Synthesis of N-substituted piperazinyl carbamoyl and acetyl derivatives of tetrahydropapaverine: potent antispasmodic agents

Papaverine, an opium alkaloid influences hepatic and pulmonary glutathione s-transferase activity and glutathione content in rats

The present study evaluates the effect of oral administration of papaverine at differential dosing regimens (100 mg/kg bw and 200 mg/kg bw) on the hepatic and pulmonary glutathione S-transferase (GST) activity and glutathione content (GSH) in male Wistar rats. Papaverine treatment caused a pronounced increase in GST activity and GSH content at the higher dosing level in the rat liver and lung. We conclude that papaverine, can possibly act as a chemopreventive agent against chemical carcinogenesis.

Stimulation of lipid peroxidation and impairment of glutathione-dependent defense system in wistar rats treated with cryptopine, a rare non-narcotic opium alkaloid

The present study was designed to evaluate the effect of repeated oral administration of cryptopine at differential dosing regimens (50, 100, 150, 200 mg/kg bwt) in vivo on lipid peroxide measures, glutathione levels (GSH) and activity of glutathione S-transferase (GST) and glutathione reductase (GR) in the liver, spleen, kidney and lung of Male Wistar rats after a 5 day treatment period. In all the tissues examined, we observed an increase in lipid peroxidation and a decline in glutathione content and activity of glutathione S-transferase and glutathione reductase in a dose-dependent manner. The decrease in GSH content did not definitively correlate with a concomitant increase of lipid peroxidation in all the tissues. Our results ensemble that the enhancement of lipid peroxidation in the tissues investigated is a consequence of depletion of glutathione to certain critical levels and impairment of the glutathione-dependent enzyme systems viz. GST and GR. Our study potentiates that decreased levels of GSH may lead to lipid peroxidation, one of the key events in cellular damage. The inhibition of GST also suggests that the detoxification of the alkaloid could be suppressed following acute exposures. Conclusively, it appears that cryptopine in vivo disturbs the cellular defense system, so that it tips in the direction of autoxidative lipid peroxidation, producing cytotoxicity.

Synthesis and Antispasmodic Activity Evaluation of Bis-(Papaverine) Analogues

A new series of N-substituted bis-(tetrahydropapaverine) ring systems have been synthesised in expectation of better antispasmodic activity in comparison with papaverine. The synthesis of the targeted heterocycles is described along with a discussion of their structure activity relationship. The general synthetic methods of bis-(tetrahydropapaverine) analogues involve tetrahydropapaverine, various piperazines, diisocyanates and diisothiocyanates as starting materials. Pharmacological evaluation involves the in vitro antispasmodic activity on a freshly removed guinea pig ileum using a force displacement transducer amplifier connected to a physiograph. Among the analogues synthesized in the present study, N,N'-bis-[2-carbamoyl-1-(3,4-dimethoxybenzyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolinyl]piperazine (22), was found to be the most potent muscle relaxant (IC(50): 0.31 microM).