title: Evaluation of the radioprotective effect of Aegle marmelos (L.) Correa in cultured human peripheral blood lymphocytes exposed to different doses of gamma-radiation: a micronucleus study.
abstract: The radioprotective effect of a hydroalcoholic extract of Aegle marmelos (AME) was evaluated in cultured human peripheral blood lymphocytes (HPBLs) by the micronucleus assay. The optimum protective dose of the extract was selected by treating HPBLs with 1.25, 2.5, 5, 6.25, 10, 20, 40, 60, 80 and 100 microg/ml AME before exposure to 3 Gy gamma-radiation and then evaluating the micronucleus frequency in cytokinesis blocked HPBLs. Treatment of HPBLs with different doses of AME reduced the frequency of radiation-induced micronuclei significantly, with the greatest reduction in micronucleus induction being observed for 5 microg/ml AME. Therefore, this dose of AME was considered as the optimum dose for radioprotection and further studies were carried out treating the HPBLs with 5 microg/ml AME before exposure to different doses (0, 0.5, 1, 2, 3 and 4 Gy) of gamma-radiation. The irradiation of HPBLs with different doses of gamma-radiation caused a dose-dependent increase in the frequency of lymphocytes bearing one, two and multiple micronuclei, while treatment of HPBLs with 5 microg/ml AME significantly reduced the frequency of lymphocytes bearing one, two and multiple micronuclei when compared with the irradiated control. The dose-response relationship for both groups was linear. To understand the mechanism of action of AME separate experiments were conducted to evaluate the free radical scavenging of OH, O2(-), DPPH, ABTS(+) and NO in vitro. AME was found to inhibit free radicals in a dose-dependent manner up to a dose of 200 microg/ml for the majority of radicals and plateaued thereafter. Our study demonstrates that AME at 5 microg/ml protected HPBLs against radiation-induced DNA damage and genomic instability and its radioprotective activity may be by scavenging of radiation-induced free radicals and increased oxidant status.
authors.affiliation: Department of Radiobiology, Kasturba Medical College, Manipal 576119, India. gc.jagetia@kmc.manipal.edu
authors.forename: Ganesh Chandra
authors.initials: GC
authors.lastname: Jagetia
authors.forename: Ponemone
authors.initials: P
authors.lastname: Venkatesh
authors.forename: Manjeshwar Shrinath
authors.initials: MS
authors.lastname: Baliga
mesh_terms: D045471:Aegle / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers / Q000494:pharmacology; D005609:Free Radicals / Q000378:metabolism; D005720:Gamma Rays; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects* / Q000528:radiation effects; D048629:Micronuclei, Chromosome-Defective / Q000187:drug effects* / Q000528:radiation effects; D018515:Plant Leaves / Q000378:metabolism; D011836:Radiation Tolerance / Q000187:drug effects*; D011837:Radiation-Protective Agents / Q000494:pharmacology*
chemical_list: D016166:Free Radical Scavengers; D005609:Free Radicals; D011837:Radiation-Protective Agents