Investigation of intracellular signalling events mediating the mechanism of action of 7-hydroxycoumarin and 6-nitro-7-hdroxycoumarin in human renal cells

Synthesis and antiproliferative evaluation of novel 3,5,8-trisubstituted coumarins against breast cancer

Aim: This study focused on designing and synthesizing novel derivatives of 3,5,8-trisubstituted coumarin. Results: The synthesized compounds, particularly compound 5, exhibited significant cytotoxic effects on MCF-7 cells, surpassing staurosporine, and reduced toxicity toward MCF-10A cells, highlighting potential pharmacological advantages. Further, compound 5 altered the cell cycle and significantly increased apoptosis in MCF-7 cells, involving both early (41.7-fold) and late stages (33-fold), while moderately affecting necrotic signaling. The antitumor activity was linked to a notable reduction (4.78-fold) in topoisomerase IIβ expression. Molecular modeling indicated compound 5's strong affinity for EGFR, human EGF2 and topoisomerase II proteins. Conclusion: These findings highlight compound 5 as a multifaceted antitumor agent for breast cancer.

8-Geranylumbelliferone isolated from Paramignya trimera triggers RIPK1/RIPK3-dependent programmed cell death upon TNFR1 ligation

In tumor necrosis factor (TNF) signaling, IκB kinase (IKK) complex-mediated activation of NF-κB is a well-known protective mechanism against cell death via transcriptional induction of pro-survival genes occurring as a late checkpoint. However, recent belief holds that IKK functions as an early cell death checkpoint to suppress the death-inducing signaling complex by regulating receptor interacting protein kinase1 (RIPK1) phosphorylation. In this study, we propose that two major gernaylated 7-hydroxy coumarins, 6-geranyl-7-hydroxycoumarin (ostruthin) and 8-geranyl-7-hydroxycoumarin (8-geranylumbelliferone, 8-GU) isolated from Paramignya timera, facilitate RIPK1-dependent dual modes of apoptosis and necroptosis by targeting IKKβ upon TNF receptor1 (TNFR1) ligation. Analysis of events upstream of NF-κB revealed that 8-GU and ostruthin drastically inhibited TNF-induced IKK phosphorylation, while having no effect on TAK1 phosphorylation and TNFR1 complex-I formation. Interestingly, 8-GU did not affect the cell death induced by Fas ligand or TNF-related apoptosis-inducing ligand or that induced by DNA-damaging agents, indicating that 8-GU sensitizes TNF-induced cell death exclusively. Moreover, 8-GU accelerated TNF-driven necroptosis by up-regulating necrosome formation in FADD deficient cancer cells harboring RIPK3. Thus, the present study provides new insights into the molecular mechanism underlying geranylated 7-hydroxy coumarin-mediated control of the RIPK1-dependent early cell death checkpoint and suggests that 8-GU is a potential anti-cancer therapeutic via an alternative apoptosis-independent strategy to overcome TNF resistance.

Synthesis and anticancer activity of cyclotriphosphazenes functionalized with 4-methyl-7-hydroxycoumarin

The synthesis of three cyclotriphosphazenes derivatives bearing 4-methyl-7-hydroxycoumarin moieties with the numbers of 2, 4, or 6 were reported, and their antitumor activities were test.

Novel glyconanoconjugates: synthesis, characterization and bioapplications

The impressive properties of nanoparticles (NPs) have caused them to gain considerable attention for biological applications such as cancer therapy.

New dicoumarol sodium compound: crystal structure, theoretical study and tumoricidal activity against osteoblast cancer cells

BACKGROUND

Enormous interest had been paid to the coordination chemistry of alkali and alkaline metal ions because of their role inside body viz; their Li(+)/Na(+) exchange inside the cell lead to different diseases like neuropathy, hypertension, microalbuminuria, cardiac and vascular hypertrophy, obesity, and insulin resistance. It has been presumed that alkali metal ions (whether Na(+) or K(+)) coordinated to chelating ligands can cross the hydrophobic cell membrane easily and can function effectively for depolarizing the ion difference. This unique function was utilized for bacterial cell death in which K(+) has been found coordinated valinomycin (antibiotic).

RESULTS

Distinct sodium adduct (1) with dicoumarol ligand, 4-Hydroxy-3-[(4-hydroxy-2-oxo-4a,8a-dihydro-2H-chromen-3-yl)-phenyl-methyl]-chromen-2-one (L) is isolated from the saturated solution of sodium methoxide. Single crystal X-ray diffraction studies of the adduct reveals that sodium is in the form of cation attached to a methoxide, methanol and a dicoumarol ligand where carbonyl functional groups of the coumarin derivative are acting as bridges. The sodium compound (1) is also characterized by IR, (1)H-NMR, and (13)C{(1)H}-NMR spectroscopic techniques. The composition is confirmed by elemental analysis. DFT study for 1 has been carried out using B3LYP/6-13G calculations which shown the theoretical confirmation of the various bond lengths and bond angles. Both the compounds were studied subsequently for the U2OS tumoricidal activity and it was found that L has LD50 value of 200 μM whereas the sodium analog cytotoxicity did not drop down below 60%.

CONCLUSION

A sodium analogue (1) with medicinally important dicoumarol ligand (L) has been reported. The crystal structure and DFT study confirm the formation of cationic sodium compound with dicoumarol. The ligand was found more active than the sodium analog attributed to the instability of 1 in solution state. Coumarin compound with sodium was observed to be less cytotoxic than the ligand, its LD50 value never dropped below 60%.

Synthesis, characterization, in vitro antimicrobial, and U2OS tumoricidal activities of different coumarin derivatives

BACKGROUND

Coumarin and its derivatives are biologically very active. It was found that the enhanced activities are dependent on the coumarin nucleus. Biological significance of these compounds include anti-bacterial, anti-thrombotic and vasodilatory, anti-mutagenic, lipoxygenase and cyclooxygenase inhibition, scavenging of reactive oxygen species, and anti-tumourigenic. Our interest in medicinal chemistry of dicoumarol compounds have been developed by keeping in view the importance of coumarins along with its derivatives in medicinal chemistry. All the synthesized compounds were fully characterized by spectroscopic and analytical techniques and were screened for antimicrobial and U2OS bone cancer activities.

RESULTS

4-hydroxycoumarin was derivatized by condensing with different aldehydes yielding the dicoumarol and translactonized products. Elemental analyses, ESI(+,-) MS, 1H and 13C{1H}-NMR, infrared spectroscopy and conductance studies were used to characterize the synthesized compounds which revealed the dicoumarol and dichromone structures for the compounds. The compounds were screened against U2OS cancerous cells and pathogenic micro organisms. The compounds with intermolecular H-bonding were found more active revealing a possible relationship among hydrogen bonding, cytotoxicity and antimicrobial activities.

CONCLUSION

Coumarin based drugs can be designed for the possible treatment of U2OS leukemia.

Studying plant-derived coumarins for their pharmacological and therapeutic properties as potential anticancer drugs

Coumarins have attracted intense interest in recent years because of their diverse pharmacological properties. Among these properties, their anticancer effect was most extensively examined. In this review, their broad range of effects on the tumours as shown by various in vitro and in vivo experiments as well as clinical investigations is discussed. Studies have indicated that coumarins elicit inhibitory effects on cell growth of various carcinoma cell lines and may be potential candidates for cancer therapy. These natural compounds have served as valuable leads for further design and synthesis of more active analogues. In view of the relative simplicity of the coumarin compounds and their mechanism of action, the coumarin pharmacophore may serve as an important model on which to develop new patterns in cancer chemotherapy. The aim of this review is to examine in detail the properties of the title compounds as anticancer agents. In view of their comparatively low toxicity, relative cheapness, presence in the diet and occurrence in various herbal remedies, it appears important to evaluate their anticancer potentialities. Moreover their synergistic activity in combination therapy with other well-known anticancer drugs could be the basis for the development of rational approaches to new forms of cancer chemotherapy.

Synthesis of new conjugated coumarin-benzimidazole hybrids and their anticancer activity

A series of novel coumarin-benzimidazole hybrids, 3-(1H-benzo[d]imidazol-2-yl)-7-(substituted amino)-2H-chromen-2-one derivatives of biological interest were synthesized. Six out of the newly synthesized compounds were screened for in vitro antitumor activity against preliminary 60 tumor cell lines panel assay. A significant inhibition for cancer cells was observed with compound 8 (more than 50% inhibition) compared with other compounds and active known drug 5-fluorouracil (in some cell lines) as positive control. Compound 8 displayed appreciable anticancer activities against leukemia, colon cancer and breast cancer cell lines.

Transport of the coumarin metabolite 7-hydroxycoumarin glucuronide is mediated via multidrug resistance-associated proteins 3 and 4

Coumarin (1,2-benzopyrone) is a natural compound that has been used as a fragrance in the food and perfume industry and could have therapeutic usefulness in the treatment of lymphedema and different types of cancer. Several previous pharmacokinetic studies of coumarin have been performed in humans, which revealed extensive first-pass metabolism of the compound. 7-Hydroxycoumarin (7-HC) and its glucuronide (7-HC-G) are the main metabolites formed in humans, and via this route, 80 to 90% of the absorbed coumarin is excreted into urine, mainly as 7-HC-G. Active transport processes play a role in the urinary excretion of 7-HC-G; however, until now, the transporters involved remained to be elucidated. In this study, we investigated whether the efflux transporters multidrug resistance-associated proteins (MRP)1-4, breast cancer resistance protein, or P-glycoprotein play a role in 7-HC and 7-HC-G transport. For this purpose, we measured uptake of the metabolites into membrane vesicles overexpressing these transporters. Our results showed that 7-HC is not transported by any of the efflux transporters tested, whereas 7-HC-G was a substrate of MRP3 and MRP4. These results are in line with the pharmacokinetic profile of coumarin and suggest that MRP3 and MRP4 are the main transporters involved in the excretion of the coumarin metabolite 7-HC-G from liver and kidney.

Effects of umbelliferone in a murine model of allergic airway inflammation

The therapeutic effects of umbelliferone (30, 60 and 90 mg/kg), a coumarin isolated from Typha domingensis (Typhaceae) were investigated in a mouse model of bronchial asthma. BALB/c mice were immunized and challenged by nasal administration of ovalbumin. Treatment with umbelliferone (60 and 90 mg/kg) caused a marked reduction of cellularity and eosinophil numbers in bronchoalveolar lavage fluids from asthmatic mice. In addition, a decrease in mucus production and lung inflammation were observed in mice treated with umbelliferone. A reduction of IL-4, IL-5, and IL-13, but not of IFN-gamma, was found in bronchoalveolar lavage fluids of mice treated with umbelliferone, similar to that observed with dexamethasone. The levels of ovalbumin-specific IgE were not significantly altered after treatment with umbelliferone. In conclusion, our results demonstrate that umbelliferone attenuates the alteration characteristics of allergic airway inflammation. The investigation of the mechanisms of action of this molecule may contribute for the development of new drugs for the treatment of asthma.

Synthesis, characterisation and antimicrobial activity of copper(II) and manganese(II) complexes of coumarin-6,7-dioxyacetic acid (cdoaH2) and 4-methylcoumarin-6,7-dioxyacetic acid (4-MecdoaH2): X-ray crystal structures of [Cu(cdoa)(phen)2].8.8H(2)O and [Cu(4-Mecdoa)(phen)2].13H2O (phen=1,10-phenanthroline)

Two novel coumarin-based ligands, coumarin-6,7-dioxyacetic acid (1) (cdoaH(2)) and 4-methylcoumarin-6,7-dioxyacetic acid (2) (4-MecdoaH(2)), were reacted with copper(II) and manganese(II) salts to give [Cu(cdoa)(H(2)O)(2)].1.5H(2)O (3), [Cu(4-Mecdoa)(H(2)O)(2)] (4), [Mn(cdoa)(H(2)O)(2)] (5) and [Mn(4-Mecdoa)(H(2)O)(2)].0.5H(2)O (6). The metal complexes, 3-6, were characterised by elemental analysis, IR and UV-Vis spectroscopy, and magnetic susceptibility measurements and were assigned a polymeric structure. 1 and 2 react with Cu(II) in the presence of excess 1,10-phenanthroline (phen) giving [Cu(cdoa)(phen)(2)].8.8H(2)O (7) and [Cu(4-Mecdoa)(phen)(2)].13H(2)O (8), respectively. The X-ray crystal structures of 7 and 8 confirmed trigonal bipyramidal geometries, with the metals bonded to the four nitrogen atoms of the two chelating phen molecules and to a single carboxylate oxygen of the dicarboxylate ligand. The complexes were screened for their antimicrobial activity against a number of microbial species, including methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and Candida albicans. The metal-free ligands 1 and 2 were active against all of the microbes. Complexes 3-6 demonstrated no significant activity whilst the phen adducts 7 and 8 were active against MRSA (MIC(80)=12.1microM), E. coli (MIC(80)=14.9microM) and Patonea agglumerans (MIC(80)=12.6microM). Complex 7 also demonstrated anti-Candida activity (MIC(80)=22microM) comparable to that of the commercially available antifungal agent ketoconazole (MIC(80)=25microM).

Novel coumarin-3-(N-aryl)carboxamides arrest breast cancer cell growth by inhibiting ErbB-2 and ERK1

A series of novel coumarin carboxamides were synthesized, and their tumor cell cytotoxic activity was investigated. These compounds specifically inhibited the growth of cancer cells that have a high level of ErbB-2 expression. Immunoprecipitation analysis of the cell lysates prepared from carboxamide treated cancer cells showed the inhibition of ErbB-2 phosphorylation suggesting the interaction of these compounds with ErbB-2 receptor. The down regulation of the kinase activity was further confirmed by performing in vitro kinase assay with recombinant ErbB-2 incubated with carboxamides. The inhibition of ErbB-2 phosphorylation correlated with down-regulation of ERK1 MAP kinase activation that is involved in proliferative signaling pathway. Furthermore, the cell-killing activity of many of these inhibitors is restricted to tumor cells with no demonstrable cytotoxicity against normal human fibroblasts suggesting that these compounds are tumor-specific.

A study of the role of cell cycle events mediating the action of coumarin derivatives in human malignant melanoma cells

6-Nitro-7-hydroxycoumarin (6-NO2-7-OHC) and 3,6,8-trinitro-7-hydroxycoumarin (3,6,8-NO2-7-OHC) have previously been shown to be potent and selective anti-proliferative agents to the human skin cell line, SK-MEL-31. Here, we investigate the reversibility of their cytotoxicity, along with their effects on DNA synthesis and cell cycle events. Comparative studies were carried out using the main metabolite of coumarin in man, 7-hydroxycoumarin (7-OHC). 6-NO2-7-OHC and 3,6,8-NO2-7-OHC, were found to be irreversible cytotoxic agents, unlike 7-OHC. All three derivatives inhibited DNA synthesis, but 7-OHC was only nitro-derivatives which acted in an irreversible manner. Flow cytometric studies demonstrated that both nitro-derivatives caused a dose- and time-dependant S phase accumulation. 7-OHC exerted a similar effect, but appeared to be less potent. Finally, the two nitro-derivatives caused a dose-dependant inhibition of the S phase regulatory protein, cyclin A. Consequently, these and other nitro-derivatives of 7-OHC may represent novel therapeutic agents for the treatment of malignant melanoma as they are capable of selective and irreversible cytotoxicity.