Antineoplastic indole-containing compounds with potential VEGFR inhibitory properties

Cancer is one of the most significant health challenges worldwide. Various techniques, tools and therapeutics/materials have been developed in the last few decades for the treatment of cancer, together with great interest, funding and efforts from the scientific society. However, all the reported studies and efforts seem insufficient to combat the various types of cancer, especially the advanced ones. The overexpression of tyrosine kinases is associated with cancer proliferation and/or metastasis. VEGF, an important category of tyrosine kinases, and its receptors (VEGFR) are hyper-activated in different cancers. Accordingly, they are known as important factors in the angiogenesis of different tumors and are considered in the development of effective therapeutic approaches for controlling many types of cancer. In this case, targeted therapeutic approaches are preferable to the traditional non-selective approaches to minimize the side effects and drawbacks associated with treatment. Several indole-containing compounds have been identified as effective agents against VEGFR. Herein, we present a summary of the recent indolyl analogs reported within the last decade (2012-2023) with potential antineoplastic and VEGFR inhibitory properties. The most important drugs, natural products, synthesized potent compounds and promising hits/leads are highlighted. Indoles functionalized and conjugated with various heterocycles beside spiroindoles are also considered.

Indole-Based Compounds as Potential Drug Candidates for SARS-CoV-2

The COVID-19 pandemic has posed a significant threat to society in recent times, endangering human health, life, and economic well-being. The disease quickly spreads due to the highly infectious SARS-CoV-2 virus, which has undergone numerous mutations. Despite intense research efforts by the scientific community since its emergence in 2019, no effective therapeutics have been discovered yet. While some repurposed drugs have been used to control the global outbreak and save lives, none have proven universally effective, particularly for severely infected patients. Although the spread of the disease is generally under control, anti-SARS-CoV-2 agents are still needed to combat current and future infections. This study reviews some of the most promising repurposed drugs containing indolyl heterocycle, which is an essential scaffold of many alkaloids with diverse bio-properties in various biological fields. The study also discusses natural and synthetic indole-containing compounds with anti-SARS-CoV-2 properties and computer-aided drug design (in silico studies) for optimizing anti-SARS-CoV-2 hits/leads.

Spiroindole-containing compounds bearing phosphonate group of potential Mpro-SARS-CoV-2 inhibitory properties

Microwave-assisted reaction of 3,5-bis((E)-ylidene)-1-phosphonate-4-piperidones 3a‒g with azomethine ylide (produced through interaction of isatins 4 and sarcosine 5) cycloaddition afforded the corresponding (dispiro[indoline-3,2'-pyrrolidine-3',3″-piperidin]-1″-yl)phosphonates 6a‒l in excellent yields (80-95%). Structure of the synthesized agents was evidenced by single crystal X-ray studies of 6d, 6i and 6l. Some of the synthesized agents revealed promising anti-SARS-CoV-2 properties in the viral infected Vero-E6 cell technique with noticeable selectivity indices. Compounds 6g and 6b are the most promising agents synthesized (R = 4-BrC₆H₄, Ph; R' = H, Cl, respectively) with considerable selectivity index values. M^pro-SARS-CoV-2 inhibitory properties supported the anti-SARS-CoV-2 observations of the potent analogs synthesized. Molecular docking studies (PDB ID: 7C8U) are consistent with the M^pro inhibitory properties. The presumed mode of action was supported by both experimentally investigated M^pro-SARS-CoV-2 inhibitory properties and explained by docking observations.

Potential RNA-dependent RNA polymerase (RdRp) inhibitors as prospective drug candidates for SARS-CoV-2

The SARS-CoV-2 pandemic is considered as one of the most disastrous pandemics for human health and the world economy. RNA-dependent RNA polymerase (RdRp) is one of the key enzymes that control viral replication. RdRp is an attractive and promising therapeutic target for the treatment of SARS-CoV-2 disease. It has attracted much interest of medicinal chemists, especially after the approval of Remdesivir. This study highlights the most promising SARS-CoV-2 RdRp repurposed drugs in addition to natural and synthetic agents. Although many in silico predicted agents have been developed, the lack of in vitro and in vivo experimental data has hindered their application in drug discovery programs.

Azomethine Ylides-Versatile Synthons for Pyrrolidinyl-Heterocyclic Compounds

Azomethine ylides are nitrogen-based three-atom components commonly used in [3+2]-cycloaddition reactions with various unsaturated 2π-electron components. These reactions are highly regio- and stereoselective and have attracted the attention of organic chemists with respect to the construction of diverse heterocycles potentially bearing four new contiguous stereogenic centers. This review article complies the most important [3+2]-cycloaddition reactions of azomethine ylides with various olefinic, unsaturated 2π-electron components (acyclic, alicyclic, heterocyclic, and exocyclic ones) reported over the past two decades.

Synthesis and bio-properties of 4-piperidone containing compounds as curcumin mimics

3,5-Diyliden-4-piperidone scaffold are considered as curcumin mimic exhibiting diverse bio-properties.

Novel Curcumin Inspired Antineoplastic 1-Sulfonyl-4-Piperidones: Design, Synthesis and Molecular Modeling Studies

Background:

Curcumin is a well-known example of plant origin exhibiting promising diverse biological properties such as, anti-inflammatory and antitumor as well as poor pharmacokinetic/pharmacodynamic properties. This is why effective agents based on its chemical scaffold were explored.

Methods:

A set of 3,5-bis(ylidene)-1-(alkylsulfonyl)piperidin-4-ones were synthesized in excellent yield (80- 96%) through dehydrohalogenation reaction of 3,5-bis(ylidene)-4-piperidinones with the corresponding alkane sulfonyl chloride in the presence of triethylamine. Antiproliferative properties of the synthesized compounds (dienone/curcumin inspired analogues) were studied by the standard MTT technique.

Results:

Most of the synthesized compounds revealed antiproliferative properties against HCT116 (colon) and A431 (skin/squamous) cancer cell lines with IC50 values at sub-micromolar level. Compound 36 also exhibited potency against MCF7 (breast) and A549 (lung) cancer cell lines (IC50 = 2.23, 4.27µM, respectively) higher than that of the reference standards (IC50 = 3.15, 5.93µM for 5-fluorouracil and doxorubicin against MCF7 and A549 cell lines, respectively). Cytotoxic properties of the synthesized compounds against non-cancer RPE1 cell line supported the safety profile of the effective agents against normal cells. Molecular modeling (3Dpharmacophore and 2D-QSAR) studies validated the observed bio-properties and explained the parameters governing activity. Inhibitory properties of compounds 27 and 29 (representative examples of the promising antiproliferative agents synthesized) supported their mode of action against topoisomerase IIα

Conclusion:

The synthesized scaffold is a promising antitumor agent (with special selectivity against colon and skin/squamous cancer cell lines) so, it can be considered for further investigation and development of highly effective hits/leads based on the computational models obtained.

Synthesis, human topoisomerase IIα inhibitory properties and molecular modeling studies of anti-proliferative curcumin mimics

Piperidinecarboxamides (curcumin mimics) show promising anti-proliferative properties against HCT116 (colon), MCF7 (breast) and A431 (squamous skin) carcinoma cell lines with potency higher than that of 5-fluorouracil.

Synthesis, X-ray powder diffraction and DFT-D studies of indole-based compounds

Four indole-based compounds have been synthesized and their crystal structures determined using high-resolution synchrotron powder X-ray diffraction. In vacuo density function theory (DFT) optimization has been used in building initial molecular models for structure solution with the help of the Cambridge structure database. All four compounds were found to crystallize in the monoclinic space group P21/c. Dispersion-corrected DFT (DFT-D) has been used for experimental crystal structure validation with acceptable agreement found between the DFT-optimized and final refined structures. Three of the compounds exhibit bronchodilation properties with potency comparable to the theophylline (standard reference).

Synthesis and 2D-QSAR Study of Active Benzofuran-Based Vasodilators

A new series of 2-alkyloxy-pyridine-3-carbonitrile-benzofuran hybrids (4a–x) was synthesized. All the new derivatives were examined via the standard technique for their vasodilation activity. Some of the investigated compounds exhibited a remarkable activity, with compounds 4w, 4e, 4r, 4s, 4f and 4g believed to be the most active hits in this study with IC₅₀ values 0.223, 0.253, 0.254, 0.268, 0.267 and 0.275 mM, respectively, compared with amiodarone hydrochloride, the reference standard used (IC50 = 0.300 mM). CODESSA PRO was employed to obtain a statistically significant 2-Dimensional Quantitative Structure Activity Relationship (2D-QSAR) model describing the bioactivity of the newly synthesized analogs (N = 24, n = 4, R² = 0.816, R²_cvOO = 0.731, R²_cvMO = 0.772, F = 21.103, s² = 6.191 × 10⁻⁸).

Identification of some novel xanthine-based derivatives with bronchodilator activity

AIM

The discovery of new bronchodilators with higher efficacy than theophylline is an important issue for asthmatic patients.

MATERIALS & METHODS

Theophylline 2, 8-bromotheophylline 4 and theobromine 6 were reacted with different 2/3-chloro-N-phenylacetamides 1a-d or their propanamide analogs 1e-g to obtain 3a-g, 5a-g and 7a-g, respectively. The target compounds were screened for their in vitro bronchodilator activity using isolated guinea pig tracheal rings precontracted with histamine and compared with their precursors.

RESULTS

Many compounds exhibited promising activity especially 3d, 3f, 5d, 7d and 7e. 2D-QSAR study resulted in a significant model (N = 24, n = 5, R ² = 0.848, R ²cvOO = 0.748, R ²cvMO = 0.745, F = 21.215, s ² = 0.0002) using CODESSA-Pro software.

CONCLUSION

These compounds can be considered as promising hits for potent bronchodilators that may be useful for further investigations. [Formula: see text].

The advancement of multidimensional QSAR for novel drug discovery - where are we headed?

INTRODUCTION

The Multidimensional quantitative structure-activity relationship (multidimensional-QSAR) method is one of the most popular computational methods employed to predict interesting biochemical properties of existing or hypothetical molecules. With continuous progress, the QSAR method has made remarkable success in various fields, such as medicinal chemistry, material science and predictive toxicology. Areas covered: In this review, the authors cover the basic elements of multidimensional -QSAR including model construction, validation and application. It includes and emphasizes the very recent developments of multidimensional -QSAR such as: HQSAR, G-QSAR, MIA-QSAR, multi-target QSAR. The advantages and disadvantages of each method are also discussed and typical examples of their application are detailed. Expert opinion: Although there are defects in multidimensional-QSAR modeling, it is still of enormous help to chemists, biologists and other researchers in various fields. In the authors' opinion, the latest more precise and feasible QSAR models should be further developed by integrating new descriptors, algorithms and other relevant computational techniques. Apart from being applied in traditional fields (e.g. lead optimization and predictive risk assessment), QSAR should be used more widely as a routine method in other emerging research fields including the modeling of nanoparticles(NPs), mixture toxicity and peptides.

Rational design, synthesis and 2D-QSAR studies of antiproliferative tropane-based compounds

Novel tropane-based compounds were synthesized exhibiting antiproliferative properties against HepG2 and MCF7 carcinoma cell lines.

Synthesis and molecular modeling studies of indole-based antitumor agents

Potent antitumor active (HeLa, cervical carcinoma cell line) indole-based compounds were synthesized via azomethine ylide 1,3-dipolar cycloaddition with 3,5-arylidene-4-piperidones.

Macrocyclic peptidomimetics with antimicrobial activity: synthesis, bioassay, and molecular modeling studies

Novel, cyclic peptidomimetics were synthesized by facile acylation reactions using benzotriazole chemistry. Microbiological testing of the synthesized compounds revealed an exceptionally high activity against Candida albicans with a minimum inhibitory concentration (MIC) two orders of magnitude lower than the MIC of the antifungal reference drug amphotericin B. A strikingly high activity was also observed against three Gram-negative bacterial strains (Pseudomonas aeruginosa, Klebsiella pneumoniae and Proteus vulgaris), two of which are known human pathogens. Thus the discovered chemotype is a potential polypharmacological agent. The toxicity against mammalian tumor cells was found to be low, as demonstrated in five different human cell lines (HeLa, cervical; PC-3, prostate; MCF-7, breast; HepG2, liver; and HCT-116, colon). The internal consistency of the experimental data was studied using 3D-pharmacophore and 2D-QSAR.

Novel antibacterial active quinolone-fluoroquinolone conjugates and 2D-QSAR studies

Novel, quinolone-fluoroquinolone conjugates 10a-f, 11a-f, 13a-f and 14a-f with amino acid linkers were synthesized in good yields utilizing benzotriazole chemistry. Antibacterial bioassay showed the synthesized bis-conjugates exhibit anti-bacterial properties comparable with the parent drugs.

Synthesis and DFT studies of an antitumor active spiro-oxindole

DFT studies of an anti-proliferative active spiro-oxindole against diverse tumor cell lines were reported.

Rational design, synthesis and molecular modeling studies of novel anti-oncological alkaloids against melanoma

Anti-oncological active spiro-alkaloids were synthesized exhibiting promising antitumor properties against melanoma cell lines. Molecular modeling studies describe the observed properties.