A promising chromone-based compounds in drug discovery for new anti-inflammatory and anti-cancer drugs

Chromone, a group of heterocyclic compounds, has been recognised as a privileged structure for new drug discovery and development. These scaffolds have exhibited extensive acceptability due to their drug-like properties and versatile binding properties. Among several approved anti-inflammatory and anti-cancer drugs, these scaffolds show high selectivity for certain specific targets. For this reason, a significantly increasing number of research groups are interested in developing new synthetic methods and evaluating biological properties. In this view, we will discuss some of the important discoveries of chromone-based compounds as anti-inflammatory and anti-cancer agents, such as 2-(3,4-dimethoxyphenyl)-3-(4- fluorophenyl)-6-methoxy-4H-chromen-4-one (KR-1401-KW) which was found to be significantly active in suppressing PGE2-associated inflammatory responses and 3-(4-(chloromethyl)phenyl)-2-(3,4- dimethoxyphenyl)-7-methoxy-4H-chromen-4-one which was displayed potential inhibitor of UNC-51-like kinase 1 (ULK1) (KR-2201-NF) modulates autophagy and induces apoptosis in colon cancer. Moreover, computational evidence, including docking and molecular dynamics (MD) simulations, makes the compounds promising candidates for new anti-inflammatory and anti-cancer drugs

Identification of novel 5-lipoxygenase-activating protein (FLAP) inhibitors by an integrated method of pharmacophore virtual screening, docking, QSAR and ADMET analyses

This study explored a series of reported 5-lipoxygenase-activating protein (FLAP) inhibitors to understand their structural requirements and identify potential new inhibitor scaffolds through automated unbiased procedures. Docking studies have revealed that inhibitor binding affinity can be influenced by several key binding interactions with Phe114 and Lys116 from chain B and Val21, Phe25, His28 and Lys29 from chain C in the FLAP-binding site. A ligand-based alignment three-dimensional (3D)-quantitative structure–activity relationship (QSAR) was adopted, resulting in a robust model with a statistically significant noncross-validated coefficient (r2=0.992), a cross-validated correlation coefficient (q2=0.681) and a predictive squared correlation coefficient (r2pred=0.736). Overall, the analysis revealed the important electrostatic and steric attributes responsible for the FLAP inhibitory activity, which appeared to correlate well with the docking results. In addition, two statistically significant two-dimensional (2D)-QSAR models (r2=0.9369, q2=0.889 and r2=0.9679, q2=0.655) were developed by a genetic function approximation (GFA). HypoGen 1, a proposed pharmacophore model, was used for database mining to identify potential new FLAP inhibitors. The bioactivity of the retrieved hits was then evaluated in silico based on the validated QSAR models, followed by pharmacokinetics and toxicity predictions

Identification of novel 5-lipoxygenase-activating protein (FLAP) inhibitors by an integrated method of pharmacophore virtual screening, docking, QSAR and ADMET analyses

This study explored a series of reported 5-lipoxygenase-activating protein (FLAP) inhibitors to understand their structural requirements and identify potential new inhibitor scaffolds through automated unbiased procedures. Docking studies have revealed that inhibitor binding affinity can be influenced by several key binding interactions with Phe114 and Lys116 from chain B and Val21, Phe25, His28 and Lys29 from chain C in the FLAP-binding site. A ligand-based alignment three-dimensional (3D)-quantitative structure-activity relationship (QSAR) was adopted, resulting in a robust model with a statistically significant noncross validated coefficient (r2=0.992), a cross-validated correlation coefficient (q2=0.681) and a predictive squared correlation coefficient (rpred2=0.736). Overall, the analysis revealed the important electrostatic and steric attributes responsible for the FLAP inhibitory activity, which appeared to correlate well with the docking results. In addition, two statistically significant two-dimensional (2D)-QSAR models (r2=0.9369, q2=0.889 and r2=0.9679, q2=0.655) were developed by a genetic function approximation (GFA). HypoGen 1, a proposed pharmacophore model, was used for database mining to identify potential new FLAP inhibitors. The bioactivity of the retrieved hits was then evaluated in silico based on the validated QSAR models, followed by pharmacokinetics and toxicity predictions

Antibacterial effects of flavonoids and their structure-activity relationship study : A comparative interpretation

According to the latest report released by the World Health Organization, bacterial resistance to well-known and widely available antibacterial drugs has become a significant and severe global health concern and a grim challenge to tackle in order to cure infections associated with multidrug-resistant pathogenic microorganisms efficiently. Consequently, various strategies have been orchestrated to cure the severe complications related to multidrug-resistant bacteria effectively. Some approaches involved the retardation of biofilm formation and multidrug-resistance pumps in bacteria as well as the discovery of new antimicrobial agents demonstrating different mechanisms of action. In this regard, natural products namely alkaloids, terpenoids, steroids, anthraquinone, flavonoids, saponins, tannins, etc., have been suggested to tackle the multidrug-resistant bacterial strains owing to their versatile pharmacological effects. Amongst these, flavonoids, also known as polyphenolic compounds, have been widely evaluated for their antibacterial property due to their tendency to retard the growth of a wide range of pathogenic microorganisms, including multidrug-resistant bacteria. The hydroxylation of C5, C7, C3′, and C4′; and geranylation or prenylation at C6 have been extensively studied to increase bacterial inhibition of flavonoids. On the other hand, methoxylation at C3′ and C5 has been reported to decrease flavonoids’ antibacterial action. Hence, the latest information on the antibacterial activity of flavonoids is summarized in this review, with particular attention to the structure-activity relationship of this broad class of natural compounds to discover safe and potent antibacterial agents as natural products

Antibacterial effects of flavonoids and their structure-activity relationship study: a comparative interpretation

According to the latest report released by the World Health Organization, bacterial resistance to well-known and widely available antibacterial drugs has become a significant and severe global health concern and a grim challenge to tackle in order to cure infections associated with multidrug-resistant pathogenic microorganisms efficiently. Consequently, various strategies have been orchestrated to cure the severe complications related to multidrug-resistant bacteria effectively. Some approaches involved the retardation of biofilm formation and multidrug-resistance pumps in bacteria as well as the discovery of new antimicrobial agents demonstrating different mechanisms of action. In this regard, natural products namely alkaloids, terpenoids, steroids, anthraquinone, flavonoids, saponins, tannins, etc., have been suggested to tackle the multidrug-resistant bacterial strains owing to their versatile pharmacological effects. Amongst these, flavonoids, also known as polyphenolic compounds, have been widely evaluated for their antibacterial property due to their tendency to retard the growth of a wide range of pathogenic microorganisms, including multidrugresistant bacteria. The hydroxylation of C5, C7, C30, and C40; and geranylation or prenylation at C6 have been extensively studied to increase bacterial inhibition of flavonoids. On the other hand, methoxylation at C30 and C5 has been reported to decrease flavonoids’ antibacterial action. Hence, the latest information on the antibacterial activity of flavonoids is summarized in this review, with particular attention to the structure–activity relationship of this broad class of natural compounds to discover safe and potent antibacterial agents as natural products

Flavonoids as antidiabetic and anti-inflammatory agents: a review on structural activity relationship-based studies and meta-analysis

Abstract: Flavonoids are a group of naturally occurring polyphenolic secondary metabolites which have been reported to demonstrate a wide range of pharmacological properties, most importantly, antidiabetic and anti-inflammatory effects. The relationship between hyperglycaemia and inflammation and vascular complications in diabetes is now well established. Flavonoids possessing antidiabetic properties may alleviate inflammation by reducing hyperglycaemia through different mechanisms of action. It has been suggested that the flavonoids’ biochemical properties are structure-dependent; however, they are yet to be thoroughly grasped. Hence, the main aim of this review is to understand the antidiabetic and anti-inflammatory properties of various structurally diverse flavonoids and to identify key positions responsible for the effects, their correlation, and the effect of different substitutions on both antidiabetic and anti-inflammatory properties. The general requirement of flavonoids for exerting both anti-inflammatory and antidiabetic effects is found to be the presence of a C2–C3 double bond (C-ring) and hydroxyl groups at the C3’, C4’, C5, and C7 positions of both rings A and B of a flavonoid skeleton. Furthermore, it has been demonstrated that substitution at the C3 position of a C-ring decreases the anti-inflammatory action of flavonoids while enhancing their antidiabetic activity. Correlation is discussed at length to support flavonoids possessing essential pharmacophores to demonstrate equipotent effects. The consideration of these structural features may play an important role in synthesizing better flavonoid-based drugs possessing dual antidiabetic and anti-inflammatory effects. A meta-analysis further established the role of flavonoids as antidiabetic and anti-inflammatory agents

Synthesis of flavone-based compounds as ros-dependent apoptosis inducers in colorectal cancer

Apoptosis is essential for maintaining cell homeostasis. It hinders the cancer cells survival and excessive ROS can induce DNA damage in cancer cells, which lead to apoptosis. Therefore, targeting apoptosis may be a universal cancer therapeutic technique. Twelve flavone-based compounds were synthesised and characterised. All compounds were evaluated for cytotoxicity against four human cancer cell lines: kidney, breast, colorectal, and bladder cancer cells. Only compound 8 exhibited excellent cytotoxicity against all investigated cancer cell lines, with notably potent cytotoxicity against colorectal (SW620) cells (IC50: 3.2 μM) and higher cytotoxicity than control (IC50: 4.2 μM). Mechanistic analyses such as colony formation, cell cycle arrests and flow cytometry analyses demonstrated an increase in intracellular ROS-induced apoptosis in SW620 cells, which is a potential mode of action for compound 8. Western blot research confirmed the apoptotic mechanism of 8 by showing overexpression of c-PARP, BAD, BAK, and AMPK and downregulation of BCL-2 and AKT. Taken together, the data showed that 8 induces apoptosis by increasing ROS. According to this study, a 4-chloromethyl substituent at the C3-phenyl group may be required for 8's cytotoxicity since other para substituents are inactive. Therefore, structure-activity analysis of 8 in related proteins can be studied

Flavonoids as antidiabetic and anti-inflammatory agents: A review on structural activity relationship-based studies and meta-analysis

Flavonoids are a group of naturally occurring polyphenolic secondary metabolites which have been reported to demonstrate a wide range of pharmacological properties, most importantly, antidiabetic and anti-inflammatory effects. The relationship between hyperglycaemia and inflammation and vascular complications in diabetes is now well established. Flavonoids possessing antidiabetic properties may alleviate inflammation by reducing hyperglycaemia through different mechanisms of action. It has been suggested that the flavonoids’ biochemical properties are structure-dependent; however, they are yet to be thoroughly grasped. Hence, the main aim of this review is to understand the antidiabetic and anti-inflammatory properties of various structurally diverse flavonoids and to identify key positions responsible for the effects, their correlation, and the effect of different substitutions on both antidiabetic and anti-inflammatory properties. The general requirement of flavonoids for exerting both anti-inflammatory and antidiabetic effects is found to be the presence of a C2–C3 double bond (C-ring) and hydroxyl groups at the C3’, C4’, C5, and C7 positions of both rings A and B of a flavonoid skeleton. Furthermore, it has been demonstrated that substitution at the C3 position of a C-ring decreases the anti-inflammatory action of flavonoids while enhancing their antidiabetic activity. Correlation is discussed at length to support flavonoids possessing essential pharmacophores to demonstrate equipotent effects. The consideration of these structural features may play an important role in synthesizing better flavonoid-based drugs possessing dual antidiabetic and anti-inflammatory effects. A meta-analysis further established the role of flavonoids as antidiabetic and anti-inflammatory agents

Mechanistic insights into anti-inflammatory and immunosuppressive effects of plant secondary metabolites and their therapeutic potential for rheumatoid arthritis

The anti-inflammatory and immunosuppressive activities of plant secondary metabolites are due to their diverse mechanisms of action against multifarious molecular targets such as modulation of the complex immune system associated with rheumatoid arthritis (RA). This review discussed and critically analyzed the potent anti-inflammatory and immunosuppressive effects of several phytochemicals and their underlying mechanisms in association with RA in experimental studies, including preliminary clinical studies of some of them. A wide range of phytochemicals including phenols, flavonoids, chalcones, xanthones, terpenoids, alkaloids, and glycosides have shown significant immunosuppressive and anti-inflammatory activities in experimental RA models and a few have undergone clinical trials for their efficacy and safety in reducing RA symptoms and improve patient outcomes. These phytochemicals have potential as safer alternatives to the existing drugs in the management of RA, which possess a wide range of serious side effects. Sufficient preclinical studies on safety and efficacy of these phytochemicals must be performed prior to proper clinical studies. Further studies are needed to address the barriers that have so far limited their human use before the therapeutic potential of these plant-based chemicals as anti-arthritic agents in the treatment of RA is fully realized

Flavonoid diversity and roles in the lipopolysaccharide-mediated inflammatory response of monocytes and macrophages

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