Protective effect of amifostine on busulfan induced DNA damage in human hepatoma cells.

Busulfan is one of the most effective chemotherapeutic agents used for the treatment of chronic myeloid leukemia. However, as a bifunctional alkylating agent, during clinical use several side effects may occur. In addition, several in vivo and in vitro studies of busulfan have shown a range of genotoxic effects including DNA strand break and inhibition of DNA synthesis. Amifostine, an organic thiophosphate compound, has been shown to exert an important cyto-protective effect in many tissues. The aim of this study was to explore whether amifostine protects against busulfan-induced genotoxicity in HepG2 cell line. Our results showed that amifostine reduced the genotoxic effects of busulfan significantly in both type of experiment conditions, as measured via comet assay. Furthermore, amifostine decreased the intracellular ROS generation induced by busulfan and also increased the intracellular GSH levels in HepG2 cells. Altogether, our results suggest a protective action of amifostine against busulfan cytotoxicity and genotoxicity via various pathways. The most protective effect was observed with amifostine when it was administrated 24 h before busulfan treatment.

Assessment of the deoxyribonucleic acid damage caused by occupational exposure to chemical compounds in Isfahan Polyacryl Company.

BACKGROUND: Chemical pollutants found in industrial environments can cause chronic genotoxicity in vulnerable individuals during the long-term exposure. The primary purpose of the present study was to assess the deoxyribonucleic acid (DNA) damage caused by occupational exposure to industrial chemicals and secondary purpose is to investigate the effect of possible risk factors of genotoxicity. MATERIALS AND METHODS: The blood samples of the workers of Isfahan Polyacryl Company were evaluated in terms of genotoxicity using the comet assay method. The percentage of DNA in the tail and tail moment were measured and DNA damage was evaluated. Furthermore, the effect of age, smoking, duration of working in the company and working in two parts of the company on the degree of vulnerability to genotoxicity was assessed. RESULTS: The amount of DNA damage in the target group (the production line workers) was significantly higher than the control group (the staffs), 3.87 versus 1.52 as tail moment, (P < 0.0001). DNA damage was significantly higher in smoker groups compared with non-smoker target group and control group, 4.18 versus 3.07 and 1.52 respectively as tail moment, (P < 0.0001). Furthermore, it was higher in person working in two different parts of the company compared to those work in one part and control group, 4.63 versus 3.74 and 1.52 respectively as tail moment, (P < 0.0001). CONCLUSION: Occupational exposure to Polyacryl caused DNA damage. Smoking and working in two parts of the company may have a significant role in DNA damage.

Medicinal Chemistry of Antisense Oligonucleotides for Therapeutic Use in SARS-CoV-2: Design Strategies and Challenges for Targeted Delivery.

BACKGROUND: The evolution of novel Severe Acute Respiratory Syndrome-related Coronavirus 2 (SARS-CoV-2) strains with greater degrees of infectivity, resistance to vaccine-induced acquired immunity, and more severe morbidity have contributed to the recent spread of COVID-19. In light of this, novel therapeutic alternatives with improved effectiveness and fewer side effects have become a necessity. Despite many new or repurposed antiviral agents recommended for Coronavirus disease (COVID-19) therapy, this objective remains unfulfilled. Under these circumstances, the scientific community holds the significant responsibility to develop classes of novel therapeutic modalities to combat SARS-CoV-2 with the least harmful side effects. OBJECTIVE: Antisense Oligonucleotides (ASOs) are short single-stranded oligonucleotides that allow the specific targeting of RNA, leading to its degradation. They may also prevent cellular factors or machinery from binding to the target RNA. It is possible to improve the pharmacokinetics and pharmacodynamics of ASOs by chemical modification or bioconjugation, which may provide conditions for customization of a particular clinical target. This study aimed to outline the potential use of ASOs in the treatment of COVID-19 disease, along with the use of antisense stabilization and transfer methods, as well as future challenges and limitations. METHODS: We have reviewed the structure and properties of ASOs containing nucleobase, sugar, or backbone modifications, and provided an overview of the therapeutic potential, delivery challenges, and strategies of ASOs in the treatment of COVID-19. RESULTS: The first-line therapy for COVID-19-infected individuals, as well as the development of oligonucleotide-based drugs, warrants further investigation. Chemical changes in the oligonucleotide structure can affect the biological processes. These chemical alterations may lead to enhanced potency, while changing the pharmacokinetics and pharmacodynamics. CONCLUSION: ASOs can be designed to target both coding and non-coding regions of the viral genome to disrupt or completely degrade the genomic RNA and thereby eliminate SARS-CoV-2. They may be very effective in areas, where vaccine distribution is challenging, and they may be helpful for future coronavirus pandemics.

Preparation of chitosan nanoparticles for simultaneous drug delivery of dacarbazine and enoxaparin in melanoma.

The aim of this study was to investigate the anti-melanoma and anti-angiogenic effects of enoxaparin surface-coated dacarbazine-loaded chitosan nanoparticles (Enox-Dac-Chi NPs). The prepared Enox-Dac-Chi NPs had a particle size of 367.95 ± 1.84 nm, zeta potential of -7.12 ± 0.25 mV, efficiency of drug loading (DL%) of 73.90 ± 3.84 %, and attached enoxaparin percentage of 98.53 ± 0.96 %. Both drugs had extended-release profiles and approximately 96 % of enoxaparin and 67 % dacarbazine were released within 8 h. The Enox-Dac-Chi NPs with IC50 of 59.60 ± 1.25 µg/ml were the most cytotoxic against melanoma cancer cells compared with chitosan nanoparticles containing only dacarbazine (Dac-Chi NPs) and free dacarbazine. There was no significant difference between the cellular uptake of Chi NPs and enoxaparin coated Chi NPs (Enox-Chi NPs) in B16F10 cells. Enox-Chi NPs with an average anti-angiogenic score of 1.75 ± 0.125 had more anti-angiogenic effect than enoxaparin. The results showed that simultaneous delivery of dacarbazine and enoxaparin by chitosan nanoparticles can enhance the anti-melanoma effect of dacarbazine. Additionally, enoxaparin can prevent the melanoma metastasis by its anti-angiogenic activity. Thus, the designed nanoparticles can be introduced as effective drug delivery vehicles for the treatment and prevention of metastatic melanoma.

Evaluation of DNA damage of hydro-alcoholic and aqueous extract of Echium amoenum and Nardostachys jatamansi.

BACKGROUND: Today most of herbal medicines are marketing without any standard safety profiles. Although common assumption is that these products are nontoxic but this assumption may be incorrect and dangerous, so toxicological studies should be done for herbal drugs. According to the frequent use of Echium amoenum as immunostimulant and useful in conditions including pain, cough, sore throat and arthritis, and Nardostachys jatamansi as tranquilizer and sleep inducer and evidences of some toxicities, we assessed the probable effect of their extracts on DNA of hepG2 cells using the comet assay. MATERIALS AND METHODS: Different concentrations of above extracts of the plants are incubated with hepG2 cells for 24 h. A mixture of cell suspension and agarose gel were put on slides, then slides were embedded in a lysing solution and were put in electrophoresis buffer (pH = 13). Then the electrophoresis procedure took place in an alkaline solution and after neutralization stage, colorization was done by ethidium bromide and comets were observed using a fluorescence microscope. At least 100 cells of each sample were evaluated and three parameters including comet length, percent of DNA in tail, and tail moment were assessed. RESULTS: Both Aqueous and hydro-alcoholic extract of E. amoenum were genotoxic in the concentrations of 25 mg/ml and aqueous and hydro-alcoholic extract of N. jatamansi were genotoxic in the concentrations 5 and 10 mg/ml, respectively. CONCLUSIONS: Although E. amoenum and N. jatamansi are highly used in medicine, these herbs have genotoxic effects in determined concentrations and they should be used cautiously.

Antioxidant and genoprotective effects of osthole against cadmium-induced DNA damage: an in vitro study using comet assay.

Background and purpose: Osthole, a plant-derived coumarin, has shown numerous pharmacological effects. However, its genoprotective effects against cadmium-induced DNA damage have not been determined yet. Therefore, this project aimed to assess the effectiveness of osthole against genotoxicity caused by cadmium. Experimental approach: For this purpose, human umbilical vein endothelial cells (HUVECs) were incubated with various concentrations of osthole (40, 60, 80, and 120 µM) 24 h before cadmium chloride (CdCl2) treatment (40 µM), and then DNA damage was evaluated by comet assay. Furthermore, DPPH and free thiol group assays were applied to evaluate reactive oxygen species scavenger and antioxidant capacities of osthole. Findings / Results: In the present study, all concentrations of osthole significantly decreased CdCl2-induced DNA damage. Furthermore, the antioxidant properties of the osthole were confirmed by DPPH and free thiol assays. Conclusion and implications: Overall, the findings of this project revealed that osthole could ameliorate cadmium-induced genotoxicity probably by its antioxidant activity.

Niosome-carvedilol protects DNA damage of supraphysiologic concentrations of insulin using comet assay: An in vitro study.

Introduction: Hyperinsulinemia occurs in type 2 diabetic patients with insulin resistance. This increase in insulin levels in the blood increases reactive oxygen species production and oxidative stress, resulting in DNA damage. Carvedilol (CRV) is a non-selective beta-blocker, and research has shown that this compound and its metabolites have anti-oxidative properties. Carvedilol can, directly and indirectly, reduce reactive oxygen species (ROS) and has a protective effect on DNA damage from oxidative stress. Given the insolubility of CRV in water, finding new methods to increase its solubility can be an essential step in research. This study aimed to determine whether carvedilol could have a protective effect on insulin-induced genomic damage. Methods: We treated cells with insulin alone, amorphous-CRV alone, and amorphous-CRV and niosomal-CRV with insulin and DNA damage were investigated using the comet method to achieve this goal. Results: Our results showed that insulin in the studied concentration has a significant genotoxic effect and non-cytotoxic at higher concentrations. CRV, both in amorphous and niosome form, reduced insulin-induced DNA damage by reducing ROS production. The comet assay results demonstrate that treating HUVEC cells in pretreatment condition with amorphous-CRV and niosome-CRV significantly reduces DNA damage of insulin.

Study of the probable genotoxic effects of Zolone (Phosalone) exposure in mice bone marrow derived cells.

BACKGROUND AND AIM: Approximately, 2 million tonnes of pesticides are utilized annually worldwide. Phosalone (Pln), an organophosphorus pesticide, acts as an insecticide and acaricide to control pests of crops such as nuts, citrus fruits, pomegranates, stone fruits, grapes, potatoes, and artichokes. The purpose of this study was to evaluate the possible genotoxic effects following exposure to Pln in the cells derived from mouse red bone marrow. MATERIALS AND METHODS: Sixty mice were divided into 6 groups including cyclophosphamide (40 mg/kg, IP) and Pln (6, 12, 20, and 40 mg/kg) exposure by gavage. After 1 and 5 days of exposure, animals were euthanized and the genotoxicity assays were done on bone marrow extracted cells. RESULTS: Comet assay shows a time and dose-dependent toxicity which further DNA degradation is observed after 5-day exposure (p < 0.05). Also, Pln significantly increased the MnPCE/PCE ratio after 12 and 20 mg/kg administration while no significant difference was reported between the doses of 6 and 40 mg/kg BW with the negative control group. CONCLUSION: Our results suggested a serious concern about its potential effects on biological life and related disease inductions. However further studies need to confirm the exact mechanism of Pln genotoxicity and the cause of diverse response of its activity at 40 mg/kg. This study also showed that increasing the dose of Pln reduces the MnNCE/Total cells ratio, which may indicate the possibility of bone marrow suppression. All of the above results emphasize the need to seriously limit the use of this compound as an agricultural pesticide.

Investigating the effects of bark extract and volatile oil of Pinus eldarica against cisplatin-induced genotoxicity on HUVECs cell line.

Cisplatin is used for treating multiple types of cancers. Alongside its therapeutic effects, there are side effects, including cytotoxicity and genotoxicity for healthy cells, which are mainly related to radical oxygen species (ROS) production by the drug. These side effects could troublesome the treatment process. Previous studies have suggested that members of Pinaceae family are rich sources of antioxidant components. This article investigates the antioxidant activity (AA) of Pinus eldarica (Pinaceae) along with its cyto/genoprotective effects following cisplatin exposure on human umbilical vein endothelial cells (HUVECs) cell line. Pinus eldarica's hydroalcoholic bark extract (PEHABE) and P. eldarica's needle volatile oil (PENVO) were prepared using maceration and hydrodistillation methods, respectively. PENVO was analysed via gas chromatograph-mass spectrometry, and the total phenolic content of PEHBAE was measured by folin-ciocalteu reagent. AA of both PEHABE and PENVO were determined using DPPH assay. Moreover, MTT test was used to determine the cytoprotective effects of both agents. Comet and micronucleus (MN) tests were also performed to investigate the genoprotective effect of P. eldarica. Germacrene D (35.72%) was the main component of PENVO. PEHABE showed higher AA compared with PENVO, with the highest AA observed at 25 and 250 µg/ml, respectively. Both PENVO and PEHABE were cytoprotective, with the latter having mitogenic effects on cells at 75, 100, and 200 µg/ml concentrations (P < 0.01 and P < 0.001). Also, both PEHABE and PENVO showed genoprotective effects against cisplatin in comet assay (P < 0.001). As PEHABE's concentrations were increased, a reduced number of MN formation was observed after cisplatin's exposure (P < 0.001). In conclusion, PEHABE had higher AA compared with PENVO, and both agents had cyto/genoprotective effects on HUVECs.

An engineered non-erythropoietic erythropoietin-derived peptide, ARA290, attenuates doxorubicin induced genotoxicity and oxidative stress.

Erythropoietin (EPO) applies anti-inflammatory, anti-apoptotic, anti-oxidant and cytoprotective effects besides its hematopoietic action. A nonhematopoietic peptide engineered from EPO, ARA 290, interacts selectively with the innate repair receptor and has similar possessions. ARA290 mediates tissue protection without hematopoietic side-effects of EPO which limit its clinical application. Doxorubicin (DOX) is the broad-spectrum chemotherapeutic agent, but its use is limited by the development of nonspecific toxicity on noncancerous tissues especially in cardiac cells. Mechanisms behind the DOX-induced toxicities are enhanced level of oxidative damage, inflammation and apoptosis. In the present study, we have investigated whether ARA290 acts as a chemoprotective agent modulating the cytotoxicity, genotoxicity and oxidative stress induced in vitro by DOX. The genoprotective effect of ARA290 on DOX-induced toxicity in three cell line (HepG2, HGF & Stem cell) were assessed. Cells were treated with ARA290 (50-400 nM) and DOX (1 µM) in pretreatment condition. Cytotoxicity was evaluated using the MTT assay, genoprotective effect of ARA290 were evaluated using the micronucleus test and comet assay. AR290 significantly reduced the percentage of DNA in tail and the frequency of micronuclei induced by DOX. Besides, DOX impaired anti-oxidant defense enzyme activities and induced inflammation and apoptotic cell death. ARA290 markedly attenuated DOX induced oxidative stress and protected against DOX induced inflammation and apoptotic cell death. This result proposes that ARA290 can act as a protective agent, reducing DOX-induced DNA damage and oxidative stress, and it is possible that this protection could also extend to cardiac cells.

Genotoxicity and phytotoxicity comparison of cigarette butt with cigarette ash.

The damage potential of cigarette butt and cigarette ash was determined and compared using genotoxicity and phytotoxicity assessments. The concentrations of five heavy metals, As, Cr, Cd, Pb, and Ni, were determined in both cigarette butt and ash leachates to find out if the results of heavy metals are in parallel with toxicity findings. Cigarette ashes and cigarette butts were soaked in distilled water for 7 days. Six leachate butt concentrations, including 200, 100, 50, 25, 12.5, and 6.25 piece/L, were examined. HUVEC cells (human umbilical vein endothelial cells) were exposed to these dilution series for genotoxicity, and Vicia faba seeds were exposed to the same dilution series for phytotoxicity assessments. Three parameters of genotoxicity, including tail length, %DNA in tail, and tail moment, were obtained by the comet assay method, and three parameters of phytotoxicity, including germination rate, root length, and water content percentage, were employed. The results showed that cigarette ash at the concentrations of 50, 25, 12.5, and 6.25 pc/L brings about DNA damage. Meanwhile, cigarette butt causes DNA damage at the concentrations of 100, 50, 25, and 12.5 pc/L. The highest concentrations (200 pc/L for cigarette butt and 200 and 100 pc/L for cigarette ash) were considered lethal for HUVEC cells. Besides, the levels of genotoxicity in the cigarette ash were twice as high as those in the cigarette butt. The Vicia faba phytotoxicity test demonstrated a germination rate restriction from 100 to 52 and 100 to 0% for cigarette butt and cigarette ash, respectively. It also caused a reduction in the length of roots from 35 to 7.85 and 3 mm for cigarette butt and cigarette ash, respectively. The moisture amounts of cigarette remnants had a decline from 93.14 to 44.61 and 36.72% for cigarette butt and cigarette ash, respectively. Concentrations of As, Cr, Cd, Pb, and Ni were 17.45, 2.5, 0.15, 6, and 0.62 ppb in the butt leachate and 7.21, 2.64, 0.29, 13.61, and 1.24 ppb in the ash leachate, respectively, indicating that heavy metals could explain the higher toxicity of cigarette ash. Based on the present study, cigarette ash imposes not only higher levels of genotoxicity and phytotoxicity but also more values of toxic heavy metals on our planet. Thus, cigarette ash plays a major role in environmental pollution, and the importance of cigarette ashes should receive attention even more than cigarette butts. This paper casts new light on the toxic impacts of cigarette ash.

Lipocalin2 Protects Human Embryonic Kidney Cells against Cisplatin-Induced Genotoxicity.

Cisplatin is one of the most useful chemotherapeutics which performs its cytotoxic effect via accumulation of platinum resulting in oxidative stress, and destruction of cell DNA. This could probably cause secondary cancers in healthy tissues. Lipocalin2 (Lcn2) is a protein which its expression is increased in oxidative stresses. Therefore, the present study was performed to evaluate the protective effects of Lcn2 up-regulation on cisplatin genotoxicity. In order to up-regulate Lcn2 expression, HEK293 cells were transfected with pcDNA3.1-Lcn2 vector. Afterwards, stable cells consistently expressing Lcn2 were selected via screening with G418 antibiotic. Next, overexpression of Lcn2 was evaluated by RT-PCR and ELISA, comparing to the control non-transfected cells. Then, in order to evaluate the cytoprotective effects of Lcn2 overexpression, transfected and non-transfected cells were subjected to cisplatin treatment followed by MTT and alkaline Comet assays. RT-PCR and ELISA assays confirmed up-regulation of Lcn2 by the stable cells. MTT assay of the Lcn2 over-expressing cells showed higher IC50 values comparing to the non-transfected cells. Furthermore, the Comet assay confirmed Lcn2 protective effects on the cisplatin (1 µg/mL) induced genotoxicity. In the present study, for the first time, we showed the protective effect of Lcn2 on cisplatin induced genotoxicity. Therefore, one of the probable mechanisms of Lcn2 cytoprotctive effects under oxidative stress conditions could be due to the prevention of genotoxicity. However, further evaluations in this regard must be considered.

Lovastatin prevents bleomycin-induced DNA damage to HepG2 cells.

Lovastatin as a member of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors is used as a lipid-lowering agent. It can also inhibit the formation of hydrogen peroxide and superoxide anion and finally leads to decline in oxidative stress processes. Here, we evaluated whether lovastatin can increase DNA damage resistance of HepG2 cells against genotoxicity of the anticancer drug bleomycin (BLM). HepG2 cells were incubated with different concentrations of lovastatin (0.1, 0.5, 1, 5 µM) before exposure to BLM (0.5 µg/mL for one h). The genotoxic dose of BLM and lovastatin was separately determined and comet assay was used to evaluate the genotoxicity. After trapping cells in agarose coated lames, they were lysed and the electrophoresis was done in alkaline pH, then colored and monitored by florescent microscope. The results of this study indicated that lovastatin in doses lower than 5 µM has genoprotective effect and in doses higher than 50 µM is genotoxic. In conclusion, lovastatin is able to protect genotoxic effects of BLM in HepG2 cells. Further studies are needed to elucidate the mechanism(s) involved in this process.

Protective role of Lactobacillus plantarum A7 against irinotecan-induced genotoxicity.

OBJECTIVE: Irinotecan is a botanical derivative and an anti-cancer drug with cytotoxic and genotoxic effects. The present study evaluated the effect of Lactobacillus plantarum A7 on the genotoxic activity of irinotecan in a hepatocellular carcinoma cell line (HepG2) by comet assay. MATERIALS AND METHODS: HepG2 were incubated with irinotecan (100 µM), heat-killed cells (0.025 µg/ml) + irinotecan (100 µM), and cell-free supernatants (0.5 and 1 µg/ml) of L. plantarum A7 + irinotecan (100 µM). Phosphate buffered saline (PBS) was used as negative control. RESULTS: Irinotecan was shown to induce DNA damage in HepG2 cells. The results showed that heat-killed cells (0.025 µg/ml) and cell-free supernatants (0.5 and 1 µg/ml) of L. plantarum significantly reduce irinotecan- induced DNA damage. CONCLUSION: Our results indicate that L. plantarum A7 can decrease the genotoxic effects of irinotecan in HepG2 cells, in vitro. This finding may be supportive for the optimization of therapeutic efficacy in irinotecan treatment.

Role of recombinant human erythropoietin loading chitosan-tripolyphosphate nanoparticles in busulfan-induced genotoxicity: Analysis of DNA fragmentation via comet assay in cultured HepG2 cells.

Busulfan is one of the most effective chemotherapeutic agents used for the treatment of chronic myeloid leukemia. Busulfan is involved in secondary malignancy due to its genotoxic potential in normal tissues. As an alkylating agent busulfan can cause DNA damage by cross-linking DNAs and DNA and proteins, induces senescence in normal cells via transient depletion of intracellular glutathione (GSH) and subsequently by a continuous increase in reactive oxygen species (ROS) production. Erythropoietin, a glycoprotein widely used against drug induced anemia in cancerous patients and regulates hematopoiesis, has been shown to exert an important cyto-protective effect in many tissues. Recombinant human erythropoietin has been demonstrated to directly limit cell injury and ROS generation during oxidative stress. Furthermore, rhEPO decreased levels of pro-apoptotic factor (Bax) and also increased expression of the anti-apoptotic factor Bcl2. According to EPO's short half-life and requirements for the frequently administration, finding the new strategies to attenuate its side effects is important. The aim of this study was to explore whether rhEPO loading chitosan-tripolyphosphate nanoparticles protects against busulfan-induced genotoxicity in HepG2 cells. For this purpose cells were incubated with busulfan alone, regular rhEPO alone and regular rhEPO and CS-TPP-EPO nanoparticles along with busulfan in pre and co-treatment condition. Our results showed that busulfan induced a noticeable genotoxic effects in HepG2 cells (p<0.0001). Both regular rhEPO and CS-TPP-EPO nanoparticles reduced the effects of busulfan significantly (p<0.0001) by reduction of the level of DNA damage via blocking ROS generation, and enhancement intracellular glutathione levels. CS-TPP-EPO nanoparticles were more effective than regular rhEPO in both pre and co-treatment conditions. In conclusion, our results show that administration of rhEPO and CS-TPP-EPO nanoparticles especially in the pre-treatment conditions, significantly decreased the level of DNA damage induced by busulfan, measured with the comet assay, in HepG2 cells compared to the regular rhEPO group.

Genotoxicity evaluation of hydroalcoholic and aqueous extracts of Dorema aucheri by the comet assay.

BACKGROUND: Dorema aucheri is a plant of Apiaceae family which is used widely in some states of Iran. Different extracts and essential oil of Dorema species contain flavonoids and cumarin compounds which have anti-hypertensive, cholesterol- and triglycerides-lowering properties. This study was undertaken to evaluate the genotoxic properties of hydroalcoholic and aqueous extracts of D. aucheri on human hepatoma cells using the comet assay method for safety evaluation. MATERIALS AND METHODS: In this method, after incubation of cells with different concentrations of extracts, cell suspensions were added to pre-coated normal agarose slides. After lysis, electrophoresis and neutralization process, staining was done by ethidium bromide and comets were observed using a fluorescence microscope. Tail length, percentage of DNA in tail and tail moment parameters were measured. RESULTS: Statistical analysis of the results demonstrated that concentrations more than 500 µg/ml of hydroalcoholic and aqueous extract of D. aucheri were genotoxic. CONCLUSION: It can be concluded from the results that taking the concentrations less than these dosages of extracts are safe but more studies are required to determine genotoxic mechanisms of this plant.

Pharmacokinetics of calycopterin and xanthmicrol, two polymethoxylated hydroxyflavones with anti-angiogenic activities from Dracocephalum kotschyi Bioss.

BACKGROUND: Recently flavonoids have attracted the attention of researchers in the fight against cancer. Calycopterin and xanthomicrol, are two polymethoxylated flavonoids found in the aerial parts of Dracocephalum kotschyi Bioss.. We have recently shown that these compounds possess antiangiogenic activity and may be of value as potential anticancer agents. In order to demonstrate putative in vivo antitumor effect of these compounds we needed preliminary information on both pharmacokinetics and toxicological properties of these two agents. METHOD: A new online SPE HPLC method for measurement of calycopterin and xanthomicrol in rat plasma was developed. Pharmacokinetic parameters of calycopterin and xanthomicrol, after i.v. administration in rats, were determined. RESULTS: The plasma half-life for both agents was around 4 h, however, the volume of distribution of calycopterin appeared to be about 8 times greater than xanthomicrol. This was probably due the greater hydrophobicity of the former which had other consequences such as much smaller maximum plasma concentration of calycopterin compared to its less methoxylated congener. Preliminary toxicological study of xanthomicrol failed to show any behavioral, histological and biochemical adverse effects after repeated administrations of high doses. Pharmacokinetics of xanthomicrol in rats.

Embryonic stem cell-derived cardiomyocytes as a model system to study cardioprotective effects of dexamethasone in doxorubicin cardiotoxicity.

Embryonic stem cell (ESC)-derived beating cardiomyocytes may be considered as a suitable model for in vitro assessment of pharmacological and toxicological studies. In this model, laboratory animals are not required. In addition, physiological functions, such as heart beat, are assessed rather than single parameters such as cell viability. Here we report that doxorubicin (DOX) cardiotoxicity on mouse ESC-derived beating cardiomyocytes can be ameliorated by treatment with dexamethasone (DEX) when DEX is administrated only before DOX and not in combination with DOX. DEX effect appears to be mediated via glucocorticoid receptor and increases cardiomyocyte-specific gene expression. Cardiotoxicity of DOX can be augmented by calcium channel blocker, verapamil (VER) which also decreases the expression of cardiac gene markers. This model provides us with a clinical suggestion which proposes that the beneficial effect of DEX is obtained when DEX was added before DOX administration.