[Show abstract][Hide abstract] ABSTRACT: Background:
Ganoderma lucidum (Ling Zhi), a basidiomycete white rot macrofungus has been used extensively for therapeutic use in China, Japan, Korea and other Asian countries for 2,000 years. The present study is an attempt to investigate its DNA protecting property in human lymphocytes.
Materials and methods:
Beta glucan (BG) was isolated by standard procedure and the structure and composition were studied by infrared radiation (IR) and nuclear magnetic resonance (NMR) spectroscopy, gel filtration chromatography and paper chromatography. The radioprotective properties of BG isolated from the macro fungi Ganoderma lucidum was assessed by single cell gel electrophoresis (comet assay). Human lymphocytes were exposed to 0, 1, 2 and 4 Gy gamma radiation in the presence and absence of BG.
The comet parameters were reduced by BG. The results indicate that the BG of G. lucidum possessed significant radioprotective activity with DNA repairing ability and antioxidant activity as the suggestive mechanism.
The findings suggest the potential use of this mushroom for the prevention of radiation induced cellular damages.
[Show abstract][Hide abstract] ABSTRACT: The radioprotective properties of polysaccharides isolated from the macro fungi Ganoderma lucidum was assessed by Single cell gel electrophoresis (Comet assay).Human lymphocytes were exposed to 0Gy, 2 Gy and 4 Gy gamma radiation in the presence and absence of polysaccharides. The comet parameters -% DNA, Tail length, Tail moment and olive tail moment were reduced by the presence of polysaccharides. The results indicate that the polysaccharides of G. lucidum possessed significant radioprotective activity. The findings suggest the potential use of this mushroom for the prevention of radiation induced cellular damages.
[Show abstract][Hide abstract] ABSTRACT: Epicatechin (EC), a polyphenolic antioxidant compound found in tea, apples and chocolate offered protection to DNA against ionizing radiation induced damages. Under in vitro conditions of radiation exposure, plasmid pBR322 DNA was protected by EC in a concentration dependent manner. The dose modifying factor for 0.2 mM EC for 50% protection of the plasmid DNA was found to be 6.0. EC when administered to mice 1 h prior to exposure to 4 Gy gamma-radiation protected cellular DNA against radiation-induced strand breaks in peripheral blood leukocytes, as revealed in alkaline comet assay studies. Thus, EC was found to protect DNA from gamma-radiation indiced strand breaks under in vitro as well as in vivo conditions of radiation exposure.
No preview · Article · Feb 2008 · Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
[Show abstract][Hide abstract] ABSTRACT: Damage to cellular DNA and its repair in the peripheral blood leucocytes of mice exposed to 4 Gy whole-body gamma-radiation was studied by alkaline single cell gel electrophoresis or comet assay. The comet parameters of DNA, such as comet tail length, % of DNA in tail, tail moment and olive tail moment, were found increased in the leucocytes from irradiated animals due to radiation-induced DNA strand breaks. The strand breaks in cellular DNA were repaired in a time dependent manner as evidenced from the decrease in the comet parameters. Thus, 15 minutes after irradiation exposure, 15% of DNA strand breaks were repaired and at 90 minutes post-irradiation, 43% were repaired. When tocopherol monoglucoside was administered to mice following radiation, it was found that at 15 and 90 minutes post-irradiation, 64% and 67% DNA, respectively, were repaired. This would suggest that administration of tocopherol monoglucoside enhanced the repair of cellular DNA damage in whole-body irradiated mice. However, in vitro studies, either with humans or mice, peripheral blood leucocytes showed that the presence of tocopherol monoglucoside (0.5 mM) in post-irradiation incubation medium did not enhance the repair of DNA strand breaks.
No preview · Article · Jan 2007 · International Journal of Low Radiation
[Show abstract][Hide abstract] ABSTRACT: Our previous studies have demonstrated that aqueous extract of Ganoderma lucidum occurring in South India possessed significant antioxidant activity. The pr esent study was aimed at evaluating the radioprotective properties of the aqueous extract of this mushroom. Single-cell gel electrophoresis (comet assay), prote ction of radiation-induced plasmid pBR322 DNA strand breaks and inhibitions of lipid peroxidation (TBARS assay) were employed to determine the level of protection of- fered by the extract. The results indicate that aqueous extract of G. lucidum possessed significant radiopro- tective activity. The findings suggest the potential use of this mushroom extract for the prevention of radi ation- induced cellular damages.
[Show abstract][Hide abstract] ABSTRACT: The effect of ferulic acid was studied on gamma-radiation-induced relaxation of plasmid pBR322 DNA and induction of DNA strand breaks in peripheral blood leukocytes and bone marrow cells of mice exposed to whole body gamma-radiation. Presence of 0.5 mM ferulic acid significantly inhibited the disappearance of supercoiled (ccc) plasmid pBR322 with a dose modifying factor (DMF) of 2.0. Intraperitoneal administration of different amounts (50, 75 and 100 mg/kg body weight) of ferulic acid 1 h prior to 4 Gy gamma-radiation exposure showed dose-dependent decrease in the yield of DNA strands breaks in murine peripheral blood leukocytes and bone marrow cells as evidenced from comet assay. The dose-dependent protection was more pronounced in bone marrow cells than in the blood leukocytes. It was observed that there was a time-dependent disappearance of radiation induced strand breaks in blood leukocytes (as evidenced from comet parameters) following whole body radiation exposure commensuration with DNA repair. Administration of 50 mg/kg body weight of ferulic acid after whole body irradiation of mice resulted disappearance of DNA strand breaks at a faster rate compared to irradiated controls, suggesting enhanced DNA repair in ferulic acid treated animals.
No preview · Article · Jan 2006 · Molecular and Cellular Biochemistry
[Show abstract][Hide abstract] ABSTRACT: The effect of troxerutin on gamma-radiation-induced DNA strand breaks in different tissues of mice in vivo and formations of the micronuclei were studied in human peripheral blood lymphocytes ex vivo and mice blood reticulocytes in vivo. Treatments with 1 mM troxerutin significantly inhibited the micronuclei induction in the human lymphocytes. Troxerutin protected the human peripheral blood leucocytes from radiation-induced DNA strand breaks in a concentration dependent manner under ex vivo condition of irradiation (2 Gy). Intraperitoneal administration of troxerutin (175 mg/kg body weight) to mice before and after whole body radiation exposure inhibited micronuclei formation in blood reticulocytes significantly. The administration of different doses (75, 125 and 175 mg/kg body weight) of troxerutin 1 h prior to 4 Gy gamma-radiation exposure showed dose-dependent decrease in the yield of DNA strand breaks in murine blood leucocytes and bone marrow cells. The dose-dependent protection was more pronounced in bone marrow cells than in blood leucocytes. Administration of 175 mg/kg body weight of the drug (i.p.) 1 h prior or immediately after whole body irradiation of mice showed that the decrease in strand breaks depended on the post-irradiation interval at which the analysis was done. The observed time-dependent decrease in the DNA strand breaks could be attributed to enhanced DNA repair in troxerutin administered animals. Thus in addition to anti-erythrocytic, anti-thrombic, fibrinolytic and oedema-protective rheological activity, troxerutin offers protection against gamma-radiation-induced micronuclei formation and DNA strand breaks and enhances repair of radiation-induced DNA strand breaks.
No preview · Article · Jan 2006 · Molecular and Cellular Biochemistry
[Show abstract][Hide abstract] ABSTRACT: Gamma-radiation induced strand breaks in plasmid pBR322 DNA. Glycyrrhizic acid (GZA) protected plasmid DNA from radiation-induced strand breaks, as the disappearance of super-coiled (ccc) form was prevented by the compound with a dose-reduction factor of 2.04 at 2.5 mM concentration. Studies of comet assay on human peripheral blood leukocytes exposed to gamma radiation in the presence and absence of glycyrrhizic acid ex vivo revealed that this compound protected the cellular DNA from radiation-induced strand breaks in a concentration-dependent manner. An intraperitoneal administration of the GZA to mice one hour before exposure to gamma radiation protected cellular DNA from radiation-induced strand breaks in peripheral blood leucocytes and bone marrow cells, as revealed by comet assay. Pulse radiolysis studies indicated that glycyrrhizic acid offered radioprotection by scavenging free radicals. The rate constants for the reaction of glycyrrhizic acid with OH* and e(aq)- are 1.2 x 10(10 ) M(-1) s(-1) and 3.9 x 10(9 ) M(-1) s(-1), respectively.
No preview · Article · Oct 2004 · Journal of Radiation Research
[Show abstract][Hide abstract] ABSTRACT: The flavanoid derivative troxerutin, used clinically for treating venous disorders, protected biomembranes and cellular DNA against the deleterious effects of gamma-radiation. The peroxidation of lipids (measured as thiobarbituric acid-reacting substances, or TBARS) in rat liver microsomal and mitochondrial membranes resulting from gamma-irradiation up to doses of 500 Gy in vitro was prevented by 0.2 mM troxerutin. The administration of troxerutin (175 mg/kg body weight) to tumor-bearing mice by ip one hour prior to 4 Gy whole-body gamma-irradiation significantly decreased the radiation-induced peroxidation of lipids in tissues such as liver and spleen, but there was no reduction of lipid peroxidation in tumor. The effect of troxerutin in gamma-radiation-induced DNA strand breaks in different tissues of tumor-bearing mice was studied by comet assay. The administration of troxerutin to tumor-bearing animals protected cellular DNA against radiation-induced strand breaks. This was evidenced from decreases in comet tail length, tail moment, and percent of DNA in the tails in cells of normal tissues such as blood leukocytes and bone marrow, and these parameters were not altered in cells of fibrosarcoma tumor. The results revealed that troxerutin could preferentially protect normal tissues against radiation-induced damages in tumor-bearing animals.
No preview · Article · Jul 2004 · Journal of Radiation Research
[Show abstract][Hide abstract] ABSTRACT: Fluorescence spectroscopic behaviour and redox reactions of trifluoperazine (TFP) were studied in aqueous solutions in the presence of silica (SiO2) particles. The effect of surface heterogeneity on the secondary reactions of the transients was determined using optical absorption and fluorescence techniques. It appears that electrostatic interaction is the driving force for adsorption of TFP over SiO2 particle. Contrary to the change in fluorescence intensity with time observed in an aqueous solution, fluorescence intensity of TFP did not change significantly with time over the surface of SiO2. Fluorescence microscopic observations of spleen cells treated with TFP over SiO2 showed that the drug got distributed in cells similar to that observed in homogeneous aqueous solution.
No preview · Article · May 2004 · Biophysical Chemistry
[Show abstract][Hide abstract] ABSTRACT: Radioprotective compounds are of importance in clinical radiation therapy, because normal tissues should be protected against radiation injury while using higher doses of radiation to obtain better cancer control. We investigated the radioprotection of cellular DNA in cancer and in various cells and tissues, in a murine system following exposure to gamma-radiation and tocopherol monoglucoside (TMG) administration. We used single-cell gel electrophoresis (comet assay) and studied the progression of murine fibrosarcoma following radiation exposure and administration of TMG. The administration of TMG to tumor-bearing mice protected the cellular DNA against radiation-induced strand breaks as shown by the decrease in comet tail length, tail moment, and percentage of DNA in the tails of the cells of normal tissues. The same parameters were not altered in the cells of fibrosarcoma. Our results showed that the administration of TMG immediately after exposure to gamma-radiation can protect normal tissues against radiation damages in tumor-bearing mice. Local gamma-radiation exposure (5 Gy) of the tumor retarded the tumor growth. Administration of TMG did not protect cancer cells from radiation damage because the growth curves of cancer cells treated with radiation alone and those treated with TMG after irradiation were not significantly different.
No preview · Article · Feb 2004 · Journal of Environmental Pathology Toxicology and Oncology