Bioactivity of dihydropyrimidinone derivatives as inhibitors of cyclooxygenase-2 (COX-2): an in silico approach.

Cyclooxygenase-2 (COX-2) is an enzyme involved in inflammation. The overexpression of COX-2 causes chronic inflammation, which can be prevented by COX-2 inhibitors. Generally, COX-2 inhibitors possess a carboxyl group and an aromatic ring in their molecular structure. These moieties are involved in the interaction with the active site of COX-2, thus playing a pivotal role in the inhibitory activity. Regarding the requisite molecular structure of COX-2 inhibitors, derivatives of dihydropyrimidinone (DHPM) are ideal candidates to be explored as COX-2 inhibitors, due to the ease of synthesis and their versatility to be transformed chemically. In this study, we prepared a novel small library consisting of 288 designed DHPM derivatives by varying the constituent components. The selection criteria of potential candidates for the COX-2 inhibitor of the data bank involve in silico studies via molecular docking investigations, prediction of ADMET and druglikeness, as well as molecular dynamics (MD) simulations. Molecular docking served as the initial step of selection, based on the comparison of grid score, docking pose, and interactions with those of lumiracoxib (LUR) as the original ligand of COX-2. The next criteria of selection were scores obtained from the ADMET and druglikeness by comparing the designed candidates with COX-2 inhibitors that were already marketed. Compound RDUE2 and SDT29 were the most potential candidates, which were further analyzed using the MD simulation. The results of the MD simulation indicated that RDUE2 and SDT29 interacted stably with amino acid residues on the active site of COX-2. The estimation of binding free energy indicated that SDT29 exhibited an inhibitory activity comparable to that of LUR, whereas RDUE2 showed a lower inhibitory activity than that of SDT29 and LUR.

Structure-based approach: molecular insight of pyranocumarins against α-glucosidase through computational studies.

α-glucosidase is an enzyme that catalyzes the release of α-glucose molecules through hydrolysis reactions. Regulation of this enzyme can increase sugar levels in type-2 diabetes mellitus (DM) patients. Pyranocoumarin derivatives have been identified as α-glucosidase inhibitors. Through an in silico approach, this work studied the inhibition of three pyranocoumarin compounds against the α-glucosidase at the molecular level. Molecular docking and molecular dynamics simulation were performed to understand the dynamics behavior of pyranocoumarin derivatives against α-glucosidase. The prediction of free binding energy (ΔG bind) using the Quantum Mechanics/Molecular Mechanics-Generalized Born (QM/MM-GBSA) approach for each system had the following results, PC1-α-Glu: -13.97 kcal mol-1, PC2-α-Glu: -3.69 kcal mol-1, and PC3-α-Glu: -13.68 kcal mol-1. The interaction energy of each system shows that the grid score, ΔG bind, and ΔG exp values had a similar correlation, that was PC1-α-Glu > PC3-α-Glu > PC2-α-Glu. Additionally, the decomposition energy analysis (ΔG residue bind) was carried out to find out the contribution of the key binding residue. The results showed that there were 15 key binding residues responsible for stabilizing pyranocumarin binding with criteria of ΔG residue bind < -1.00 kcal mol-1. The evaluation presented in this work could provide information on the molecular level about the inhibitory efficiency of pyranocoumarin derivatives against a-glucosidase enzyme based on computational studies.

In Vitro Assessment on Designing Novel Antibiofilms of Pseudomonas aeruginosa Using a Computational Approach.

An anti-biofilm that can inhibit the matrix of biofilm formation is necessary to prevent recurrent and chronic Pseudomonas aeruginosa infection. This study aimed to design compounds with a new mechanism through competitive inhibitory activity against phosphomannomutase/phosphoglucomutase (PMM/PGM), using in vitro assessment and a computational (in silico) approach. The active site of PMM/PGM was assessed through molecular redocking using L-tartaric acid as the native ligand and other small molecules, such as glucaric acid, D-sorbitol, and ascorbic acid. The docking program set the small molecules to the active site, showing a stable complex formation. Analysis of structural similarity, bioavailability, absorption, distribution, metabolism, excretion, and toxicity properties proved the potential application of ligands as an anti-biofilm. In vitro assessment with crystal violet showed that the ligands could reach up to 95.87% inhibition at different concentrations. The nitrocellulose membrane and scanning electron microscopic visualization showed that the untreated P. aeruginosa biofilm was denser than the ligand-treated biofilm.

Elucidation of reactive oxygen species scavenging pathways of norbergenin utilizing DFT approaches.

Bergenin is a polyphenolic compound that contains isocoumarin skeletal derived from C-glycosylated 4-O-methylgallic acid. The biological activities of this compound and its derivatives are quite diverse. Recent studies reveal neuroprotective effects in vitro and in vivo in Alzheimer's. Norbergenin is a demethylated form of bergenin, known for better antioxidant capacity and associated with neuroprotective properties through oxidative stress inhibition. This study focused on investigating the scavenging mechanism of norbergenin with the •OH, •OOH, and O 2 ∙ - as a radical model under physiological and lipid environments. The thermodynamic and kinetic parameters of the hydrogen transfer (HT), single electron transfer (SET), sequential proton lost-electron transfer (SPLET) and radical adduct formation (RAF) mechanisms were determined theoretically by the density functional theory (DFT) at M06-2X/6-311 + + G(d,p) level of theory. Based on the computational results, this compound has proved as an excellent •OOH and •OH scavenger under physiological conditions better than Trolox and vitamin C, whereas its radical demonstrated as an efficient O 2 ∙ - scavenger.

3,4,3'-Tri-O-methylellagic acid as an anticancer agent: in vitro and in silico studies.

We report a natural product compound isolated from Syzygium polycephalum known as 3,4,3'-tri-O-methylellagic acid (T-EA) as a candidate drug for cancer treatment. The characterization of the isolated T-EA compound was carried out using various spectroscopic methods. The in vitro evaluation showcased the inhibition activity of T-EA towards the T47D and HeLa cell lines with EC50 values of 55.35 ± 6.28 µg mL-1 and 12.57 ± 2.22 µg mL-1, respectively. Meanwhile, the in silico evaluation aimed to understand the interaction of T-EA with enzymes responsible for cancer regulation at the molecular level by targeting the hindrance of cyclin-dependent kinase 9 (CDK9) and sirtuin 1 (SIRT1) enzymes. T-EA showed a binding free energy towards the SIRT1 protein of ΔG bind (MM-GBSA): -30.98 ± 0.25 kcal mol-1 and ΔG bind (MM-PBSA): -24.07 ± 0.30 kcal mol-1, while that of CDK9 was ΔG bind (MM-GBSA): -29.50 ± 0.22 kcal mol-1 and ΔG bind (MM-PBSA): -25.87 ± 0.40 kcal mol-1. The obtained results from this research could be considered as important information on 3,4,3'-tri-O-methylellagic acid as a drug to treat cervical and breast cancers.

Anticancer potential of ß-sitosterol and oleanolic acid as through inhibition of human estrogenic 17beta-hydroxysteroid dehydrogenase type-1 based on an in silico approach.

The human estrogenic enzyme 17beta-hydroxysteroid dehydrogenase type-1 (HSD17B1) provides biosynthesis regulation of active estrogen in stimulating the development of breast cancer through cell proliferation. The ß-sitosterol is classified as a steroid compound and is actually a type of triterpenoid compound that has a similar structure to a steroid. This similarity provides a great opportunity for the inhibitor candidate to bind to the HDS17B1 enzyme because of the template similarity on the active site. Several in silico approaches have been applied in this study to examine the potential of these two inhibitor candidates. Pharmacokinetic studies showed positive results by meeting several drug candidate criteria, such as drug-likeness, bioavailability, and ADMET properties. A combination of molecular docking and MD simulation showed good conformational interaction of the inhibitors and HSD17B1. Prediction of binding free energy (ΔG bind) using the Molecular Mechanics-Generalized Born Surface Area (MM-GBSA) approach shows ΔG bind (kcal mol-1) of C1-HSD17B1: -49.31 ± 0.23 and C2-HSD17B1: -33.54 ± 0.34. Meanwhile, decomposition energy analysis (ΔG residue bind) suggested several key residues that were also responsible for the interaction with inhibitors, such as C1-HSD17B1 (six residues: Leu96, Leu149, Pro187, Met193, Val225, and Phe226) and C2-HSD17B1 (four residues: Ile14, Gly94, Pro187, and Val188). Hopefully, the obtained results from this research could be considered for the mechanistic inhibition of the HSDS17B1 enzyme at molecular and atomistic levels.

An in vitro study of dual drug combinations of anti-viral agents, antibiotics, and/or hydroxychloroquine against the SARS-CoV-2 virus isolated from hospitalized patients in Surabaya, Indonesia.

A potent therapy for the infectious coronavirus disease COVID-19 is urgently required with, at the time of writing, research in this area still ongoing. This study aims to evaluate the in vitro anti-viral activities of combinations of certain commercially available drugs that have recently formed part of COVID-19 therapy. Dual combinatory drugs, namely; Lopinavir-Ritonavir (LOPIRITO)-Clarithromycin (CLA), LOPIRITO-Azithromycin (AZI), LOPIRITO-Doxycycline (DOXY), Hydroxychloroquine (HCQ)-AZI, HCQ-DOXY, Favipiravir (FAVI)-AZI, HCQ-FAVI, and HCQ-LOPIRITO, were prepared. These drugs were mixed at specific ratios and evaluated for their safe use based on the cytotoxicity concentration (CC50) values of human umbilical cord mesenchymal stem cells. The anti-viral efficacy of these combinations in relation to Vero cells infected with SARS-CoV-2 virus isolated from a patient in Universitas Airlangga hospital, Surabaya, Indonesia and evaluated for IC50 24, 48, and 72 hours after viral inoculation was subsequently determined. Observation of the viral load in qRT-PCR was undertaken, the results of which indicated the absence of high levels of cytotoxicity in any samples and that dual combinatory drugs produced lower cytotoxicity than single drugs. In addition, these combinations demonstrated considerable effectiveness in reducing the copy number of the virus at 48 and 72 hours, while even at 24 hours, post-drug incubation resulted in low IC50 values. Most combination drugs reduced pro-inflammatory markers, i.e. IL-6 and TNF-α, while increasing the anti-inflammatory response of IL-10. According to these results, the descending order of effective dual combinatory drugs is one of LOPIRITO-AZI>LOPIRITO-DOXY>HCQ-AZI>HCQ-FAVI>LOPIRITO-CLA>HCQ-DOX. It can be suggested that dual combinatory drugs, e.g. LOPIRITO-AZI, can potentially be used in the treatment of COVID-19 infectious diseases.

The dolabellane diterpenes as potential inhibitors of the SARS-CoV-2 main protease: molecular insight of the inhibitory mechanism through computational studies.

An investigation has been carried out on natural products from dolabellane derivatives to understand their potential in inhibiting the SARS-CoV-2 main protease (3CLpro) using an in silico approach. Inhibition of the 3CLpro enzyme is a promising target in stopping the replication of the SARS-CoV-2 virus through inhibition of the subsite binding pocket. The redocking process aims to determine the 3CLpro active sites. The redocking requirement showed a good pose with an RMSD value of 1.39 Å. The combination of molecular docking and MD simulation shows the results of DD13 as a candidate which had a good binding affinity (kcal mol-1) to inhibit the 3CLpro enzyme activity. Prediction of binding free energy (kcal mol-1) of DD13 using the Molecular Mechanics-Poisson Boltzmann/Generalized Born Surface Area (MM-PB/GBSA) approach shows the results ΔG bind(MM-GBSA): -52.33 ± 0.34 and ΔG bind(MM-PBSA): -43.52 ± 0.42. The key residues responsible for the inhibition mechanism are Hie41, Ser46, Met49, Asn142, Cys145, Hie163, Met165, and Gln189. Additionally, pharmacokinetic prediction recommended that DD13 had promising criteria as a drug candidate. The results demonstrated in this study provide theoretical information to obtain a potential inhibitor against the SARS-CoV-2 main protease.

Exploration of stilbenoid trimers as potential inhibitors of sirtuin1 enzyme using a molecular docking and molecular dynamics simulation approach.

A combination of molecular docking and molecular dynamics simulation (250 ns) has been carried out to study the interaction of stilbenoid trimer compounds with the SIRT1 enzyme as the target protein. SIRT1 expression regulates cellular stress responses that lead to the development of cancer. Redocking showed a good native ligand pose with an RMSD value of 1.40 Å at the receptor active site's coordinates. The molecular docking score uses a grid score functional (kcal mol-1), which shows results of 1NS: 79.56, TS1: -26.83, TS2: -87.77, and TS3: -83.67. The TS2 and TS3 candidates were chosen for further analysis because they had a lower grid score than the native ligand (1NS). Furthermore, prediction of binding free energy (kcal mol-1) using the Quantum Mechanics/generalized Born Surface Area (QM/MM-GBSA) method shows the results of 1NS: -31.52 ± 0.39, TS2: -58.99 ± 0.34, and TS3: -43.38 ± 0.35. These results indicate that the TS2 and TS3 compounds have good potential as inhibitors of the SIRT1 enzyme. Additionally, the amino acid residues were responsible for the inhibition mechanism through hydrogen bond interactions at the molecular level, including ASP22, PHE91, PRO11, ILE165, ASP166, and VAL230. The observations made in this study provide theoretical information for exploring the stilbenoid trimers as anticancer agents by targeting the SIRT1 enzyme.

In silico approach: biological prediction of nordentatin derivatives as anticancer agent inhibitors in the cAMP pathway.

A combination of computational techniques has been carried out to predict the binding of nordentatin derivatives based on pyranocoumarin semi-synthesis with the target protein from the expression of the PDE4B gene. The inhibition of the cAMP pathway is the main target of anti-cancer drugs, which is responsible for uncontrolled cell division in cancer. Modeling was done using a combination of semi-empirical methods and the density functional theory (PM3-DFT/6-31G*/B3LYP) to obtain the optimal structure of a small ligand that could be modeled. Studies on the interaction of the ligands and amino acid residues on protein targets were carried out using a combination of molecular docking and molecular dynamic simulation. Molecular docking based on functional grid scores showed a very good native ligand pose with an RMSD of 0.93 Å in determining the initial coordinates of the ligand-receptor interactions. Furthermore, the amino acid residues responsible for interaction through H-bonds were Tyr103, His104, His177, Met217, and Gln313. The binding free energy (kcal mol-1) results of the candidates were PS-1 (-36.84 ± 0.31), PS-2 (-35.34 ± 0.28), PS-3 (-26.65 ± 0.30), PS-5 (-42.66 ± 0.26), PS-7 (-35.33 ± 0.23), and PS-9 (-32.57 ± 0.20), which are smaller than that of the native ligand Z72 (-24.20 ± 0.19), and thus these have good potential as drugs that can inhibit the cAMP pathway. These results provide theoretical information for the efficient inhibition of the cAMP pathway in the future.

Inhibitory Activity and Docking Analysis of Antimalarial Agents from Stemona sp. toward Ferredoxin-NADP+ Reductase from Malaria Parasites.

Ferredoxin-NADP+ reductases (FNRs, EC 1.18.1.2) were found in the plastids of Plasmodium and have been considered as a target for the development of new antimalarial agents. Croomine, epi-croomine, tuberostemonine, javastemonine A, and isoprotostemonine are isolated alkaloids from the roots of Stemona sp. and their inhibitory effect on FNRs from Plasmodium falciparum (PfFNR) was investigated. Croomine showed the highest level of inhibition (33.9%) of electron transfer from PfFNR to PfFd, while tuberstemonine displayed the highest level of inhibition (55.4%) of diaphorase activity of PfFNR. Docking analysis represented that croomine is located at the middle position of PfFNR and PfFd. Croomine from S. tuberosa appeared to have potential as an antimalarial agent.