Cytotoxic activity of methanolic fractions of different Marrubium spp. against melanoma cells is independent of antioxidant activity and total phenolic content.

The Marrubium genus (horehound) has proved to be an abundant source of biologically active compounds, but there is little knowledge about its potential anticancer activity. Moreover, some Marrubium species have not been the subject of study in this regard. In this study, we performed comparative analysis of phenolic acid (PhA) content and total phenolic content in fractions obtained from methanolic extracts of Marrubium vulgare L. (common horehound), Marrubium cylleneum Boiss. & Heldr. and Marrubium friwaldskyanum Boiss herbs. We examined the cytotoxicity of these fractions against a human melanoma cancer cell line (A375) and normal human skin fibroblasts (BJ) using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide test, cell cycle analysis and real-time monitoring of cell viability. We detected caffeic, p-coumaric, ferulic and gentisic acids among the PhAs. Although the extracts obtained demonstrated low total phenolic content and did not show significant antioxidative properties, the nonhydrolyzed PhA fraction exhibited cytotoxic activity against a human melanoma cancer cell line, without affecting normal fibroblasts. Both acidic and alkaline hydrolysis abolished this activity, indicating that the esterified forms of phenolic compounds caused the observed cytotoxic effects. Further investigation of these compounds may facilitate the development of novel drugs for cancer treatment.

The influence of a thyroxine supplemented diet on selected hepatic redox equilibrium markers, liver morphology and the serum lipid profile in rats treated with doxorubicin.

INTRODUCTION: Cytotoxicity of doxorubicin (DOX) - an anticancer drug, mostly results from reactive oxygen species (ROS) generation. Some enzymes catalyzing this process and enzymes of antioxidant defense are regulated by iodothyronine hormones. Thus, disorders in iodothyronine hormone status may affect doxorubicin-induced redox imbalance and anabolic/catabolic disorders. The aim of this study was to evaluate the influence of doxorubicin and thyroxine (T4) associated treatment on liver morphology, markers of oxidative stress and plasma lipid parameters. MATERIALS AND METHODS: Rats were intraperitoneally treated with doxorubicin (1.5 mg/kg) once a week for ten weeks. Thyroxine was simultaneously given in drinking water (0.2 or 2.0 mg/l) for 14 weeks. RESULTS: There were higher hepatic level of malonyldialdehyde (MDA) of all tested groups and at the same time in rats treated with DOX plus T4 lower concentrations of total glutathione compared to controls were observed. Morphology of liver did not show any features of necrosis or steatosis but a decrease of glycogen content in T4+DOX groups compared to DOX treatment was observed. The concomitant administration of a lower dose of thyroxine and doxorubicin decreased triglycerides (TG) and increased LDL level compared to the DOX group. DISCUSSION: Thyroxin supplementation caused redox equilibrium disorders and oxidative stress in liver of rats receiving DOX. The study revealed the normalizing influence of thyroxin on glycogen deposits that were observed after doxorubicin treatment. Apart from an adverse impact of thyroxine administration on LDL in rats treated with doxorubicin, a beneficial effect of lower dose of thyroxine on serum TG level was revealed.

Different effects of resveratrol on dose-related Doxorubicin-induced heart and liver toxicity.

The aim of the study was to evaluate the effect of resveratrol in doxorubicin-induced cardiac and hepatic toxicity. Doxorubicin was administered once a week throughout the period of 7 weeks with 1.0 or 2.0 mg/kg body weight or concomitantly with resveratrol (20 mg/kg of feed). Heart and liver toxicity was histologically and biochemically evaluated. Resveratrol protected from the heart lipid peroxidation caused by 1 mg doxorubicin and it sharply diminished superoxide dismutase activity. An insignificant effect of resveratrol on the lipid peroxidation level and the superoxide dismutase activity was observed in the hearts of rats administered a higher dose of doxorubicin. However, resveratrol attenuate necrosis and other cardiac histopathological changes were induced by a high dose of doxorubicin. Interestingly, it slightly intensified adverse cardiac histological changes in rats receiving a lower dose of doxorubicin. Resveratrol did not have any protective effect on the hepatic oxidative stress, while exerting a mild beneficial effect on the morphological changes caused by doxorubicin. All in all, this study has shown different effects of resveratrol on dose-related doxorubicin-induced heart and liver toxicity. Resveratrol may modulate the hepatic and cardiac effect of doxorubicin, depending on the drug dose.

Tirapazamine-doxorubicin interaction referring to heart oxidative stress and Ca²âº balance protein levels.

Doxorubicin (DOX) causes long-term cardiomyopathy that is dependent on oxidative stress and contractility disorders. Tirapazamine (TP), an experimental adjuvant drug, passes the same red-ox transformation as DOX. The aim of the study was to evaluate an effect of tirapazamine on oxidative stress, contractile protein level, and cardiomyocyte necrosis in rats administered doxorubicin. Rats were intraperitoneally injected six times once a week with tirapazamine in two doses, 5 (5TP) and 10 mg/kg (10TP), while doxorubicin was administered in dose 1.8 mg/kg (DOX). Subsequent two groups received both drugs simultaneously (5TP+DOX and 10TP+DOX). Tirapazamine reduced heart lipid peroxidation and normalised RyR2 protein level altered by doxorubicin. There were no significant changes in GSH/GSSG ratio, total glutathione, cTnI, AST, and SERCA2 level between DOX and TP+DOX groups. Cardiomyocyte necrosis was observed in groups 10TP and 10TP+DOX.