Hepatoprotective activity of Trichopus zeylanicus extract against paracetamol-induced hepatic damage in rats.

Trichopus zeylanicus extract has been evaluated for its antihepatotoxic and choleretic activities in rats. The plant leaf suspension (1000 mg/kg; wet weight) as well as its methanol extract (100 mg/kg) showed a remarkable hepatoprotective activity against paracetamol-induced hepatotoxicity as judged from the serum marker enzymes, liver histology and levels of lipid peroxides in liver. The effect of the methanol extract was found to be concentration dependent. The water and hexane extracts were almost inactive. The methanol extract (100 mg/kg) also exhibited choleretic activity in anesthetized normal rats. In short, we report here for the first time the antihepatotoxic as well as choleretic properties of T. zeylanicus.

Influence of mancozeb on mitogenically responsive lipids in rat cerebrum and liver.

Mancozeb, a commonly used fungicide, has been shown to induce tumours in mouse skin and maneb, unit constituent of mancozeb, is reported to induce tumours in rats. The mechanism by which mancozeb induced tumorigenicity is not known. Since the levels of inositol phospholipids and phosphatidic acid have roles in the regulation of cell proliferation, the effects of mancozeb on the levels of these lipids were studied in rats. Daily oral administration of commercial grade mancozeb at a concentration of 50 mg/kg body wt for 30 days (5 days a week) caused no significant change in the levels of inositol phospholipids and phosphatidic acid (PA) in both cerebrum and liver, while at high concentration (250 mg/kg body wt) under the same treatment schedule mancozeb increased the levels of these lipids. In cerebrum, the levels of phosphatidylinositol (PI) and PA were increased by 36 and 43% respectively without affecting the levels of polyphosphoinositides, whereas in liver the levels of not only PI (50%) and PA (49%) but also those of polyphosphoinositides were increased. These results show that mancozeb influences the levels of PA and inositol phospholipids, involved in phospholipase C-pathway of signalling.

Effect of iron deficiency on phosphoinositide levels in rat brain.

Adult rats raised on 90% iron deficient diet for 6 weeks showed a decrease in the levels of brain phosphatidylinositol (60%), phosphatidylinositol 4-phosphate (25%) and phosphatidylinositol 4,5-bisphosphate (30%), the precursors for the second messengers, diacylglycerol and inositol phosphates. Rehabilitation to normal diet for 24 days was found to restore the levels to control values. The data suggests that iron deficiency could lead to alterations in the functions related to phosphoinositide-linked receptor system(s).