Identification of novel phenylalanine derivatives bearing a hydroxamic acid moiety as potent quorum sensing inhibitors.

Phenylalanine derivatives are a well-known small moiety responsible for controlling the virulence factors of several bacteria. Herein, for the first time, we report novel structures of phenylalanine derivatives bearing a hydroxamic acid moiety which were designed, synthesized, and evaluated for use as quorum sensing inhibitors. Biological results reveal that six compounds showed good quorum sensing inhibitors properties with an IC50 ranging from 7.12 ± 2.11 µM-92.34 ± 2.09 µM (4NPO, a reference compound, IC50 = 29.13 ± 0.88 µM). In addition, three out of the six compounds (4a, 4c, 4h) showed strong anti-biofilm formation and CviR inhibitory activity when compared to that of 4NPO. These biological data were also confirmed by computational studies. In this series of compounds, 4h is the most promising compound for future drug development targeting quorum sensing. Our results concluded that the fragment-based drug design is a good approach for the discovery of novel quorum-sensing inhibitors in the future.

Determination of drug-related problems among type 2 diabetes outpatients in a hospital in Vietnam: A cross-sectional study.

INTRODUCTION: Drug-related problems (DRPs) are common in clinical practice and occur at all stages of the medication process. The major factor contributing to DRPs is prescription, although patients' poor adherence to treatment is also a significant factor. This study evaluated type 2 diabetes outpatients in a hospital in Vietnam for drug-related problems (DRPs) and related variables. METHODS: A cross-sectional descriptive study was conducted on 495 outpatients who met the criteria and 157 people agreed to participate in the interview. Medication order review and medication adherence review were used to identify DRPs. The types of DRP were based on the Pharmaceutical Care Network Europe (PCNE) categories version 9.0. The identification and assessment DRPs were carried out by clinical pharmacists and get agreed upon by physicians who had not directly prescribed patients who participated in the study. RESULTS: A total of 762 DRPs were identified via prescribing review process, the average number of DRP on each prescription was 1.54±1.07, while 412 DRPs were determined through patient interviewing. The most frequent DRPs were "ADR (Adverse Drug Reaction) occurring" (68.8%). The main causes were "patient is unable to understand instructions properly" or "patient is not properly instructed", "patient stores insulin inappropriately", "patient decides to use unnecessary drugs" and "patient intentionally uses/takes less drug than prescribed or does not take the drug at all for whatever reason" which accounted for 65.0%, 41.4%, 38.2%, and 28.7%, respectively. From the prescribing review, the most observed DRPs were "Inappropriate drug according to guidelines/formulary" and "No or incomplete drug treatment in spite of existing indication", accounting for 45.0% and 42.9%, respectively. There was a significant association between age (OR 3.38, 95% CI: 1.01-11.30), duration of diabetes (OR 3.61, 95%CI: 1.11-11.74), presence of comorbidity (OR 5.31, 95%CI: 1.97-14.30), polypharmacy (OR: 2.95, 95%CI: 1.01-8.72) and DRPs. In patients, poor knowledge of antidiabetic agents was the main reason to lack adherence and occurring ADR (OR 2.73, 95%CI: 1.32-5.66, p = 0.007 and OR 2.49, 95%CI: 1.54-4.03, p = 0.001 respectively). CONCLUSION: DRPs occurred in the prescribing stage and relating to patient's behavior of drug administration was high. Clear identification of DRPs and the associated factors are essential for building the intervention process to improve effectiveness and safety in the treatment of type 2 diabetes mellitus patients.

Drug Discovery and Development on Pma1, Where Are We Now? A Critical Review from 1995 to 2022.

Plasma membrane H+ -ATPase (Pma1) is an enzyme uniquely found in plants and fungi. The enzyme controls the nutrient uptake of plants and fungi via an electrochemical gradient processes, which is essential for their survival. Inhibiting Pma1, therefore, constitutes an alternative antifungal target void of toxicity to humans. From a medicinal chemistry point of view, this review provides a first summary of the recent drug design, synthesis, evaluation, and discovery of molecules targeting Pma1 for 25 years from 1995 to 2022.

Application of the All-Hydrocarbon Stapling Technique in the Design of Membrane-Active Peptides.

The threats of drug resistance and new emerging pathogens have led to an urgent need to develop alternative treatment therapies. Recently, considerable research efforts have focused on membrane-active peptides (MAPs), a category of peptides in drug discovery with antimicrobial, anticancer, and cell penetration activities that have demonstrated their potential to be multifunctional agents. Nonetheless, natural MAPs have encountered various disadvantages, which mainly include poor bioavailability, the lack of a secondary structure in short peptides, and high production costs for long peptide sequences. Hence, an "all-hydrocarbon stapling system" has been applied to these peptides and proven to effectively stabilize the helical conformations, improving proteolytic resistance and increasing both the potency and the cell permeability. In this review, we summarized and categorized the advances made using this powerful technique in the development of stapled MAPs. Furthermore, outstanding issues and suggestions for future design within each subcategory were thoroughly discussed.

Multiple roles of ribosomal antimicrobial peptides in tackling global antimicrobial resistance.

In the last century, conventional antibiotics have played a significant role in global healthcare. Antibiotics support the body in controlling bacterial infection and simultaneously increase the tendency of drug resistance. Consequently, there is a severe concern regarding the regression of the antibiotic era. Despite the use of antibiotics, host defence systems are vital in fighting infectious diseases. In fact, the expression of ribosomal antimicrobial peptides (AMPs) has been crucial in the evolution of innate host defences and has been irreplaceable to date. Therefore, this valuable source is considered to have great potential in tackling the antimicrobial resistance (AMR) crisis. Furthermore, the possibility of bacterial resistance to AMPs has been intensively investigated. Here, we summarize all aspects related to the multiple applications of ribosomal AMPs and their derivatives in combating AMR.

Design, Synthesis and Evaluation of Novel (E)-N'-((1-(4-chlorobenzyl)-1H-indol-3-yl)methylene)-2-(4-oxoquinazolin-3(4H)-yl)acetohydrazides as Antitumor Agents.

BACKGROUND: Herein, we have designed and synthesized a series of the novel (E)-N'-((1-(4-chlorobenzyl)- 1H-indol-3-yl)methylene)-2-(4-oxoquinazolin-3(4H)-yl)acetohydrazides (5) as potent small molecules activating procaspase- 3. The compounds were designed by the amalgamation of structural features of PAC-1 (the first procaspase-3 activator) and oncrasin-1, one potential anticancer agent. METHODS: The target acetohydrazides (5a-m) were prepared via the Niementowski condensation of anthranilic acid (1a) or 5-substituted-2-aminobenzoic acid (1b-m) and formamide. The compound libraries were evaluated for their cytotoxicity, caspase-3 activation, cell cycle analysis, and apoptosis. In addition, computational chemistry is also performed. RESULTS: A biological evaluation revealed that all thirteen compounds designed and synthesized showed strong cytotoxicity against three human cancer cell lines (SW620, colon cancer; PC-3, prostate cancer; NCI-H23, lung cancer) with eight compounds (5a, 5c-i, 5k), which were clearly more potent than both PAC-1 and oncrasin-1. In this series, four compounds, including 5c, 5e, 5f, and 5h, were the most potent members with approximately 4- to 5-fold stronger than the reference compounds PAC-1 and oncrasin-1 in terms of IC50. In comparison to 5-FU, these compounds were even 18- to 29-fold more potent in terms of cytotoxicity in three human cell lines tested. In the caspase activation assay, the caspase activity was activated to 285% by compound 5e compared to PAC-1, the first procaspase activating compound, which was used as a control. Our docking simulation revealed that compound 5e was a potent allosteric inhibitor of procaspase-3 through chelation of inhibitory zinc ion. Physicochemical and ADMET calculations for 5e provided useful information of its suitable absorption profile and some toxicological effects that need further optimization to be developed as a promising anticancer agent. CONCLUSION: Compound 5e has emerged as a potential hit for further design and development of caspases activators and anticancer agents.

Amide bond formation in aqueous solution: direct coupling of metal carboxylate salts with ammonium salts at room temperature.

Herein, we report a green, expeditious, and practically simple protocol for direct coupling of carboxylate salts and ammonium salts under ACN/H2O conditions at room temperature without the addition of tertiary amine bases. The water-soluble coupling reagent EDC·HCl is a key component in the reaction. The reaction runs smoothly with unsubstituted/substituted ammonium salts and provides a clean product without column chromatography. Our reaction tolerates both carboxylate (which are unstable in other forms) and amine salts (which are unstable/volatile when present in free form). We believe that the reported method could be used as an alternative and suitable method at the laboratory and industrial scales.

Comparison between Three Techniques for Determining Glomerular Filtration Rates: 99mTc-Diethylene Triamine Penta-Acetic Acid Renography, Double Plasma Sampling Method, and Single Plasma Sampling Method in Vietnamese Patients.

Glomerular filtration rate (GFR) is an important indicator of renal function. Many methods have been developed to determine GFR in clinical examinations. This study aims to correlate between radionuclide plasma sampling methods (single and double blood samples, in vitro methods) and in vivo Gate's method using 99mTc-diethylene triamine penta-acetic acid (99mTc-DTPA) renography. MATERIALS AND METHODS: 43 patients underwent this study, including 31 renal donors (Group 1) and 12 patients with obstructive uropathy (Group 2). All patients were administered with a range of 5-7 mCi of 99mTc-DTPA. Then, renography performed simultaneously after injection and GFR calculation followed by Gate's method. Blood samples were collected at 60- and 120-min postinjection, samples were counted by a thyroid uptake system, and GFR was calculated using a single plasma sample method (SPSM) and a double plasma sample method (DPSM). RESULTS: The mean GFRs calculated by Gate's method in Groups 1 and 2 were 85.8 ± 18.2 ml/min and 118.4 ± 13.9 ml/min, respectively. Meanwhile, using the in vitro blood sampling methods (DPSM and SPSM), the mean GFRs in Group 1 were 73.8 ± 15.4 ml/min and 56.4 ± 20.9 ml/min, respectively, and in Group 2 were 116.8 ± 12.9 ml/min and 106.3 ± 18.5 ml/min, respectively. There is a high correlation between Gate's method and DPSM in two groups (r = 0.86 and 0.72, respectively), and a moderate correlation was found between Gate's method and SPSM in both groups (r = 0.49 and r = 0.37, respectively). The two in vitro methods (DPSM and SPSM) revealed that moderate correlation in both groups (r = 0.74 and r = 0.67, respectively) was observed. CONCLUSION: Renography is a simple method but considered inaccurate for GFR determination. However, in vitro plasma sampling is rarely used in Vietnam. In this study, Gate's method correlated well with DPSM and tended to overestimate GFR. Further, the in vitro methods can be applied to correct the in vivo method as a confirmatory test in some cases.

Discovery of novel ß-turn mimetic-based peptides as novel quorum sensing inhibitors of gram-negative bacteria.

To date, a very limited number of peptides reported as quorum sensing inhibitors. Herein, we report the synthesis and evaluation of a series of ß-turn mimetic-based peptides as potent quorum sensing inhibitors and antibiofilm formation. In this series, peptides P1, P4, and P5 showed very promising anti-quorum sensing activity on lasB-gfp reporter strain of Pseudomonas aeruginosa without affecting bacterial growth. Under our condition, these compounds also showed good anti-violacein production of Chromobacterium violaceum. In terms of antibiofilm formation, except P5, two ß-turn mimetic-based peptides P1 and P4 showed maximum inhibition of 80% total biomass of Pseudomonas aeruginosa. This report provides the first ß-turn mimetic-based scaffold for future drug development.

2-Difluoromethylpyridine as a bioisosteric replacement of pyridine-N-oxide: the case of quorum sensing inhibitors.

Herein, we demonstrate that 2-difluoromethylpyridine is a bioisosteric replacement of pyridine-N-oxide. Using the quorum sensing inhibitor 4NPO as a model compound, a library of 2-difluoromethylpyridine derivatives was designed, synthesized, and evaluated toward quorum sensing activity, biofilm formation, anti-violacein activity, and protease activity. As a result, compounds 1 (IC50 of 35 ± 1.12 µM), 5 (IC50 of 19 ± 1.01 µM), and 6 (IC50 of 27 ± 0.67 µM) showed a similar or better activity in comparison to 4NPO (IC50 of 33 ± 1.12 µM) in a quorum sensing system of Pseudomonas aeruginosa. In addition, compounds 1, 5, 6, and 4NPO showed good antibiofilm biomass of Pseudomonas aeruginosa and reduced violacein production in Chromobacterium violaceum. In terms of protease activity, compounds 1, 5, and 6 showed significant activity compared to 4NPO. Overall, the replacement of pyridine-N-oxide by 2-difluoromethylpyridine enhances the activity of the model compound, which could open a new path for bioisosteric replacement in drug discovery and development.

Design, synthesis and evaluation of novel indirubin-based N-hydroxybenzamides, N-hydroxypropenamides and N-hydroxyheptanamides as histone deacetylase inhibitors and antitumor agents.

Several novel indirubin-based N-hydroxybenzamides, N-hydropropenamides and N-hydroxyheptanamides (4a-h, 7a-h, 10a-h) were designed using a fragment-based approach with structural features extracted from several previously reported HDAC inhibitors, such as SAHA (vorinostat), MGCD0103 (mocetinostat), nexturastat A and PXD-101 (belinostat). The biological results reveal that our compounds showed excellent cytotoxicity toward three common human cancer cell lines (SW620, PC-3 and NCI-H23) with IC50 values ranging from 0.09 to 0.007 µM. The cytotoxicity of the compounds was equipotent or even up to 10-times more potent than adriamycin and up to 205-times more potent than SAHA. Among the series of N-hydroxypropenamides, compounds 10a-d were the most potent HDAC inhibitors as well as cytotoxicity toward the cell lines tested. In addition, the strong inhibitory activites toward HDAC of our compounds were observed with IC50 values of below-micromolar range. Especially, compound 4a inhibited HDAC6 with an IC50 value of 29-fold lower than that against HDAC2 isoform. Representative compounds 4a and 7a were found to significantly arrest SW620 cells at G0/G1 phase. Compounds 7a and 10a were found to strongly induce apoptosis in SW620 cells. Docking studies revealed some important features affecting the selectivity against HDAC6 isoform. The results clearly demonstrate the potential of the indirubin-hydroxamic acid hybrids and these compounds should be very promising for further development.

Design, synthesis, and evaluation of novel N'-substituted-1-(4-chlorobenzyl)-1H-indol-3-carbohydrazides as antitumor agents.

In continuity of our search for novel anticancer agents acting as procaspase activators, we have designed and synthesised two series of (E)-N'-benzylidene-carbohydrazides (4a-m) and (Z)-N'-(2-oxoindolin-3-ylidene)carbohydrazides (5a-g) incorporating 1-(4-chlorobenzyl)-1H-indole core. Bioevaluation showed that the compounds, especially compounds in series 4a-m, exhibited potent cytotoxicity against three human cancer cell lines (SW620, colon cancer; PC-3, prostate cancer; NCI-H23, lung cancer). Within series 4a-m, compounds with 2-OH substituent (4g-i) exhibited very strong cytotoxicity in three human cancer cell lines assayed with IC50 values in the range of 0.56-0.83 µM. In particular, two compounds 4d and 4f bearing 4-Cl and 4-NO2 substituents, respectively, were the most potent in term of cytotoxicity with IC50 values of 0.011-0.001 µM. In caspase activation assay, compounds 4b and 4f were found to activate caspase activity by 314.3 and 270.7% relative to PAC-1. This investigation has demonstrated the potential of these simple acetohydrazides, especially compounds 4b, 4d, and 4f, as anticancer agents.

LEGO-Inspired Drug Design: Unveiling a Class of Benzo[d]thiazoles Containing a 3,4-Dihydroxyphenyl Moiety as Plasma Membrane H+ -ATPase Inhibitors.

The fungal plasma membrane H+ -ATPase (Pma1p) is a potential target for the discovery of new antifungal agents. Surprisingly, no structure-activity relationship studies for small molecules targeting Pma1p have been reported. Herein, we disclose a LEGO-inspired fragment assembly strategy for the design, synthesis, and discovery of benzo[d]thiazoles containing a 3,4-dihydroxyphenyl moiety as potential Pma1p inhibitors. A series of 2-(benzo[d]thiazol-2-ylthio)-1-(3,4-dihydroxyphenyl)ethanones was found to inhibit Pma1p, with the most potent IC50 value of 8 µm in an in vitro plasma membrane H+ -ATPase assay. These compounds were also found to strongly inhibit the action of proton pumping when Pma1p was reconstituted into liposomes. 1-(3,4-Dihydroxyphenyl)-2-((6-(trifluoromethyl)benzo[d]thiazol-2-yl)thio)ethan-1-one (compound 38) showed inhibitory activities on the growth of Candida albicans and Saccharomyces cerevisiae, which could be correlated and substantiated with the ability to inhibit Pma1p in vitro.

Metformin, an Anthropogenic Contaminant of Seidlitzia rosmarinus Collected in a Desert Region near the Gulf of Aqaba, Sinai Peninsula.

A phytochemical investigation of Seidlitzia rosmarinus collected along the shoreline of the Gulf of Aqaba in the remote southern desert region of the Sinai peninsula has revealed the presence of the registered drug metformin (4). However, analysis of the 14C content revealed the drug to be an anthropogenic contaminant. Consequently, natural product researchers should be aware that compounds isolated from plants might originate from environmental contamination rather than biosynthesis. The new natural product N-(4-hydroxyphenylethyl)-α-chloroferuloylamide was isolated as a mixture of the E and Z isomers along with a number of other well-established secondary metabolites.

Difluoroacetic Acid as a New Reagent for Direct C-H Difluoromethylation of Heteroaromatic Compounds.

A technically simple procedure for direct C-H difluoromethylation of heteroaromatic compounds using off-the-shelf difluoroacetic acid as the difluoromethylating reagent has been developed. Mono-difluoromethylation versus bis-difluoromethylation is controlled as the result of the reaction temperature. The reactions described here enable access to the late-stage C-H mono- and bis-difluoromethylation for preparation of tool compounds for chemical biology and provide access to this hitherto untapped substituent for drug discovery.

Fusaric acid and analogues as Gram-negative bacterial quorum sensing inhibitors.

Taking advantage of microwave-assisted synthesis, efficient and expedite procedures for preparation of a library of fusaric acid and 39 analogues are reported. The fusaric acid analogues were tested in cell-based screening assays for inhibition of the las and rhl quorum sensing system in Pseudomonas aeruginosa and the lux quorum sensing system in Vibrio fischeri. Eight of the 40 compounds in the library including fusaric acid inhibited lux quorum sensing and one compound inhibited activity of the las quorum sensing system. To our delight, none of the compounds showed growth inhibitory effects in the tested concentration ranges.

Demethoxycurcumin Is A Potent Inhibitor of P-Type ATPases from Diverse Kingdoms of Life.

P-type ATPases catalyze the active transport of cations and phospholipids across biological membranes. Members of this large family are involved in a range of fundamental cellular processes. To date, a substantial number of P-type ATPase inhibitors have been characterized, some of which are used as drugs. In this work a library of natural compounds was screened and we first identified curcuminoids as plasma membrane H+-ATPases inhibitors in plant and fungal cells. We also found that some of the commercial curcumins contain several curcuminoids. Three of these were purified and, among the curcuminoids, demethoxycurcumin was the most potent inhibitor of all tested P-type ATPases from fungal (Pma1p; H+-ATPase), plant (AHA2; H+-ATPase) and animal (SERCA; Ca2+-ATPase) cells. All three curcuminoids acted as non-competitive antagonist to ATP and hence may bind to a highly conserved allosteric site of these pumps. Future research on biological effects of commercial preparations of curcumin should consider the heterogeneity of the material.

Privileged substructure-based diversity-oriented synthesis pathway for diverse pyrimidine-embedded polyheterocycles.

A new diversity-oriented synthesis pathway for the fabrication of a pyrimidine-embedded polyheterocycles library was developed for potential interactions with diverse biopolymers. Five different pyrimidine-embedded core skeletons were synthesized from ortho-alkynylpyrimidine carbaldehydes by a silver- or iodine-mediated tandem cyclization strategy. The resulting polyheterocycles possess diverse fused ring sizes and positions with potential functionalities for further modification.

New benzothiazole/thiazole-containing hydroxamic acids as potent histone deacetylase inhibitors and antitumor agents.

Results from clinical studies have demonstrated that inhibitors of histone deacetylase (HDAC) enzymes possess promise for the treatment of several types of cancer. Zolinza(®) (widely known as SAHA) has been approved by the FDA for the treatment of T-cell lymphoma. As a continuity of our ongoing research to find novel small molecules to target these important enzymes, we synthesized a series of benzothiazole-containing analogues of SAHA and found several compounds with very potent anticancer cytotoxicity. In this study, three more compounds of this type, including N(1)-(6-chlorobenzo[d]thiazol-2-yl)-N(8)-hydroxyoctanediamide (3a), N(1)-[6-(trifluoromethyl)benzo[d]thiazol-2-yl]-N(8)-hydroxyoctanediamide (3b) and N(1)-(thiazol-2-yl)-N(8)-hydroxyoctanediamide (6) were synthesized and evaluated for HDAC inhibition and cytotoxic activities. All three compounds showed very potent HDAC inhibitory effects. Docking revealed that both two compounds 3a, 3b showed higher affinities towards HDAC(8) compared to SAHA. In vitro, compound 3a exhibited cytotoxicity equipotent to SAHA against five human cancer cell lines. In term of in vivo activity, compound 3a demonstrated equivalent efficacy to SAHA in mouse xenograft model.