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Kombucha is a fermented tea drink using a symbiotic culture of bacteria and yeast. This drink has been widely used to maintain blood sugar levels. Meanwhile, leaf boiled water of Syzygium polyanthum (Wight) Walp. has been used as an alternative medicine for diabetes mellitus in Indonesia. If this herb is made into kombucha, it may have higher antihyperglycemic activity than kombucha from tea leaves. However, there are no scientific reports of antihyperglycemic activity from S. polyanthum leaf kombucha by inhibiting alpha-glucosidase. This study aims to determine the activity and kinetics inhibition of S. polyanthum leaves kombucha against α-glucosidase. Samples were prepared at varying concentrations (12.5, 25, 37.5, 50 g/L), while phytochemical components in the products were identified, and the inhibitory activity as well as kinetics were comprehensively analyzed. In silico evaluations were conducted to further explore the inhibitory activity. The results showed that the products contained secondary metabolites such as flavonoids, saponins, and tannins. The inhibitory activity against α-glucosidase ranged from 81.05 to 89.41%. The inhibition mechanism was identified as uncompetitive, with a Michaelis-Menten constant (KM) of 0.1357 mM and a vmax value of 27.7008 U/ml minute. Several metabolites showed promising inhibition potential due to their strong binding interactions with α-glucosidase, including hydrogen bonding (H-bond), hydrophobic interactions, van der Waals forces, and electrostatic forces. Additionally, two metabolites, farnesol and α-pinene, were found to interact with other human proteins. These observations showed the potential of S. polyanthum leaves kombucha as a health-promoting beverage that might aid blood sugar control in diabetic individuals. [ABSTRACT FROM AUTHOR]

Infectious diseases caused by trypanosomatids, including African trypanosomiasis (sleeping sickness), Chagas disease, and different forms of leishmaniasis, are Neglected Tropical Diseases affecting millions of people worldwide, mainly in vulnerable territories of tropical and subtropical areas. In general, current treatments against these diseases are old-fashioned, showing adverse effects and loss of efficacy due to misuse or overuse, thus leading to the emergence of resistance. For these reasons, searching for new antitrypanosomatid drugs has become an urgent necessity, and different metabolic pathways have been studied as potential drug targets against these parasites. Considering that trypanosomatids possess a unique redox pathway based on the trypanothione molecule absent in the mammalian host, the key enzymes involved in trypanothione metabolism, trypanothione reductase and trypanothione synthetase, have been studied in detail as druggable targets. In this review, we summarize some of the recent findings on the molecules inhibiting these two essential enzymes for Trypanosoma and Leishmania viability. [ABSTRACT FROM AUTHOR]

The shikimate pathway is crucial for the biosynthesis of aromatic amino acids in plants and represents a promising target for developing new herbicides. This work aimed to identify inhibitors of shikimate dehydrogenase (SDH), a key enzyme of the shikimate pathway that catalyzes the conversion of 3-dehydroshikimate to shikimate. Virtual screening and molecular dynamic simulations were performed on the SDH active site of Arabidopsis thaliana (AtSDH), and 6-nitroquinazoline-2,4-diol (NQD) was identified as a potential inhibitor. In vitro assays showed that NQD decreased the activity of AtSDH by reducing Vmax while keeping KM unchanged, indicating non-competitive inhibition. In vivo, hydroponic experiments revealed that NQD reduced the root length of soybean and maize. Additionally, NQD increased the total protein content and certain amino acids. Soybean roots uptake NQD more efficiently than maize roots. Furthermore, NQD reduced shikimate accumulation in glyphosate-treated soybean roots, suggesting its potential to restrict the flow of metabolites along the shikimate pathway in soybean. The simultaneous treatment of maize seedlings with glyphosate and NQD accumulated gallic acid in the roots, indicating that NQD inhibits SDH in vivo. Overall, the data indicate that NQD inhibits SDH both in vitro and in vivo, providing valuable insights into the potential development of herbicides targeting SDH. [ABSTRACT FROM AUTHOR]

While cytochrome P450 (CYP; P450) enzymes are commonly associated with the metabolism of organic xenobiotics and drugs or the biosynthesis of organic signaling molecules, they are also impacted by a variety of inorganic species. Metallic nanoparticles, clusters, ions, and complexes can alter CYP expression, modify enzyme interactions with reductase partners, and serve as direct inhibitors. This commonly overlooked topic is reviewed here, with an emphasis on understanding the structural and physiochemical basis for these interactions. Intriguingly, while both organometallic and coordination compounds can act as potent CYP inhibitors, there is little evidence for the metabolism of inorganic compounds by CYPs, suggesting a potential alternative approach to evading issues associated with rapid modification and elimination of medically useful compounds. [ABSTRACT FROM AUTHOR]

Inhibition of insulin-regulated aminopeptidase (IRAP) has been shown to improve cognitive functions in several animal models. Recently, we performed a screening campaign of approximately 10,000 compounds, identifying novel small-molecule-based compounds acting as inhibitors of the enzymatic activity of IRAP. Here we report on the chemical synthesis, structure-activity relationships (SAR) and initial characterization of physicochemical properties of a series of 48 imidazo [1,5-α]pyridine-based inhibitors, including delineation of their mode of action as non-competitive inhibitors with a small L-leucine-based IRAP substrate. The best compound displays an IC50 value of 1.0 µM. We elucidate the importance of two chiral sites in these molecules and find they have little impact on the compound's metabolic stability or physicochemical properties. The carbonyl group of a central urea moiety was initially believed to mimic substrate binding to a catalytically important Zn2+ ion in the active site, although the plausibility of this binding hypothesis is challenged by observation of excellent selectivity versus the closely related aminopeptidase N (APN). Taken together with the non-competitive inhibition pattern, we also consider an alternative model of allosteric binding. [ABSTRACT FROM AUTHOR]

Based on our previous success in using cyclobutanone derivatives as enzyme inhibitors, we have designed and prepared a 37-member library of α-aminocyclobutanone amides and sulfonamides, screened for inhibition of the bacterial enzyme diaminopimelate desuccinylase (DapE), which is a promising antibiotic target, and identified several inhibitors with micromolar inhibitory potency. Molecular docking suggests binding of the deprotonated hydrate of the strained cyclobutanone, and thermal shift analysis with the most potent inhibitor (3y, IC50 = 23.1 µM) enabled determination of a Ki value of 10.2 +/− 0.26 µM and observed two separate Tm values for H. influenzae DapE (HiDapE). [ABSTRACT FROM AUTHOR]

Boronic acids/esters have recently emerged in the field of medicinal and pharmaceutical research due to their exceptional oxophilicity, low toxicity, and unique structure. They are known as potent enzyme inhibitors, cancer therapy capture agents, and can mimic certain types of antibodies to fight infections. They have been designed and developed into drugs, and this approach has emerged in the last 20 years. Five boronic acid drugs have been approved by the FDA and Health Canada, two of which are used to treat cancer, specifically multiple myeloma. The purpose of this review is to investigate boronic acid/ester derivatives as potential pharmaceutical agents as well as the mechanism of action. It will concentrate on six types of cancer: multiple myeloma, prostate cancer, breast cancer, lung cancer, cervical cancer, and colon cancer. Some newly developed boron-containing compounds have already demonstrated highly promising activities, but further investigation is required before final conclusions can be drawn. [ABSTRACT FROM AUTHOR]

The shikimate pathway is crucial for the biosynthesis of aromatic amino acids in plants and represents a promising target for developing new herbicides. This work aimed to identify inhibitors of shikimate dehydrogenase (SDH), a key enzyme of the shikimate pathway that catalyzes the conversion of 3-dehydroshikimate to shikimate. Virtual screening and molecular dynamic simulations were performed on the SDH active site of Arabidopsis thaliana (AtSDH), and 6-nitroquinazoline-2,4-diol (NQD) was identified as a potential inhibitor. In vitro assays showed that NQD decreased the activity of AtSDH by reducing Vmax while keeping KM unchanged, indicating non-competitive inhibition. In vivo, hydroponic experiments revealed that NQD reduced the root length of soybean and maize. Additionally, NQD increased the total protein content and certain amino acids. Soybean roots uptake NQD more efficiently than maize roots. Furthermore, NQD reduced shikimate accumulation in glyphosate-treated soybean roots, suggesting its potential to restrict the flow of metabolites along the shikimate pathway in soybean. The simultaneous treatment of maize seedlings with glyphosate and NQD accumulated gallic acid in the roots, indicating that NQD inhibits SDH in vivo. Overall, the data indicate that NQD inhibits SDH both in vitro and in vivo, providing valuable insights into the potential development of herbicides targeting SDH.

While cytochrome P450 (CYP; P450) enzymes are commonly associated with the metabolism of organic xenobiotics and drugs or the biosynthesis of organic signaling molecules, they are also impacted by a variety of inorganic species. Metallic nanoparticles, clusters, ions, and complexes can alter CYP expression, modify enzyme interactions with reductase partners, and serve as direct inhibitors. This commonly overlooked topic is reviewed here, with an emphasis on understanding the structural and physiochemical basis for these interactions. Intriguingly, while both organometallic and coordination compounds can act as potent CYP inhibitors, there is little evidence for the metabolism of inorganic compounds by CYPs, suggesting a potential alternative approach to evading issues associated with rapid modification and elimination of medically useful compounds.

Boronic acids/esters have recently emerged in the field of medicinal and pharmaceutical research due to their exceptional oxophilicity, low toxicity, and unique structure. They are known as potent enzyme inhibitors, cancer therapy capture agents, and can mimic certain types of antibodies to fight infections. They have been designed and developed into drugs, and this approach has emerged in the last 20 years. Five boronic acid drugs have been approved by the FDA and Health Canada, two of which are used to treat cancer, specifically multiple myeloma. The purpose of this review is to investigate boronic acid/ester derivatives as potential pharmaceutical agents as well as the mechanism of action. It will concentrate on six types of cancer: multiple myeloma, prostate cancer, breast cancer, lung cancer, cervical cancer, and colon cancer. Some newly developed boron-containing compounds have already demonstrated highly promising activities, but further investigation is required before final conclusions can be drawn.

Background: Salivary glands from blood-feeding arthropods secrete several molecules that inhibit mammalian hemostasis and facilitate blood feeding and pathogen transmission. The salivary functions from Simulium guianense, the main vector of Onchocerciasis in South America, remain largely understudied. Here, we have characterized a salivary protease inhibitor (Guianensin) from the blackfly Simulium guianense. Materials and methods: A combination of bioinformatic and biophysical analyses, recombinant protein production, in vitro and in vivo experiments were utilized to characterize the molecula mechanism of action of Guianensin. Kinetics of Guianensin interaction with proteases involved in vertebrate inflammation and coagulation were carried out by surface plasmon resonance and isothermal titration calorimetry. Plasma recalcification and coagulometry and tail bleeding assays were performed to understand the role of Guianensin in coagulation. Results: Guianensin was identified in the sialotranscriptome of adult S. guianense flies and belongs to the Kunitz domain of protease inhibitors. It targets various serine proteases involved in hemostasis and inflammation. Binding to these enzymes is highly specific to the catalytic site and is not detectable for their zymogens, the catalytic site-blocked human coagulation factor Xa (FXa), or thrombin. Accordingly, Guianensin significantly increased both PT (Prothrombin time) and aPTT (Activated partial thromboplastin time) in human plasma and consequently increased blood clotting time ex vivo. Guianensin also inhibited prothrombinase activity on endothelial cells. We show that Guianensin acts as a potent anti-inflammatory molecule on FXa-induced paw edema formation in mice. Conclusion: The information generated by this work highlights the biological functionality of Guianensin as an antithrombotic and anti-inflammatory protein that may play significant roles in blood feeding and pathogen transmission. [ABSTRACT FROM AUTHOR]

Inhibition of insulin-regulated aminopeptidase (IRAP) has been shown to improve cognitive functions in several animal models. Recently, we performed a screening campaign of approximately 10,000 compounds, identifying novel small-molecule-based compounds acting as inhibitors of the enzymatic activity of IRAP. Here we report on the chemical synthesis, structure-activity relationships (SAR) and initial characterization of physicochemical properties of a series of 48 imidazo [1,5-α]pyridine-based inhibitors, including delineation of their mode of action as non-competitive inhibitors with a small L-leucine-based IRAP substrate. The best compound displays an IC50 value of 1.0 µM. We elucidate the importance of two chiral sites in these molecules and find they have little impact on the compound’s metabolic stability or physicochemical properties. The carbonyl group of a central urea moiety was initially believed to mimic substrate binding to a catalytically important Zn2+ ion in the active site, although the plausibility of this binding hypothesis is challenged by observation of excellent selectivity versus the closely related aminopeptidase N (APN). Taken together with the non-competitive inhibition pattern, we also consider an alternative model of allosteric binding.

Based on our previous success in using cyclobutanone derivatives as enzyme inhibitors, we have designed and prepared a 37-member library of α-aminocyclobutanone amides and sulfonamides, screened for inhibition of the bacterial enzyme diaminopimelate desuccinylase (DapE), which is a promising antibiotic target, and identified several inhibitors with micromolar inhibitory potency. Molecular docking suggests binding of the deprotonated hydrate of the strained cyclobutanone, and thermal shift analysis with the most potent inhibitor (3y, IC50 = 23.1 µM) enabled determination of a Ki value of 10.2 +/− 0.26 µM and observed two separate Tm values for H. influenzae DapE (HiDapE).

BackgroundSalivary glands from blood-feeding arthropods secrete several molecules that inhibit mammalian hemostasis and facilitate blood feeding and pathogen transmission. The salivary functions from Simulium guianense, the main vector of Onchocerciasis in South America, remain largely understudied. Here, we have characterized a salivary protease inhibitor (Guianensin) from the blackfly Simulium guianense.Materials and methodsA combination of bioinformatic and biophysical analyses, recombinant protein production, in vitro and in vivo experiments were utilized to characterize the molecula mechanism of action of Guianensin. Kinetics of Guianensin interaction with proteases involved in vertebrate inflammation and coagulation were carried out by surface plasmon resonance and isothermal titration calorimetry. Plasma recalcification and coagulometry and tail bleeding assays were performed to understand the role of Guianensin in coagulation.ResultsGuianensin was identified in the sialotranscriptome of adult S. guianense flies and belongs to the Kunitz domain of protease inhibitors. It targets various serine proteases involved in hemostasis and inflammation. Binding to these enzymes is highly specific to the catalytic site and is not detectable for their zymogens, the catalytic site-blocked human coagulation factor Xa (FXa), or thrombin. Accordingly, Guianensin significantly increased both PT (Prothrombin time) and aPTT (Activated partial thromboplastin time) in human plasma and consequently increased blood clotting time ex vivo. Guianensin also inhibited prothrombinase activity on endothelial cells. We show that Guianensin acts as a potent anti-inflammatory molecule on FXa-induced paw edema formation in mice.ConclusionThe information generated by this work highlights the biological functionality of Guianensin as an antithrombotic and anti-inflammatory protein that may play significant roles in blood feeding and pathogen transmission.

Polygoni Cuspidati Rhizoma et Radix (PCR), the rhizome and root of Polygonum cuspidatum Sieb. et Zucc., has been used as an herbal medicine for a long time. In this study, the ultrafiltration combined with high performance liquid chromatography (UF-HPLC) method was developed to screen tyrosinase (TYR), α-glucosidase (α-GLU), and xanthine oxidase (XOD) inhibitors from PCR. Firstly, the inhibitory activity of 50% methanol PCR extract on TYR, α-GLU, XOD, and acetylcholinesterase (ACHE) was tested. The extract showed a good inhibition on the enzymes, except for ACHE. Therefore, UF-HPLC experiments were carried out to screen TYR, α-GLU, and XOD inhibitors from PCR extract. Seven potential bioactive components were discovered, including methylgallate (1), 1,6-di-O-galloyl-D-glucose (2), polydatin-4′-O-D-glucoside (3), resveratrol-4′-O-D-glucoside (4), polydatin (5), malonyl glucoside resveratrol (6), and resveratrol-5-O-D-glucoside (7). Most of them were found as enzyme inhibitors from PCR for the first time, except polydatin (5), which had been reported as an α-GLUI in PCR in the literature. Finally, molecular docking analysis was applied to validate the interactions of these seven potential active components with the enzymes. Compounds 1–7 were proven as TYR inhibitors, compounds 2, 4–7 were identified as XOD inhibitors, and compounds 4–6 were confirmed as α-GLU inhibitors. In short, the current study provides a good reference for the screening of enzyme inhibitors through UF-HPLC, and provides scientific data for future studies of PCR. [ABSTRACT FROM AUTHOR]

Context Brassica incana Ten. (Brassicaceae) is an edible plant with very limited available information. Previous studies have demonstrated the polyphenolic profile and the antioxidant and cytotoxic properties of the leaf and flowering top hydroalcoholic extracts.Objective The volatile composition and the antidiabetic and anti-obesity potential of B. incana leaf and flowering top extracts have been investigated.Material and methods The volatile characterization of the extracts was attained by HS-SPME-GC/MS analysis. The antidiabetic and anti-obesity potential was investigated spectrophotometrically in vitro by the ability to modulate pancreatic lipase and α-glucosidase at different concentrations using orlistat and acarbose as reference drugs. The inhibition of advanced glycation end-products (AGEs) was measured with aminoguanidine as reference and the antioxidant activity with the xanthine/xanthine oxidase system and Trolox for comparative purposes.Results Several volatiles belonging to different chemical classes were identified, being sulphur compounds the most abundant in both leaf and flowering top extracts (56.33% and 64.40% of all volatiles). Although the leaf extract showed lower IC50 values in most of the assays (0.968 and 1.921 mg/mL for α-glucosidase; 0.192 and 0.262 mg/mL for AGEs; 0.022 and 0.038 mg/mL for superoxide scavenging), there were no statistically significant differences between both samples. These extracts showed a similar behaviour to Trolox in the xanthine oxidase assay (IC50 values of 0.022 mg/mL for leaf extract; 0.038 mg/mL for flowering top and 0.028 for Trolox).Conclusions Leaves and flowering tops from B. incana can be used as sources of functional compounds that could act as antidiabetic and anti-obesogenic agents.

Carbonic anhydrases (EC 4.2.1.1) catalyse the reversible hydration of CO2 into bicarbonate and protons. As a hypoxia-sensitive and tumour-associated isoform, isoform CA IX, is significantly overexpressed in various malignancies, being a validated target for new anticancer/antimetastatic drugs. A multitude of studies has shown that CA IX inhibition decreases cancer cell proliferation and metastasis through pHe/pHi modulation and enhancement of ferroptosis among others. Numerous studies demonstrated increased efficacy of cytotoxic drugs combined with CA inhibitors (CAIs) in various cancer types. We tested the inhibitory effect of boric acid (BA), an inorganic Lewis acid, on CA IX as well as other isoforms (CA I, II, and XII). BA acted as a millimolar in vitro CAI, decreased proliferation of two cancer cell lines, although not strong correlations between the in vitro inhibition and in vivo effects were observed. The mechanism of antiproliferative action of BA should be investigated in more detail.

The landscape of viral strains and lineages of SARS-CoV-2 keeps changing and is currently dominated by Delta and Omicron variants. Members of the latest Omicron variants, including BA.1, are showing a high level of immune evasion, and Omicron has become a prominent variant circulating globally. In our search for versatile medicinal chemistry scaffolds, we prepared a library of substituted ɑ-aminocyclobutanones from an ɑ-aminocyclobutanone synthon (11). We performed an in silico screen of this actual chemical library as well as other virtual 2-aminocyclobutanone analogs against seven SARS-CoV-2 nonstructural proteins to identify potential drug leads against SARS-CoV-2, and more broadly against coronavirus antiviral targets. Several of these analogs were initially identified as in silico hits against SARS-CoV-2 nonstructural protein 13 (Nsp13) helicase through molecular docking and dynamics simulations. Antiviral activity of the original hits as well as ɑ-aminocyclobutanone analogs that were predicted to bind more tightly to SARS-CoV-2 Nsp13 helicase are reported. We now report cyclobutanone derivatives that exhibit anti-SARS-CoV-2 activity. Furthermore, the Nsp13 helicase enzyme has been the target of relatively few target-based drug discovery efforts, in part due to a very late release of a high-resolution structure accompanied by a limited understanding of its protein biochemistry. In general, antiviral agents initially efficacious against wild-type SARS-CoV-2 strains have lower activities against variants due to heavy viral loads and greater turnover rates, but the inhibitors we are reporting have higher activities against the later variants than the wild-type (10–20X). We speculate this could be due to Nsp13 helicase being a critical bottleneck in faster replication rates of the new variants, so targeting this enzyme affects these variants to an even greater extent. This work calls attention to cyclobutanones as a useful medicinal chemistry scaffold, and the need for additional focus on the discovery of Nsp13 helicase inhibitors to combat the aggressive and immune-evading variants of concern (VOCs). [ABSTRACT FROM AUTHOR]

The reuse of food by-products is crucial for the well-being of the planet. Considering the high content of nutrients and other bioactive compounds in many of them, investigating their suitability for use as human food ingredients is an interesting challenge. In this study, in addition to the proximate composition, phenol content and antioxidant activity (AOA = 3.2 mmol Trolox equivalent (TE)/100 g, db) of orange juice powder by-product (CoP), different in vitro properties related to carbohydrate metabolism have been characterised. Specifically, the glycaemic index (GI), the glycaemic load (GL), the glucose dialysis retardation index (GDRI = 13.6%), the glucose adsorption capacity (GAC = 22.5 mM) and the inhibition capacity of α-amylase (α-A = 46.9%) and α-glucosidase (α-G = 93.3%) of powdered orange juice waste have been determined and related to fibre and phenolics composition. Taking advantage of the high fibre content of the by-product (36.67%), its GL was calculated for a CoP dose that allows labelling the food to which it is added as a source of fibre. The low GI value (24.4%) and the low GL (0.918 g available carbohydrates per serving) allowed us to conclude that the product studied could be an interesting opportunity for the food industry to offer it as a healthy food ingredient to be included in the diet, especially for those suffering from type 2 diabetes mellitus. Of the total phenolic compounds (TP = 509 mg equivalent of gallic acid (GAE)/100 g, db), 68% were found in free fraction (FP), and their contribution to the total AOA was 40.6%, while this was 54.9% for the 32% of phenols bound to plant tissues (BP). [ABSTRACT FROM AUTHOR]

Planar chromatography has recently been combined with six different effect-directed assays for three golden root (Rhodiola rosea L.) samples. However, the profiles obtained showed an intense tailing, making zone differentiation impossible. The profiling was therefore improved to allow for the detection of individual bioactive compounds, and the range of samples was extended to 15 commercial golden root products. Further effect-directed assays were studied providing information on 15 different effect mechanisms, i.e., (1) tyrosinase, (2) acetylcholinesterase, (3) butyrylcholinesterase, (4) β-glucuronidase, and (5) α-amylase inhibition, as well as endocrine activity via the triplex planar yeast antagonist-verified (6–8) estrogen or (9–11) androgen screen, (12) genotoxicity via the planar SOS-Umu-C bioassay, antimicrobial activity against (13) Gram-negative Aliivibrio fischeri and (14) Gram-positive Bacillus subtilis bacteria, and (15) antioxidative activity (DPPH• radical scavengers). Most of the golden root profiles obtained were characteristic, but some samples differed substantially. The United States Pharmacopeia reference product showed medium activity in most of the assays. The six most active compound zones were further characterized using high-resolution mass spectrometry, and the mass signals obtained were tentatively assigned to molecular formulae. In addition to confirming the known activities, this study is the first to report that golden root constituents inhibit butyrylcholinesterase (rosin was tentatively assigned), β-glucuronidase (rosavin, rosarin, rosiridin, viridoside, and salidroside were tentatively assigned), and α-amylase (stearic acid and palmitic acid were tentatively assigned) and that they are genotoxic (hydroquinone was tentatively assigned) and are both agonistic and antagonistic endocrine active. [ABSTRACT FROM AUTHOR]

Xanthomonas spp. are important plant pathogens that seriously endanger crop yields and food security. RpfF is a key enzyme that is involved in the synthesis of diffusible signal factor (DSF) signals and predominates in the signaling pathway regulating quorum sensing (QS) in Xanthomonas. Currently, novel RpfF enzyme-based quorum sensing agents have been proposed as a promising strategy for the development of new pesticides. However, few reports are available that comprehensively summarize the progress in this field. Therefore, we provide a comprehensive review of the recent advances in DSF-mediated QS and recently reported inhibitors that are proposed as bactericide candidates to target the RpfF enzyme and control plant bacterial diseases. [ABSTRACT FROM AUTHOR]

The acid catalyzed hydrolysis of the N-(p-substitutedphenyl) phthalimides in three different acids was investigated at 50.0 ± 0.1 °C. Two different antioxidant activity tests as DPPH• and ABTS•+ scavenging activities, and three various enzyme inhibition activity tests as urease, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) inhibition activities, were applied. Compound 3c (2.03 μg/mL) has higher antioxidant activity than other compounds and standards according to DPPH test. In AChE assay, compounds 3a and 3b (13.13 and 9.59 μg/mL) has higher enzyme inhibition activity than the standard Galantamine (14.37 μg/mL). In BChE and urease tests, all compounds (6.84-13.60 and 10.49-17.73 μg/mL) have higher enzyme inhibition activity than the standard Galantamine (49.40 μg/mL) and thiourea (26.19 μg/mL), respectively. The molecule interaction for each of the three compounds with the active sites of AChE, BChE, and urease enzymes was examined via molecular docking simulations. [ABSTRACT FROM AUTHOR]

Aldehyde dehydrogenase 3A1 (ALDH3A1) by oxidizing medium chain aldehydes to their corresponding carboxylic acids, is involved in the detoxification of toxic byproducts and is considered to play an important role in antioxidant cellular defense. ALDH3A1 has been implicated in various other functions such as cell proliferation, cell cycle regulation, and DNA damage response. Recently, it has been identified as a putative biomarker of prostate, gastric, and lung cancer stem cell phenotype. Although ALDH3A1 has multifaceted functions in both normal and cancer homeostasis, its modes of action are currently unknown. To this end, we utilized a random 12-mer peptide phage display library to identify efficiently human ALDH3A1-interacting peptides. One prevailing peptide (P1) was systematically demonstrated to interact with the protein of interest, which was further validated in vitro by peptide ELISA. Bioinformatic analysis indicated two putative P1 binding sites on the protein surface implying biomedical potential and potent inhibitory activity of the P1 peptide on hALDH3A1 activity was demonstrated by enzymatic studies. Furthermore, in search of potential hALDH3A1 interacting players, a BLASTp search demonstrated that no protein in the database includes the full-length amino acid sequence of P1, but identified a list of proteins containing parts of the P1 sequence, which may prove potential hALDH3A1 interacting partners. Among them, Protein Kinase C Binding Protein 1 and General Transcription Factor II-I are candidates of high interest due to their cellular localization and function. To conclude, this study identifies a novel peptide with potential biomedical applications and further suggests a list of protein candidates be explored as possible hALDH3A1-interacting partners in future studies.

Campylobacter jejuni infection poses a serious global threat to public health. The increasing incidence and antibiotic resistance of this bacterial infection have necessitated the adoption of various strategies to curb this trend, primarily through developing new drugs with new mechanisms of action. The enzyme malate:quinone oxidoreductase (MQO) has been shown to be essential for the survival of several bacteria and parasites. MQO is a peripheral membrane protein that catalyses the oxidation of malate to oxaloacetate, a crucial step in the tricarboxylic acid cycle. In addition, MQO is involved in the reduction of the quinone pool in the electron transport chain and thus contributes to cellular bioenergetics. The enzyme is an attractive drug target as it is not conserved in mammals. As a preliminary step in assessing the potential application of MQO from C. jejuni (CjMQO) as a new drug target, we purified active recombinant CjMQO and conducted, for the first time, biochemical analyses of MQO from a pathogenic bacterium. Our study showed that ferulenol, a submicromolar mitochondrial MQO inhibitor, and embelin are nanomolar inhibitors of CjMQO. We showed that both inhibitors are mixed-type inhibitors versus malate and noncompetitive versus quinone, suggesting the existence of a third binding site to accommodate these inhibitors; indeed, such a trait appears to be conserved between mitochondrial and bacterial MQOs. Interestingly, ferulenol and embelin also inhibit the in vitro growth of C. jejuni, supporting the hypothesis that MQO is essential for C. jejuni survival and is therefore an important drug target.

A new triterpene glycoside, silviridoside, was isolated from the aerial parts of Silene viridiflora (Caryophyllaceae) using different chromatographic techniques. The structure of silviridoside was comprehensively elucidated as 3-O-β-D-galacturonopyranosyl-quillaic acid 28-O-β-D-glucopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→3)]-β-D-fucopyranosyl ester by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HR-MS). Silviridoside showed promising antioxidant activity in different antioxidant assays such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) (2.32 mg TE/g), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (1.24 mg TE/g), cupric-reducing antioxidant capacity (CUPRAC) (9.59 mg TE/g), ferric-reducing antioxidant power (FRAP) (5.13 mg TE/g), phosphomolybdenum (PHD) (0.28 mmol TE/g), and metal-chelating (MCA) (6.62 mg EDTA/g) assays. It exhibited a good inhibitory potential on acetylcholinesterase (AChE) (2.52 mg GALAE/g), butyrylcholinesterase (BChE) (7.16 mg GALAE/g), α-amylase (0.19 mmol ACAE/g), α-glucosidase (1.21 mmol ACAE/g), and tyrosinase (38.83 mg KAE/g). An in silico evaluation of the pharmacodynamic, pharmacokinetic, and toxicity properties of silviridoside showed that the new compound exhibited reasonable pharmacodynamic and pharmacokinetic properties without any mutagenic effect, but slight toxicity. Thus, it could be concluded that silviridoside could act as a promising lead drug for pharmaceutical and nutraceutical developments to combat oxidative stress and various disorders, but a future optimization is necessary. [ABSTRACT FROM AUTHOR]

Carbonic anhydrases (EC 4.2.1.1) catalyse the reversible hydration of CO2 into bicarbonate and protons. As a hypoxia-sensitive and tumour-associated isoform, isoform CA IX, is significantly overexpressed in various malignancies, being a validated target for new anticancer/antimetastatic drugs. A multitude of studies has shown that CA IX inhibition decreases cancer cell proliferation and metastasis through pHe/pHi modulation and enhancement of ferroptosis among others. Numerous studies demonstrated increased efficacy of cytotoxic drugs combined with CA inhibitors (CAIs) in various cancer types. We tested the inhibitory effect of boric acid (BA), an inorganic Lewis acid, on CA IX as well as other isoforms (CA I, II, and XII). BA acted as a millimolar in vitro CAI, decreased proliferation of two cancer cell lines, although not strong correlations between the in vitro inhibition and in vivo effects were observed. The mechanism of antiproliferative action of BA should be investigated in more detail. [ABSTRACT FROM AUTHOR]

Calcineurin (CN) controls the immune response by regulating nuclear factor of activated T cells (NFAT). Inhibition of CN function is an effective treatment for immune diseases. The PVIVIT peptide is an artificial peptide based on the NFAT-PxIxIT motif, which exhibits stronger binding to CN. A bioactive peptide (named pep4) that inhibits the CN/NFAT interaction was designed. Pep4 contains a segment of A238L as the linker and the LxVP motif and PVIVIT motif as CN binding sites. Pep4 has strong binding capacity to CN and inhibits CN activity competitively. 11-arginine-modified pep4 (11 R-pep4) inhibits the nuclear trans-location of NFAT and reduces the expression of IL-2. 11 R-pep4 improves the pathological characteristics of asthmatic mice to a certain extent. The above results indicated that pep4 is a high-affinity CN inhibitor. These findings will contribute to the discovery of new CN inhibitors and promising immunosuppressive drugs. [ABSTRACT FROM AUTHOR]

Context: Brassica incana Ten. (Brassicaceae) is an edible plant with very limited available information. Previous studies have demonstrated the polyphenolic profile and the antioxidant and cytotoxic properties of the leaf and flowering top hydroalcoholic extracts. Objective: The volatile composition and the antidiabetic and anti-obesity potential of B. incana leaf and flowering top extracts have been investigated. Material and methods: The volatile characterization of the extracts was attained by HS-SPME-GC/MS analysis. The antidiabetic and anti-obesity potential was investigated spectrophotometrically in vitro by the ability to modulate pancreatic lipase and α-glucosidase at different concentrations using orlistat and acarbose as reference drugs. The inhibition of advanced glycation end-products (AGEs) was measured with aminoguanidine as reference and the antioxidant activity with the xanthine/xanthine oxidase system and Trolox for comparative purposes. Results: Several volatiles belonging to different chemical classes were identified, being sulphur compounds the most abundant in both leaf and flowering top extracts (56.33% and 64.40% of all volatiles). Although the leaf extract showed lower IC50 values in most of the assays (0.968 and 1.921 mg/mL for α-glucosidase; 0.192 and 0.262 mg/mL for AGEs; 0.022 and 0.038 mg/mL for superoxide scavenging), there were no statistically significant differences between both samples. These extracts showed a similar behaviour to Trolox in the xanthine oxidase assay (IC50 values of 0.022 mg/mL for leaf extract; 0.038 mg/mL for flowering top and 0.028 for Trolox). Conclusions: Leaves and flowering tops from B. incana can be used as sources of functional compounds that could act as antidiabetic and anti-obesogenic agents. [ABSTRACT FROM AUTHOR]

Aristotelia chilensis is a plant whose fruit is considered a powerful natural antioxidant. During the last years, some investigations of the fruit have been carried out, finding antioxidant properties in the juice or the phenolic fraction. The antioxidant properties of the plant are useful in the inhibition of enzymes related to diabetes such as pancreatic aldose reductase and alpha-amylase. Because many synthetic drugs used today have limitations and potentially harmful side effects, the use of naturally occurring compounds, such as flavonoids, is clinically attractive. In this study, the characterization of aqueous extracts of fruits and in vitro plants of A. chilensis was carried out based on their content of anthocyanins and total phenols, the antioxidant capacity by the antiradical activity 2,2-diphenyl-1-picrilhydrazil (DPPH), and the profile of anthocyanins and other phenolic compounds by liquid chromatography coupled to mass spectrometry (LC-MS/MS). Subsequently, the effect of these extracts on the inhibition of bovine aldose reductase and pancreatic alpha-amylase enzymes was determined. According to our results, extracts of fruits and in vitro plants of A. chilensis achieved inhibition of the bovine aldose reductase enzyme of 85.54 ± 1.86% and 75.67 ± 1.21%, respectively. Likewise, the percentage of inhibition of the pancreatic alpha-amylase enzyme for fruit extracts was 29.64 ± 0.63%, while for in vitro plant extracts it was 47.66 ± 0.66%. The antioxidant and enzymatic inhibition activity of the extracts were related to the content of anthocyanins, such as delphinidin and cyanidin glycosides as well as the phenols derived from quercetin, myricetin, and kaempferol. The results obtained allow us to suggest that the in vitro culture of plants of A. chilensis represents a viable biotechnological alternative to obtain phenolic compounds for the inhibition of aldose reductase and pancreatic alpha-amylase enzymes. [ABSTRACT FROM AUTHOR]

Background: Quercetin is a food supplement with multiple biological activities including antihypertensive, vasodilator effects, antiobesity, antihypercholesterolemic, antiatherosclerotic and other activities, it is available in wide range of dietary supplement and daily food intake, after oral ingestion, quercetin is metabolized by intestinal enzymes and absorbed by the duodenum, then be transported to the liver where is transformed into its glucuronidated, methylated and sulfo-substituted metabolites. Aim of Study: Boosting the bioavailability of Quercetin by enzyme inhibitor effect of ketoconazole. Method: 10 apparently healthy adult, male (5) and female (5) were grouped A and B, with a 1-week wash-period, Group A received Quercetin 1000 mg, group B received Quercetin 1000 mg and Ketoconazole 400 mg, and 15 blood samples are collected on the following timing 0, 0.5 - 12.5 by 1 hour interval and other by hour 24 for HPLC Assay. Results: Concurrent ketoconazole administration with Quercetin significantly improves the mean plasma concentration under the curve from zero time to infinity (AUC0-8) by 176% (403.41 ± 62.28 vs. 228.51 ± 28.67 µg.h/mL; P <0.0001) and prolonged time to complete elimination (44.66 ± 9.17 vs. 12.93 ± 1.4 hr.; P <0.0000) compared with Quercetin alone. Conclusion: Bioavailability of Quercetin will be increased by its administration together with ketoconazole, due to enzyme inhibiting effect of ketoconazole which delay elimination and increase the AUC of Quercetin. [ABSTRACT FROM AUTHOR]

ABSTRACT: Objectives: : Chagas disease, caused by the parasitic protozoan Trypanosoma cruzi, affects approximately 6–7 million people worldwide. There are limited available therapies and they exhibit low efficacy, often high toxicity in chronic cases and some drug resistance. In this study, our objective was to develop ester prodrugs that inhibit proline racemase (TcPRAC), a parasitic enzyme previously identified and characterised as a promising target because of its essential role in the parasite's life cycle and virulence, and to test their activity against T. cruzi. Methods: : Using structural bioinformatics, we modelled several functional intermediates of the catalytic site between the opened and closed conformations of TcPRAC based on its crystal structures in complex with its competitive inhibitor, pyrrole-2-carboxylic acid. Guided by these intermediates, which were later validated in cocrystals, we designed and evaluated numerous compounds and tested them enzymatically on live parasites and in mice with our quick and straightforward drug screening method, which is based on state-of-the-art bioluminescent T. cruzi parasites injected subcutaneously. Results: : Some of our novel compounds specifically inhibited racemase activity, as determined through biochemical assays, and covalently bound to TcPRAC. Furthermore, the corresponding ester prodrugs were effective in killing parasites in vitro. Bioluminescent T. cruzi assays in mice showed that JR1531, a TcPRAC inhibitor prodrug, can kill parasites in living animals, with boosted action when combined with low doses of benznidazole. Conclusion: : This approach, based on TcPRAC inhibitor prodrugs in association with low doses of benznidazole, may lead to more effective, specific and non-toxic therapies against Chagas disease.

The cyclooxygenases COX-1 and COX-2 oxygenate arachidonic acid (AA) to prostaglandin H2 (PGH2). COX-2 also oxygenates the endocannabinoids 2-arachidonoylglycerol (2-AG) and arachidonoylethanolamide (AEA) to the corresponding PGH2 analogs. Both enzymes are targets of nonsteroidal anti-inflammatory drugs (NSAIDs), but NSAID-mediated COX inhibition is associated with gastrointestinal toxicity. One potential strategy to counter this toxicity is to also inhibit fatty acid amide hydrolase (FAAH), which hydrolyzes bioactive fatty acid ethanolamides (FAEs) into fatty acids and ethanolamine. Here, we investigated the mechanism of COX inhibition by ARN2508, an NSAID that inhibits both COXs and FAAH with high potency, target selectivity, and decreased gastrointestinal toxicity in mouse models, presumably due to its ability to increase levels of FAEs. A 2.27-Å-resolution X-ray crystal structure of the COX-2·(S)-ARN2508 complex reveals that ARN2508 adopts a binding pose similar to that of its parent NSAID flurbiprofen. However, ARN2508's alkyl tail is inserted deep into the top channel, an active site region not exploited by any previously reported NSAID. As for flurbiprofen, ARN2508's potency is highly dependent on the configuration of the α-methyl group. Thus, (S)-ARN2508 is more potent than (R)-ARN2508 for inhibition of AA oxygenation by both COXs and 2-AG oxygenation by COX-2. Also, similarly to (R)-flurbiprofen, (R)-ARN2508 exhibits substrate selectivity for inhibition of 2-AG oxygenation. Site-directed mutagenesis confirms the importance of insertion of the alkyl tail into the top channel for (S)-ARN2508's potency and suggests a role for Ser-530 as a determinant of the inhibitor's slow rate of inhibition compared with that of (S)-flurbiprofen.

In lipoxygenases, the topologically conserved C-terminal domain catalyzes the oxidation of polyunsaturated fatty acids, generating an assortment of biologically relevant signaling mediators. Plant and animal lipoxygenases also contain a 100-150-amino acid N-terminal C2-like domain that has been implicated in interactions with isolated fatty acids and at the phospholipid bilayer. These interactions may lead to increased substrate availability and contribute to the regulation of active-site catalysis. Because of a lack of structural information, a molecular understanding of this lipid-protein interaction remains unresolved. Herein, we employed hydrogen-deuterium exchange MS (HDXMS) to spatially resolve changes in protein conformation upon interaction of soybean lipoxygenase with a fatty acid surrogate, oleyl sulfate (OS), previously shown to act at a site separate from the substrate-binding site. Specific, OS-induced conformational changes are detected both at the N-terminal domain and within the substrate portal nearly 30 Å away. Combining previously measured kinetic properties in the presence of OS with its impact on the Kd for linoleic acid substrate binding, we conclude that OS binding brings about an increase in rate constants for both the ingress and egress of substrate. We discuss the role of OS-induced changes in protein flexibility in the context of changes in the mechanism of substrate acquisition.

Proteins and peptides (PPs) have gradually become more attractive therapeutic molecules than small molecular drugs due to their high selectivity and efficacy, but fewer side effects. Owing to the poor stability and limited permeability through gastrointestinal (GI) tract and epithelia, the therapeutic PPs are usually administered by parenteral route. Given the big demand for oral administration in clinical use, a variety of researches focused on developing new technologies to overcome GI barriers of PPs, such as enteric coating, enzyme inhibitors, permeation enhancers, nanoparticles, as well as intestinal microdevices. Some new technologies have been developed under clinical trials and even on the market. This review summarizes the history, the physiological barriers and the overcoming approaches, current clinical and preclinical technologies, and future prospects of oral delivery of PPs.

Polygoni Cuspidati Rhizoma et Radix (PCR), the rhizome and root of Polygonum cuspidatum Sieb. et Zucc., has been used as an herbal medicine for a long time. In this study, the ultrafiltration combined with high performance liquid chromatography (UF-HPLC) method was developed to screen tyrosinase (TYR), α-glucosidase (α-GLU), and xanthine oxidase (XOD) inhibitors from PCR. Firstly, the inhibitory activity of 50% methanol PCR extract on TYR, α-GLU, XOD, and acetylcholinesterase (ACHE) was tested. The extract showed a good inhibition on the enzymes, except for ACHE. Therefore, UF-HPLC experiments were carried out to screen TYR, α-GLU, and XOD inhibitors from PCR extract. Seven potential bioactive components were discovered, including methylgallate (1), 1,6-di-O-galloyl-D-glucose (2), polydatin-4′-O-D-glucoside (3), resveratrol-4′-O-D-glucoside (4), polydatin (5), malonyl glucoside resveratrol (6), and resveratrol-5-O-D-glucoside (7). Most of them were found as enzyme inhibitors from PCR for the first time, except polydatin (5), which had been reported as an α-GLUI in PCR in the literature. Finally, molecular docking analysis was applied to validate the interactions of these seven potential active components with the enzymes. Compounds 1–7 were proven as TYR inhibitors, compounds 2, 4–7 were identified as XOD inhibitors, and compounds 4–6 were confirmed as α-GLU inhibitors. In short, the current study provides a good reference for the screening of enzyme inhibitors through UF-HPLC, and provides scientific data for future studies of PCR.

This paper discusses a complex nonlinear fractional model of enzyme inhibitor reaction where reaction memory is taken into account. Analytical expressions of the concentrations of enzyme, substrate, inhibitor, product, and other complex intermediate species are derived using Laplace decomposition and differential transformation methods. Since different rate constants, large initial concentrations, and large time domains are unavoidable in biochemical reactions, different dynamics will result; hence, the convergence of the approximate concentrations may be lost. In this case, the proposed analytical methods will be coupled with Padé approximation. The validity and accuracy of the derived analytical solutions will be established by direct comparison with numerical simulations. [ABSTRACT FROM AUTHOR]

In insects, melanism plays important roles in defense, immunoreactions, and body color. The underlying molecular mechanisms of melanism in different insects are diverse and remain elusive. In contrast to another silkworm, Bombyx mori , the Chinese oak silkworm, Antheraea pernyi , produces melanic pupae under natural environmental conditions. DOPA and dopamine synthesis are crucial for melanin formation. Disruption of these processes reportedly influences body colors in many insects. Most research focuses on newly emerged pupae, and the larval process preceding pupation remains unknown. Due to the large size and long pupation period in A. pernyi , the entire process was studied at least every 12 h. The expression patterns of tyrosine hydroxylase (TH) and DOPA decarboxylase (DDC), which are involved in DOPA and dopamine synthesis in the epidermis, were evaluated during larval–pupal metamorphosis. We also performed RNA interference (RNAi) and used enzyme inhibitors to examine morphological changes. The amino acid sequences of TH and DDC share 90.91% and 86.64% identity with those of B. mori. TH and DDC expression was upregulated during the 48–72 h period prior to pupal emergence, especially at 60 h. RNAi of TH and DDC induced partial melanism in some pupae. The inhibitors 3-iodo-tyrosine (3-IT) and L-α-methyl-DOPA (L-DOPA) influenced pupal melanization. Different concentrations of inhibitors led to pupal deformity and even mortality. Four different monoamines, only DOPA and Dopamine synthezed from Tyrosine will be influenced by TH and DDC inhibitor. These results indicate that TH and DDC are key genes associated with pupal melanization during larval–pupal transformation in A. pernyi. Overall, our results suggest that TH and DDC expression alterations in a particular stage can affect body color, setting the molecular basis for artificial control of pupal melanization. [ABSTRACT FROM AUTHOR]

The Na+-pumping NADH-quinone oxidoreductase (Na+-NQR) is the first enzyme of the respiratory chain and the main ion transporter in many marine and pathogenic bacteria, including Vibrio cholerae The V. cholerae Na+-NQR has been extensively studied, but its binding sites for ubiquinone and inhibitors remain controversial. Here, using a photoreactive ubiquinone PUQ-3 as well as two aurachin-type inhibitors [125I]PAD-1 and [125I]PAD-2 and photoaffinity labeling experiments on the isolated enzyme, we demonstrate that the ubiquinone ring binds to the NqrA subunit in the regions Leu-32-Met-39 and Phe-131-Lys-138, encompassing the rear wall of a predicted ubiquinone-binding cavity. The quinolone ring and alkyl side chain of aurachin bound to the NqrB subunit in the regions Arg-43-Lys-54 and Trp-23-Gly-89, respectively. These results indicate that the binding sites for ubiquinone and aurachin-type inhibitors are in close proximity but do not overlap one another. Unexpectedly, although the inhibitory effects of PAD-1 and PAD-2 were almost completely abolished by certain mutations in NqrB (i.e. G140A and E144C), the binding reactivities of [125I]PAD-1 and [125I]PAD-2 to the mutated enzymes were unchanged compared with those of the wild-type enzyme. We also found that photoaffinity labeling by [125I]PAD-1 and [125I]PAD-2, rather than being competitively suppressed in the presence of other inhibitors, is enhanced under some experimental conditions. To explain these apparently paradoxical results, we propose models for the catalytic reaction of Na+-NQR and its interactions with inhibitors on the basis of the biochemical and biophysical results reported here and in previous work.

A series of benzylidene analogs of oleanolic acid 4a∼4s were synthesized and assessed for their α-glucosidase and α-amylase inhibitory activities. The results presented that all synthesized analogs exhibited excellent-to-moderate inhibitory effects on α-glucosidase and α-amylase. Analog 4i showed the highest α-glucosidase inhibition (IC50: 0.40 μM), and analog 4o presented the strongest α-amylase inhibition (IC50: 9.59 μM). Inhibition kinetics results showed that analogs 4i and 4o were reversible and mixed-type inhibitors against α-glucosidase and α-amylase, respectively. Simulation docking results demonstrated the interaction between analogs and two enzymes. Moreover, analogs 4i and 4o showed a high level of safety against 3T3-L1 and HepG2 cells.

Coumarin and chalcone, two important kinds of natural product skeletons, both exhibit α-glucosidase inhibitory activity. In this work, coumarin-chalcone derivatives 3 (a∼v) were synthesized, and their α-glucosidase inhibitory activity was screened. The results showed that all synthetic derivatives (IC50: 24.09 ± 2.36 to 125.26 ± 1.18 μM) presented better α-glucosidase inhibitory activity than the parent compounds 3-acetylcoumarin (IC50: 1.5 × 105 μM) and the positive control acarbose (IC50: 259.90 ± 1.06 μM). Among them, compound 3t displayed the highest α-glucosidase inhibitory activity (IC50: 24.09 ± 2.36 μM), which was approximately 10 times stronger than that of acarbose. The kinetic assay of 3t (KI = 18.82 μM, KIS = 59.99 μM) revealed that these compounds inhibited α-glucosidase in a mixed-type manner. Molecular docking was used to simulate the interaction between α-glucosidase and compound 3t.

In insects, melanism plays important roles in defense, immunoreactions, and body color. The underlying molecular mechanisms of melanism in different insects are diverse and remain elusive. In contrast to another silkworm, Bombyx mori, the Chinese oak silkworm, Antheraea pernyi, produces melanic pupae under natural environmental conditions. DOPA and dopamine synthesis are crucial for melanin formation. Disruption of these processes reportedly influences body colors in many insects. Most research focuses on newly emerged pupae, and the larval process preceding pupation remains unknown. Due to the large size and long pupation period in A. pernyi, the entire process was studied at least every 12 h. The expression patterns of tyrosine hydroxylase (TH) and DOPA decarboxylase (DDC), which are involved in DOPA and dopamine synthesis in the epidermis, were evaluated during larval–pupal metamorphosis. We also performed RNA interference (RNAi) and used enzyme inhibitors to examine morphological changes. The amino acid sequences of TH and DDC share 90.91% and 86.64% identity with those of B. mori. TH and DDC expression was upregulated during the 48–72 h period prior to pupal emergence, especially at 60 h. RNAi of TH and DDC induced partial melanism in some pupae. The inhibitors 3-iodo-tyrosine (3-IT) and L-α-methyl-DOPA (L-DOPA) influenced pupal melanization. Different concentrations of inhibitors led to pupal deformity and even mortality. Four different monoamines, only DOPA and Dopamine synthezed from Tyrosine will be influenced by TH and DDC inhibitor. These results indicate that TH and DDC are key genes associated with pupal melanization during larval–pupal transformation in A. pernyi. Overall, our results suggest that TH and DDC expression alterations in a particular stage can affect body color, setting the molecular basis for artificial control of pupal melanization.

The topic 'Sulfa-Drugs in secondary school chemistry' has been developed in cooperation of three high schools (Kantonsschulen). Three essential aspects are covered that ideally complement each other: 1. The synthesis of sulfamethoxazole – an antibiotic 'without side effects' – as a practical course in a school laboratory; 2. An introduction to the topic 'drug design' with the question of structure, effect and side effects of sulfonamides; 3. A detailed answer to the question of how side effects can be avoided by the design of drugs using molecular modelling. Teaching materials on all topics can be downloaded free of charge from Swisseduc. ch (see box). The article discusses various possible approaches in high school chemistry along the lines of a well-established teaching unit on sulfonamides.

The reuse of food by-products is crucial for the well-being of the planet. Considering the high content of nutrients and other bioactive compounds in many of them, investigating their suitability for use as human food ingredients is an interesting challenge. In this study, in addition to the proximate composition, phenol content and antioxidant activity (AOA = 3.2 mmol Trolox equivalent (TE)/100 g, db) of orange juice powder by-product (CoP), different in vitro properties related to carbohydrate metabolism have been characterised. Specifically, the glycaemic index (GI), the glycaemic load (GL), the glucose dialysis retardation index (GDRI = 13.6%), the glucose adsorption capacity (GAC = 22.5 mM) and the inhibition capacity of α-amylase (α-A = 46.9%) and α-glucosidase (α-G = 93.3%) of powdered orange juice waste have been determined and related to fibre and phenolics composition. Taking advantage of the high fibre content of the by-product (36.67%), its GL was calculated for a CoP dose that allows labelling the food to which it is added as a source of fibre. The low GI value (24.4%) and the low GL (0.918 g available carbohydrates per serving) allowed us to conclude that the product studied could be an interesting opportunity for the food industry to offer it as a healthy food ingredient to be included in the diet, especially for those suffering from type 2 diabetes mellitus. Of the total phenolic compounds (TP = 509 mg equivalent of gallic acid (GAE)/100 g, db), 68% were found in free fraction (FP), and their contribution to the total AOA was 40.6%, while this was 54.9% for the 32% of phenols bound to plant tissues (BP).

Planar chromatography has recently been combined with six different effect-directed assays for three golden root (Rhodiola rosea L.) samples. However, the profiles obtained showed an intense tailing, making zone differentiation impossible. The profiling was therefore improved to allow for the detection of individual bioactive compounds, and the range of samples was extended to 15 commercial golden root products. Further effect-directed assays were studied providing information on 15 different effect mechanisms, i.e., (1) tyrosinase, (2) acetylcholinesterase, (3) butyrylcholinesterase, (4) β-glucuronidase, and (5) α-amylase inhibition, as well as endocrine activity via the triplex planar yeast antagonist-verified (6–8) estrogen or (9–11) androgen screen, (12) genotoxicity via the planar SOS-Umu-C bioassay, antimicrobial activity against (13) Gram-negative Aliivibrio fischeri and (14) Gram-positive Bacillus subtilis bacteria, and (15) antioxidative activity (DPPH• radical scavengers). Most of the golden root profiles obtained were characteristic, but some samples differed substantially. The United States Pharmacopeia reference product showed medium activity in most of the assays. The six most active compound zones were further characterized using high-resolution mass spectrometry, and the mass signals obtained were tentatively assigned to molecular formulae. In addition to confirming the known activities, this study is the first to report that golden root constituents inhibit butyrylcholinesterase (rosin was tentatively assigned), β-glucuronidase (rosavin, rosarin, rosiridin, viridoside, and salidroside were tentatively assigned), and α-amylase (stearic acid and palmitic acid were tentatively assigned) and that they are genotoxic (hydroquinone was tentatively assigned) and are both agonistic and antagonistic endocrine active.

Xanthomonas spp. are important plant pathogens that seriously endanger crop yields and food security. RpfF is a key enzyme that is involved in the synthesis of diffusible signal factor (DSF) signals and predominates in the signaling pathway regulating quorum sensing (QS) in Xanthomonas. Currently, novel RpfF enzyme-based quorum sensing agents have been proposed as a promising strategy for the development of new pesticides. However, few reports are available that comprehensively summarize the progress in this field. Therefore, we provide a comprehensive review of the recent advances in DSF-mediated QS and recently reported inhibitors that are proposed as bactericide candidates to target the RpfF enzyme and control plant bacterial diseases.

Antibiotic resistance is a challenge for the control of bacterial infections. In an effort to explore unconventional avenues for antibacterial drug development, we focused on the FMN‐transferase activity of the enzyme Ftp from the syphilis spirochete, Treponema pallidum (Ftp_Tp). This enzyme, which is only found in prokaryotes and trypanosomatids, post‐translationally modifies proteins in the periplasm, covalently linking FMN (from FAD) to proteins that typically are important for establishing an essential electrochemical gradient across the cytoplasmic membrane. As such, Ftp inhibitors potentially represent a new class of antimicrobials. Previously, we showed that AMP is both a product of the Ftp_tp‐catalyzed reaction and an inhibitor of the enzyme. As a preliminary step in exploiting this property to develop a novel Ftp_Tp inhibitor, we have used structural and solution studies to examine the inhibitory and enzyme‐binding properties of several adenine‐based nucleosides, with particular focus on the 2‐position of the purine ring. Implications for future drug design are discussed. PDB Code(s): 7MGT; [ABSTRACT FROM AUTHOR]

Antibiotic resistance is a continually growing challenge in the treatment of various bacterial infections worldwide. New drugs and new drug targets are necessary to curb the threat of infectious diseases caused by multidrug‐resistant pathogens. The tryptophan biosynthesis pathway is essential for bacterial growth but is absent in higher animals and humans. Drugs that can inhibit the bacterial biosynthesis of tryptophan offer a new class of antibiotics. In this work, we combined a structure‐based strategy using in silico docking screening and molecular dynamics (MD) simulations to identify compounds targeting the α subunit of tryptophan synthase with experimental methods involving the whole‐cell minimum inhibitory concentration (MIC) test, solution state NMR, and crystallography to confirm the inhibition of L‐tryptophan biosynthesis. Screening 1,800 compounds from the National Cancer Institute Diversity Set I against α subunit revealed 28 compounds for experimental validation; four of the 28 hit compounds showed promising activity in MIC testing. We performed solution state NMR experiments to demonstrate that a one successful inhibitor, 3‐amino‐3‐imino‐2‐phenyldiazenylpropanamide (Compound 1) binds to the α subunit. We also report a crystal structure of Salmonella enterica serotype Typhimurium tryptophan synthase in complex with Compound 1 which revealed a binding site at the αβ interface of the dimeric enzyme. MD simulations were carried out to examine two binding sites for the compound. Our results show that this small molecule inhibitor could be a promising lead for future drug development. PDB Code(s): 6XIN; [ABSTRACT FROM AUTHOR]

Cholest-4-en-3-one, whether added exogenously or generated intracellularly from cholesterol, inhibits the growth ofMycobacterium tuberculosiswhen CYP125A1 and CYP142A1, the cytochrome P450 enzymes that initiate degradation of the sterol side chain, are disabled. Here we demonstrate that a 16-hydroxy derivative of cholesterol, which was previously reported to inhibit growth ofM. tuberculosis, acts by preventing the oxidation of the sterol side chain even in the presence of the relevant cytochrome P450 enzymes. The finding that (25R)-cholest-5-en-3β,16β,26-triol (1) (and its 3-keto metabolite) inhibit growth suggests that cholesterol analogs with non-degradable side chains represent a novel class of anti-mycobacterial agents. In accord with this, two cholesterol analogs with truncated, fluorinated side chains have been synthesized and shown to similarly block the growth in culture ofM. tuberculosis.