Gentiana asclepiadea and Armoracia rusticana can modulate the adaptive response induced by zeocin in human lymphocytes.

Zeocin is a member of bleomycin/phleomycin family of antibiotics isolated from Streptomyces verticullus. This unique radiomimetic antibiotic is known to bind to DNA and induce oxidative stress in different organisms producing predominantly single- and double- strand breaks, as well as a DNA base loss resulting in apurinic/apyrimidinic (AP) sites. The aim of this study was to induce an adaptive response (AR) by zeocin in freshly isolated human lymphocytes from blood and to observe whether plant extracts could modulate this response. The AR was evaluated by the comet assay. The optimal conditions for the AR induction and modulation were determined as: 2 h-intertreatment time (in PBS, at 4°C) given after a priming dose (50 µg/ml) of zeocin treatment. Genotoxic impact of zeocin to lymphocytes was modulated by plant extracts isolated from Gentiana asclepiadea (methanolic and aqueous haulm extracts, 0.25 mg/ml) and Armoracia rusticana (methanolic root extract, 0.025 mg/ml). These extracts enhanced the AR and also decreased DNA damage caused by zeocin (after 0, 1 and 4 h-recovery time after the test dose of zeocin application) to more than 50%. These results support important position of plants containing many biologically active compounds in the field of pharmacology and medicine.

Biological activity of plant extract isolated from Papaver rhoeas on human lymfoblastoid cell line.

Varied medicinal plants are known as a source of natural phytochemicals with antioxidant activities that can protect organisms from oxidative stress and from various chronic diseases. Papaver rhoeas has a long history of medicinal usage, especially for ailments in adults and children. The possible cytotoxicity, genotoxicity and potential antioxidant effect of plant extract isolated from flowers of Papaver rhoeas was investigated in human lymfoblastoid cell line (TK6). Antioxidant activity of this extract was determined using the DPPH assay. The plant extract exhibited dose dependent free radical scavenging ability. The growth activity assay was used for determination of cytotoxicity. To assess potential genotoxicity the comet assay was used. The lower extract concentrations (0.25 and 0.5 mg/ml) neither exerted cytotoxic, nor genotoxic effects in TK6 cells but they stimulated cell proliferation. The concentration 25 mg/ml scavenged almost 85% of DPPH free radical. On the other hand, this concentration had strong cytotoxic and genotoxic effect on TK6 cells. The balance between beneficial and harmful effects should be always considered when choosing the effective dose.

The influence of ascorbic acid on lipid peroxidation in guinea pigs intoxicated with cadmium.

Cadmium (as CdCl2) administered at a dose of 1 mg Cd/animal/day in drinking water to guinea pigs with a low intake of ascorbic acid (2 mg/animal/day) increased lipid peroxidation (LPO) in the kidney, liver and serum after 5 wk of treatment. A high intake of ascorbic acid (100 mg/animal/day) decreased LPO (determined from malondialdehyde levels) in the kidney, liver and serum of Cd-treated guinea pigs. Administration of Cd to guinea pigs with a low intake of ascorbic acid significantly increased LPO in the kidney at 5 wk, in comparison with controls given low levels of ascorbic acid but no Cd. However, at 12 wk, LPO in the kidney of Cd-treated guinea pigs was significantly lower than in the controls. These results indicate that the level of lipid peroxides in the kidney of guinea pigs with a low intake of ascorbic acid depends on the amount of accumulated cadmium.

Synergism between vitamins C and E: effect on microsomal hydroxylation in guinea pig liver.

A separate administration of high doses of L-ascorbic acid or DL-alpha-tocopherylacetate to guinea pigs, fed a cholesterol diet with low content of vitamins C and E enhances the activity of aniline hydroxylase and p-nitro-anisole O-demethylase in hepatal microsomes. A simultaneous administration of the two vitamins exerts a synergic action on aniline hydroxylase. An optimum combination of vitamins C and E may substantially enhance the detoxicating ability of the liver.

Parabolic response of hepatic microsomal hydroxylating system and lipids to graded doses of ascorbic acid in guinea pigs on low and high alpha-tocopherol intake.

The influence of marginal ascorbic acid (AA) deficiency and excessive AA consumption on hepatic microsomal cytochrome P-450, aniline hydroxylase and O-demethylase, serum and liver cholesterol, serum triglycerides and liver alpha-tocopherol was investigated in guinea pigs with low and high vitamin E intake. Male guinea pigs were fed 9 weeks a scorbutogenic diet low in vitamin E (6 mg alpha-tocopherol per kilogram diet), supplemented with four levels of AA: A, deficient, 1 mg AA per animal per day per os; B, control, 500 mg/kg diet; C, control, 5000 mg/kg diet; D, excess, 20,000 mg/kg diet. The response of the microsomal cytochrome P-450 and aniline hydroxylase, serum and liver cholesterol and serum triglycerides to increasing AA doses showed a parabolic pattern. Deficiency (A): high cholesterol in serum and liver, hypertriglyceridemia, low cytochrome P-450 and aniline hydroxylase in liver microsomes; control groups (B and C): decrease of serum and liver cholesterol and serum triglycerides, increase of cytochrome P-450 and aniline hydroxylase; excess (D): return of all parameters to values not significantly different from the AA-deficient group. When guinea pigs were fed the same diets with four levels of AA plus 10 mg alpha-tocopherol acetate per animal orally five times a week, the response of the microsomal hydroxylating system and serum triglycerides to the graded AA doses again proved to be parabolic.