Vanadium Complexes with Thioanilide Derivatives of Amino Acids: Inhibition of Human Phosphatases and Specificity in Various Cell Models of Metabolic Disturbances.

In the text, the synthesis and characteristics of the novel ONS-type vanadium (V) complexes with thioanilide derivatives of amino acids are described. They showed the inhibition of human protein tyrosine phosphatases (PTP1B, LAR, SHP1, and SHP2) in the submicromolar range, as well as the inhibition of non-tyrosine phosphatases (CDC25A and PPA2) similar to bis(maltolato)oxidovanadium(IV) (BMOV). The ONS complexes increased [14C]-deoxy-D-glucose transport into C2C12 myocytes, and one of them, VC070, also enhanced this transport in 3T3-L1 adipocytes. These complexes inhibited gluconeogenesis in hepatocytes HepG2, but none of them decreased lipid accumulation in the non-alcoholic fatty liver disease model using the same cells. Compared to the tested ONO-type vanadium complexes with 5-bromosalicylaldehyde and substituted benzhydrazides as Schiff base ligand components, the ONS complexes revealed stronger inhibition of protein tyrosine phosphatases, but the ONO complexes showed greater activity in the cell models in general. Moreover, the majority of the active complexes from both groups showed better effects than VOSO4 and BMOV. Complexes from both groups activated AKT and ERK signaling pathways in hepatocytes to a comparable extent. One of the ONO complexes, VC068, showed activity in all of the above models, including also glucose utilizatiand ONO Complexes are Inhibitors ofon in the myocytes and glucose transport in insulin-resistant hepatocytes. The discussion section explicates the results within the wider scope of the knowledge about vanadium complexes.

Curcumin exerts protective effects on the thyroid gland in propylthiouracil-treated rats.

INTRODUCTION: Among the plant ingredients, some compounds interfere with the functions of the thyroid gland. However, there is limited research on the effect of curcumin (CMN) on the functions of this gland. The aim of this study was to analyze the effect of CMN on morphology, histochemical reactivity of cytochrome c oxidase (CCO) and secretion functions of the thyroid gland under conditions of hypothyroidism induced by propylthiouracil (PTU). MATERIAL AND METHODS: The rats were treated for 30 days by gavage with CMN (100 mg/kg b.w.) and/or PTU (1 mg/kg b.w.). Control rats received vehicle only. Histomorphometric tests were performed on the thyroid glands, cytochrome c oxidase activity was visualized using the histochemical method, and the levels of thyroid hormones were measured using the radioimmunoassay method. RESULTS: Rats receiving PTU showed compensatory changes in their thyroid glands, including a significant increase in thyroid epithelium height, a decrease in colloid volumen density, a decrease in the percentage of small follicles, an increase in medium-sized follicles compared to the control group, as well as a significant increase in CCO histochemical reactivity in the columnar epithelium and a decrease in FT4 serum level compared to the control group. The administration of CMN reversed these adverse changes caused by PTU. The PTU + CMN group exhibited a significant decrease in the height of the thyroid follicle epithelium compared to the PTU group. The percentage of small and medium-size follicles in the CMN + PTU group did not differ from the control group. Furthermore, CCO reactivity in the cubic epithelium and serum FT4 levels increased compared to the PTU group. Administration of CMN alone resulted in a significant increase in FT4 levels compared to the control group. CONCLUSIONS: The administration of CMN to rats with induced hypothyroidism resulted in a reduction of hyperplasia, hypertrophy, and increase in secretory activity of the thyroid gland. These findings suggest the protective effect of CMN against induced hypothyroidism.

Biological Therapies in the Treatment of Cancer-Update and New Directions.

Biological therapies have changed the face of oncology by targeting cancerous cells while reducing the effect on normal tissue. This publication focuses mainly on new therapies that have contributed to the advances in treatment of certain malignancies. Immunotherapy, which has repeatedly proven to be a breakthrough therapy in melanoma, as well as B-ALL therapy with CAR T cells, are of great merit in this progress. These therapies are currently being developed by modifying bispecific antibodies and CAR T cells to improve their efficiency and bioavailability. Work on improving the therapy with oncolytic viruses is also progressing, and efforts are being made to improve the immunogenicity and stability of cancer vaccines. Combining various biological therapies, immunotherapy with oncolytic viruses or cancer vaccines is gaining importance in cancer therapy. New therapeutic targets are intensively sought among neoantigens, which are not immunocompromised, or antigens associated with tumor stroma cells. An example is fibroblast activation protein α (FAPα), the overexpression of which is observed in the case of tumor progression. Universal therapeutic targets are also sought, such as the neurotrophic receptor tyrosine kinase (NTRK) gene fusion, a key genetic driver present in many types of cancer. This review also raises the problem of the tumor microenvironment. Stromal cells can protect tumor cells from chemotherapy and contribute to relapse and progression. This publication also addresses the problem of cancer stem cells resistance to treatment and presents attempts to avoid this phenomenon. This review focuses on the most important strategies used to improve the selectivity of biological therapies.

The role of oxidative stress in the cooperation of parthenolide and etoposide in HL-60 cells.

BACKGROUND: The aim of this study was to determine the effect of sesquiterpene lactone parthenolide on the cytotoxic and pro-oxidative effects of etoposide in HL-60 cells. METHODS: Cytotoxic effects were determined by incubation of HL-60 cells with various concentrations of examined compounds and combinations thereof, which were then stained with propidium iodide and analyzed using a flow cytometer. To determine the role of oxidative stress in the action of the compounds, co-incubation with N-acetyl-l-cysteine (NAC) and parthenolide and/or etoposide was used and the level of reduced glutathione (GSH) was detected. RESULTS: Parthenolide significantly enhanced the cytotoxic and pro-apoptotic effects of etoposide. However, in most cases of the combinations of parthenolide and etoposide, their effect was antagonistic, as confirmed by an analysis using the CalcuSyn program. The examined compounds significantly reduced the level of GSH in HL-60 cells. Combination of etoposide at a concentration of 1.2 µM and parthenolide also significantly reduced GSH level. However, in the case of a combination of etoposide at a concentration of 2.5 µM with parthenolide, a significant increase in the level of GSH was obtained compared to compounds acting alone. This last observation seems to confirm the antagonism between the compounds tested. CONCLUSIONS: Parthenolide did not limit the cytotoxic effect of etoposide in HL-60 cells even in the case of antagonistic interaction. If parthenolide does increase GSH levels in combination with etoposide in the normal hematopoietic cells, it could protect them against the pro-oxidative effects of this anti-cancer drug.

Curcumin enhances the cytogenotoxic effect of etoposide in leukemia cells through induction of reactive oxygen species.

Curcumin may exert a more selective cytotoxic effect in tumor cells with elevated levels of free radicals. Here, we investigated whether curcumin can modulate etoposide action in myeloid leukemia cells and in normal cells of hematopoietic origin. HL-60 cell line, normal myeloid progenitor cluster of differentiation (CD)-34(+) cells, and granulocytes were incubated for 4 or 24 hours at different concentrations of curcumin and/or etoposide. Brown Norway rats with acute myeloid leukemia (BNML) were used to prove the influence of curcumin on etoposide action in vivo. Rats were treated with curcumin for 23 days and etoposide was administered for the final 3 days of the experiment. Curcumin synergistically potentiated the cytotoxic effect of etoposide, and it intensified apoptosis and phosphorylation of the histone H2AX induced by this cytostatic drug in leukemic HL-60 cells. In contrast, curcumin did not significantly modify etoposide-induced cytotoxicity and H2AX phosphorylation in normal CD34(+) cells and granulocytes. Curcumin modified the cytotoxic action of etoposide in HL-60 cells through intensification of free radical production because preincubation with N-acetyl-l-cysteine (NAC) significantly reduced the cytotoxic effect of curcumin itself and a combination of two compounds. In contrast, NAC did not decrease the cytotoxic effect of etoposide. Thus, oxidative stress plays a greater role in the cytotoxic effect of curcumin than that of etoposide in HL-60 cells. In vitro results were confirmed in a BNML model. Pretreatment with curcumin enhanced the antileukemic activity of etoposide in BNML rats (1.57-fold tumor reduction versus etoposide alone; P<0.05) and induced apoptosis of BNML cells more efficiently than etoposide alone (1.54-fold change versus etoposide alone; P<0.05), but this treatment protected nonleukemic B-cells from apoptosis. Thus, curcumin can increase the antileukemic effect of etoposide through reactive oxygen species in sensitive myeloid leukemia cells, and it is harmless to normal human cells.

Effect of histatin-5 and lysozyme on the ability of Streptococcus mutans to form biofilms in in vitro conditions.

INTRODUCTION: The mechanisms of adhesion to solid surfaces enable S. mutans to colonize oral cavities and form biofilms, which play an important role in caries development. Additional properties enabling the survival of S. mutans in the oral cavity include its ability to survive in acidic environments and specific interactions with other microorganisms inhabiting this ecosystem. AIM OF THE STUDY: The aim of this study was to determine the antibacterial activity of saliva histatin-5 (peptide) and lysozyme (protein) against S. mutans and L. rhamnosus, as representatives of physiological flora. MATERIALS AND METHODS: The study involved strains of physiological (L. rhamnosus) and cariogenic (S. mutans) flora isolated from one patient with diagnosed early caries of the deciduous teeth. RESULTS: It was proved that the presence of probiotic L. rhamnosus bacteria in the environment had a negative impact on the ability of S. mutans to produce biofilm. Moreover, the antibacterial activity of histatin-5 was confirmed, and it inhibited S. mutans growth at concentrations of 27.2 µg/ml and 54.4 µg/ml, both individually and in a mixture with lysozyme (in a total concentration of 54.4 µg/ml). CONCLUSIONS: The data obtained constitute a promising result due to their potential future application in the prevention and early diagnosis of caries.

Inhibition of myeloperoxidase activity have impact on the formation of DNA double-strand breaks induced by etoposide in HL-60 cell line.

Many studies have shown the role of myeloperoxidase (MPO) in leukemogenic activity of etoposide. The aim of our study was to determine whether inhibition of MPO activity has influence on the formation of double-stranded DNA breaks (DSBs) that may contribute to the characteristic of leukemia translocations. Studies were carried out on HL-60 cell line, which were preincubated with the MPO inhibitor 4-aminobenzoic acid hydrazide (ABAH), or antioxidant N-acetyl-L-cysteine (NAC), followed by incubation at different concentrations of etoposide (1-10 mM) for 4 hours. Cytotoxicity was investigated using propidium iodide staining. Marker of DSBs, a phosphorylated form of histone 2AX (gH2AX) was detected using immunocytochemical methods. Cells were analyzed by flow cytometry. ABAH significantly reduced the cytotoxicity and the gH2AX level induced by lower concentrations of etoposide (1 and 1.5 mM) and did not modify the action of higher concentration (10 mM) of this cytostatic drug. NAC exerted similar impact as ABAH on the level of gH2AX induced by etoposide. The results of this study suggest that MPO contributes to increase of the DSBs level induced by low concentrations of etoposide in myeloid cells.

The antioxidant quercetin protects HL-60 cells with high myeloperoxidase activity against pro-oxidative and apoptotic effects of etoposide.

The protective action of quercetin against the pro-oxidant and apoptotic effect of etoposide was investigated in HL-60 cells with a high level of myeloperoxidase (MPO) activity and in cells treated with MPO inhibitor, 4-aminobenzoic acid hydrazide (ABAH). Quercetin significantly protected MPO-rich cells against the pro-oxidative (p<0.05) and apoptotic (p<0.05) effects of etoposide. Pre-treatment with ABAH abolished this protective influence of quercetin on apoptosis induced by etoposide but actually enhanced the action effect of quercetin against etoposide-generated reactive oxygen species (ROS) level by this cytostatic drug. Thus quercetin can protect HL-60 cells against the pro-oxidative activity of etoposide regardless of MPO activity.

The effect of quercetin on oxidative DNA damage and myelosuppression induced by etoposide in bone marrow cells of rats.

There is increasing evidence for the existence of an association between the presence of etoposide phenoxyl radicals and the development of treatment-related acute myeloid leukemia (t-AML), which occurs in a few percent of patients treated with this chemotherapeutic agent. The most common side effect caused by etoposide is myelosuppression, which limits the use of this effective drug. The goal of the study was to investigate the influence of antioxidant querectin on myelosuppression and oxidative DNA damage caused by etoposide. The influence of quercetin and/or etoposide on oxidative DNA damage was investigated in LT-12 cell line and bone marrow cells of rats via comet assay. The effect of quercetin on myelosuppression induced by etoposide was invetsigated by cytological analysis of bone marrow smears stained with May-Grünwald-Giemsa stain. Etoposide caused a significant increase in oxidative DNA damage in bone marrow cells and LT-12 cell line in comparison to the appropriate controls. Quercetin significantly reduced the oxidative DNA damage caused by etoposide both in vitro and in vivo. Quercetin also significantly protected against a decrease in the percentage of myeloid precursors and erythroid nucleated cells caused by etoposide administration in comparison to the group treated with etoposide alone. The results of the study indicate that quercetin could be considered a protectively acting compound in bone marrow cells during etoposide therapy.

The dual effect of curcumin on etoposide action in leukemic and healthy bone marrow cells of rats with acute myeloid leukemia.

The effect of curcumin, a promising anticancer agent, on the action of certain cytostatic drugs, including etoposide, is not well understood. This paper examines the effect of curcumin on etoposide action in leukemic and normal bone marrow cells in vivo conditions. The experimental model used was Brown Norway rats with a transplantable acute promyelocytic leukemia. Leukemia was induced by intravenous injection of BNML (Brown Norway Myeloid Leukemia) cells. Curcumin was administered by oral gavage (200 mg/kg) for 23 consecutive days and etoposide was used intraperitoneally (50 mg/kg) for the last three days of the experiment. Control leukemic and healthy rats received the solvent for the tested compounds only. Curcumin significantly reduced the number of leukemic promyelocytes in the bone marrow of BNML rats in comparison to the leukemic control. Treatment with curcumin plus etoposide led to a decrease in the number of promyelocytes to the normal values occurring in healthy individuals. In contrast, the percentage of the normal precursors of granulocytes (p <0.001) and erythrocytes (p <0.001) increased significantly in comparison to the group treated with only etoposide. The results of the study indicate that curcumin may protect healthy myeloid cells against the cytotoxic effect of etoposide and potentiate the antileukemic action of this anticancer drug.

Influence of fructose and fatty-rich diet combined with vanadium on bone marrow cells.

The aim of the study is to investigate the influence of diet treatment on bone marrow cells. Normal male Wistar rats were divided into six groups (n = 6 per group): control with normal diet (C), increased fructose (31 % w/w in fodder) (Fr) and high fatty (30 % w/w of animal fat in fodder) diet (Fa), and the same diets with vanadium complex ([VO(4,4' Me2-2,2' Bpy)2]SO4) · H2O (CV, FrV and FaV). During 5 weeks, the animals had unlimited access to food and water. Immediately after anaesthetizing and sacrificing the animals, bone marrow smears were prepared from the femurs. Different types of cell lines in the animal smears were examined under the microscope: erythroid line, myeloid line, monocytic line, megakariocytic line and lymphoid line. Addition of fructose or animal fat had evident influence on the proportional composition of the bone marrow cells. In erythroid precursors, addition of both investigated products resulted in a statistically significant increase of percentage of this type of cells. A reverse effect was observed for the lymphoid cell line where addition of both tested diets decreased quantity of these cells in comparison to the control diet. In the same lines, addition of vanadium intensified the observed changes. In the case of other types of cell lines, statistically significant changes were not observed.

The influence of curcumin and (-)-epicatechin on the genotoxicity and myelosuppression induced by etoposide in bone marrow cells of male rats.

Oxidative DNA damage, caused by etoposide cytostatic drug in healthy myeloid precursors, is likely to contribute to the development of treatment-related acute myeloid leukemia (t-AML) in some cancer patients. A frequent side effect of etoposide is myelosuppression, which restricts the use of this drug. Antioxidants from the polyphenol group have the potential to limit this damage. The aim of this study was to determine the effect of (-)-epicatechin and curcumin on DNA damage and myelosuppression induced by etoposide in bone marrow cells of male rats. Rats were treated with the following: 1) (-)-epicatechin [20 and 40 mg/kg body weight (b.w.) by gavage] or curcumin (100 and 200 mg/kg b.w. by gavage) for 7 days; 2) etoposide (50 mg/kg b.w., intraperitoneally) for 3 days; 3) (-)-epicatechin or curcumin for 4 days, followed by coadministration of etoposide for the last 3 days of the experiment; and 4) solvents of the examined compounds (control group). Bone marrow cells were isolated, and DNA damage was analyzed by comet assay. Bone marrow smears were evaluated cytologically. Etoposide administration induced serious DNA damage and hypoplasia of bone marrow. Both curcumin and (-)-epicatechin significantly attenuated etoposide-induced oxidative DNA damage. Curcumin also significantly reduced the DNA strand break and hypoplasia caused by cytostatic drug. This polyphenol increased the percentage of granulocytic precursors and lymphocytes diminished by etoposide. Curcumin exerted greater protection than (-)-epicatechin against undesirable effects induced by the cytostatic.

The influence of curcumin on the action of etoposide in a rat acute myeloid leukemia cell line.

BACKGROUND: There are contradictory results from studies on the effect of curcumin, a plant phenolic compound with a well-established anticancer effect in vitro, on the action of etoposide in cancer cells. OBJECTIVE: The aim of this study was to evaluate the influence of curcumin on the genotoxic and cytostatic action of etoposide in the LT12 cell line derived from BN rat acute myeloid leukemia cells. MATERIAL & METHODS: The LT12 cells were treated with different doses of curcumin for 1-72 hours followed by application of etoposide. The amount of DNA damage was estimated via a comet assay. Viability, cell cycle and apoptosis were examined by using flow cytometry technique. RESULTS: The combined effect of curcumin and etoposide on viability was synergistic at low micro- molar concentrations. In comparison to treatment with curcumin and etoposide alone, co-treatment with these compounds increased the extent of DNA damage, the percentage of cells arrested in the G2/M phase and the number of annexin-V-positive cells. CONCLUSIONS: The interaction between etoposide and curcumin points to an enhanced antileukemic potential to be derived from the combination of these compounds.

(-)-Epicatechin enhances etoposide-induced antileukaemic effect in rats with acute myeloid leukaemia.

BACKGROUND: (-)-Epicatechin (EC) is a naturally occurring compound which induces oxidative DNA damage in human acute myeloid leukaemia (AML) cells. AIM: The aim of the study was to examine the influence of EC on the antileukaemic effect of etoposide in rats with AML. MATERIALS AND METHODS: Brown Norway rats with AML were treated with EC for 23 days and etoposide was administered for the last three days of the experiment. Bone marrow and splenic cell apoptosis was investigated by flow cytometry using annexin V-allophycocyanin staining. The oxidative status was investigated in homogenates of the liver. RESULTS: EC was found to increase the in vivo apoptotic effect of etoposide resulting in the decrease of the percentage of leukaemia cells in EC-treated rats in comparison to those treated with etoposide only. Investigation of malondialdehyde and ferric ion-reducing ability of plasma levels indicated that EC increases the oxidative stress induced by etoposide in leukaemic rats. CONCLUSION: EC can enhance the antileukaemia properties of etoposide in vivo through augmentation of oxidative stress.

Iron content (PIXE) in competent and incompetent veins is related to the vein wall morphology and tissue antioxidant enzymes.

Impaired venous drainage of the lower extremities determines a cascade of pathologic events leading to chronic venous disease (CVD). It is believed that the one cause of CVD is red blood cell extravasation and local iron overload that could generate free radicals and iron-dependent inflammation. The aim of this study was to investigate the relationship between: the intracellular iron deposits in varicose veins and tissue oxidative state measured by: the Proton Induced X-ray Emission Spectroscopy (Fe(PIXE)), (tSOD), (tGPx), (tTBARs) and (boxDNA). Patients with diagnosed CVD were qualified for surgical procedure. Entire trunk of the great saphenous vein (GSV) was extracted. Part located near medial ankle was considered competent (C) in duplex ultrasonography (USG) examination. The incompetent (I) part was extracted from GSV where USG showed incompetent valves and massive venous reflux. The difference between local tFe(PIXE), tTBARS, boxDNA, tGPx, tSOD in incompetent and competent part of vein tissue was statistically significant. Intima/media ratio directly correlated with Fe(PIXE) C/I concentration. Iron deposition in competent vs incompetent part of vein was also related to the oxidative stress parameters (boxDNA). The findings from this pilot study suggest that Fe(PIXE) measurement may be useful for explaining the progression of chronic venous disease.

Epicatechin administration leads to necrotic cell death of rat leukaemia promyelocytes in vivo.

BACKGROUND: (-)-Epicatechin (EC) induces oxidative DNA damage in HL-60 cells. The association between genotoxic and apoptotic/necrotic effects of EC was studied in rats with acute myeloid leukaemia. MATERIALS AND METHODS: Healthy and leukaemic rats were given EC by oral gavage at a dose of 40 mg/kg body weight for 22 consecutive days. Bone marrow cells were subjected to analysis of DNA damage by the comet assay and apoptosis by flow cytometry. RESULTS: EC significantly increased DNA strand breaks in bone marrow cells of leukaemic animals but it did not exert such an effect on healthy rats. EC action led to necrosis of leukaemia cells but it did not induce apoptosis of these cells in comparison to the controls. CONCLUSION: EC has genotoxic and necrotic effects which may have utility in anticancer therapy against acute myeloid leukaemia.

Evaluation of oxidative status and depression-like responses in Brown Norway rats with acute myeloid leukemia.

It has been proved that oxidative stress increases when leukemia is accompanied by depression. This fact may indicate the role of oxidative stress in the development of depression in cancer patients. The aim of this study was to determine whether the acute myeloid leukemia of Brown Norway rats, which is accompanied by oxidative stress, evoked behavioral and receptor changes resembling alterations characteristic of rat models of depression. The rats were divided into two groups: leukemic rats and healthy control. Leukemia was induced through intraperitoneal injection of 10(7) promyelocytic leukemia cells to the Brown Norway rats. Depression-like behavior was evaluated in the forced swim test at 30 or 34 days after leukemic cells injection. The rats were killed after the evaluation and the spleen, brain cortex and hippocampus were excised. The red-ox state was assessed in homogenates of tissues by measuring total glutathione (GSH) content, the ferric ion reducing ability of plasma (FRAP) level, expression of heme oxygenase-1 (HO-1), biliverdin reductase (BvR) and ferritin mRNA, superoxide dismutase (SOD) activity, as well as malondialdehyde (MDA) concentration. Radioligand binding assay was used to assess of the effect of leukemia on cortical receptors. Leukemic cells were identified using RM-124 antibody by FACS Calibur flow cytometry. Leukemia influenced locomotory activity as well as forced swim test behavior in a 34-day series of experiments. Signs of oxidative stress in leukemic rats were observed in each examined stage of leukemia development. The FRAP values and glutathione contents, were significantly lowered whereas HO-1 mRNA expression, and malonodialdehyde concentrations were significantly increased in the spleen and brain structures of leukemic rats in comparison with the healthy controls. A significant increase in the potency of glycine to displace [(3)H]L-689,560 from the strychnine-insensitive glycine site of the N-methyl-D-aspartic (NMDA) receptors receptor complex in cortical homogenates of the leukemic rats in 30- and 34-day experimental series was observed in comparison with the control. Upregulation of 5-HT(2A) receptors was observed in rat cortex after 30 days of leukemia development but not in 34-days series compared with the control. It is concluded that disturbances in antioxidant system in brain cortex were accompanied by an activation of glycine sites of the NMDA receptor complex, regardless of stage of leukemia development, which are characteristic of model of depression. Findings of our study demonstrate the link between glutamatergic activity, oxidative stress and leukemia.

Age-dependent different action of curcumin in thyroid of rat.

The aging is associated with alterations in the hypothalamic-pituitary-thyroidal axis which can lead to hypothyreosis. Our previous investigations has shown that polyphenol curcumin can enhance the manifestation of hypothyreosis in rats simultaneous treated with propylthiouracil. The aim of the study was to investigate the relationship between age-related changes and curcumin action in the thyroid of old rats. To this end, morphometric and radioimmunological methods were used. The study was conducted on 3- and 18-month-old male Wistar rats. The experimental rats were treated daily for 30 days by gavage with 100 mg/kg b.w. of curcumin. There were observed age-related changes in morphology and endocrine function of the thyroid. It was increase in the percentages of large follicles and significant decrease in FT3 level in 18-month-old rats in comparison to 3-month ones. Curcumin treatment lead to significant increase in FT3 and FT4 levels in 3-month-old experimental rats, but the level of FT3 significantly decreased in 18-month-old rats after curcumin administration. Our results show that curcumin activity depends on the functional condition of the rat thyroid which changes with age. This compound exerts stimulatory influence on the secretory function of the thyroid gland in young rats, but has rather weak antithyroid activity in old animals.

Prolonged quercetin administration diminishes the etoposide-induced DNA damage in bone marrow cells of rats.

The DNA damage in bone marrow cells induced by etoposide (E) injected intraperitoneally to rats (100 mg/kg b.w.) decreased to the control level when quercetin (Q) was administered subcutaneously for 10 consecutive days (40 mg/kg b.w.per day) before E was injected. The antioxidant power (FRAP assay) increased significantly after Q or E compared with control rats but did not change when Q preceded the E injection. The superoxide dismutase activity significantly increased in Q+E-treated rats compared with quercetin given alone. The study provides evidence that Q protects bone marrow cells against long-lived E-induced DNA damage and alters the redox balance in lung tissue.

The influence of hollyhock extract administration on testicular function in rats.

It has been reported, recently that an aqueous extract from hollyhock flowers (Althaea rosea Cav. varietas nigra) induces weak metabolic changes in rat testes. In the present study, the in vivoinfluence of a methanolic extract was investigated on the metabolism and morphology of the rat testis. To this end, histochemical, morphometric and radioimmunological methods were used. The rats drank the extract at a dose of 100 mg/day for 7 weeks. The histochemical activities of glucose-6-phosphate dehydrogenase (G6PDH) and Delta(5)beta-hydroxysteroid dehydrogenase (Delta(5)betaHSD) increased significantly statistically in the Leydig cells of the experimental rats in comparison with controls. There were no significant changes in either the diameter of seminiferous tubules or the height of seminiferous epithelium after hollyhock administration. Further, only a small amount of hyperplasia of the interstitial tissue was observed. The morphological and histoenzymatic changes in the Leydig cells indicate that the methanolic hollyhock extract has a direct but small influence on rat testes. The insignificant changes in testicular testosterone and estradiol content suggest that the extract does not disturb steroidogenesis.