Some important coumarin members have been isolated from microbial sources e.g. 6 Pharmacological activities: Antimicrobial activity: Coumarin derivatives are having promising antimicrobial activities as per recent literature survey, details of which have been presented as given below: Rama Ganesh by agar cup diffusion method.
DMF was used as blank, Streptomycin was used as anti-bacterial standard and Clotrimazole was used as anti-fungal standard drug at concentration of 1000μg/ml.
Ethyl 2-oxo-2H-chromene-3-carboxylate was prepared by cyclization of salicylaldehyde with diethylmalonate in presence of catalytic amount of piperidine.
Reaction of this ester compound with hydrazine hydrate in ethanol formed 2-oxo-2H-chromene-3-carbohydrazide.
some mannich base of 5-methyl-[(2-oxo-2H-chromen-3-yl) carbonyl]-2,4-dihydro-3H-pyrazol-3-one (Fig.
20) by using conventional and non conventional (microwave) techniques.The key intermediate was prepared by cyclization of compound with ethyl acetoacetate in presence of glacial acetic acid.The key intermediate pyrazolone considered as a cyclic amide and hydrogen atom attached to C4 atom should be appreciably labile to participate in the Mannich condensation.The one pot reaction preparation, spectral analysis, and molecular modeling experiments on the new 3,4-annelated coumarin systems with bioactivity associated structural features are described.These provided the insight into the equilibrium of the respective tautomeric forms making possible the reconciliation of previously published spectral data with the structure assignments as well as the correction of erroneously established structures.Activity of other compounds indicated that the presence of an additional fused benzene ring between the C-5` and C-6` positions inhibited the antibacterial activity towards ) compared to in Potato Dextrose Broth medium (PDB).Appropriate volumes of tested compounds were added to produce concentrations ranging from 10 to 100μg/m L. 12) and (Fig.13) showed good activity as antifungals compared to the antifungal ability of fluconazole, which was used as a standard drugs. 12 FIG.13 4-Heteroaryl-coumarin-3-carbaldehydes Streptomycin was used as standard anti-bacterial drug and ketoconazole was used as standard anti-fungal drug. 17) had activity equal to that of standard drug ketoconazole (31.25 μg/m L) against ntiinflammatory and analgesic activity: Parmar V et al synthesized 4-methyl coumarin derivatives 7,8-dihydroxy-3-ethoxycarbonyl methyl -4-methylcoumarin (DHEMC) and 7,8-diacetoxy-3 - ethoxycarbonylmethyl - 4 - methylcoumarin (DAEMC) (Fig.Coumarins have been under extensive studies for their versatile biodynamic activities, for example coumarins with phenolic hydroxyl group have the ability to scavenge reactive oxygen species and thus prevent the formation of 5- HETE and 5- HHT in arachadonic acid pathway of suppression of inflammation.Recent in vivo studies have revealed the role of coumarins in hepatotoxicity and also in depletion of cytochrome P450.Specifically, coumarin-3-sulfonamides and carboxamides were reported to exhibit selective cytotoxicity against mammalian cancer cell lines.The C4-substituted aryloxymethyl, arylaminomethyl, and dichloroacetamidomethyl coumarins, along with the corresponding 1-azacoumarins, have been demonstrated to be potential anti-microbial and anti-inflammatory agents.