Inhibition Of Esterase Activity Research Articles

Unraveling the binding behavior of the antifouling biocide 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one with human serum albumin: Multi-spectroscopic, atomic force microscope, computational simulation, and esterase activity

As a marine antifouling biocide, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) exhibited high toxicity to marine organisms. This study investigated the interaction between DCOIT and human serum albumin (HSA) using several spectroscopic techniques combined with computer prediction methods. The UV–vis absorption spectra, Stern-Volmer constant (KSV) and fluorescence resonance energy transfer (FRET) results indicated that DCOIT caused static quenching of HSA fluorescence. The ΔG°, ΔH° and ΔS° values were −31.03 ± 0.17 kJ·mol−1, −133.54 ± 0.88 kJ·mol−1 and −348.46 ± 2.86 J.mol−1·K−1, respectively, suggesting that van der Waals forces and hydrogen bonds governed the spontaneous formation of the complex. Synchronous fluorescence and circular dichroism (CD) spectroscopy observed the burial of Trp residues within HSA and the unfolding of HSA secondary structure induced by DCOIT. Three-dimensional (3D) fluorescence and Atomic Force Microscopy (AFM) further detected DCOIT-induced loosening of HSA peptide chain structure. Site displacement experiments indicated that DCOIT binding at site I of HSA. Computational predictions indicated that hydrophobic interactions were also essential in the complex. The increased RMSD, Rg, SASA, and RMSF confirmed that DCOIT weakened the stability and compactness of HSA, rendering residues more flexible. Lastly, esterase activity assays demonstrated that DCOIT inhibited esterase activity and interfered with the human detoxification process.

Widely targeted metabolomics-based analysis of the impact of L. plantarum and L. paracasei fermentation on rosa roxburghii Tratt juice

Rosa roxburghii Tratt fruits (RRT) exhibit extremely high nutritional and medicinal properties due to its unique phytochemical composition. Probiotic fermentation is a common method of processing fruits. Variations in the non-volatile metabolites and bioactivities of RRT juice caused by different lactobacilli are not well understood. Therefore, we aimed to profile the non-volatile components and investigate the impact of L. plantarum fermentation (LP) and L. paracasei fermentation (LC) on RRT juice (the control, CG). There were both similarities and differences in the effects of LP and LC on RRT juice. Both of the two strains significantly increased the content of total phenolic, total flavonoid, and some bioactive compounds such as 2-hydroxyisocaproic acid, hydroxytyrosol and indole-3-lactic acid in RRT juice. Interestingly, compared with L. paracasei, L. plantarum showed better ability to increase the content of total phenolic and these valuable compounds, as well as certain bioactivities. The antioxidant capacity and α-glucosidase inhibitory activity of RRT juice were notably enhanced after the fermentations, whereas its cholesterol esterase inhibitory activity was reduced significantly. Moreover, a total of 1466 metabolites were identified in the unfermented and fermented RRT juices. There were 278, 251 and 134 differential metabolites in LP vs CG, LC vs CG, LC vs LP, respectively, most of which were upregulated. The key differential metabolites were classified into amino acids and their derivatives, organic acids, nucleotides and their analogues, phenolic acids and alkaloids, which can serve as potential markers for authentication and discrimination between the unfermented and lactobacilli fermented RRT juice samples. The KEGG enrichment analysis uncovered that metabolic pathways, purine metabolism, nucleotide metabolism and ABC transporters contributed mainly to the formation of unique composition of fermented RRT juice. These results provide good coverage of the metabolome of RRT juice in both unfermented and fermented forms and also provide a reference for future research on the processing of RRT or other fruits.

Secondary metabolite profiles and bioactivities of red raspberry juice during fermentation with Wickerhamomyces anomalus

Raspberry contains a broad array of valuable phytochemicals and therefore has positive effects on health. Fermentation can transform these components. The variations in the secondary metabolite profiles and bioactivities of red raspberry juice during Wickerhamomyces anomalus fermentation remain unknown. Herein, the effects of W. anomalus on the secondary metabolites, other constituents (total sugars, reducing sugars, and total acids) and bioactivities of raspberry juice were investigated. The fermentation significantly decreased the level of total sugars, reducing sugars, total acids and anthocyanins, but greatly increased the content of polyphenols and flavonoids. The antioxidant capacity and α-glucosidase inhibitory activity of raspberry juice were markedly enhanced after fermentation, whereas the cholesterol esterase inhibitory activity was reduced significantly. Moreover, 721 secondary metabolites were identified, wherein 437 secondary metabolites (240 upregulated, 197 downregulated) were selected as differential metabolites via targeted metabolomics. A total of 89 secondary metabolites were annotated in the Kyoto Encyclopedia of Genes and Genomes pathways, most of which were matched to biosynthesis of secondary metabolites and metabolic pathways. Phenolic acids were mainly transformed via phenylalanine metabolism and tyrosine metabolism. These results can provide reference for the development of functional raspberry beverages.

In vitro Neuroprotective Activity of Vigna radiata L. and Vigna pilosa L. on Amyloid Beta-induced Cytotoxicity

Background Alzheimer’s disease (AD) is considered to be the most common form of dementia. The drugs that are available for the treatment of AD provide only partial improvement of the condition. In recent years, natural ingredients have received increased attention in generating novel medications for treating various neurological disorders, including AD. Vigna radiata and Vigna pilosa are plants that are routinely included in many Ayurvedic formulations used to manage memory impairment. Objectives The present study was conducted to evaluate the in vitro anticholinesterase and neuroprotective activities of the plants V. radiata and V. pilosa. Materials and Methods A modified 96-well microplate assay according to Ellman’s method was employed to measure acetyl choline esterase (AChE) inhibitory activity. In vitro neuroprotective effect was measured by the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay using the SHSY-5Y (neuroblastoma cells) cell line against β-amyloid induced neurotoxicity. The ethyl acetate extract of V. radiata and the ethanolic extract of V. pilosa, which showed maximum AChE inhibitory activity, were selected for the MTT assay. The cell viability was evaluated by direct observation of cells with the help of an inverted phase contrast microscope, followed by the MTT assay method. Results Maximum AChE inhibitory activity was exhibited by an ethyl acetate extract of V. radiata. It showed AChE activity with a half-maximal inhibitory concentration (IC50) value of 286.40 µg/mL, while the ethanol extract of V. pilosa showed an IC50 value of 160.19 µg/mL. Extracts of both plants, V. radiata and V. pilosa, significantly ( p ≤ 0.001) improved the percentage of cell viability in a dose-dependent manner. Conclusion The plants V. radiata and V. pilosa showed potent anti-Alzheimer activity when tested using in vitro AChE inhibitory activity and by MTT assay using an β-amyloid-induced in vivo cytotoxicity model. These findings demand the need for further studies using in vivo models.

Plasma Protein Binding Determination for Unstable Ester Prodrugs: Remdesivir and Tenofovir Alafenamide

Remdesivir (RDV) and tenofovir alafenamide (TAF) are prodrugs designed to be converted to their respective active metabolites. Plasma protein binding (PPB) determination of these prodrugs is important for patients with possible alteration of free fraction of the drugs due to plasma protein changes in renal impairment, hepatic impairment, or pregnancy. However, the prodrugs’ instability in human plasma presents a challenge for accurate PPB determination. In this research work, two approaches were used in the method development and qualification for PPB assessment of RDV and TAF. For RDV, dichlorvos was used to inhibit esterase activity to stabilize the prodrug in plasma during equilibrium dialysis (ED). The impact of dichlorvos on protein binding was evaluated and determined to be insignificant by comparing the unbound fraction (fu) determined by the ED method with dichlorvos present and the fu determined by an ultrafiltration method without dichlorvos. In contrast to RDV, TAF degradation in plasma is ∼3-fold slower, and TAF stability cannot be improved by dichlorvos. Fit-for-purpose acceptance criteria for the TAF PPB method were chosen, and an ED method was developed based on these criteria. These two methods were then qualified and applied for PPB determinations in clinical studies.

Development of a Qualitative Test to Detect the Presence of Organophosphate Pesticides on Fruits and Vegetables.

In recent decades, the use of pesticides in agriculture has increased at a fast pace, highlighting safety problems for the environment and human health, which in turn has made it necessary to develop new detection and decontamination systems for pesticides. A new qualitative test capable of detecting the presence of pesticides on fruits and vegetables by using thermostable enzymes was discovered, and the test was carried out on apples and aubergines. The contaminating pesticides were extracted from fruits with acetonitrile and analyzed with a biosensor system based on the thermostable esterase EST2 immobilized on a nitrocellulose filter. This enzyme is irreversibly inhibited mainly in the presence of organophosphates pesticides. Therefore, by observing esterase activity inhibition, we revealed the presence of residual pesticides on the fruits and vegetables. By analyzing the rate of esterase activity inhibition, we predicted that residual pesticides are present on the surface of the fruits. When we cleaned the fruits by washing them in the presence of the phosphotriesterase SsoPox before the detection of the esterase activity on filters, we observed a full recovery of the activity for apples and 30% for aubergines, indicating that the enzymatic decontamination of organophosphates pesticides took place. The reported method permitted us to assess the pesticides present on the vegetables and their decontamination.

Purification, identification and hypolipidemic activities of three novel hypolipidemic peptides from tea protein

In this study, hypolipidemic peptides were obtained from tea protein by enzymatic hydrolysis, ultrafiltration and high-performance liquid chromatography. Subsequently, the hypolipidemic peptides were identified by mass spectrometry and screened through molecular docking technology, and the hypolipidemic activities and mechanisms of the active peptides were explored. The results showed that the hydrolysate of hypolipidemic peptides obtained by pepsin hydrolysis for 3 h had good bile salt binding ability. After purification, identification and molecular docking screening, three novel hypolipidemic peptides FLF, IYF and QIF were obtained. FLF, IYF and QIF can interact with the receptor proteins 1LPB and 1F6W through hydrogen bonds, π-π bonds, hydrophobic interactions and van der Waals forces, thus exerting hypolipidemic activities. Activity studies showed that, compared with the positive controls, FLF, IYF and QIF had excellent sodium taurocholate binding abilities, pancreatic lipase inhibitory activities and cholesterol esterase inhibitory activities. Moreover, FLF, IYF and QIF can effectively inhibit lipogenic differentiation of 3T3-L1 preadipocytes, reduce intracellular lipid and low-density lipoprotein content and increase high-density lipoprotein content. These results indicated that the three novel hypolipidemic peptides screened in this study had excellent hypolipidemic activities and were expected to be used as natural-derived hypolipidemic active ingredients for the development and application in functional foods.

Anti‐hypercholesteraemic and antioxidative activities of camel skin gelatin hydrolysate: effect of enzyme type, enzyme: substrate ratio and time of hydrolysis

SummaryCamel skin gelatin hydrolysate (CSGH) was prepared using different proteolytic enzymes [alcalase (A), protease (P) and their combination (AP (1:1))], hydrolysis time (2, 4 and 6 h) and enzyme: substrate (E/S) ratio (1%, 3% and 5%). In general, the degree of hydrolysis (DH) increased with increasing hydrolysis time for all enzyme treatments. CSGHs generated with alcalase showed significantly higher lipase (LP) inhibitory activity compared with protease‐derived CSGH at all hydrolysis conditions (P < 0.05). Whereas higher cholesterol esterase (CE) inhibitory activity was observed with CSGH produced by protease (P < 0.05). However, when CSGHs were produced using AP, the highest LP and CE inhibitory activity were recorded at 3 and 1% E/S ratio during 2 and 4 h of hydrolysis, respectively (P < 0.05). Antioxidant assays revealed that CSGHs showed improved radical scavenging activities compared with native CSG (P < 0.05). Overall results indicated that CSGHs with higher in vitro anti‐hypercholesteraemic and antioxidant activities could be obtained by enzymatic hydrolysis.

In vitro determination of anti-lipidemic, anti-inflammatory, and anti-oxidant properties and proximate composition of range of millet types and sorghum varieties in Sri Lanka

Methanolic extracts of whole grains of five millet types and two sorghum varieties were evaluated for anti-lipidemic, anti-inflammatory, and a range of anti-oxidant properties in vitro (n = 3 each). Furthermore, proximate composition (n = 3 each) was also studied. Results showed significant differences (P < 0.05) among the selected samples for studied parameters. Pancreatic lipase and cholesterol esterase inhibitory activities of selected samples (2 mg/ml) ranged from 21.16 ± 1.58 to 66.65 ± 3.30 and 17.43 ± 0.60 to 52.09 ± 1.61%, respectively. Nitric oxide inhibitory activity of selected samples (2 mg/ml) ranged from −1.17 ± 0.32 to 13.56 ± 0.93%. Total polyphenolic content (TPC), total flavonoid content (TFC), and total proanthocyanidin content (TPAC) were in the range of 0.19 ± 0.01–12.50 ± 0.87 mg gallic acid equivalents/g, 0.05 ± 0.00–1.57 ± 0.01 mg quercetin equivalents/g, and 0.35 ± 0.01–12.87 ± 0.25 mg cyaniding equivalents/g of samples, respectively. Ferric reducing anti-oxidant power, oxygen radical absorbance capacity, ferrous ion chelating activity, and ABTS and DPPH anti-oxidant properties ranged from 0.15 ± 0.00 to 4.56 ± 0.03 mg of Trolox equivalents (TEs)/g, 0.19 ± 0.01 to 8.50 ± 0.72 mg of TEs/g, 0.13 ± 0.00 to 0.79 ± 0.03 mg EDTA equivalents/g, 0.22 ± 0.00 to 25.57 ± 0.35 mg of TEs/g, and 0.07 ± 0.00 to 22.97 ± 0.83 mg of TEs/g of samples, respectively. Among the studied samples, pigmented sweet sorghum exhibited the highest activities for all the tested parameters. The observed activities were moderate compared to the reference standards used. The highest values for proximate composition parameters tested varied with the different samples studied. In conclusion, the consumption of especially pigmented millet and sorghum in Sri Lanka may play an important role in the prevention and management of oxidative stress–associated chronic diseases. This is the first study to report pancreatic lipase and cholesterol esterase inhibitory activities of any millet types and sorghum varieties in Sri Lanka and the first report of cholesterol esterase inhibitory activity of millet and sorghum the world over.

Interaction of mancozeb with human hemoglobin: Spectroscopic, molecular docking and molecular dynamic simulation studies

Mancozeb is a broad-spectrum fungicide used extensively in agriculture to protect plants from numerous diseases. Hemolysis of human erythrocytes on exposure to mancozeb has been reported. In the present study, we investigated the interaction of mancozeb with human hemoglobin (Hb) using multi-spectroscopic techniques, molecular docking and molecular dynamic simulation. UV–visible spectroscopy studies suggested intimate binding of mancozeb to Hb. Mancozeb quenched the intrinsic fluorescence of Hb and Stern-Volmer plots revealed that the quenching mechanism was of static type. Evaluation of thermodynamic parameters indicated that the binding of Hb to mancozeb was spontaneous, with van der Waals forces and hydrogen bonding being the key contributors in the binding reaction. Synchronous fluorescence experiments demonstrated that mancozeb altered the microenvironment around tryptophan residues, whereas polarity around tyrosine residues was not changed. Circular dichroism studies showed a decrease in the α helical content of Hb upon interaction with mancozeb. The inhibition of esterase activity showed that mancozeb can impair the enzymatic functions of Hb. Molecular docking study revealed that strong binding affinity existed between mancozeb and Hb, with hydrophobic forces playing a crucial role in the interaction. Molecular dynamic simulation showed that mancozeb formed a stable complex with Hb resulting in slight unfolding of the protein. To sum up, the results of this study show that mancozeb binds strongly to Hb, induces conformational changes in Hb and adversely affects its function.

One-pot hydrothermal green synthesis of Polygala tenuifolia mediated graphene quantum dots for acetylcholine esterase inhibitory activity

The present paper reports the synthesis of Donepezil hydrochloride functionalized Graphene quantum dots (DO-ptGQD) for the cure of Alzheimer disease. Graphene quantum dots were synthesized through root extract of Polygala tenuifolia by using one-pot hydrothermal synthesis method. Using UV/Visible spectroscopy, FTIR, SEM, TEM and XPS methods, the synthesized ptGQD was evaluated. Further the formulated DO-ptGQD was evaluated by SEM, TEM, FTIR, XPS techniques and was further evaluated for the encapsulation study, in-vitro study and various in-vivo models. Through behavioural model (Radial arm maze and Water morris maze assay) the learning and memory ability of the formulations was evaluated and the outcomes indicate that the DO-ptGQD markedly decreases the transmission latency to get in the baited arm in 12.19 ± 0.39 s or to the hidden stage in 15.37 ± 0.45 in 7 days. DO-ptGQD show more percentage inhibition of AchE enzyme that is 86.23 ± 1.28 as likened with the drug and ptGQD. DO-ptGQD considerably increases the protein and glutathione level and decreases the nitric oxide and lipid peroxide level. The Histopathological image indicates that DO-ptGQD treats the disorganization of the cell and show more preservation of small pyramidal cells as compared with the other formulations. In conclusion, DO-ptGQD was safe and effective drug delivery system for the treatment of Alzheimer disease and also the root extract of Polygala tenuifolia provide synergistic effect for the treatment of disease.

A comprehensive study on essential oil compositions, antioxidant, anticholinesterase and antityrosinase activities of three Iranian Artemisia species

Artemisia is one of the most diverse genera in the Asteraceae family. The genus is wildly distributed in Irano-Turanian habitats and includes 34 species in Iran. Here, for the first time the essential oil variability, antioxidants and anti-cholinesterase and anti-tyrosinase activities of extracts of three Artemisia species (A. tournefortiana, A. khorassanica, A. haussknechtii), from different regions of Iran were evaluated. Based on GC–MS analyses, 81.84% to 98.70% of the total oils were identified. Cluster analysis grouped the studied populations in three different chemotypes. The highest and the lowest essential oil contents were observed in A. khorassanica and A. haussknechtii species, respectively. Camphor, en-in-dicycloether, 1,8-cineole and (Z)-β-farnesene were the dominant components of essential oil in investigated ecotypes. The results revealed that the total phenol content was higher in A. tournefortiana collected from Kerman and A. haussknechtii collected from Chaharmahal and Bakhtiari. However, the lowest phenol content was recorded for A. haussknechtii collected from Isfahan province. The highest flavonoids content was found in A. tournefortiana collected from West Azerbaijan and A. khorassanica collected from North Khorasan. The highest FRAP antioxidant activity was observed in A. tournefortiana (Kerman) and the lower amount was in A. haussknechtii collected from Kohgiluyeh and Boyer-Ahmad. The highest antioxidant activity by DPPH method was in A. khorassanica collected from South Khorasan and the lowest activity was in Isfahan's A. haussknechtii. The acetycholine esterase inhibitory activity was higher in A. tournefortiana collected from West Azerbaijan; and the lowest activity was in A. haussknechtii collected from Chaharmahal and Bakhtiari province. The highest tyrosinase inhibitory activity was in A. khorassanica collected from North Khorasan; and the lowest was in A. haussknechtii collected from Chaharmahal and Bakhtiari.

Evaluation of in vitro Cholesterol Esterase Inhibitory Activity of Few Selected Vegetables – An Indication of Cardioprotective Property

Pharmacognosy Research,2022,14,2,188-194.DOI:10.5530/pres.14.2.27Published:April 2022Type:Original ArticleAuthors:Thiyagarajan Sathishkumar, Muruvanda Bhuvan Uthaiah, Ravichandran Vinu Varshith, Kuppamuthu Kumaresan, and Vinohar Stephen Rapheal Author(s) affiliations:Thiyagarajan Sathishkumar, Muruvanda Bhuvan Uthaiah*, Ravichandran Vinu Varshith, Kuppamuthu Kumaresan, Vinohar Stephen Rapheal Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, Tamil Nadu, INDIA. Abstract:Background: Cardiovascular diseases are responsible for severe mortality rate amongst the population. Several drugs available to control and/ or cure the same, cause severe adverse effects amidst human population. Contextually, the present study was devised to screen the in vitro cholesterol esterase (CEase) activity of few selected vegetables as an indicator of cardioprotective property. Objectives: To screen and purify the polyphenolic fractionate from the vegetable(s) extract that record an optimal CEase activity. Materials and Methods: CEase inhibitory activity was investigated using standard spectrophotometric assay. Microwave assisted central composite design based response surface methodology (CCD based RSM) was executed to quantify an improvement in the CEase inhibitory activity of Solanum melongena extract. One dimensional thin layer chromatography (1D TLC) and two-dimensional preparative thin layer chromatography (2D PTLC) analyses were carried out for Brassica oleracea var. botrytis hot water extract to identify and eluate the polyphenolic fractionate, respectively. Results: Significant CEase inhibitory activity was noticed in the hot water extract of Brassica oleracea var. botrytis (84.65 ± 3.29%) than the other vegetable extracts. Even though the optimal process model was validated (at 5% level), no significant improvement was recorded in the CEase inhibition. The presence of polyphenolic content in the hot water extract of Brassica oleracea var. botrytis (Rf = 0.69) was confirmed by comparing with standard quercetin (Rf = 0.60). Strong blue and moderate brownish yellow color spots revealed the presence of phenolic acid and flavonoid eluates respectively, were purified using 2D PTLC technique. The eluate has recorded a near moderate (28.57 ± 2.12%) CEase inhibitory activity. Conclusion: Brassica oleracea var. botrytis possess significant CEase inhibitory activity and proved to be a good diet to protect from various cardiovascular diseases. Key words: Brassica oleracea var. botrytis, Cholesterol esterase, Solanum melongena, Microwave Assisted Response Surface Methodology, Flavonoid. View:PDF (245.05 KB)

Structural and biochemical evidence that ATP inhibits the cancer biomarker human aldehyde dehydrogenase 1A3

Human aldehyde dehydrogenase (ALDH) participates in the oxidative stress response and retinoid metabolism, being involved in several diseases, including cancer, diabetes and obesity. The ALDH1A3 isoform has recently elicited wide interest because of its potential use as a cancer stem cell biomarker and drug target. We report high-resolution three-dimensional ALDH1A3 structures for the apo-enzyme, the NAD+ complex and a binary complex with ATP. Each subunit of the ALDH1A3-ATP complex contains one ATP molecule bound to the adenosine-binding pocket of the cofactor-binding site. The ATP complex also shows a molecule, putatively identified as a polyethylene glycol aldehyde, covalently bound to the active-site cysteine. This mimics the thioacyl-enzyme catalytic intermediate, which is trapped in a dead enzyme lacking an active cofactor. At physiological concentrations, ATP inhibits the dehydrogenase activity of ALDH1A3 and other isoforms, with a Ki value of 0.48 mM for ALDH1A3, showing a mixed inhibition type against NAD+. ATP also inhibits esterase activity in a concentration-dependent manner. The current ALDH1A3 structures at higher resolution will facilitate the rational design of potent and selective inhibitors. ATP binding to ALDH1A3 enables activity modulation by the energy status of the cell and metabolic reprogramming, which may be relevant in several disease conditions.

Green Synthesis and Characterization of Zinc Oxide Nanoparticles (ZnO NPs) from Camellia sinensis Leaf Extract and Its Potential of Antibacterial Activity and Acetyl Cholinesterase Inhibitory Activities

Nanoparticles are widely used in the biotechnology and biomedicalfield. Green synthetic methods of nanoparticles are a simple and environmentallybenign process that declines the demerits of conventional chemical andphysical methods. The synthesis of semiconductor and metal nanoparticles is a risingdo research part, due to the possible applications in the progress of new technologies.The present research information the synthesis and characterization of zinc oxide nanoparticles (ZnO NPs) using C. Sinensis leaf extract. The findings of these studies show the green synthesized ZnO NPs are effective, safe, and eco-friendly as they arestable and have abundant flower shapes with maximum particles in size ranging from 100 nm indiameter. The synthesized ZnO NPs have been tested against the pathogenic microorganismsand showed an excellent zone of inhibition. DPPH radical scavenging activity of synthesized ZnO NPs expressed DPPH free radicals as a percentage of inhibition andIC50value of 70.37%. Acetylcholine esterase (AChE) inhibitory activity possesses the maximum amount of the synthesized ZnO NPs. Since the results ofthe current work, it was concluded that the synthesized ZnO NPs exhibited significant antibacterial and acetylcholine esterase inhibitory activities. Hence it can beused as a drug with multifunction in treating Alzheimer’s disease (AD).

Specificity of Saliva Esterases by Wine Carboxylic Esters and Inhibition by Wine Phenolic Compounds Under Simulated Oral Conditions.

The specificity of human esterase activity (EA) from the stimulated (SS) and non-stimulated (NSS) saliva toward different typical wine odorant carboxylic esters and its inhibition by the wine phenolic compounds has been evaluated. For the specificity, six p-nitrophenyl linked esters with different carbon chain lengths (from 2 to 12 carbons) were employed. The five single phenolic compounds (catechin, quercetin, kaempferol, myricetin, and resveratrol) at typical wine concentrations were assayed in the salivary EA inhibition study. Additionally, the inhibition exerted by the mixtures of wine polyphenols was evaluated using four commercial phenolic extracts [a grape seed extract (GSE), the monomers and oligomer fraction of the GSE, and a red wine extract (RWE)]. Finally, the saliva EA under the wine consumption conditions (pH = 5 and 11.3% ethanol) was evaluated. The results showed a higher EA in SS than NSS. It was also shown that the EA was higher toward the smaller than bigger esters regardless of the saliva types (SS or NSS). However, the inhibition exerted on saliva EA by the individual and mixtures of phenolic compounds was proven. Catechin was the phenolic compound that mostly inhibited saliva EA, while resveratrol showed the lowest EA inhibition. This inhibition was mainly related to the concentration of the phenolic compounds, but also with its structure. Finally, under simulated wine consumption, a decrease in EA was produced, which was mainly provoked by the decrease in the salivary pH. Nonetheless, since salivary pH recovers a few seconds after wine consumption, saliva EA might be relevant for the long-lasting perception of wine esters.

Inhibitory in vitro effects of Basil ( Ocimum basilicum ) leaf extracts on cholesterol esterase activity and the growth of Escherichia coli

The present study was to analyze the in vitro antibacterial activity and the effects on cholesterol esterase activity of the methanol extract from basil leaves and its hexane, ethyl acetate, butanol, and aqueous fractions. The highest total phenolic and flavonoid contents were recorded in the methanol extract. Total 92 compounds were determined by using gas chromatography-mass spectrometry belong to hydrocarbons, fatty acids, alcohols, esters, and phenols which reportedly have a variety of biological activities such as antibacterial, antiviral, anti-inflammatory, and anti-carcinogenic activities. This study evaluated the antibacterial activity of the basil methanol extract and its fractions based on the inhibitory concentrations of Escherichia coli at 50 mg/ml. The best results were obtained with the methanol extract, hexane, and ethyl acetate fractions, which exhibited anti-cholesterol esterase activity. Novelty impact statement The highest phenolic content, flavonoid content, and cholesterol esterase inhibitory activity were detected in the methanol extract. Ninety-two compounds were identified using gas chromatography-mass spectrometry from Thai Basi. Methanol extract, hexane, and ethyl acetate fractions had strong antibacterial activity at 50 mg/ml.

Cladamide: a new ceramide from the endophytic fungus Cladosporium cladosporioides

A new ceramide, named cladamide (1), in addition to cinnamic acid (2), para-coumaric acid (3), stigmasterol-3-O-β-D-glucoside (4), and uracil (5), was isolated from the white beans culture of Cladosporium cladosporioides, a marine-derived endohpytic fungus isolated from the leaves of the mangrove, Avicennia marina (Forssk.) Vierh. Structure elucidation of compound 1 was established on the basis of extensive 1D and 2D NMR spectroscopic techniques in combination with HR-ESI-MS. The ability of the isolated compounds to inhibit acetylcholine esterase was evaluated. Compound 3 showed the highest acetylcholine esterase inhibitory activity (IC50 = 0.057 ± 0.003 µM), followed by compound 4 (IC50 = 0.068 ± 0.003 µM) and compound 1 (IC50 = 0.099 ± 0.005 µM) compared to donepezil, the positive control, (IC50 = 0.044 ± 0.002 µM). Compounds 2 and 5 showed lower activity (IC50 = 0.182 ± 0.009 and 0.236 ± 0.012 µM, respectively). The results were further validated by molecular docking study.

Metabolic Resistance in Permethrin-Resistant Florida Aedes aegypti (Diptera: Culicidae).

Simple SummaryPyrethroid-oriented vector control programs have increased worldwide to control adult Aedes aegypti mosquitoes and quell Aedes-borne disease epidemics. Due to years of pyrethroid use, resistance to pyrethroids in Ae. aegypti has become a global issue. In Florida, permethrin is the most common pyrethroid adulticide active ingredient used to control mosquito populations. Thus far, all wild Florida Ae. aegypti populations tested against permethrin have been found to be resistant. Metabolic resistance is a major mechanism of resistance in insects in which enzyme-mediated reactions cause the degradation or sequestration of insecticides. We performed assays to investigate the presence of metabolic resistance in 20 Florida Ae. aegypti populations and found that 11 populations (55%) exhibited metabolic resistance due to the action of at least one of three classes of metabolizing enzymes: oxidases, esterases, and glutathione transferases. Additionally, we identified two metabolic enzyme inhibitors: S.S.S-tributyl phosphorotrithioate (DEF; inhibits esterase activity) and diethyl maleate (DM; inhibits glutathione transferase activity), in addition to the commonly used piperonyl butoxide (PBO; inhibits oxidase activity), which were able to increase the efficacy of permethrin against resistant Ae. aegypti populations. Pre-exposure to DEF, PBO, and DM resulted in increased mortality after permethrin exposure in eight (73%), seven (64%), and six (55%) of the Ae. aegypti populations, respectively. Increasing the effectiveness of pyrethroids is important for mosquito control, as it is the primary method used for adult control during mosquito-borne disease outbreaks. Considering that DEF and DM performed similarly to PBO, they may be good candidates for inclusion in formulated pyrethroid products to increase their efficacy against resistant mosquitoes.Aedes aegypti is the principal mosquito vector for many arthropod-borne viruses (arboviruses) including dengue, chikungunya, and Zika. In the United States, excessive permethrin use has led to a high frequency of resistance in mosquitoes. Insecticide resistance is a significant obstacle in the struggle against vector-borne diseases. To help overcome metabolic resistance, synergists that inhibit specific metabolic enzymes can be added to formulated pyrethroid products. Using modified CDC bottle bioassays, we assessed the effect of three inhibitors (piperonyl butoxide (PBO), which inhibits oxidase activity; S.S.S-tributyl phosphorotrithioate (DEF), which inhibits esterase activity; and diethyl maleate (DM), which inhibits glutathione transferase activity) + permethrin. We performed these against 20 Florida Ae. aegypti populations, all of which were resistant to permethrin. Our data indicated that 11 out of 20 populations (55%) exhibited metabolic resistance. Results revealed 73% of these populations had significant increases in mortality attributed to DEF + permethrin, 64% to PBO + permethrin, and 55% to DM + permethrin compared to permethrin alone. Currently, PBO is the only metabolic enzyme inhibitor added to formulated pyrethroid products used for adult mosquito control. Our results suggest that the DEF and DM inhibitors could also be useful additives in permethrin products, especially against metabolically resistant Ae. aegypti mosquitoes. Moreover, metabolic assays should be conducted to better inform mosquito control programs for designing and implementing integrated vector management strategies.

Acetylcholine esterase inhibitory activity of green synthesized nanosilver by naphthopyrones isolated from marine-derived Aspergillus niger.

Aspergillus niger metabolites exhibited a wide range of biological properties including antioxidant and neuro-protective effects and some physical properties as green synthesis of silver nanoparticles AgNP. The present study presents a novel evidence for the various biological activities of green synthesized AgNPs. For the first time, some isolated naphtho-γ-pyrones from marine-derived Aspergillus niger, flavasperone (1), rubrofusarin B (2), aurasperone A (3), fonsecinone A (4) in addition to one alkaloid aspernigrin A (7) were invistigated for their inhibitory activity of acetylcholine esterase AChE, a hallmark of Alzheimer's disease (AD). The ability to synthesize AgNPs by compounds 3, 4 and 7 has been also tested for the first time. Green synthesized AgNPs were well-dispersed, and their size was ranging from 8-30 nm in diameter, their morphology was obviously spherical capped with the organic compounds. Further biological evaluation of their AChE inhibitory activity was compared to the parent compounds. AgNps dramatically increased the inhibitory activity of Compounds 4, 3 and 7 by 84, 16 and 13 fold, respectively to be more potent than galanthamine as a positive control with IC50 value of 1.43 compared to 0.089, 0.311 and 1.53 of AgNPs of Compounds 4, 3 and 7, respectively. Also compound 2 showed moderate inhibitory activity. This is could be probably explained by closer fitting to the active sites or the synergistic effect of the stabilized AgNPs by the organic compouds. These results, in addition to other intrinsic chemical and biological properties of naphtho-γ-pyrones, suggest that the latter could be further explored with a view towards other neuroprotective studies for alleviating AD.