Gopala Reddy Palnati

Discovery of coumarin–monastrol hybrid as potential antibreast tumor-specific agent

Development of new, targeted antibreast cancer drug which can treat both the hormone receptor (positive and negative) breast cancers is a very challenging task. The concept of molecular hybridization led us to discover a novel class of coumarin-monastrol hybrid, as a novel breast cancer agent which selectively induce apoptosis in both primary and metastatic breast cancer cell lines.

Coumarin chalcone fibrates: a new structural class of lipid lowering agents.

In our continuing search for safe and efficacious antidyslipidemic agents, structurally interesting coumarin-chalcone fibrates were synthesized and evaluated in triton WR-1339 induced hyperlipidemic rats. The most active compound 41 decreased the total cholesterol (TC), phospholipids (PL) and triglycerides (TG), of hyperlipidemic rats by 26, 24, and 25% respectively. In addition, the compound 41 significantly reversed the levels of VLDL, LDL HDL and also increased the LPL activity. Altogether, our data suggests that these novel hybrids would be a potential new class of therapeutic agents against dyslipidemia.

Synthesis and in vitro evaluation of new chloroquine-chalcone hybrids against chloroquine-resistant strain of Plasmodium falciparum.

The control of malaria has been complicated with increasing resistance of malarial parasite against existing antimalarials. Herein, we report the synthesis of a new series of chloroquine-chalcone based hybrids (8-22) and their antimalarial efficacy against both chloroquine-susceptible (3D7) and chloroquine-resistant (K1) strains of Plasmodium falciparum. Most of the compounds showed enhanced antimalarial activity as compared to chloroquine in chloroquine-resistant (K1) strain of Plasmodium falciparum. Furthermore, to unfold the mechanism of action of these synthesized hybrid molecules, we carried out hemin dependent studies, in which three compounds were found to be active.

Molecular iodine catalysed one-pot synthesis of chromeno[4,3-b]quinolin-6-ones under microwave irradiation

We demonstrate a facile one pot approach for the regioselective synthesis of chromeno[4,3-b]quinolin-6-one derivatives in excellent yields under microwave (MW) irradiation. This transformation presumably proceeds via a three-component tandem annulation of 4-hydroxycoumarin with aromatic aldehydes and aromatic amines, involving a Povarov type reaction.

Discovery of amide based fibrates as possible antidyslipidemic and antioxidant agents

A novel series of amide based fibrates were synthesized and evaluated for antidyslipidemic activity in triton induced hyperlipidemic rats. Interestingly, the compound 13 produced striking reduction in serum levels of total cholesterol (TC), phospholipids (PL) and triglycerides (TG). In addition, it exhibited improved lipoprotein lipase activity and found to possess moderate radical scavenging potential. The results of the above studies shows that the compounds synthesized on fibrate based pharmacophores might result in identification of new lead for dyslipidemia.

Design, synthesis and in vitro evaluation of coumarin–imidazo[1,2-a]pyridine derivatives against cancer induced osteoporosis

A series of biologically important 6-(imidazo[1,2-a]pyridin-2-yl)-2H-chromen-2-one derivatives were synthesized by employing the silver(I) catalysed Groebke–Blackburn–Bienayme multicomponent reaction. The synthesized compounds were tested in a primary calvarial osteoblast cells by alkaline phosphatase assay and an alizarin red-S staining assay for their possible osteoprotective properties. Further, the effects of active compounds 6h, 6l, and 6o on the expression of osteogenic genes BMP2, RUNX2, COL1, and OCN were measured by qPCR. Out of three promising compounds, 6l and 6o significantly induced apoptosis in MDA-MB-231 cancer cells via mitochondrial depolarisation without affecting normal cells. In an in vitro co-culture model of bone metastasis, we investigated the ability of coumarin–imidazo[1,2-a]pyridine hybrids to reverse the negative impact of MDA-MB-231 cancer cells on osteoblast differentiation. The results illustrate the potential of designed hybrids to re-establish the bone homeostasis. These findings demonstrate the significance of newly synthesized hybrids as lead molecules, possessing both antiosteoporotic and anticancer properties that can be developed into new therapeutic agents to alleviate osteoporosis and bone metastasis.

Synthesis and evaluation of anti-thrombotic activity of benzocoumarin amide derivatives☆

A series of novel benzocoumarin amide derivatives have been synthesized and evaluated for their anti-thrombotic activity. Amongst these, compounds 5, 7 and 8 exhibited promising anti-thrombotic profile in an established model of mouse thrombosis. Hence, comprehensive profiling on platelet aggregation and coagulation parameters was carried out to assess its potential as a lead candidate. In vitro treatment of these compounds in mice plasma resulted into significant reduction in ADP (p<0.01) and collagen (p<0.001) induced platelet aggregation. Moreover, Compounds 5, 7 and 8 also significantly increased thrombin time (p<0.05). Thus, in the present study, these benzocoumarin amide derivatives exhibited anti-thrombotic profile via both anti-platelet as well as anti-coagulant action.

Coumarin–benzimidazole hybrids as a potent antimicrobial agent: synthesis and biological elevation

Molecular hybridization approach is an emerging tool in drug discovery for designing new pharmacophores with biological activity. A novel, new series of coumarin–benzimidazole hybrids were designed, synthesized and evaluated for their broad spectrum antimicrobial activity. Among all the synthesized molecules, compound (E)-3-(2-1H-benzo[d]imidazol-1-yl)-1-((4-chlorobenzyl)oxy)imino)ethyl)-2H-chromen-2-one showed the most promising broad spectrum antibacterial activity against Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and Proteus vulgaris. In addition, it has showed no cytotoxicity and hemolysis at 10 times the MIC concentration. SAR studies indicate that position of the chlorine atom in the hybrid critically determines the antibacterial activity.