Evaluation of antioxidant potential of pyrazolone derivatives.

In this article the antioxidant property of pyrazolones derivatives (PYZ1 to PYZ10) are reported. It was assessed by estimation of Malonaldehyde (MDA) and 4-Hydroxyl-2-noneal (4-HNE) as lipid peroxidation markers in myocardial ischemic reperfusion injury. The inhibition of lipid peroxidation was compared with the standard ascorbic acid. Among synthesized derivatives PYZ2, PYZ3, PYZ7, PYZ8, PYZ9, and PYZ10 were found to have potent antioxidant effect against MDA marker. In case of 4-HNE, PYZ4, PYZ5, PYZ6, PYZ7, PYZ8, PYZ9 and PYZ10 were found to have effective antioxidant activity and the rest of the compounds are moderately active. Comparatively PYZ7, PYZ8, PYZ9 and PYZ10 are having effective role to control both MDA and 4-HNE generation. All the experimental data were statistically significant at p< 0.05 level. Interestingly, beyond its NSAID property, this study explores the protective role of pyrazolone derivatives in ischemic heart injury.

Membrane bound pyrophosphatase and P-type adenosine triphosphatase of Leishmania donovani as possible chemotherapeutic targets: similarities and differences in inhibitor sensitivities.

The activities of inorganic pyrophosphatase (PPase) and adenosine triphosphatase (ATPase) were studied in the plasma membrane of Leishmania donovani promastigotes and amastigotes. It was shown that the specific activity of PPase was greater than that of ATPase in the promastigote plasma membrane. We characterized H+-PPase present in the plasma membrane of L. donovani and investigated its possible role in the survival of promastigote and amastigote. PPase activity was stimulated by K+ and sodium orthovanadate and inhibited by pyrophosphate analogs (imidodiphosphate and alendronate), KF, N,N'-dicyclohexylcarbodiimide (DCCD), thiol reagents (p-chloromercuribenzenesulfonate (PCMBS), N-ethylmaleimide (NEM), and phenylarsine oxide (PAO)), the ABC superfamily transport modulator verapamil, and also by the F(1)F(o)-ATPase inhibitor quercetin. ATPase activity was stimulated by K+ and verapamil, inhibited by DCCD, PCMBS, NEM, sodium azide, sodium orthovanadate, and quercetin, and was unaffected by PAO. We conclude that there are significant differences within promastigote, amastigote, and mammalian host in cytosolic pH homeostasis to merit the inclusion of PPase transporter as a putative target for rational drug design.

Characterization of plasma membrane bound inorganic pyrophosphatase from Leishmania donovani promastigotes and amastigotes.

BACKGROUND: Currently, a major problem in the management of visceral leishmaniasis or kala-azar, especially in the Indian subcontinent, is the growing unresponsiveness to conventional antimonial therapy. Membrane bound pyrophophatase (PPases) do not exist in plasma membrane from mammals. Thus, H(+)-PPases from Leishmania plasma membrane might be potential target in rational chemotherapy of the disease caused by Leishmania parasites. OBJECTIVE: To characterize the activities of inorganic pyrophophatase (PPase) in the plasma membrane of Leishmania donovani promastigote and amastigote. METHODS: Culture method of promastigote and amastigote were developed. We assayed PPase activity in isolated plasma membrane of L. donovani. RESULTS: We characterized K(+)-PPase present in the plasma membrane of Leishmania donovani and investigated its possible role in the survival of promastigote and amastigote. PPase activity was stimulated by K(+) ions and sodium orthovanadate, inhibited by pyrophosphate analogs imidodiphosphate and alendronate, KF, DCCD, thiol reagent parachloromercuribenzenesulfonate (PCMBS), N-ethylmaliemide (NEM), phenylarsineoxide, ABC superfamily transport modulator verapamil and was also by F(1)F(o)-ATPase inhibitor quercetin. CONCLUSION: We conclude that there are significant differences within promastigote, amastigote and mammalian host in cytosolic pH homeostasis to merit the inclusion of PPase transporter as putative targets for rational drug design.