Tricin lacked genotoxic properties in the systems studied here. Tricin (50 μM) failed to cause MLL gene breakage, and it inhibited topoisomerase II only at 500 μM, but not at 10, 50 or 100 μM. Results: Neither tricin, quercetin, or genistein caused pathological or morphological changes in any of the murine tissues studied. The mutagenicity of tricin was assessed in the Salmonella/Escherichia coli assay, and its clastogenicity was adjudged by chromosomal aberrations in Chinese hamster ovary cells and occurrence of micronuclei in bone marrow erythrocytes in Swiss-Webster mice. The ability of tricin (50 μM) to cleave the MLL gene was studied in human leukaemia cells by Southern blotting, and its effect on human topoisomerase II activity was investigated in incubations with supercoiled DNA. Methods: Evidence of pathological or morphological changes in liver, lung, heart, spleen, kidney, adrenal gland, pancreas or thymus tissues was studied in mice which received tricin, genistein or quercetin 1,000 mg/kg daily by the oral route on five consecutive days. Here, we explored safety aspects of the novel flavone tricin, a constituent of rice bran and other grass species, which has recently been found to interfere with murine gastrointestinal carcinogenesis. The choice of flavonoids to be developed as cancer chemopreventive agents depends crucially on their safety. Furthermore in leukaemia cells some flavonoids cleave the breakpoint cluster region of the mixed lineage leukaemia (MLL) gene as a consequence of inhibition of topoisomerase II. However, adverse effects such as their mutagenicity confound their potential clinical usefulness. Purpose: Naturally occurring flavonoids such as quercetin and genistein possess cancer chemopreventive properties in experimental models. Despite substantial contamination and mutagenic hazards, the risk of adverse effect (e.g., mutation, cancer) in humans or terrestrial biota is difficult to quantify. Remediation of more refractory genotoxic material (e.g., explosives, creosote) frequently showed increases in mutagenic hazard that remained for extended periods. Review of published remediation exercises showed effective removal of genotoxic petrochemical wastes within one year. Induction of micronuclei in Tradescantia is significantly related to the soil concentration of several metals (e.g., Sb, Cu, Cr, As, Pb, Cd, Ni, Zn). Additional data analyses showed empirical relationships between anaphase aberrations in Allium, or mutations in Arabidopsis, and the 137Cs contamination of soils. The Tradescantia assays appeared to be less responsive, particularly for exposures to aqueous soil leachates. The plant assay data revealed excellent response ranges and significant differences between heavily contaminated, industrial, rural/agricultural, and reference sites, for the anaphase aberration in Allium cepa (direct soil contact) and the waxy locus mutation assay in Zea mays (direct soil contact). Additional analyses showed significant empirical relationships between S9-activated TA98 mutagenicity and soil polycyclic aromatic hydrocarbon (PAH) concentration (r2 = 0.19 to 0.25, p < 0.0001), and between direct-acting TA98 mutagenicity and soil dinitropyrene (DNP) concentration (r2 = 0.87, p < 0.0001). The compiled data on Salmonella mutagenicity indicates significant differences (p < 0.0001) in mean potency (revertents per gram dry weight) between industrial, urban, and rural/agricultural sites. An additional 37.6% of the assessments employed a variety of plant species (e.g., Tradescantia clone 4430, Vicia faba, Zea mays, Allium cepa) to assess mutagenic activity. The majority of the assessments (37.6%) employed the Salmonella mutagenicity test with strains TA98 and/or TA100. In total, 1312 assessments of genotoxic activity from 118 works were examined. This work is a comprehensive review of published information on soil mutagenicity. In some cases (e.g., wood preserving wastes, coal-tar, airborne combustion by-products), the contaminated soil constitutes a genotoxic hazard. The intentional and accidental discharges of toxic pollutants into the lithosphere results in soil contamination.
0 Comments
Leave a Reply. |