Current Enzyme Inhibition - Volume 17, Issue 1, 2021

Background: Bacterial manganese superoxide dismutase (MnSOD) occurs as a dimer, which is responsible for its activity and stability. Therefore, increasing the dimeric strength would increase the stability of the enzyme while maintaining its activity. Objective: An N73F substitution was introduced to strengthen interactions between the monomers at the dimer interface. This substitution would introduce a π-stacking interaction between F73 of one monomer to F124 from the other monomers. Methods: Site-directed mutagenesis was carried out to substitute N73 with phenylalanine. The activity of the mutant was qualitative- and quantitatively checked while the stability was evaluated with a fluorescence- based thermal-shift assay. Finally, the structure of the mutant was elucidated by means of Xray crystallography. Results: The N73F mutant activity was only ∼40% of the wild type. The N73F mutant showed one TM at 60+1°C while the wild type has two (at 52-55°C and 63-67°C). The crystal structure of the mutant showed the interactions between F73 from one monomer to F124 from the other monomer. The N73F structure presents an enigma because of no change in the enzyme structure including the active site. Furthermore, N73 and F124 position and interaction are conserved in human MnSOD but with a different location in the amino acid sequence. N73 has a role in the enzyme activity, likely related to its interaction with F124, which resides in the active site region but has not been considered to participate in the reaction. Conclusion: The N73F substitution has revealed the unprecedented role of the N73-F124 pair in the enzyme activity.

Background: For the past 70 years, the focus of research is on the search for poisons and toxins found in venomous and poisonous organisms, purely directed towards the pharmacological properties of the toxins. In the research of finding novel compounds in pharmaceutical research, the identified source was the piscine venom. Objective: The Scorpaenidae family was considered the most venomous of all. The toxins isolated from stonefish and lionfish are responsible for the effects caused in cardiovascular and neuromuscular systems and also for causing cytolytic activities. The main objective of the review is to study the mechanism of the stonefish venom and portray its benefits in the field of drug discovery. Methods: A study on the mechanism of stonefish venom was carried out by inducing cardiovascular endothelium. The release of neurotransmitter signals thus leads to the depolarisation of cell membrane by the formation of pores in the cell membrane in the neuromuscular system of rabbits, porcine artery, mice and rats. Lionfish venom in cross-reactivity with the results evolved from a stonefish venom activity. The presence of enzymatic hyaluronidases in the primary structures of lionfish has evolved from stonefish and their anticancer potential has also been demonstrated for the benefits of drug discovery as they possess biological and chemical activity. Conclusion: This review depicts an overview of the pharmacological activities of lionfish venom in comparison with the stonefish venom and their purpose of applications for future research in drug discovery.

Introduction: 5α-reductase inhibitors have been proven useful for the treatment of prostate diseases, which can be due to the unregulated activity of 5α-reductase enzyme. This study was focused on determining the activity of four different derivatives of 17β-phenyl carbamoyl-androst-4-en-3-one 1–4 as inhibitors of 5α-reductase (5RD5A), to improve the effects of current drugs. Methods: In vitro effect of compounds 1-4 on the activity of the human prostate enzyme, 5α-reductase, was determined by measuring IC50 values, the concentration of a compound that inhibits the activity of 5RD5A2 by 50%. In vivo, the pharmacological effects of compounds 1-4 were identified in a hamster model of prostate hypertrophy. Results: The steroidal 17β-carboxamides 1, 3, and 4 (IC50 = 5±0.5, 0.112±0.045, 0.167±0.056 nM) significantly inhibited the in vitro activity of the 5RD5A2 enzyme with higher potency than finasteride, which is a drug known as a specific 5RD5A2 inhibitor (IC50 = 8.5±0.3 nM). Compounds 1, 3, and 4 were more potent than finasteride to decrease the size of hamster flank organs in castrated animals treated with testosterone. Also, compounds 1-4 were more effective than finasteride itself to reduce the weight of the prostate in the hamster model, without producing toxicological effects during the six days of treatment. Conclusion: In conclusion, the steroidal 17 β-carboxamides 1-4 were suitable inhibitors of human 5RD5A2 activity, in addition to being able to reduce prostate weight without causing toxicity. These steroids could, therefore, have promising therapeutic potential for the treatment of benign prostatic hyperplasia.

Background: The Spectrophotometric method is one of the most suitable analytical techniques for testing the activity of enzymes under the influence of various factors. Methods: The effect of H1-antihistamines of loratadine and calcium ions on enzyme catalase under in vitro conditions was investigated in this paper. Results and Discussion: It has been shown that loratadine is a partial inhibitor of catalase, but this effect is diminished in the presence of calcium ions. Calcium as well as other cations are important for many biological and cellular functions. The kidneys play a central role in the homeostasis of these ions. The activity of the catalase enzyme under the given conditions, the type of inhibition, and the kinetic parameters of the enzyme reaction were determined. Conclusion: We concluded that loratadine is a partially competitive inhibitor.

Introduction: Prostate cancer (Pc) is the most frequent neoplasia in men and the second cause of death in Brazil. Objective: To analyze the interactions and biologicals responses of Pc oxidative stress and prostatespecific antigen (PSA), E-cadherin and MMP-13. Demonstrate whether the increase of the amount of the form of E-cadherin found in the plasma of Pc patients, correlates with decrease of the PSA. Methods: Samples were obtained through peripheral venipuncture to analyse parameters of biomarkers pc as PSA, E-cadherin, MMP-13, Homocysteine, Folic acid, Vitamin B12, Testosterone T and free following the patients diagnosis, 3 and 6 months during their treatment to analyze the biological responses of Pc oxidative stress. Results: The analysis was performed by using immunoenzymatic assay. Statistical data processed through Excel in Windows Vista and analyzed through the Shapiro-wilk Test, ANOVA, and Spearman Test. An increase in the concentration of E-cadherin (p = 0.02), as a decrease in concentration of PSA (p < 0.001), total testosterone (p < 0.001) and free testosterone (p = 0.02) was observed during the treatment period without significant alterations in the remaining markers for either of the periods. Discussion: It was found that during treatment of men diagnosed with pc that there was an an increase in the concentration of plasmatic E-cadherin, which was negatively correlated with the concentrations of folic acid (-0,03 (0,87) rs (p). It was observed that the levels of hcy are positively correlated with concentrations of total testosterone and a negative correlation. Vitamins B12 remained within the parameters of normality during the entire study. Conclusion: P.S.A levels were free and total testosterone levels decreased. In this way, monitoring the folic acid, E-cadherin dosages of patients during the treatment phases can effectively complement in the face of remission, since it would be a way of preventing abnormal cell replications, with a clinical view prudent so that the cell methylation cycle is not affected.

Background: Phyllanthus fraternus Webster Linn (family, Euphorbiaceae) is used as a traditional medication for the treatment of various disorders and has therapeutic implications. Objective: This study intends to investigate the anxiolytic potential of Phyllanthus fraternus standardized extract and prediction of the probable role of its marker phytoconstituents. Methods: We tested the standardized hydro-ethanolic extract of Phyllanthus fraternus (whole plant) for the Elevated plus-maze model (EPM) and Light & Dark Exploration test as classical models for anxiety. Phyto-chemical HPTLC fingerprint analysis was performed for the detection of two classes of compounds lignans and tannins. HPTLC analysis of the standardized extract was performed using phyllanthin hypophyllanthin and corilagin as marker compounds. Additionally, GABA receptor antagonism was studied in other sets of experiments to assess the involvement of this receptor in the anxiolytic- like effects produced by Phyllanthus fraternus. Results: The lower doses of the lignan and tannin-rich extract of the Phyllanthus fraternus possess significant anxiolytic-like activity compared to the standard diazepam. Additionally, the results of the present study suggested that high doses (400mg/kg) of Phyllanthus fraternus have exerted some sedative- like effects. Phytochemical screening and HPTLC fingerprint analysis indicate the presence of lignans and tannins, whereas HPLC analysis of the standardized extract revealed the presence of marker lignan (Hypophyllanthin) and Tannin (Corilagin). The anxiolytic-like effect of Phyllanthus fraternus observed in the mice models were blocked by Flumazenil indicating the involvement of GABAA receptors in the modulation of this effect. Our molecular docking studies also supported probable anxiolytic and sedative effects. Conclusion: To summarize, results support the use of Phyllanthus fraternus in the anxiety-like symptoms/ disease condition and suggest its anxiolytic-like effect governed by the GABA-A receptors.

Background: Curcumin, a providential spice, has its role in protecting the brain from neurodegeneration. Despite its ubiquitous role, it is not exploited alone due to its hampered bioavailability. By restraining the intestinal and liver enzymatic metabolism, one can boost the bioavailability of curcumin and promotes reabsorption of the curcumin. Diclofenac inhibits uridine 5'-diphosphoglucuronosyltransferase enzymes specifically responsible for the metabolism and elimination of curcumin. Lactobacillus rhamnosus is able to synthesize and release the β -d-glucuronidase enzyme, which reverts curcumin into the active form. Objective: In this research, we aim to combine curcumin with Lactobacillus rhamnosus and diclofenac as an adjuvant with curcumin to potentiate anti-Alzheimer effect in mice impaired with memory by scopolamine. Methods: To induce amnesia, scopolamine was used in mice model (1mg/kg, daily for 10 days i.p.). After execution of behavioural tests (Morris Water Maze test), brain and liver were isolated for further neurochemical and histopathology examination. Results: Our finding showed a marked rise in the level of antioxidant enzymes in curcumin with L. rhamnosus and diclofenac compared to curcumin alone. Additionally, the behavioural study revealed that cognition in mice with curcumin adjuvant with L. rhamnosus and diclofenac showed a marked improvement. The histology study proves that curcumin alone possesses less and a non-significant neuroprotective effect as compared to curcumin with L. rhamnosus and diclofenac. Conclusion: This entire outcome ratifies that curcumin with L. rhamnosus and diclofenac has higher activity as compared to curcumin alone, which reversed the cognition in the Alzheimer disease model.

Background: Lymphatic filariasis, regularly known as elephantiasis, is a dismissed tropical malady. A filarial parasite causes the disease when it is transmitted to humans through mosquitoes. The World Health Organization distinguished that this is one of the subsequent driving reasons for lasting and long haul inability. Inaccessibility of immunization and medication opposition of a large portion of the ebb and flow hostile to filarial drugs necessitate quest of novel medication that focuses on creating elective medications. UDP-galactopyranose mutase (UGM) is a flavoenzyme that catalyzes the change of UDP-galactopyranose mutase to UDP-galactofuranose, which is a focal response in galactofuranose biosynthesis. This UGM is fundamental for some pathogens however, it is missing in people, makes UGM a potential medication target. Objective: In the current investigation, UGM from the parasitic nematode Brugia malayi has been considered as an objective during in silico medicate planning of powerful filarial inhibitor. Methods: Here, we build up the homology model of UGM protein dependent on the gem structure of 4DSG. To break down the quality and unwavering quality of the created model, model approval was performed utilizing the SAVES server. Mixes from Specs, Enamine, and Maybridge databases were screened to recognize a potential ligand that could hinder the action of the UGM protein utilizing Glide HTVS and Glide XP. Results: Because of the scoring boundaries, the best 6 hit mixes were chosen and exposed to ADME forecast utilizing QikProp module from Schrodinger. To check the security of docked buildings, an atomic element study was completed. Conclusion: The consequences of this examination give six novel lead mixes to building up an enemy of filarial medication focusing on the UGM protein.

Background: Oxidative stress is caused due to the overproduction of the reactive oxygen species (ROS) and the disturbance developed in the antioxidant potential of biochemical processes. ROS mostly form in the brain due to the high consumption of oxygen and the insufficiency of endogenous antioxidant resistance mechanisms. Cytochrome P450 2E1 has an excessive percentage of NADPH oxidase activity, which causes the production of ROS and increases oxidative stress. Objectives: We have studied the effect of ethyl acetate extract of Achyranthes Aspera (EAAA) on ROS in the brain of diabetes-induced rats. We have also investigated the possible molecular mechanism of reduction in ROS through molecular docking. Methods: To study the oxidative stress induced by ROS in diabetic rats, we estimated the ROS in rat brain through flow cytometry. The oral dose of EAAA 50mg/kg and 100 mg/kg was given to diabetesinduced rats. Results were articulated as mean ± standard deviation (SD). Data were analyzed using analysis of variance (ANOVA) followed by Bonferroni as a post hoc test. We performed molecular docking of flavonoids on CYP2E1 to study the inhibitory potential. Results: The results have shown that EAAA reduces the generation of ROS in the diabetes-induced rat in a dose-dependent manner. The oral dose of EAAA 50mg/kg and 100 mg/kg was given to the rats and the ROS generation got affected accordingly. Luteolin, quercetin, and apigenin inhibited the CYP2E1 very effectively. Luteolin formed 4 hydrogen bonds with CYP2E1, which indicated its potential inhibition. Although, luteolin and apigenin showed a very good binding affinity with the enzyme. Conclusion: From the present work, we have concluded that the ethyl acetate extract of achyrantesaspera can effectively inhibit the ROS generation in the diabetes-induced rats by inhibiting the activity of CYP2E1.