Synthesis and characterization of bis-amide SSE1917 as a microtubule-stabilizing anticancer agent.

Microtubule dynamics are critical for spindle assembly and chromosome segregation during cell division. Pharmacological inhibition of microtubule dynamics in cells causes prolonged mitotic arrest, resulting in apoptosis, an approach extensively employed in treating different types of cancers. The present study reports the synthesis of thirty-two novel bis-amides (SSE1901-SSE1932) and the evaluation of their antiproliferative activities. N-(1-oxo-3-phenyl-1-(phenylamino)propan-2-yl)benzamide (SSE1917) exhibited the most potent activity with GI50 values of 0.331 ± 0.01 µM in HCT116 colorectal and 0.48 ± 0.27 µM in BT-549 breast cancer cells. SSE1917 stabilized microtubules in biochemical and cellular assays, bound to taxol site in docking studies, and caused aberrant mitosis and G2/M arrest in cells. Prolonged treatment of cells with the compound increased p53 expression and triggered apoptotic cell death. Furthermore, SSE1917 suppressed the growth of both mouse and patient-derived human colon cancer organoids, highlighting its potential therapeutic value as an anticancer agent.

Selenoneine-inspired selenohydantoins with glutathione peroxidase-like activity.

Chronic diseases such as cystic fibrosis, inflammatory bowel diseases, rheumatoid arthritis, and cardiovascular illness have been linked to a decrease in selenium levels and an increase in oxidative stress. Selenium is an essential trace element that exhibits antioxidant properties, with selenocysteine enzymes like glutathione peroxidase being particularly effective at reducing peroxides. In this study, a series of synthetic organoselenium compounds were synthesized and evaluated for their potential antioxidant activities. The new selenohydantoin molecules were inspired by selenoneine and synthesized using straightforward methods. Their antioxidant potential was evaluated and proven using classical radical scavenging and metal-reducing methods. The selenohydantoin derivatives exhibited glutathione peroxidase-like activity, reducing hydroperoxides. Theoretical calculations using Density Functional Theory (DFT) revealed the selenone isomer to be the only one occurring in solution, with selenolate as a possible tautomeric form in the presence of a basic species. Cytocompatibility assays indicated that the selenohydantoin derivatives were non-toxic to primary human aortic smooth muscle cells, paving the way for further biological evaluations of their antioxidant activity. The results suggest that selenohydantoin derivatives with trifluoro-methyl (-CF3) and chlorine (-Cl) substituents have significant activities and could be potential candidates for further biological trials. These compounds may contribute to the development of effective therapies for chronic diseases such cardiovascular diseases.

Identification and Characterization of Natural and Semisynthetic Quinones as Aurora Kinase Inhibitors.

Aurora kinases (Aurora A, B, and C) are a family of serine/threonine kinases that play critical roles during mitotic initiation and progression. Aurora A and B kinases are ubiquitously expressed, and their overexpression and/or amplification in many cancers have been associated with poor prognosis. Several inhibitors that target Aurora kinases A, B, or both have been developed during the past decade with efficacy in different in vitro and in vivo models for a variety of cancers. Recent studies have also identified Aurora A as a synthetic lethal target for different tumor suppressors, including RB1, SMARCA4, and ARID1A, which signifies the need for Aurora-A-selective inhibitors. Here, we report the screening of a small library of quinones (nine naphthoquinones, one orthoquinone, and one anthraquinone) in a biochemical assay for Aurora A kinase that resulted in the identification of several quinones as inhibitors. IC50 determination against Aurora A and B kinases revealed the inhibition of both kinases with selectivity toward Aurora A. Two of the compounds, natural quinone naphthazarin (1) and a pseudo anthraquinone, 2-(chloromethyl)quinizarin (11), potently inhibited the proliferation of various cancer cell lines with IC50 values ranging from 0.16 ± 0.15 to 1.7 ± 0.06 and 0.15 ± 0.04 to 6.3 ± 1.8 µM, respectively. Treatment of cancer cells with these compounds for 24 h resulted in abrogated mitosis and apoptotic cell death. Direct binding of both the compounds with Aurora A kinase was also confirmed through STD NMR analysis. Docking studies predicted the binding of both compounds to the ATP binding pocket of Aurora A kinase. We have, therefore, identified quinones as Aurora kinase inhibitors that can serve as a lead for future drug discovery endeavors.

Indole-Containing Natural Products 2019-2022: Isolations, Reappraisals, Syntheses, and Biological Activities.

Indole alkaloids represent a large subset of natural products, with more than 4100 known compounds. The majority of these alkaloids are biologically active, with some exhibiting excellent antitumor, antibacterial, antiviral, antifungal, and antiplasmodial activities. Consequently, the natural products of this class have attracted considerable attention as potential leads for novel therapeutics and are routinely isolated, characterized, and profiled to gauge their biological potential. However, data on indole alkaloids, their various structures, and bioactivities are complex due to their diverse sources, such as plants, fungi, bacteria, sponges, tunicates, and bryozoans; thus, isolation methods produce an incredible trove of information. The situation is exacerbated when synthetic derivatives, as well as their structures, bioactivities, and synthetic schemes, are considered. Thus, to make such data comprehensive and inform researchers about the current field's state, this review summarizes recent reports on novel indole alkaloids. It deals with the isolation and characterization of 250 novel indole alkaloids, a reappraisal of previously reported compounds, and total syntheses of indole alkaloids. In addition, several syntheses and semi-syntheses of indole-containing derivatives and their bioactivities are reported between January 2019 and July 2022.

Synthesis and evaluation of novel 1, 2, 4-substituted triazoles for urease and anti-proliferative activity.

1,2,4-triazoles are a major group of heterocyclic compounds. In the current work, a concise library of such triazoles synthesized through a multistep protocol. The synthesis involved hydrazinolysis of ethyl-2-(p-Cl-phenoxy) acetate followed by reflux with phenyl isothiocyanate to yield the intermediate 2-[2-(p-Cl-phenoxy)acetyl)-N-phenyl-hydrazinecarbothioamide. This intermediate was then cyclized to form 5-[p-(Cl-phenoxy)-methyl]-4-phenyl-4H-1,2,4-triazole-3-thiol (the parent moiety) at alkaline pH. In parallel, 3-bromopropionyl bromide was reacted with a series of phenylamines to yield N-(substituted-phenyl)bromopropanamides. In the final step, N-substitution of 5-[p-(Cl-phenoxy)-methyl]-4- phenyl-4H-1,2,4-triazole-3-thiol was carried out with N-(substituted-phenyl)bromopropanamides to give desired library of 3-[5-[(p-Cl-phenoxy)-methyl]-4- phenyl-4H-1,2,4-triazole-3-ylthio]-N-(substituted-phenyl) propan-amides (8a-l). The prepared moieties were identified via IR, NMR, & EIMS and evaluated for urease and anti-proliferative activities. 3-[5-[(p-Cl-phenoxy)-methyl]-4- phenyl-4H-1,2,4-triazole-3-ylthio]-N-(3-methyl-phenyl)propanamide 8k, was found to be most prominent hit as urease inhibitor (IC50= 42.57± 0.13 µM) using thiourea as standard (IC50= 21.25±0.15µM). The interaction of 8k with urease were studied using docking studies. Anti-proliferative activity results showed 8k as promising candidates and rest of the synthesized derivatives were found to be moderately anti-proliferative. Molecular docking results also displayed 8k, 8h, and 8c as potential hits for further study.

CCT245718, a dual FLT3/Aurora A inhibitor overcomes D835Y-mediated resistance to FLT3 inhibitors in acute myeloid leukaemia cells.

BACKGROUND: Activating mutations in the Fms-like tyrosine kinase 3 (FLT3) are among the most prevalent oncogenic mutations in acute myeloid leukaemia. Inhibitors selectively targeting FLT3 kinase have shown promising clinical activity; their success in the clinic, however, has been limited due to the emergence of acquired resistance. METHODS: CCT245718 was identified and characterised as a dual Aurora A/FLT3 inhibitor through cell-based and biochemical assays. The ability of CCT245718 to overcome TKD-mediated resistance was evaluated in a cell line-based model of drug resistance to FLT3 inhibitors. RESULTS: CCT245718 exhibits potent antiproliferative activity towards FLT3-ITD + AML cell lines and strongly binds to FLT3-ITD and TKD (D835Y) mutants in vitro. Activities of both FLT3-ITD and Aurora A are also inhibited in cells. Inhibition of FLT3 results in reduced phosphorylation of STAT5, downregulation of survivin and induction of apoptotic cell death. Moreover, CCT245718 overcomes TKD-mediated resistance in a MOLM-13-derived cell line containing FLT3 with both ITD and D835Y mutations. It also inhibits FLT3 signalling in both parental and resistant cell lines compared to FLT3-specific inhibitor MLN518, which is only active in the parental cell line. CONCLUSIONS: Our results demonstrate that CCT245718 is a potent dual FLT3/Aurora A inhibitor that can overcome TKD-mediated acquired resistance.

Detection of aflatoxin M1 by fiber cavity attenuated phase shift spectroscopy.

Aflatoxin M1 (AFM1) is a carcinogenic compound commonly found in milk in excess of the WHO permissible limit, especially in developing countries. Currently, state-of-the-art tests for detecting AFM1 in milk include chromatographic systems and enzyme-linked-immunosorbent assays. Although these tests provide fair accuracy and sensitivity, they require trained laboratory personnel, expensive infrastructure, and many hours to produce final results. Optical sensors leveraging spectroscopy have a tremendous potential of providing an accurate, real-time, and specialist-free AFM1 detector. Despite this, AFM1 sensing demonstrations using optical spectroscopy are still immature. Here, we demonstrate an optical sensor that employs the principle of cavity attenuated phase shift spectroscopy in optical fiber cavities for rapid AFM1 detection in aqueous solutions at 1550 nm. The sensor constitutes a cavity built by two fiber Bragg gratings. We splice a tapered fiber of < 10 µm waist inside the cavity as a sensing head. For ensuring specific binding of AFM1 in a solution, the tapered fiber is functionalized with DNA aptamers followed by validation of the conjugation via FTIR, TGA, and EDX analyses. We then detect AFM1 in a solution by measuring the phase shift between a sinusoidally modulated laser input and the sensor output at resonant frequencies of the cavity. Our results show that the sensor has the detection limit of 20 ng/L (20 ppt), which is well below both the U.S. and the European safety regulations. We anticipate that the present work will lead towards a rapid and accurate AFM1 sensor, especially for low-resource settings.

Natural and Semisynthetic Chalcones as Dual FLT3 and Microtubule Polymerization Inhibitors.

Activating mutations in FLT3 receptor tyrosine kinase are found in a third of acute myeloid leukemia (AML) patients and are associated with disease relapse and a poor prognosis. The majority of these mutations are internal tandem duplications (ITDs) in the juxtamembrane domain of FLT3, which have been validated as a therapeutic target. The clinical success of selective inhibitors targeting oncogenic FLT3, however, has been limited due to the acquisition of drug resistance. Herein the identification of a dual FLT3/microtubule polymerization inhibitor, chalcone 4 (2'-allyloxy-4,4'-dimethoxychalcone), is reported through screening of 15 related chalcones for differential antiproliferative activity in leukemia cell lines dependent on FLT3-ITD (MV-4-11) or BCR-ABL (K562) oncogenes and by subsequent screening for mitotic inducers in the HCT116 cell line. Three natural chalcones (1-3) were found to be differentially more potent toward the MV-4-11 (FLT3-ITD) cell line compared to the K562 (BCR-ABL) cell line. Notably, the new semisynthetic chalcone 4, which is a 2'-O-allyl analogue of the natural chalcone 3, was found to be more potent toward the FLT3-ITD+ cell line and inhibited FLT3 signaling in FLT3-dependent cells. An in vitro kinase assay confirmed that chalcone 4 directly inhibited FLT3. Moreover, chalcone 4 induced mitotic arrest in these cells and inhibited tubulin polymerization in both cellular and biochemical assays. Treatment of MV-4-11 cells with this inhibitor for 24 and 48 h resulted in apoptotic cell death. Finally, chalcone 4 was able to overcome TKD mutation-mediated acquired resistance to FLT3 inhibitors in a MOLM-13 cell line expressing FLT3-ITD with the D835Y mutation. Chalcone 4 is, therefore, a promising lead for the discovery of dual-target FLT3 inhibitors.

A Comprehensive Review of Aminochalcones.

Chalcones, members of the flavonoid family, display a plethora of interesting biological activities including but not limited to antioxidant, anticancer, antimicrobial, anti-inflammatory, and antiprotozoal activities. The literature cites the synthesis and activity of a range of natural, semisynthetic, and synthetic chalcones. The current review comprehensively covers the literature on amino-substituted chalcones and includes chalcones with amino-groups at various positions on the aromatic rings as well as those with amino-groups containing mono alkylation, dialkylation, alkenylation, acylation, and sulfonylation. The aminochalcones are categorized according to their structure, and the corresponding biological activities are discussed as well. Some compounds showed high potency against cancer cells, microbes, and malaria, whereas others did not. The purpose of this review is to serve as a one-stop location for information on the aminochalcones reported in the literature in recent years.

Facile Synthesis of NH-Free 5-(Hetero)Aryl-Pyrrole-2-Carboxylates by Catalytic C-H Borylation and Suzuki Coupling.

A convenient two-step preparation of NH-free 5-aryl-pyrrole-2-carboxylates is described. The synthetic route consists of catalytic borylation of commercially available pyrrole-2-carboxylate ester followed by Suzuki coupling without going through pyrrole N-H protection and deprotection steps. The resulting 5-aryl substituted pyrrole-2-carboxylates were synthesized in good- to excellent yields. This synthetic route can tolerate a variety of functional groups including those with acidic protons on the aryl bromide coupling partner. This methodology is also applicable for cross-coupling with heteroaryl bromides to yield pyrrole-thiophene, pyrrole-pyridine, and 2,3'-bi-pyrrole based bi-heteroaryls.

Synthesis and evaluation of novel α-substituted chalcones with potent anti-cancer activities and ability to overcome multidrug resistance.

A series of forty α-substituted chalcones were synthesized and screened for their antiproliferative activities against HCT116 (colorectal) and HCC1954 (breast) cancer cell lines. Compounds 5a and 5e were found to be the most potent compounds with GI50 values of 0.63 µM and 0.725 µM in HCC1954 cell line and 0.69 µM and 1.59 µM in HCT116 cell line, respectively. Both compounds induced a G2/M cell cycle arrest and caused apoptotic cell death in HCT116 cells as shown by the induction of PARP cleavage. The compounds also stabilized p53 in a dose-dependent manner in HCT116 cells following 24-hour treatment. Furthermore, both 5a and 5e were able to overcome multidrug resistance in two MDR-1 overexpressing multidrug resistant cell lines.

Synthesis and identification of novel pyridazinylpyrazolone based diazo compounds as inhibitors of human islet amyloid polypeptide aggregation.

We have carried out a docking inspired synthesis and screening of a library of diazenyl-derivatives of pyridazinylpyrazolone molecules for their ability to modulate the amyloidogenic self-assembly of human islet amyloid polypeptide (hIAPP). hIAPP is a 37-residue peptide which is involved in glycemic control along with insulin. Its extracellular fibrillar assemblies in pancreatic ß-cells are responsible for type 2 diabetes. A three-step synthetic scheme was used to prepare these novel compounds using 2-(6-chloropyridazin-3-yl)-5-methyl-2,4-dihydro-3H-pyrazol-3-one as a key intermediate that was reacted with various diazo electrophiles to generate a library of compounds with yields ranging from 64 to 85%. The effect of the compounds on hIAPP amyloid fibril formation was evaluated with a thioflavin T (ThT) fluorescence-based kinetic assay. Furthermore, TEM imaging was carried out to corroborate the interactions of the compounds with hIAPP and subsequent hIAPP inhibition at the different level of fibrillization. The CD spectroscopy showed that upon incubation with SSE15314 for 12 h, the percentage of α-helices was maintained to a level of hIAPP at 0 h. The current study presents identification and characterization of SSE15314 as the hit, which completely inhibited the fibril formation and can be further optimized into a lead compound.

Synthesis, in vitro and in silico studies of S-alkylated 5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazole-3-thiols as cholinesterase inhibitors.

The research was aimed to unravel the enzymatic potential of sequentially transformed new triazoles by chemically converting 4-methoxybenzoic acid via Fischer's esterification to 4-methoxybenzoate which underwent hydrazinolysis and the corresponding hydrazide (1) was cyclized with phenyl isothiocyanate (2) via 2-(4-methoxybenzoyl)-N-phenylhydrazinecarbothioamide (3); an intermediate to 5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazol-3-thiol (4). The electrophiles; alkyl halides 5(a-g) were further reacted with nucleophilic S-atom to attain a series of S-alkylated 5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazole-3-thiols 6(a-g). Characterization of synthesized compounds was accomplished by contemporary spectral techniques such as FT-IR, 1H-NMR, 13C-NMR and EI-MS. Excellent cholinesterase inhibitory potential was portrayed by 3-(n-heptylthio)-5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazole; 6g against AChE (IC50; 38.35±0.62µM) and BChE (IC50; 147.75±0.67µM) enzymes. Eserine (IC50; 0.04±0.01µM) was used as reference standard. Anti-proliferative activity results ascertained that derivative encompassing long straight chain substituted at S-atom of the moiety was the most potent with 4.96 % cell viability (6g) at 25µM and with 2.41% cell viability at 50µMamong library of synthesized derivatives. In silico analysis also substantiated the bioactivity statistics.

Synthesis and evaluation of modified chalcone based p53 stabilizing agents.

Tumor suppressor protein p53 induces cell cycle arrest and apoptotic cell death in response to various cellular stresses thereby preventing cancer development. Activation and stabilization of p53 through small organic molecules is, therefore, an attractive approach for the treatment of cancers retaining wild-type p53. In this context, a series of nineteen chalcones with various substitution patterns of functional groups including chloro, fluoro, methoxy, nitro, benzyloxy, 4-methyl benzyloxy was prepared using Claisen-Schmidt condensation. The compounds were characterized using NMR, HRMS, IR and melting points. Evaluation of synthesized compounds against human colorectal (HCT116) and breast (CAL-51) cancer cell lines revealed potent antiproliferative activities. Nine compounds displayed GI50 values in the low micromolar to submicromolar range; for example (E)-1-phenyl-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (SSE14108) showed GI50 of 0.473±0.043µM against HCT116 cells. Further analysis of these compounds revealed that (E)-3-(4-chlorophenyl)-1-phenylprop-2-en-1-one (SSE14105) and (E)-3-(4-methoxyphenyl)-1-phenylprop-2-en-1-one (SSE14106) caused rapid (4 and 8-h post-treatment) accumulation of p53 in HCT116 cells similar to its induction by positive control, Nutlin-3. Such activities were absent in 3-(4-methoxyphenyl)propiophenone (SSE14106H2) demonstrating the importance of conjugated ketone for antiproliferative and p53 stabilizing activity of the chalcones. We further evaluated p53 levels in the presence of cycloheximide (CHX) and the results showed that the p53 stabilization was regulated at post-translational level through blockage of its degradation. These chalcones can, therefore, act as fragment leads for further structure optimization to obtain more potent p53 stabilizing agents with enhanced anti-proliferative activities.

Molecular Targets of Plant-based Alkaloids and Polyphenolics in Liver and Breast Cancer- An Insight into Anticancer Drug Development.

Liver and Breast cancer are ranked as the most prevailing cancers that cause high cancer-related mortality. As cancer is a life-threatening disease that affects the human population globally, there is a need to develop novel therapies. Among the available treatment options include radiotherapy, chemotherapy, surgery, and immunotherapy. The most superlative modern method is the use of plant-derived anticancer drugs that target the cancerous cells and inhibit their proliferation. Plant-derived compounds are generally considered safer than synthetic drugs/traditional therapies and could serve as potential novel targets to treat liver and breast cancer to revolutionize cancer treatment. Alkaloids and Polyphenols have been shown to act as anticancer agents through molecular approaches. They disrupt various cellular mechanisms, inhibit the production of cyclins and CDKs to arrest the cell cycle, and activate the DNA repairing mechanism by upregulating p53, p21, and p38 expression. In severe cases, when no repair is possible, they induce apoptosis in liver and breast cancer cells by activating caspase-3, 8, and 9 and increasing the Bax/Bcl-2 ratio. They also deactivate several signaling pathways, such as PI3K/AKT/mTOR, STAT3, NF-kB, Shh, MAPK/ERK, and Wnt/ß-catenin pathways, to control cancer cell progression and metastasis. The highlights of this review are the regulation of specific protein expressions that are crucial in cancer, such as in HER2 over-expressing breast cancer cells; alkaloids and polyphenols have been reported to reduce HER2 as well as MMP expression. This study reviewed more than 40 of the plant-based alkaloids and polyphenols with specific molecular targets against liver and breast cancer. Among them, Oxymatrine, Hirsutine, Piperine, Solamargine, and Brucine are currently under clinical trials by qualifying as potent anticancer agents due to lesser side effects. As a lot of research is there on anticancer compounds, there is a desideratum to compile data to move towards clinical trials phase 4 and control the prevalence of liver and breast cancer.

Fabrication of Supported and Unsupported Gold Nanorods for Nonenzymatic Glucose Sensing and Study of Their Growth Kinetics.

This work includes a novel approach for synthesis/fabrication of AuNRs of varied aspect ratios leading to investigation on the kinetics of their growth mechanism. The synthesized AuNRs were further functionalized with MWCNTs (AuNRs@MWCNTs) by one-pot synthesis. The synthesized AuNRs and AuNRs@MWCNTs were characterized by employing UV-vis spectroscopy. Red shifts in the spectra of AuNRs confirmed the formation of nanorods of higher aspect ratios. Morphology of AuNRs and functionalized AuNRs was confirmed by high-resolution scanning electron microscopy. Biological studies were carried out by fabricating efficient nonenzymatic glucose sensors for optical and electrochemical sensing via UV and cyclic voltammetry in the detection ranges of 0.7-28 mM glucose (UV) and 5.5 µM-0.33 mM (CV). An electrochemical sensing study was carried out via AuNR- and AuNRs@MWCNT-modified GCEs in a 0.1 M NaOH electrolyte solution. The modified electrodes exhibited very high sensitivity with a broad linear range. The order of sensitivity (via CV) was found to be AuNRX0@MWCNTs > AuNRD5@MWCNTs > AuNRD5 > AuNRX0.

Discovery and prospects of new heterocyclic Isatin-hydrazide derivative with a novel role as estrogen receptor α degrader in breast cancer cells.

Introduction: Isatin, a heterocycle scaffold, is the backbone of many anticancer drugs and has previously been reported to engage multiple cellular targets and mechanisms, including angiogenesis, cell cycle, checkpoint pathways and multiple kinases. Here, we report that a novel isatin derivative, 5i, degrades estrogen receptor alpha (ERα) in estrogen-dependent breast cancer cells. This effect of the isatin nucleus has not been previously reported. Tamoxifen and fulvestrant represent standard therapy options in estrogen-mediated disease but have their own limitations. Isatin-based triple angiokinase inhibitor BIBF1120 (Nintedanib) and multikinase inhibitor Sunitinib (Sutent) have been approved by the FDA. Methods: Keeping this in view, we synthesized a series of N'-(1-benzyl-2-oxo-1, 2-dihydro-3H-indol-3-ylidene) hydrazide derivatives and evaluated them in vitro for antiproliferative activities in MCF-7 (ER+) cell line. We further investigated the effect of the most potent compound (5i) on the Erα through Western Blot Analysis. We used in silico pharmacokinetics prediction tools, particularly pkCSM tool, to assess the activity profiles of the compounds. Results and discussion: Compound 5i showed the best antiproliferative activity (IC50 value; 9.29 ± 0.97 µM) in these cells. Furthermore, 5i downregulated ERα protein levels in a dose-dependent manner in MCF-7. A multifaceted analysis of physicochemical properties through Data Warrior software revealed some prominent drug-like features of the synthesized compounds. The docking studies predicted the binding of ligands (compounds) with the target protein (ERα). Finally, molecular dynamics (MD) simulations indicated stable behavior of the protein-ligand complex between ERα and its ligand 5i. Overall, these results suggest that the new isatin derivative 5i holds promise as a new ERα degrader.

Lahorenoic acids A-C, ortho-dialkyl-substituted aromatic acids from the biocontrol strain Pseudomonas aurantiaca PB-St2.

Three new aromatic acids, named lahorenoic acids A (1), B (2), and C (3), have been isolated along with the known compounds phenazine-1-carboxylic acid (4), 2-hydroxyphenazine-1-carboxylic acid (5), 2-hydroxyphenazine (6), 2,8-dihydroxyphenazine (7), cyclo-Pro-Tyr (8), cyclo-Pro-Val (9), cyclo-Pro-Met (10), and WLIP (11) and characterized from the biocontrol strain Pseudomonas aurantiaca PB-St2. The structures of these compounds were deduced by 1D and 2D NMR spectroscopic and mass spectral data interpretation. Compounds 2, 4, and 7 showed moderate antibacterial activity against mycobacteria and other Gram-positive bacteria, while 4 was also found to exhibit cytotoxic and antifungal properties.

Heterocyclic pyrimidine derivatives as promising antibacterial agents.

Antibiotic resistance is a growing public health concern. The quest to understand the underlying mechanisms of drug resistance needs to be accompanied by an expanded arsenal of drugs. This calls for the development of new compounds with anti-bacterial properties. The ease of functionalization of the pyrimidine core, to produce structurally distinct compound libraries, has made pyrimidine a privileged structure for identifying anti-bacterial hits. The activity of pyrimidine derivatives can be attributed to the various subunits linked with the main core, especially at C-2 or C-4 or C-6. Particularly, presence of NH2 attached to C-2 of the pyrimidine nucleus has been shown to enhance the anti-bacterial activity against pathogenic Gram-positive and Gram-negative bacteria. The diversity of synthetic routes used for the synthesis of such compounds, the reported biological activities, and a growing need to develop novel anti-bacterial agents warrant a review that presents recent reports on the synthesis and anti-bacterial activities of pyrimidine-containing compounds.

Perplexing Polyphenolics: The Isolations, Syntheses, Reappraisals, and Bioactivities of Flavonoids, Isoflavonoids, and Neoflavonoids from 2016 to 2022.

Flavonoids, isoflavonoids, neoflavonoids, and their various subcategories are polyphenolics-an extensive class of natural products. These compounds are bioactive and display multiple activities, including anticancer, antibacterial, antiviral, antioxidant, and neuroprotective activities. Thus, these compounds can serve as leads for therapeutic agents or targets for complex synthesis; they are coveted and routinely isolated, characterized, biologically evaluated, and synthesized. However, data regarding the compounds' sources, isolation procedures, structural novelties, bioactivities, and synthetic schemes are often dispersed and complex, a dilemma this review aims to address. To serve as an easily accessible guide for researchers wanting to apprise themselves of the latest advancements in this subfield, this review summarizes seventy-six (76) articles published between 2016 and 2022 that detail the isolation and characterization of two hundred and forty-nine (249) novel compounds, the total and semisyntheses of thirteen (13) compounds, and reappraisals of the structures of twenty (20) previously reported compounds and their bioactivities. This article also discusses new synthetic methods and enzymes capable of producing or modifying flavonoids, isoflavonoids, or neoflavonoids.