rats were treated with Cd (25 mg/kg) and treated with CRV (25 and 50 mg/kg body weight) for 7 consecutive days.

KEY FINDINGS

CRV could modulate Cd-induced elevations of ALT, ALP, AST, urea, creatinine, MDA and enhance antioxidant enzymes' activities such as SOD, CAT, and GPx, and GSH's level. CRV also reversed the changes in levels of inflammatory biomarker and apoptotic genes that include NF-κB, Bcl-3, MAPK-14, iNOS, COX-2, MPO, PGE2, Bax, Bcl-2, P53, Caspase-9, Caspase-6 and Caspase-3 in both tissues. The levels of 8-OHdG in the Cd-induced liver and kidney tissues were modulated after CRV treatment. Furthermore, CRV treatment considerably lowered Cd, Na, Fe, and Zn content while increased K, Ca, Mg and Cu contents in both tissues as compared to the Cd-exposed rats.

SIGNIFICANCE

The results of the present study revealed that CRV supplementation could be a promising strategy to protect the liver and kidney tissues against Cd-induced oxidative damage, inflammation and apoptosis.

Synthesis of novel tris-chalcones and determination of their inhibition profiles against some metabolic enzymes

In this study, we report the synthesis of novel tris-chalcones and testing of human carbonic anhydrase I, and II isoenzymes (hCA I, and hCA II), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α-glycosidase (α-Gly) inhibitors for the development of novel chalcone structures towards for treatment of some diseases. The compounds demonstrated K_i values between 13.6 ± 1.1 and 50.0 ± 17.1 nM on hCA I, 9.9 ± 0.8 and 39.5 ± 15.1 nM on hCA II, 3.1 ± 0.2 and 20.1 ± 1.9 nM on AChE, 4.9 ± 0.4 and 14.7 ± 5.2 nM on BChE and 3.9 ± 0.2 and 22.4 ± 10.7 nM on α-Gly enzymes. The results revealed that novel tris-chalcones can have promising drug potential for glaucoma, leukaemia, epilepsy; Alzheimer's disease that was associated with the high enzymatic activity of hCA I, hCA II, AChE, and BChE enzymes.

The effects of chrysin and naringin on cyclophosphamide-induced erythrocyte damage in rats: biochemical evaluation of some enzyme activities in vivo and in vitro

In recent years, there have been efforts to develop therapeutic agents that target metabolic enzyme systems in addition to existing treatment in possible cancer treatments. Cyclophosphamide (CYP) is an anticancer drug commonly used in various cancer treatments. Chrysin (CH) and naringin (NR) are natural flavonoids that possess many medicinal and pharmacological properties. In the present study, we aimed to investigate the effect of CH and NR against CYP-induced toxicity on some metabolic enzyme activities. For this purpose, 56 male rats were randomly divided into 8 groups in our in vivo study. The rats were pretreated with CH (25 and 50 mg/kg bw) and NR (50 and 100 mg/kg bw) for 7 days before administering a single dose of CYP (200 mg/kg bw) on the seventh day. According to the in vivo results of our study, it was observed that CH and NR regulated abnormal changes in CYP-induced enzyme activities. In addition, our in vitro study, G6PD enzyme was purified from rat erythrocyte using affinity chromatography. The effects of CH, NR, and CYP were investigated on the purified enzyme. It was determined that CH increased the enzyme activity, CYP ineffective on the enzyme activity, whereas NR inhibited the enzyme activity noncompetitively. Graphical abstract.

Design, synthesis, molecular docking, and some metabolic enzyme inhibition properties of novel quinazolinone derivatives

3-Amino-2-ethylquinazolin-4(3H)-one (3) was synthesized in two steps from the reaction of amide (2), which was obtained from the treatment of methyl anthranilate (1) with propionyl chloride, with hydrazine. From the reaction of 3-amino-2-ethylquinazolin-4(3H)-one (3) with various aromatic aldehydes, novel benzylidenaminoquinazolin-4(3H)-one (3a-n) derivatives were synthesized. The structures of the novel molecules were characterized using infrared spectroscopy, nuclear magnetic resonance spectroscopy (¹ H-NMR and ¹³ C-NMR), and high-resolution mass spectroscopy. The novel compounds were tested against some metabolic enzymes, including α-glucosidase (α-Glu), acetylcholinesterase (AChE), and human carbonic anhydrases I and II (hCA I and II). The novel compounds showed K_i values in the range of 244-988 nM for hCA I, 194-900 nM for hCA II, 30-156 nM for AChE, and 215-625 nM for α-Glu. The binding affinities of the most active compounds were calculated as -7.636, -6.972, -10.080, and -8.486 kcal/mol for hCA I, hCA II, AChE, and α-Glu enzymes, respectively. The aromatic ring of the quinazoline moiety plays a critical role in the inhibition of the enzymes.

Phenols from Origanum dictamnus L. and Thymus vulgaris L. and their activity against Malassezia globosa carbonic anhydrase

Malassezia spp. are lipophilic fungi that are part of the normal flora of the human skin and are the etiological agents of dandruff and seborrheic dermatitis. β-Carbonic Anhydrases (CAs; EC 4.2.1.1) expressed from the pathogenic fungi are an alternative/complementary drug target. Previous work by our groups demonstrated that flavonoids and depsides can effectively inhibit Malassezia globosa β-CA (MgCA). In continuation of this study herein we report the inhibitory activity of a variety of phenols from Origanum dictamnus L. and Thymus vulgaris L. against β-MgCA, among them I4-II7-di-carvacrol, a new natural product. Structure elucidation of the compounds was performed by 1 D, 2 D NMR and spectrometric analyses. Xanthomicrol and rosmarinic acid were active in the (sub)micromolar range (K_IS 0.6 and 2.2 μM, respectively vs 40.0 μM of the standard inhibitor acetazolamide). Finally, the compounds were not cytotoxic, but showed in vitro no activity against Malassezia furfur.

Synthesis, characterization, crystal structure, α-glycosidase, and acetylcholinesterase inhibitory properties of 1,3-disubstituted benzimidazolium salts

Chloro-/fluorobenzyl-substituted benzimidazolium salts were synthesized from the reaction of 4-fluorobenzyl/2-chloro-4-fluorobenzyl-substituted benzimidazole and chlorinated aromatic hydrocarbons. They were characterized using various spectroscopic techniques (Fourier-transform infrared and nuclear magnetic resonance) and elemental analysis. In addition, the crystal structures of the complexes 1a -d and 2b were determined by single-crystal X-ray diffraction methods. These compounds were crystallized in the triclinic crystal system with a P-1 space group. The crystal packing of all complexes is dominated by O-H⋯Cl hydrogen bonds, which link the water molecules and chloride anions, forming a chloride-water tetrameric cluster. These synthesized salts were found to be effective inhibitors for α-glycosidase and acetylcholinesterase (AChE), with K_i values ranging from 45.77 ± 6.83 to 102.61 ± 11.56 µM for α-glycosidase and 0.94 ± 0.14 to 10.24 ± 1.58 µM for AChE. AChE converts acetylcholine into choline and acetic acid, thus causing the return of a cholinergic neuron to its resting state. Discovering AChE and α-glycosidase inhibitors is one of the important ways to develop new drugs for the treatment of Alzheimer's disease and diabetes.

Design, synthesis, characterization, enzymatic inhibition evaluations, and docking study of novel quinazolinone derivatives

In this study, novel quinazolinone derivatives 7a-n were synthesized and evaluated against metabolic enzymes including α-glycosidase, acetylcholinesterase, butyrylcholinesterase, human carbonic anhydrase I, and II. These compounds exhibited high inhibitory activities in comparison to used standard inhibitors with K_i values in the range of 19.28-135.88 nM for α-glycosidase (K_i value for standard inhibitor = 187.71 nM), 0.68-23.01 nM for acetylcholinesterase (K_i value for standard inhibitor = 53.31 nM), 1.01-29.56 nM for butyrylcholinesterase (K_i value for standard inhibitor = 58.16 nM), 10.25-126.05 nM for human carbonic anhydrase I (K_i value for standard inhibitor = 248.18 nM), and 13.46-178.35 nM for human carbonic anhydrase II (K_i value for standard inhibitor = 323.72). Furthermore, the most potent compounds against each enzyme were selected in order to evaluate interaction modes of these compounds in the active site of the target enzyme. Cytotoxicity assay of the title compounds 7a-n against cancer cell lines MCF-7 and LNCaP demonstrated that these compounds do not show significant cytotoxic effects.

Novel quinazolin-sulfonamid derivatives: synthesis, characterization, biological evaluation, and molecular docking studies

In the design of novel drugs, the formation of hybrid molecules via the combination of several pharmacophores can give rise to compounds with interesting biochemical profiles. A series of novel quinazolin-sulfonamid derivatives (9a-m) were synthesized, characterized and evaluated for their in vitro antidiabetic, anticholinergics, and antiepileptic activity. These synthesized novel quinazolin-sulfonamid derivatives (9a-m) were found to be effective inhibitor molecules for the α-glycosidase, human carbonic anhydrase I and II (hCA I and hCA II), butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) enzyme, with Ki values in the range of 100.62 ± 13.68-327.94 ± 58.21 nM for α-glycosidase, 1.03 ± 0.11-14.87 ± 2.63 nM for hCA I, 1.83 ± 0.24-15.86 ± 2.57 nM for hCA II, 30.12 ± 3.81-102.16 ± 13.87 nM for BChE, and 26.16 ± 3.63-88.52 ± 20.11 nM for AChE, respectively. In the last step, molecular docking calculations were made to compare biological activities of molecules against enzymes which are achethylcholinesterase, butyrylcholinesterase and α-glycosidase.Communicated by Ramaswamy H. Sarma.