Detection of Cellular and Molecular Toxicity of Aloe vera Gel Crude Extract on the Roots of the Allium cepa


onion (Allium cepa) roots were studied . Different concentrations of this crude extract(%2 , %5 ,%10, %20and 40%) were used at different periods ; 24 ,48 and 72 hour . Numberof chromosomal aberrations and the mitotic index was calculated . In addition, the geneticeffects were observed by using randomly amplified polymorphic DNA ( RAPD ) technique .The results showed that the gel crud extract of Aloe vera had inhibition effects on the growthof the onion roots with 10% EC50 value. Significant effects of this gel crud extract were alsoobserved on the chromosomal aberration and mitotic index by decreasing of divided cell rates.The toxic effect of 20% concentration of gel crud extract was decreased the mitotic indexunder 50% , in the comparison with control sample . Chromosomal aberration were alsoobserved in divided cells of onion roots, which exposed to different concentrations at differentperiods . The higher frequent type of this chromosomal aberrations , which observed arestickiness , disturbed , bridge , c-mitosis , vagrant and star telophase . The result of RAPDtechnique reveled differences in number of DNA bands and their molecular weights of thetreated samples , which exposed to high concentration of crud extract in comparison with thecontrol sample . The result of the genetic stability ratio (% GTS), also showed that Aloe veracrud extract have genetic toxicity at 40% concentration