Veena Salvi | University of Mumbai (original) (raw)

Papers by Veena Salvi

The FASEB Journal, 2008

We prove explicit and sharp eigenvalue estimates for Neumann p-Laplace eigenvalues in domains tha... more We prove explicit and sharp eigenvalue estimates for Neumann p-Laplace eigenvalues in domains that admit a representation in Fermi coordinates. More precisely, if γ denotes a non-closed curve in R 2 symmetric with respect to the y-axis, let D ⊂ R 2 denote the domain of points that lie on one side of γ and within a prescribed distance δ(s) from γ(s) (here s denotes the arc length parameter for γ). Write µ odd 1 (D) for the lowest nonzero eigenvalue of the Neumann p-Laplacian with an eigenfunction that is odd with respect to the y-axis. For all p > 1, we provide a lower bound on µ odd 1 (D) when the distance function δ and the signed curvature k of γ satisfy certain geometric constraints. In the linear case (p = 2), we establish sufficient conditions to guarantee µ odd 1 (D) = µ 1 (D). We finally study the asymptotics of µ 1 (D) as the distance function tends to zero. We show that in the limit, the eigenvalues converge to the lowest nonzero eigenvalue of a weighted one-dimensional Neumann p-Laplace problem.

Molecular and Cellular Biochemistry, 2005

The effect of troxerutin on gamma-radiation-induced DNA strand breaks in different tissues of mic... more 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.

Journal of Biological Chemistry, 2008

Current Science, 2006

Our previous studies have demonstrated that aqueous extract of Ganoderma lucidum occurring in Sou... more Our previous studies have demonstrated that aqueous extract of Ganoderma lucidum occurring in South India possessed significant antioxidant activity. The present study was aimed at evaluating the radioprotective properties of the aqueous extract of this mushroom. Single-cell gel ...

Journal of Radiation Research, 2004

The flavanoid derivative troxerutin, used clinically for treating venous disorders, protected bio... more The flavanoid derivative troxerutin, used clinically for treating venous disorders, protected biomembranes and cellular DNA against the deleterious effects of γ-radiation. The peroxidation of lipids (measured as thiobarbituric acid-reacting substances, or TBARS) in rat liver microsomal and mitochondrial membranes resulting from γ-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 wholebody γ-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 γ-radiationinduced 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.

Journal of Radiation Research, 2004

Glycyrrhizic acid/Pulse radiolysis/Radiation protection/Plasmid DNA/DNA strand breaks/Comet assay... more Glycyrrhizic acid/Pulse radiolysis/Radiation protection/Plasmid DNA/DNA strand breaks/Comet assay 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 radiationinduced 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 aqare 1.2 ¥ 10 10 M-1 s-1 and 3.9 ¥ 10 9 M-1 s-1 , respectively.

Damage to cellular DNA and its repair in the peripheral blood leucocytes of mice exposed to 4 Gy ... more 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 m...

The complement lectin pathway, an essential component of the innate immune system, is geared for ... more The complement lectin pathway, an essential component of the innate immune system, is geared for rapid recognition of infections as each C4b deposited via this pathway is capable of forming a C3/ C5 convertase. In the present study, role of C4b-binding protein (C4BP) in regulating the lectin pathway C3/C5 convertase assembled on zymosan and sheep erythrocytes coated with mannan (E Man) was examined. While the C4BP concentration for inhibiting 50% (IC 50) formation of surfacebound C3 convertase on the two surfaces was similar to that obtained for the soluble C3 convertase (1.05 nM), ∼3and 41-fold more was required to inhibit assembly of the C5 convertase on zymosan (2.81 nM) and E Man (42.66 nM). No difference in binding interactions between C4BP and surfacebound C4b alone or in complex with C3b was observed. Increasing the C4b density on zymosan (14,000-431,000 C4b/Zym) increased the number of C4b bound per C4BP from 2.87 to 8.23 indicating that at high C4b density all seven α-chains of C4BP are engaged in C4b-binding. In contrast, the number of C4b bound per C4BP remained constant (3.79 ± 0.60) when the C4b density on E Man was increased. The data also show that C4BP regulates assembly and decay of the lectin pathway C3/C5 convertase more stringently than the classical pathway C3/C5 convertase because of a ∼7 to 13-fold greater affinity for C4b deposited via the lectin pathway than the classical pathway. C4BP thus regulates efficiently the four times greater potential of the lectin pathway than the classical pathway in generating the C3/C5 convertase and hence production of pro-inflammatory products, which are required to fight infections but occasionally cause pathological inflammatory reactions.

Molecular Immunology, 2007

The Journal of Immunology, Apr 1, 2007

The Journal of Immunology, Apr 1, 2007

Molecular and Cellular Biochemistry, 2005

The effect of ferulic acid was studied on γ-radiation-induced relaxation of plasmid pBR322 DNA an... more The effect of ferulic acid was studied on γ-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 γ-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 γ-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.

Molecular Immunology, 2008

The radioprotective properties of polysaccharides isolated from the macro fungi Ganoderma lucidum... more 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.

Annals of translational medicine, 2014

Ganoderma lucidum (Ling Zhi), a basidiomycete white rot macrofungus has been used extensively for... more 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. 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 ...

Journal of Environmental Pathology, Toxicology and Oncology, 2004

Radioprotective compounds are of importance in clinical radiation therapy, because normal tissues... more 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.

Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 2008

Epicatechin (EC), a polyphenolic antioxidant compound found in tea, apples and chocolate offered ... more 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.

Molecular Immunology, 2010

Human astroviruses (HAstVs) constitute a family of non-enveloped, RNA viruses which cause infanti... more Human astroviruses (HAstVs) constitute a family of non-enveloped, RNA viruses which cause infantile gastroenteritis. We have previously demonstrated that purified HAstV coat protein (CP), multiple copies of which compose the viral capsid, bind C1q resulting in inhibition of classical complement pathway activity. The objective of this study was to further analyze the mechanism by which CP inhibits C1 activation. CP inhibited C1 activation, preventing cleavage of C1s to its active form in the presence of heat-aggregated IgG, a potent classical pathway activator. CP also inhibited generation of the potent anaphylatoxin C5a. CP dose-dependently bound to C1q, the isolated globular heads and the collagen-like regions of the C1q molecule. When CP was added to C1, C1s dissociated from C1q suggesting that CP functionally displaces the protease tetramer (C1s-C1r-C1r-C1s). Given the structural and functional relatedness of C1q and MBL, we subsequently investigated the interactions between CP and MBL. CP bound to purified MBL and was able to inhibit mannan-mediated activation of the lectin pathway. Interestingly, CP did not bind to a variant of MBL that replaces a lysine residue (Lys55) critical for binding to MASP-2, a functional homolog of C1s. Finally, CP was shown to cross the species barrier to inhibit C3 activation and MAC formation in rat serum. These findings suggest CP inhibits C1 and MBL activation via a novel mechanism of interference with the normal interaction of the recognition molecule with its cognate serine proteases.

Molecular Immunology, 2007

Molecular Immunology, 2007

The FASEB Journal, 2008

We prove explicit and sharp eigenvalue estimates for Neumann p-Laplace eigenvalues in domains tha... more We prove explicit and sharp eigenvalue estimates for Neumann p-Laplace eigenvalues in domains that admit a representation in Fermi coordinates. More precisely, if γ denotes a non-closed curve in R 2 symmetric with respect to the y-axis, let D ⊂ R 2 denote the domain of points that lie on one side of γ and within a prescribed distance δ(s) from γ(s) (here s denotes the arc length parameter for γ). Write µ odd 1 (D) for the lowest nonzero eigenvalue of the Neumann p-Laplacian with an eigenfunction that is odd with respect to the y-axis. For all p > 1, we provide a lower bound on µ odd 1 (D) when the distance function δ and the signed curvature k of γ satisfy certain geometric constraints. In the linear case (p = 2), we establish sufficient conditions to guarantee µ odd 1 (D) = µ 1 (D). We finally study the asymptotics of µ 1 (D) as the distance function tends to zero. We show that in the limit, the eigenvalues converge to the lowest nonzero eigenvalue of a weighted one-dimensional Neumann p-Laplace problem.

Molecular and Cellular Biochemistry, 2005

The effect of troxerutin on gamma-radiation-induced DNA strand breaks in different tissues of mic... more 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.

Journal of Biological Chemistry, 2008

Current Science, 2006

Our previous studies have demonstrated that aqueous extract of Ganoderma lucidum occurring in Sou... more Our previous studies have demonstrated that aqueous extract of Ganoderma lucidum occurring in South India possessed significant antioxidant activity. The present study was aimed at evaluating the radioprotective properties of the aqueous extract of this mushroom. Single-cell gel ...

Journal of Radiation Research, 2004

The flavanoid derivative troxerutin, used clinically for treating venous disorders, protected bio... more The flavanoid derivative troxerutin, used clinically for treating venous disorders, protected biomembranes and cellular DNA against the deleterious effects of γ-radiation. The peroxidation of lipids (measured as thiobarbituric acid-reacting substances, or TBARS) in rat liver microsomal and mitochondrial membranes resulting from γ-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 wholebody γ-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 γ-radiationinduced 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.

Journal of Radiation Research, 2004

Glycyrrhizic acid/Pulse radiolysis/Radiation protection/Plasmid DNA/DNA strand breaks/Comet assay... more Glycyrrhizic acid/Pulse radiolysis/Radiation protection/Plasmid DNA/DNA strand breaks/Comet assay 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 radiationinduced 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 aqare 1.2 ¥ 10 10 M-1 s-1 and 3.9 ¥ 10 9 M-1 s-1 , respectively.

Damage to cellular DNA and its repair in the peripheral blood leucocytes of mice exposed to 4 Gy ... more 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 m...

The complement lectin pathway, an essential component of the innate immune system, is geared for ... more The complement lectin pathway, an essential component of the innate immune system, is geared for rapid recognition of infections as each C4b deposited via this pathway is capable of forming a C3/ C5 convertase. In the present study, role of C4b-binding protein (C4BP) in regulating the lectin pathway C3/C5 convertase assembled on zymosan and sheep erythrocytes coated with mannan (E Man) was examined. While the C4BP concentration for inhibiting 50% (IC 50) formation of surfacebound C3 convertase on the two surfaces was similar to that obtained for the soluble C3 convertase (1.05 nM), ∼3and 41-fold more was required to inhibit assembly of the C5 convertase on zymosan (2.81 nM) and E Man (42.66 nM). No difference in binding interactions between C4BP and surfacebound C4b alone or in complex with C3b was observed. Increasing the C4b density on zymosan (14,000-431,000 C4b/Zym) increased the number of C4b bound per C4BP from 2.87 to 8.23 indicating that at high C4b density all seven α-chains of C4BP are engaged in C4b-binding. In contrast, the number of C4b bound per C4BP remained constant (3.79 ± 0.60) when the C4b density on E Man was increased. The data also show that C4BP regulates assembly and decay of the lectin pathway C3/C5 convertase more stringently than the classical pathway C3/C5 convertase because of a ∼7 to 13-fold greater affinity for C4b deposited via the lectin pathway than the classical pathway. C4BP thus regulates efficiently the four times greater potential of the lectin pathway than the classical pathway in generating the C3/C5 convertase and hence production of pro-inflammatory products, which are required to fight infections but occasionally cause pathological inflammatory reactions.

Molecular Immunology, 2007

The Journal of Immunology, Apr 1, 2007

The Journal of Immunology, Apr 1, 2007

Molecular and Cellular Biochemistry, 2005

The effect of ferulic acid was studied on γ-radiation-induced relaxation of plasmid pBR322 DNA an... more The effect of ferulic acid was studied on γ-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 γ-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 γ-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.

Molecular Immunology, 2008

The radioprotective properties of polysaccharides isolated from the macro fungi Ganoderma lucidum... more 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.

Annals of translational medicine, 2014

Ganoderma lucidum (Ling Zhi), a basidiomycete white rot macrofungus has been used extensively for... more 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. 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 ...

Journal of Environmental Pathology, Toxicology and Oncology, 2004

Radioprotective compounds are of importance in clinical radiation therapy, because normal tissues... more 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.

Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 2008

Epicatechin (EC), a polyphenolic antioxidant compound found in tea, apples and chocolate offered ... more 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.

Molecular Immunology, 2010

Human astroviruses (HAstVs) constitute a family of non-enveloped, RNA viruses which cause infanti... more Human astroviruses (HAstVs) constitute a family of non-enveloped, RNA viruses which cause infantile gastroenteritis. We have previously demonstrated that purified HAstV coat protein (CP), multiple copies of which compose the viral capsid, bind C1q resulting in inhibition of classical complement pathway activity. The objective of this study was to further analyze the mechanism by which CP inhibits C1 activation. CP inhibited C1 activation, preventing cleavage of C1s to its active form in the presence of heat-aggregated IgG, a potent classical pathway activator. CP also inhibited generation of the potent anaphylatoxin C5a. CP dose-dependently bound to C1q, the isolated globular heads and the collagen-like regions of the C1q molecule. When CP was added to C1, C1s dissociated from C1q suggesting that CP functionally displaces the protease tetramer (C1s-C1r-C1r-C1s). Given the structural and functional relatedness of C1q and MBL, we subsequently investigated the interactions between CP and MBL. CP bound to purified MBL and was able to inhibit mannan-mediated activation of the lectin pathway. Interestingly, CP did not bind to a variant of MBL that replaces a lysine residue (Lys55) critical for binding to MASP-2, a functional homolog of C1s. Finally, CP was shown to cross the species barrier to inhibit C3 activation and MAC formation in rat serum. These findings suggest CP inhibits C1 and MBL activation via a novel mechanism of interference with the normal interaction of the recognition molecule with its cognate serine proteases.

Molecular Immunology, 2007

Molecular Immunology, 2007