Selectivity Index Values Research Articles

Integrated study of Quercetin as a potent SARS-CoV-2 RdRp inhibitor: Binding interactions, MD simulations, and In vitro assays.

To find an effective inhibitor for SARS-CoV-2, Quercetin's chemical structure was compared to nine ligands associated with nine key SARS-CoV-2 proteins. It was found that Quercetin closely resembles Remdesivir, the co-crystallized ligand of RNA-dependent RNA polymerase (RdRp). This similarity was confirmed through flexible alignment experiments and molecular docking studies, which showed that both Quercetin and Remdesivir bind similarly to the active site of RdRp. Molecular dynamics (MD) simulations over a 200 ns trajectory, analyzing various factors like RMSD, RG, RMSF, SASA, and hydrogen bonding were conducted. These simulations gave detailed insights into the binding interactions of Quercetin with RdRp compared to Remdesivir. Further analyses, including MM-GBSA, Protein-Ligand Interaction Fingerprints (ProLIF) and Profile PLIP studies, confirmed the stability of Quercetin's binding. Principal component analysis of trajectories (PCAT) provided insights into the coordinated movements within the systems studied. In vitro assays showed that Quercetin is highly effective in inhibiting RdRp, with an IC50 of 122.1 ±5.46 nM, which is better than Remdesivir's IC50 of 21.62 ±2.81 μM. Moreover, Quercetin showed greater efficacy against SARS-CoV-2 In vitro, with an IC50 of 1.149 μg/ml compared to Remdesivir's 9.54 μg/ml. The selectivity index (SI) values highlighted Quercetin's safety margin (SI: 791) over Remdesivir (SI: 6). In conclusion, our comprehensive study suggests that Quercetin is a promising candidate for further research as an inhibitor of SARS-CoV-2 RdRp, providing valuable insights for developing an effective anti-COVID-19 treatment.

Cytotoxicity of norstictic acid derivatives, a depsidone from Ramalina anceps Nyl.

Structural modifications in lichen phenolic compounds have been one of the tools to potentiate their biological activity. In the present work, seven alkyl derivatives of norstictic acid were prepared and evaluated against eight cell lines. Norstictic acid was isolated from the lichen Ramalina anceps and the alkyl derivatives were obtained through reactions with alcohols. Cytotoxicity was evaluated against the 786-0 (kidney carcinoma), MCF7 (breast carcinoma), HT-29 (colon carcinoma), PC-03 (prostate carcinoma), HEP2 (laryngeal carcinoma), B16-F10 (murine melanoma), UACC-62 (human melanoma), and NIH/3T3 (mouse embryonic fibroblast) cell lines using the sulforhodamine B assay. Norstictic acid exhibited poor activity, while the 8'-O-n-butyl-norstictic acid and 8'-O-sec-butyl-norstictic acid derivatives showed potential activity (GI50 values of 6.37-45.0 μM and 6.8-52.40 μM, respectively) and high selectivity (selectivity index (SI) values of 13.88-98.11 and SI 11.30-87.40, respectively) against all tumor cells. The 8'-O-n-hexyl-norstictic acid showed good activity (5.96-9.53 μM) and moderate selectivity (SI 9.2-5.76) against MCF7, HT-29, PC-03, and HEP2 cells, while 8'-O-isopropyl-norstictic acid demonstrated high activity and selectivity against PC-03 cells (GI50 1.28 μM and SI 33.8), and was highly active but moderately selective against UACC, HEP2, and B16-F10 cells (GI50 6.2, 7.78, and 9.65 μM; SI 7.0, 5.5, and 4.5, respectively). Additionally, 8'-O-n-pentyl- and 8'-O-tert-butyl-norstictic acids were active and selective against PC-03 cells (GI50 8.77 and 7.60 μM; SI 6.53 and 5.0, respectively). Chemometric analysis revealed a clear relationship between all compounds and their biological activities. The insertion of a four-carbon alkyl chain (n-butyl and sec-butyl) produced potentially active compounds on all tested tumor cells.

Determination of Cytotoxic Activity of Aronia melanocarpa (Michx.) Elliot Fruit Extracts on Breast Cancer (MCF-7) and Cervical Cancer (HeLa) Cell Lines

Aronia (chokeberry) fruits are consumed as fresh fruit due to their high antioxidant activity, and are also preferred among the public in the production of natural medicines. Aronia melanocarpa (Michx.) Elliot, a species of the Rosaceae family, contains many phytochemical compounds such as flavonoids, phenolic compounds, lignans, terpenes, tocopherols, phospholipids, organic acids and high amounts of anthocyanins. In this study, it was aimed to determine the in vitro anticarcinogenic activities of A. melanocarpa (Michx.) Elliot fruit extracts prepared with 6 different solvents. In the study, the cytotoxic effects of the fruits were investigated using breast cancer cell line (MCF-7) and cervical cancer cell line (HeLa), and their effects on healthy cells were investigated using human endothelial cells (HUVEC) and mouse fibroblast cells (L929) by the MTT method. As a result of the study; It was determined that the highest cytotoxicity on the breast cancer (MCF-7) cell line was observed in the ethanol extract (IC50=111.44 µg/mL) and the lowest cytotoxicity was observed in the hexane extract (IC50=661.80 µg/mL). It was determined that the highest cytotoxicity on the cervical cancer (HeLa) cell line was observed in the ethanol extract (IC50=95.14 µg/mL) and the lowest cytotoxicity was observed in the ethyl acetate extract (IC50=319.51 µg/mL). According to these values; It was determined that all extracts of Aronia fruit had cytotoxic effects on MCF-7 and HeLa cell lines, selectivity index values were higher in HeLa cells, and they did not have cytotoxic effects on HUVEC and L929 healthy cell lines (IC50=411.25-663.27 µg/mL). Thus, it has been determined that the fruits of the Aronia melanocarpa species are promising in the development of new natural resources, new drugs and therapeutic agents in cancer treatment, thanks to their anticancer activities and low cytotoxicity. It is recommended that further research be conducted on the mechanisms of anticancer activity in the future

Inverse versus convolution treatment planning algorithms for gamma knife radiosurgery.

To compare the convolution and inverse algorithm plans. The cross-sectional study was conducted from January to May 2022 at the Icon Gamma Knife Centre, Al- Taj Hospital, Baghdad, Iraq, and comprised patients with malignant and benign brain tumours who underwent gamma knife therapy. Each patient's brain was imaged using computed tomography and magnetic resonance imaging. The neurosurgeon prescribed the dose depending on the tumour volume and type, while the medical physicist generated the two plans based on inverse and convolution algorithms. The prescribed dose was delivered to 50% of the isodose line of the tumour. Each plan was evaluated with respect to tumour conformity index, coverage, gradient index, number of shots, and time of treatment. Of the 30 patients, 17(56.7%) were males and 13(43.3%) were females. The overall mean age was 46.29±15.20 years (range: 10-71 years). The mean dose delivered was 15.86±3.86Gy, and the mean number of gamma radiation shots was 12.56±6.95. There was significant difference between the two algorithm plans for all dosimetric parameters, with the inverse plan providing higher coverage and selectivity than convolution plan, but taking longer time(p<0.05), while plan was inverse plan better than convolution plan in terms of gradient and conformity (p<0.05). With more extended treatment, the inverse plan was found to have superior selectivity, coverage, gradient index and Paddick conformity index values compared to the convolution plan.

IN VITRO EFFICACY OF VITEX AGNUS-CASTUS EXTRACTS AGAINST TRICHOMONAS VAGINALIS: A POTENTIAL THERAPEUTIC APPROACH

Aim and objectives: Trichomonas vaginalis is the most prevalent nonviral sexually transmitted infection globally. The current treatment, 5-nitroimidazole derivatives has raised concerns as a result of drug reliance, allergies, and drug resistance, driving efforts to identify alternative therapies. The Vitex species recognized for their pharmacological attributes including anti-inflammatory, antibacterial, antifungal, and antimicrobial properties are promising candidates for further investigation. Methods: In this study, the potential of Vitex agnus-castus extracts against T. vaginalis was explored. The water, ethanol, and 60% aqueous ethanol extracts from both leaves and fruits were examined for their effects on metronidazole (MET)-resistant (TV 50143) and sensitive strains (TV-78). Cytotoxicity was evaluated on L929 mouse fibroblast cells to determine the minimum lethal dose for each extract under aerobic and anaerobic conditions. Results: Antitrichomonial activity, cytotoxic activity and Selectivity Index (SI) values revealed distinct efficacy profiles. Leaf water extract displayed a balanced selectivity profile, while leaf 60% ethanol extract showed moderate to high selectivity. The fruit 60% ethanol extract exhibited significantly elevated selectivity with SI values of 2 and 1 under aerobic and anaerobic conditions, respectively, for the MET-sensitive reference strain, and 3 and 5, respectively, for the MET-resistant reference strain. Conclusion: These findings underscore the potential of the fruit 60% ethanol extract as a promising candidate for future drug development. Further investigations into its mechanisms and optimization are warranted to enhance its efficacy against T. vaginalis. Peer Review History: Received 13 May 2024; Reviewed 15 July 2024; Accepted 21 August; Available online 15 September 2024 Academic Editor: Dr. Amany Mohamed Alboghdadly, Ibn Sina National College for Medical Studies in Jeddah, Saudi Arabia, amanyalboghdadly@gmail.com Average Peer review marks at initial stage: 6.0/10 Average Peer review marks at publication stage: 7.5/10 Reviewers: Prof. Ali Gamal Ahmed Al-kaf, Sana'a university, Yemen, alialkaf21@gmail.com Dr. Marwa A. A. Fayed, University of Sadat City, Egypt, maafayed@gmail.com Dr. Sangeetha Arullappan, Universiti Tunku Abdul Rahman, Malaysia, sangeetha@utar.edu.my

Design, synthesis, and evaluation of novel oxyacanthine derivatives for anti-SARS-CoV-2 activity

Here, we report the synthesis of a series of oxyacanthine derivatives and evaluation for their anti-SARS-CoV-2 activity in Vero E6 cells. In order to eliminate the potential metabolic activation caused by para-methylene phenol moiety in oxyacanthine, totally 29 derivatives were designed and synthesized, resulting in 23 compounds with antivirus IC50 below 5.00 μM and 9 compounds with antivirus IC50 below 1.00 μM. Among them, amides compound 4a and 4d exhibited potent anti-SARS-CoV-2 activity and the most favorable selectivity index (SI) in vitro with the SI values of 115 and 70, respectively. The pharmacokinetic properties of 4a and 4d were also assessed. Much more improved exposure in mice, longer half-life (T1/2), and increased oral bioavailability were observed for both compounds 4a and 4d compared with oxyacanthine.

Chemometrics Evaluation of Lemongrass Essential Oils: Authenticity, Quality and Selection Of Bioactives against t. cruzi.

AbstractThe effectiveness of treatments against the parasite Trypanosoma cruzi, the causative agent of Chagas disease, is limited in the chronic phase of the disease. The essential oils of lemongrass (Cymbopogon citratus and Cymbopogon flexuosus) have shown activity against this parasite. This study aimed to use principal component analysis (PCA) to analyze the data of lemongrass essential oils submitted to gas chromatography with flame ionization detector (GC‐FID) and proton nuclear magnetic resonance (1H NMR) as well as partial least squares (PLS) regressions to correlate chemical variability with the results of biological assays. The PLS models highlighted geraniol, caryophyllene, and limonene as the main compounds responsible for antioxidant activity. Regarding cytotoxicity, the PLS models indicated that this activity is a cumulative effect of multiple compounds. For the trypanocidal effect, median lethal concentration (CL50) values ranged from 15.12 ± 3.96 to 110.10 ± 11.22 μg mL−1, resulting in selectivity index (SI) values of 2.99 to 22.55 times more selective for T. cruzi compared to host cells. PLS indicated that geraniol, neral and geranial were the main contributors to the trypanocidal effect, suggesting the potential for somatic or synergistic effects against trypomastigote forms.

Effect of halogens on 3-[4-(dimethylamino) phenyl]-1-phenylprop-2-en-1-ones: development of a new class of monoamine oxidase-B inhibitors

Five dimethylamino-based chalcone derivatives (AC) were synthesized and evaluated for their inhibition degree against monoamine oxidase (MAO) enzymes. All AC compounds showed better inhibitory activity against MAO-B than that against MAO-A. AC4 showed the highest inhibitory ability with an IC50 value of 0.020 µM, similar to that of a reference drug safinamide (IC50 = 0.019 µM) against MAO-B, followed by AC1 (IC50 = 0.068 µM) and AC3 (IC50 = 0.083 µM). Substituent -F in ring A (AC4) increased the MAO-B inhibition, followed by -H (AC1), -Br (AC3), and -Cl (AC2). The selectivity index (SI) value of AC4 was high (SI = 82.00) as well as other compounds (44.41 to 98.15). AC4 was found to be a reversible inhibitor as confirmed through analysis using the dialysis method. Interestingly, AC4 was observed to be a noncompetitive MAO-B inhibitor with a rare case and with Ki values of 0.011 ± 0.0036 µM. These experiments confirmed that AC4 is a reversible and potent selective inhibitor of MAO-B. Molecular docking experiments revealed that AC4 showed the highest inhibitory activity with a docking score (-9.510 kcal/mol). A study using molecular dynamics modeling revealed that the protein–ligand complex was more stable. It was observed that AC4 was non-cytotoxic in the study using L929 cell line. In conclusion, compound AC4 shows promise as a MAO-B inhibitor.

Discovery of Novel Amino Acids (Analogues)-Substituted Thiophene[3,2-d]pyrimidine Derivatives as Potent HIV-1 Non-Nucleoside Reverse Transcriptase Inhibitors: Design, Synthesis, and Biological Evaluation.

Inspired by our previous work on the modification of diarylpyrimidine-typed non-nucleoside reverse transcriptase inhibitors (NNRTIs) and the reported crystallographic studies, a series of novel amino acids (analogues)-substituted thiophene[3,2-d]pyrimidine derivatives were designed and synthesized by targeting the solvent-exposed region of the NNRTI-binding pocket. The biological evaluation results showed that compound 5k was the most active inhibitor, exhibiting moderate-to-excellent potency against HIV-1 wild-type (WT) and a panel of NNRTI-resistant strains, with EC50 values ranging from 0.042 μM to 7.530 μM. Of special note, 5k exhibited the most potent activity against single-mutant strains (K103N and E138K), with EC50 values of 0.031 μM and 0.094 μM, being about 4.3-fold superior to EFV (EC50 = 0.132 μM) and 1.9-fold superior to NVP (EC50 = 0.181 μM), respectively. In addition, 5k demonstrated lower cytotoxicity (CC50 = 27.9 μM) and higher selectivity index values. The HIV-1 reverse transcriptase (RT) inhibition assay was further performed to confirm their binding target. Moreover, preliminary structure-activity relationships (SARs) and molecular docking studies were also discussed in order to provide valuable insights for further structural optimizations. In summary, 5k turned out to be a promising NNRTI lead compound for further investigations of treatments for HIV-1 infections.

Inhibition of monoamine oxidases and neuroprotective effects: chalcones vs. chromones.

Eighteen compounds derived from two sub-series, (HC1-HC9) and (HF1-HF9), were synthesized and evaluated for their inhibitory activities against monoamine oxidase (MAO). HC (chalcone) series showed higher inhibitory activity against MAO-B than against MAO-A, whereas the HF (chromone) series showed reversed inhibitory activity. Compound HC4 most potently inhibited MAO-B with an IC50 value of 0.040μM, followed by HC3 (IC50 = 0.049μM), while compound HF4 most potently inhibited MAO-A (IC50 = 0.046μM), followed by HF2 (IC50 = 0.075μM). The selectivity index (SI) values of HC4 and HF4 were 50.40 and 0.59, respectively. Structurally, HC4 (4-OC2H5 in B-ring) showed higher MAO-B inhibition than other derivatives, suggesting that the -OC2H5 substitution of the 4-position in the B-ring contributes to the increase of MAO-B inhibition, especially -OC2H5 (HC4) > -OCH3 (HC3) > -F (HC7) > -CH3 (HC2) > -Br (HC8) > -H (HC1) in order. In MAO-A inhibition, the substituent 4-OC2H5 in the B-ring of HF4 contributed to an increase in inhibitory activity, followed by -CH3 (HF2), -F (HF7), -Br (HF8), -OCH3 (HF3), and-H (HF1). In the enzyme kinetics and reversibility study, the Ki value of HC4 for MAO-B was 0.035 ± 0.005μM, and that of HF4 for MAO-A was 0.035 ± 0.005μM, and both were reversible competitive inhibitors. We confirmed that HC4 and HF4 significantly ameliorated rotenone-induced neurotoxicity, as evidenced by the reactive oxygen species and superoxide dismutase assays. This study also supports the significant effect of HC4 and HF4 on mitochondrial membrane potential in rotenone-induced toxicity. A lead molecule was used for molecular docking and dynamic simulation studies. These results show that HC4 is a potent selective MAO-B inhibitor and HF4 is a potent MAO-A inhibitor, suggesting that both compounds can be used as treatment agents for neurological disorders.

Effect of heat stress on semen characteristics and genetics in Thai native grandparent roosters

Grandparent roosters are crucial in poultry breeding programs and significantly influence future bird generations' genetic makeup and performance. However, these roosters face considerable challenges from heat stress, which can adversely affect their reproductive performance, semen quality, and overall health and welfare. Our study aimed to investigate the effects of heat stress on the genetics of semen characteristics, identify the appropriate temperature and humidity indices (THI), and determine the threshold point of heat stress to prevent thermal stress. We analyzed data from 3,895 records of 242 Thai native grandparent roosters in conjunction with the THI using 7 THI functions and the regression method. The threshold point of heat stress, genetic parameters, rate of decline of semen characteristics per level of THI, estimated breeding values and selection index values were analyzed using the multivariate test-day model in the AIREML and BLUPF90 programs. Based on the regression coefficient and statistical criteria of the lowest -2logL and AIC values, the results showed that a THI of 78 was considered the threshold point of heat stress. The estimated heritability values ranged from 0.023 to 0.032, 0.066 to 0.069, 0.047 to 0.057, and 0.022 to 0.024 for mass movement, semen volume, sperm concentration, and the semen index, respectively. The reduction rates of mass movement, semen volume, sperm concentration, and semen index at a THI of 78 were -0.009, -0.003, -0.170, and -0.083 per THI, respectively. The genetic correlations among the semen traits were moderately to strongly positive and ranged from 0.562 to 0.797. The genetic correlations between semen traits and heat stress were negative and ranged from -0.437 to -0.749. The permanent environmental correlations among the semen traits (0.648-0.929) were positive and greater than the genetic correlations. Permanent environmental correlations between semen traits and heat stress were negative and ranged from -0.539 to -0.773. The results of the selection indices showed that the higher the selection intensity was, the greater the degree to which the selection index corresponded to genetic progress. The recommendation for animal genetic selection is that the top 10% is appropriate because it seems most preferred. Therefore, using a multivariate test-day model and selection index for the high genetic potential of semen traits and heat tolerance in Thai native grandparent roosters makes it possible to achieve genetic assessment in a large population.

Induction of Apoptosis and ROS Production in Liver Cancer Cells by Saponin Fraction from Alcea rosea L. Seeds

Background: Natural compounds are essential targets in anticancer research due to the toxic effects of current chemotherapy and drug resistance. Methods: Saponin extraction from Alcea rosea L. was carried out using 20% methanol and liquid-liquid extraction coupled with the Solid phase extraction (SPE) approach. The saponin fraction was explored for its cytotoxic activity against Huh-7 and MDA-MB-231 cancer cell lines and a non–cancer cell line (HUVEC). The cytotoxic activity and oxidative stress were assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and 2,7 dichlorofluorescein diacetate dyes respectively. The apoptotic potential was investigated using DAPI and acridine orange-ethidium bromide dual staining. Result: The saponin fraction exhibited cytotoxic potential against the cell lines investigated. The IC50 values of the saponin fraction were 49.02, 300 and 325 µg\mL against Huh-7, MDA-MB-231 and HUVEC cell lines, respectively. The cytotoxicity for the extract was dose-dependent. The saponin fraction calculated selectivity index (SI) value indicated high selectivity towards Huh-7 cells (SI = 6.62) compared with normal HUVEC cells. Huh-7 cells treated with saponin fraction showed cellular and nuclear morphological changes, such as apoptotic body formation and chromatin condensation, as observed using light and fluorescent microscopy. However, further investigation is required to assess the the saponin fraction as a potential therapeutic agent.

Comparison of Mutant Prevention Concentrations of Fluoroquinolones Against ESBL-Positive and ESBL-Negative Klebsiella pneumoniae Isolates from Orthopedic Patients.

The majority of Klebsiella pneumonia isolates possess the extended-spectrum beta-lactamase (ESBL) enzymes. Therefore, K. pneumoniae can easily develop drug resistance. How to effectively overcome the problem of drug resistance in K. pneumoniae is still a research hotspot. This study aimed to compare the mutant prevention concentration (MPC) of ESBL-positive and ESBL-negative K. pneumoniae isolated from orthopedic patients, which may provide a basis for the effective use of drugs to control the enrichment of resistance mutants of K. pneumoniae. The MPC90 values of 55 isolates of ESBL-positive K. pneumoniae against 4 fluoroquinolones were 32 µg/mL for levofloxacin and gatifloxacin, 16 µg/mL for ciprofloxacin, and 4 µg/mL for gemifloxacin. The selection index value was 8 for levofloxacin and ciprofloxacin and 2 for gemifloxacin and gatifloxacin, respectively. For ESBL-negative K. pneumoniae isolates, the MPC90 values were 16 µg/mL for levofloxacin and ciprofloxacin, 4 µg/mL for gemifloxacin, and 32 µg/mL for gatifloxacin. The selection index value was 8 for levofloxacin and ciprofloxacin, 2 for gemifloxacin, and 4 for gatifloxacin. For the ESBL-positive K. pneumoniae, the %T>MIC90 order was gemifloxacin > levofloxacin > ciprofloxacin > gatifloxacin. For the ESBL-negative K. pneumoniae, the %T>MIC90 order was levofloxacin > gemifloxacin > ciprofloxacin > gatifloxacin. The mutant-preventing ability of gatifloxacin and gemifloxacin was the strongest among the 4 fluoroquinolones. So gemifloxacin may be the first choice of drug to treat K. pneumoniae infection.

Design, synthesis, and anti-mycobacterial evaluation of 1,8-naphthyridine-3-carbonitrile analogues.

Twenty-eight compounds, viz., 1,8-naphthyridine-3-carbonitrile (ANC and ANA) derivatives, were designed and synthesized through a molecular hybridization approach. The structures of these compounds were analyzed and confirmed using 1H NMR, 13C NMR, LCMS, and elemental analyses. The synthesized compounds were evaluated by in vitro testing for their effectiveness against tuberculosis using the MABA assay, targeting the Mycobacterium tuberculosis H37Rv strain. Their minimum inhibitory concentration (MIC) was determined, showing that the tested compounds' MIC values ranged from 6.25 to ≤50 μg mL-1. Among the derivatives studied, ANA-12 demonstrated prominent anti-tuberculosis activity with a MIC of 6.25 μg mL-1. Compounds ANC-2, ANA-1, ANA 6-8, and ANA-10 displayed moderate to good anti-tuberculosis activity with MIC values of 12.5 μg mL-1. Compounds with MIC ≤ 12.5 μg mL-1 were screened against human embryonic kidney cells to assess their potential cytotoxicity. Interestingly, these compounds showed less toxicity towards normal cells, with a selectivity index value ≥ 11. To further evaluate the binding pattern in the active site of enoyl-ACP reductase (InhA) from Mtb (PDB-4TZK), a molecular docking analysis of compound ANA-12 was performed using the glide module of Schrodinger software. The stability, confirmation, and intermolecular interactions of the cocrystal ligand and the highly active compound ANA-12 on the chosen target protein were investigated through molecular dynamics simulations lasting 100 ns. In silico predictions were utilized to assess the ADMET properties of the final compounds. A suitable single crystal was developed and analyzed for compound ANA-5 to gain a deeper understanding of the compounds' structures.

The interactive effects of medicinal dyes with conventional antimicrobials against skin pathogens.

This study aimed to explore potential synergistic effects of medicinal dyes with antimicrobials against pathogens responsible for skin infections. Antimicrobial testing was conducted using minimum inhibitory concentrations and minimum bactericidal/fungicidal concentration assays. The fractional inhibitory index (ΣFIC) of combinations was calculated, and isobolograms were constructed on selected combinations. Toxicity studies were conducted using the brine-shrimp lethality assay. Combination (1:1 ratio) studies noted that 26% of dye-antibiotic combinations were synergistic against the Gram-positive strains, 15% against the Gram-negative strains, and 14% against the yeasts. The Mercurochrome: Betadine® combination noted synergy at ratios against all the Staphylococcus aureus strains with ΣFIC values ranging from 0.05 to 0.48. The combination of Gentian violet with Gentamycin noted a 15-fold decrease in toxicity, and a selectivity index of 977.50 against the Escherichia coli (DSM 22314) strain. Time-kill studies were conducted on the combinations with the highest safe selectivity index (SI) value and lowest safe SI value i.e. Gentian violet with Gentamycin and Malachite green with Neomycin. Both combinations demonstrated better antimicrobial activity in comparison to the independent values and the controls. This study highlights the potential for medicinal dye combinations as a treatment for skin infections.

Inhibition of Monoamine Oxidases by Pyridazinobenzylpiperidine Derivatives.

Monoamine oxidase inhibitors (MAOIs) have been crucial in the search for anti-neurodegenerative medications and continued to be a vital source of molecular and mechanistic diversity. Therefore, the search for selective MAOIs is one of the main areas of current drug development. To increase the effectiveness and safety of treating Parkinson's disease, new scaffolds for reversible MAO-B inhibitors are being developed. A total of 24 pyridazinobenzylpiperidine derivatives were synthesized and evaluated for MAO. Most of the compounds showed a higher inhibition of MAO-B than of MAO-A. Compound S5 most potently inhibited MAO-B with an IC50 value of 0.203 μM, followed by S16 (IC50 = 0.979 μM). In contrast, all compounds showed weak MAO-A inhibition. Among them, S15 most potently inhibited MAO-A with an IC50 value of 3.691 μM, followed by S5 (IC50 = 3.857 μM). Compound S5 had the highest selectivity index (SI) value of 19.04 for MAO-B compared with MAO-A. Compound S5 (3-Cl) showed greater MAO-B inhibition than the other derivatives with substituents of -Cl > -OCH3 > -F > -CN > -CH3 > -Br at the 3-position. However, the 2- and 4-position showed low MAO-B inhibition, except S16 (2-CN). In addition, compounds containing two or more substituents exhibited low MAO-B inhibition. In the kinetic study, the Ki values of S5 and S16 for MAO-B were 0.155 ± 0.050 and 0.721 ± 0.074 μM, respectively, with competitive reversible-type inhibition. Additionally, in the PAMPA, both lead compounds demonstrated blood-brain barrier penetration. Furthermore, stability was demonstrated by the 2V5Z-S5 complex by pi-pi stacking with Tyr398 and Tyr326. These results suggest that S5 and S16 are potent, reversible, selective MAO-B inhibitors that can be used as potential agents for the treatment of neurological disorders.

Discovery of procyanidin condensed tannins of (−)-epicatechin from Kratom, Mitragyna speciosa, as virucidal agents against SARS-CoV-2

Kratom, Mitragyna speciosa, is one of the most popular herbs in the West and Southeast Asia. A number of previous works have focused on bioactive alkaloids in this plant; however, non-alkaloids have never been investigated for their biological activities. Antiviral and virucidal assays of a methanol leaf extract of Kratom, M. speciosa, revealed that a crude extract displayed virucidal activity against the SARS-CoV-2. Activity-guided isolation of a methanol leaf extract of Kratom led to the identification of B-type procyanidin condensed tannins of (−)-epicatechin as virucidal compounds against SARS-CoV-2. The fraction containing condensed tannins exhibited virucidal activity with an EC50 value of 8.38 μg/mL and a selectivity index (SI) value >23.86. LC-MS/MS analysis and MALDI-TOF MS identified the structure of the virucidal compounds in Kratom as B-type procyanidin condensed tannins, while gel permeation chromatograph (GPC) revealed weight average molecular weight of 238,946 Da for high molecular-weight condensed tannins. In addition to alkaloids, (−)-epicatechin was found as a major component in the leaves of M. speciosa, but it did not have virucidal activity. Macromolecules of (−)-epicatechin, i.e., procyanidin condensed tannins, showed potent virucidal activity against SARS-CoV-2, suggesting that the high molecular weights of these polyphenols are important for virucidal activity.

Synthesis, structural investigations, in vitro cytotoxicity, apoptotic activity, cell cycle analysis, and molecular modeling studies of nano‐sized Zn(II) Schiff base complex

A new novel tetradentate ligand, [(1E,1′E)‐N,N′‐(1,2‐phenylene)bis(1‐(5‐(2‐fluorophenyl)furan‐2‐yl)methanimine) (PFPFMI), and its nano‐sized [Zn(PFPFMI)Cl2].3H2O complex were synthesized. The geometry of PFPFMI and its Zn(II) complex was described through CHN analyses, Fourier‐transform infrared spectroscopy (FTIR), UV–visible, X‐ray diffraction (XRD), thermal gravimetric analysis (TGA), and mass spectral data tests. The spectral data of the nano‐sized [Zn(PFPFMI)Cl2].3H2O complex indicates that the PFPFMI ligand functions as a tetradentate (N2O2) coordination through two azomethine nitrogen groups (N) and two furan ring oxygen (O) atoms. Density functional theory (DFT) calculations were performed using the molecular studio software to investigate the optimal geometry of PFPFMI and its [Zn(PFPFMI)Cl2].3H2O complex. The SEM, TEM, XRD, AFM, and energy dispersive X‐ray analysis (EDX) analyses of the studied complex unveil distinct and strong diffraction peaks, indicating its crystalline nature and providing evidence of its nano‐sized particle sizes. Additionally, the inhibition zone diameter was used to assess the in vitro antimicrobial action of PFPFMI and the particular complex against Gram‐positive bacteria Streptococcus pneumonia and Bacillus subtilis, Gram‐negative bacteria Pseudomonas aeruginosa, Salmonella typhi, and Escherichia coli, as well as fungi Aspergillus fumigatus, Geotricum candidum, Syncephalastrum racemosum, and Candida tropicalis. The [Zn(PFPFMI)Cl2].3H2O complex exhibits higher activity than the ligand PFPFMI. In vitro cytotoxicity of the synthesized [Zn(PFPFMI)Cl2].3H2O complex was explored using MCF7 (breast cancer), HCT116 (colon cancer), A549 (lung cancer), HePG‐2 (liver cancer), A375 (melanoma cancer), and normal lung fibroblast (WI38) cell lines. Based on IC50 and selective index (SI) values, it was shown that the complex exhibited higher potency against MCF7 cell lines. Moreover, the Zn(II) complex exhibited the ability to induce DNA damage in MCF7 cells, resulting in dose‐dependent cell apoptosis. Subsequent investigations revealed that complex 2 also induced cell cycle arrest in the G2 and S phases.

Rational design, synthesis, biological evaluation, and molecular modeling of novel naphthamide derivatives possessing potent, reversible, and competitive inhibitory mode of action over human monoamine oxidase.

Herein, a novel series of naphthamide derivatives has been rationally developed, synthesized, and evaluated for their inhibitory activity against monoamine oxidase (MAO) and cholinesterase (ChE) enzymes. Compared to the reported naphthalene-based hit IV, the new naphthamide hybrids 2a, 2c, 2g and 2h exhibited promising MAO inhibitory activities; with an IC50 value of 0.294μM, compound 2c most potently inhibited MAO-A, while compound 2g exhibited most potent MAO-B inhibitory activity with an IC50 value of 0.519μM. Compounds 2c and 2g showed selectivity index (SI) values of 6.02 for MAO-A and 2.94 for MAO-B, respectively. On the other hand, most compounds showed weak inhibitory activity against ChEs except 2a and 2h over butyrylcholinesterase (BChE). The most potent compounds 2c and 2g were found to be competitive and reversible MAO inhibitors based on kinetic and reversibility studies. Plausible interpretations of the observed biological effects were provided through molecular docking simulations. The drug-likeness predicted by SwissADME and Osiris property explorer showed that the most potent compounds (2a, 2c, 2g, and 2h) obey Lipinski's rule of five. Accordingly, in the context of neurological disorders, hybrids 2c and 2g may contribute to the identification of safe and potent therapeutic approaches in the near future.

Exploring Subsite Selectivity within Plasmodium vivax N-Myristoyltransferase Using Pyrazole-Derived Inhibitors.

N-myristoyltransferase (NMT) is a promising antimalarial drug target. Despite biochemical similarities between Plasmodium vivax and human NMTs, our recent research demonstrated that high selectivity is achievable. Herein, we report PvNMT-inhibiting compounds aimed at identifying novel mechanisms of selectivity. Various functional groups are appended to a pyrazole moiety in the inhibitor to target a pocket formed beneath the peptide binding cleft. The inhibitor core group polarity, lipophilicity, and size are also varied to probe the water structure near a channel. Selectivity index values range from 0.8 to 125.3. Cocrystal structures of two selective compounds, determined at 1.97 and 2.43 Å, show that extensions bind the targeted pocket but with different stabilities. A bulky naphthalene moiety introduced into the core binds next to instead of displacing protein-bound waters, causing a shift in the inhibitor position and expanding the binding site. Our structure-activity data provide a conceptual foundation for guiding future inhibitor optimizations.