The actions of tamoxifen, a selective estrogen receptor modulator used in chemotherapy and chemo-prevention of breast cancer, on glycolysis and gluconeogenesis were investigated in the isolated perfused rat liver. Tamoxifen inhibited gluconeogenesis from both lactate and fructose at very low concentrations (e.g., 5μM). The opposite, i.e., stimulation, was found for glycolysis from both endogenous glycogen and fructose. Oxygen uptake was unaffected, inhibited or stimulated, depending on the conditions. Stimulation occurred in both microsomes and mitochondria. Tamoxifen did not affect the most important key-enzymes of gluconeogenesis, namely, phosphoenolpyruvate carboxykinase, pyruvate carboxylase, fructose 1,6-bisphosphatase and glucose 6-phosphatase. Confirming previous observations, however, tamoxifen inhibited very strongly NADH- and succinate-oxidase of freeze-thawing disrupted mitochondria. Tamoxifen promoted the release of both lactate dehydrogenase (mainly cytosolic) and fumarase (mainly mitochondrial) into the perfusate. Tamoxifen (200μM) clearly diminished the ATP content and increased the ADP content of livers in the presence of lactate with a diminution of the ATP/ADP ratio from 1.67 to 0.79. The main causes for gluconeogenesis inhibition are probably: (a) inhibition of energy metabolism; (b) deviation of intermediates (malate and glucose 6-phosphate) for the production of NADPH required in hydroxylation and demethylation reactions; (c) deviation of glucosyl units toward glucuronidation reactions; (d) secondary inhibitory action of nitric oxide, whose production is stimulated by tamoxifen; (e) impairment of the cellular structure, especially the membrane structure. Stimulation of glycolysis is probably a compensatory phenomenon for the diminished mitochondrial ATP production. The multiple actions of tamoxifen at relatively low concentrations can represent a continuous burden to the overall hepatic functions during long treatment periods.

This study evaluated the influence of the alcohol present in a formulation of the antiophidic phytotherapic tincture, Específico-Pessôa, on rat blood biochemical and hematological parameters, and on organ histology. Three groups of rats were treated orally for 10, 15, or 30 days; one group received the tincture, the other received alcohol alone, and the third was a control group. The results of this study indicated that cholesterol levels were significantly increased after 10 days in the alcohol and tincture groups, although these decreased after 30 days in the tincture group. Triglyceride levels were significantly reduced after 15 days in the tincture group and after 30 days in the alcohol and tincture groups. A higher creatinine level was observed in the alcohol and tincture groups after 15 and 30 days. The uric acid levels in these groups were reduced at 10 and 30 days, although this metabolite was elevated at 15 days in the alcohol group. Hydropic multifocal degeneration with lymphohistiocytic infiltration and some polymorphonuclear cells was observed in the livers of rats treated with either the tincture or alcohol. These data demonstrate the importance of considering the potential actions of the alcohol present in pharmaceutical formulations.

Harpalyce brasiliana Benth, known as snakeroot, is one of the most popular herbal medicines against snakebite in South America. A hydroalcoholic solution is traditionally prepared from the roots of H. brasiliana. In the last two decades, understanding the pharmacological properties and the possible medicinal applications of H. brasiliana has increased considerably. H. brasiliana has antivenom activity and anticarcinogenic, antimicrobial and antioxidant properties. Various in vitro and in vivo studies have shown H. brasiliana's diverse biological properties and its potential for disease treatment. The different biological effects of this plant may be attributable to the presence of secondary active metabolites such as pterocarpans, triterpenoids, chalcones and flavonoids. This overview presents different aspects of this plant and the pharmacological properties of its compounds through a review of the available literature. The results support the use of H. brasiliana in the treatment of snakebite and its potential for treatment of other diseases in folk medicine.

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