Novel azulene-based derivatives as potent multi-receptor tyrosine kinase inhibitors

Azulene and Its Derivatives as Potential Compounds in the Therapy of Dermatological and Anticancer Diseases: New Perspectives against the Backdrop of Current Research

The scientific article focuses on the role of azulene and its derivatives in the therapy of dermatological diseases, presenting the latest laboratory and clinical research as well as prospects for further studies. In a synthetic literature review, various databases such as PubMed, Scopus, Web of Science, and the Database of Polish Scientific Journals were queried to select relevant articles concerning azulene. The conclusions drawn from the thematic analysis of the studies emphasize the multifaceted pharmacological actions of azulene and its derivatives including their anti-inflammatory properties, potential anticancer effects, photoprotective abilities, alleviation of itching, management of atopic dermatitis, and treatment of erectile dysfunction. However, there are certain limitations associated with the application of unmodified azulene on the skin, particularly related to photodecomposition and the generation of reactive oxygen species under UV radiation. These effects, in turn, necessitate further research on the safety of azulene and azulene-derived substances, especially regarding their long-term use and potential application in phototherapy. The authors of this work emphasize the necessity of conducting further preclinical and clinical studies to fully understand the mechanisms of action. Incorporating azulene and its derivatives into the therapy of dermatological disorders may represent an innovative approach, thereby opening new treatment avenues for patients.

Selective ring expansion and C-H functionalization of azulenes

We report a transition metal-catalyzed ring expansion of azulene that can be contrasted with C-H functionalization. This study represents the first example of the successful ring expansion of azulene using Cu(hfacac)2 (hfacac: hexafluoroacetylacetonate) with a diazo reagent. This result is notable for extending the Buchner reaction, previously limited to benzenoid aromatics, to nonbenzenoid compounds. The chemoselectivity of the reaction can be directed towards C-H functionalization by substituting the Cu catalyst with AgOTf. This approach does not require the addition of phosphine, NHC, or related ligands, and prefunctionalization of azulenes is unnecessary. Furthermore, the method exhibits excellent functional group tolerance, allowing for the synthesis of a wide range of 6,7-bicyclic compounds and C-H functionalized azulenes. We also present a theoretical study that explains the experimental observations, explaining why copper afford the ring expansion product while silver forms the C-H alkylation product.

Proliferative Effect of Aqueous Extract of Sea Cucumber (Holothuria parva) Body Wall on Human Umbilical Cord Mesenchymal Stromal/Stem Cells

Sea cucumber extracts and their bioactive compounds have the potential for stem cell proliferation induction and for their beneficial therapeutic properties. In this study, human umbilical cord mesenchymal stromal/stem cells (hUC-MSCs) were exposed to an aqueous extract of Holothuria parva body walls. Proliferative molecules were detected using gas chromatography-mass spectrometry (GC-MS) analysis in an aqueous extract of H. parva. The aqueous extract concentrations of 5, 10, 20, 40, and 80 µg/mL and 10 and 20 ng/mL of human epidermal growth factor (EGF) as positive controls were treated on hUC-MSCs. MTT, cell count, viability, and cell cycle assays were performed. Using Western blot analysis, the effects of extracts of H. parva and EGF on cell proliferation markers were detected. Computational modeling was done to detect effective proliferative compounds in the aqueous extract of H. parva. A MTT assay showed that the 10, 20, and 40 µg/mL aqueous extract of H. parva had a proliferative effect on hUC-MSCs. The cell count, which was treated with a 20 µg/mL concentration, increased faster and higher than the control group (p < 0.05). This concentration of the extract did not have a significant effect on hUC-MSCs' viability. The cell cycle assay of hUC-MSCs showed that the percentage of cells in the G2 stage of the extract was biologically higher than the control group. Expression of cyclin D1, cyclin D3, cyclin E, HIF-1α, and TERT was increased compared with the control group. Moreover, expression of p21 and PCNA decreased after treating hUC-MSCs with the extract. However, CDC-2/cdk-1 and ERK1/2 had almost the same expression as the control group. The expression of CDK-4 and CDK-6 decreased after treatment. Between the detected compounds, 1-methyl-4-(1-methyl phenyl)-benzene showed better affinity to CDK-4 and p21 than tetradecanoic acid. The H. parva aqueous extract showed proliferative potential on hUC-MSCs.

Guaiazulene and related compounds: A review of current perspective on biomedical applications

BACKGROUND

Thousands of people worldwide pass away yearly due to neurological disorders, cardiovascular illnesses, cancer, metabolic disorders, and microbial infections. Additionally, a sizable population has also been impacted by hepatotoxicity, ulcers, gastroesophageal reflux disease, and breast fissure. These ailments are likewise steadily increasing along with the increase in life expectancy. Finding innovative therapies to cure and consequently lessen the impact of these ailments is, therefore, a global concern.

METHODS AND MATERIALS

All provided literature on Guaiazulene (GA) and its related compounds were searched using various electronic databases such as PubMed, Google Scholar, Web of Science, Elsevier, Springer, ACS, CNKI, and books via the keywords Guaiazulene, Matricaria chamomilla, GA-related compounds, and Guaiazulene analogous.

RESULTS

The FDA has approved the bicyclic sesquiterpene GA, commonly referred to as azulon or 1,4-dimethyl-7-isopropylazulene, as a component in cosmetic colorants. The pleiotropic health advantages of GA and related substances, especially their antioxidant and anti-inflammatory effects, attracted a lot of research. Numerous studies have found that GA can help to manage various conditions, including bacterial infections, tumors, immunomodulation, expectorants, diuretics, diaphoresis, ulcers, dermatitis, proliferation, and gastritis. These conditions all involve lipid peroxidation and inflammatory response. In this review, we have covered the biomedical applications of GA. Moreover, we also emphasize the therapeutic potential of guaiazulene derivatives in pre-clinical and clinical settings, along with their underlying mechanism(s).

CONCLUSION

GA and its related compounds exhibit therapeutic potential in several diseases. Still, it is necessary to investigate their potential in animal models for various other ailments and establish their safety profile. They might be a good candidate to advance to clinical trials.

C4-aldehyde of guaiazulene: synthesis and derivatisation

Guaiazulene is an alkyl-substituted azulene available from natural sources and is a much lower cost starting material for the synthesis of azulene derivatives than azulene itself. Here we report an approach for the selective functionalisation of guaiazulene which takes advantage of the acidity of the protons on the guaiazulene C4 methyl group. The aldehyde produced by this approach constitutes a building block for the construction of azulenes substituted on the seven-membered ring. Derivatives of this aldehyde synthesised by alkenylation, reduction and condensation are reported, and the halochromic properties of a subset of these derivatives have been studied.

In vitro and in vivo biological activities of azulene derivatives with potential applications in medicine

Azulene is an aromatic hydrocarbon that possesses a unique chemical structure and interesting biological properties. Azulene derivatives, including guaiazulene or chamazulene, occur in nature as components of many plants and mushrooms, such as Matricaria chamomilla, Artemisia absinthium, Achillea millefolium, and Lactarius indigo. Due to physicochemical properties, azulene and its derivatives have found many potential applications in technology, especially in optoelectronic devices. In medicine, the ingredients of these plants have been widely used for hundreds of years in antiallergic, antibacterial, and anti-inflammatory therapies. Herein, the applications of azulene, its derivatives and their conjugates with biologically active compounds are presented. The potential use of these compounds concerns various areas of medicine, including anti-inflammatory with peptic ulcers, antineoplastic with leukemia, antidiabetes, antiretroviral with HIV-1, antimicrobial, including antimicrobial photodynamic therapy, and antifungal.

Azulene Functionalization by Iron-Mediated Addition to a Cyclohexadiene Scaffold

The functionalization of azulenes via reaction with cationic η5-iron carbonyl diene complexes under mild reaction conditions is demonstrated. A range of azulenes, including derivatives of naturally occurring guaiazulene, were investigated in reactions with three electrophilic iron complexes of varying electronic properties, affording the desired coupling products in 43-98% yield. The products were examined with UV-vis/fluorescence spectroscopy and showed interesting halochromic properties. Decomplexation and further derivatization of the products provide access to several different classes of 1-substituted azulenes, including a conjugated ketone and a fused tetracycle.

Structure-Activity Relationships of 1-Benzoylazulenes at the OX1 and OX2 Orexin Receptors

We previously demonstrated the potential of di- or trisubstituted azulenes as ligands (potentiators, weak agonists, and antagonists) of the orexin receptors. In this study we investigated 27 1-benzoylazulene derivatives, uncovering seven potentiators of the orexin response on OX₁ and two weak dual orexin receptor agonists. For potentiators, replacement of the azulene scaffold by indole retained the activity of four out of six compounds. The structure-activity relationships for agonism and potentiation can be summarized into a bicyclic aromatic ring system substituted with two hydrogen-bond acceptors (1-position, benzoyl; 6-position, carboxyl/ester) within 7-8 Å of each other; a third acceptor at the 3-position is also well tolerated. The same pharmacophoric signature is found in the preferred conformations of the orexin receptor agonist Nag26 from molecular dynamics simulations. Subtle changes switch the activity between weak agonism and potentiation, suggesting overlapping binding sites.

Azulenes with aryl substituents bearing pentafluorosulfanyl groups: synthesis, spectroscopic and halochromic properties

Azulenes with SF₅-containing substituents gave significantly different spectroscopic responses to protonation depending on the regioisomer in question.

Dual or multi-targeting inhibitors: The next generation anticancer agents

Dual-targeting/Multi-targeting of oncoproteins by a single drug molecule represents an efficient, logical and alternative approach to drug combinations. An increasing interest in this approach is indicated by a steady upsurge in the number of articles on targeting dual/multi proteins published in the last 5 years. Combining different inhibitors that destiny specific single target is the standard treatment for cancer. A new generation of dual or multi-targeting drugs is emerging, where a single chemical entity can act on multiple molecular targets. Dual/Multi-targeting agents are beneficial for solving limited efficiencies, poor safety and resistant profiles of an individual target. Designing dual/multi-target inhibitors with predefined biological profiles present a challenge. The latest advances in bioinformatic tools and the availability of detailed structural information of target proteins have shown a way of discovering multi-targeting molecules. This neoteric artifice that amalgamates the molecular docking of small molecules with protein-based common pharmacophore to design multi-targeting inhibitors is gaining great importance in anticancer drug discovery. Current review focus on the discoveries of dual targeting agents in cancer therapy using rational, computational, proteomic, bioinformatics and polypharmacological approach that enables the discovery and rational design of effective and safe multi-target anticancer agents.

Antiretroviral (HIV-1) activity of azulene derivatives

The antiretroviral activity of azulene derivatives was detected for the first time. A series of eighteen diversely substituted azulenes was synthesized and tested in vitro using HIV-1 based virus-like particles (VLPs) and infectious HIV-1 virus in U2OS and TZM-bl cell lines. Among the compounds tested, the 2-hydroxyazulenes demonstrated the most significant activity by inhibiting HIV-1 replication with IC50 of 2-10 and 8-20 μM for the VLPs and the infectious virus, respectively. These results indicate that azulene derivatives may be potentially useful candidates for the development of antiretroviral agents.

Azulenesulfonium Salts: Accessible, Stable, and Versatile Reagents for Cross-Coupling

Azulenesulfonium salts may be readily prepared from the corresponding azulenes by an SE Ar reaction. These azulene sulfonium salts are bench-stable species that may be employed as pseudohalides for cross-coupling. Specifically, their application in Suzuki-Miyaura reactions has been demonstrated with a diverse selection of coupling partners. These azulenesulfonium salts possess significant advantages in comparison with the corresponding azulenyl halides, which are known to be unstable and difficult to prepare in pure form.

Synthesis and biological evaluation of C-glucosides with azulene rings as selective SGLT2 inhibitors for the treatment of type 2 diabetes mellitus: discovery of YM543

Here, a series of C-glucosides with azulene rings in the aglycon moiety was synthesized and the inhibitory activities toward hSGLT1 and hSGLT2 were evaluated. Starting from the azulene derivative 7 which had relatively good SGLT2 inhibitory activity, compound 8a which has a 3-[(azulen-2-yl)methyl]phenyl group was identified as a lead compound for further optimization. Introduction of a phenolic hydroxyl group onto the central benzene ring afforded a potent and selective SGLT2 inhibitor 8e, which reduced blood glucose levels in a dose-dependent manner in rodent diabetic models. A mono choline salt of 8e (YM543) was selected as a clinical candidate for use in treating type 2 diabetes mellitus.

One-pot four-component synthesis of pyrimidyl and pyrazolyl substituted azulenes by glyoxylation-decarbonylative alkynylation-cyclocondensation sequences

A novel one-pot four-component synthesis of pyrimidyl- and pyrazolylazulenes through the use of glyoxylation-decarbonylative alkynylation-cyclocondensation sequences starting from azulene or guaiazulene as substrates, gives rise to the formation of the target compounds in moderate to good yields.