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الكشف عن السمية الوراثية لمستخلص نبات الصبار Aloe vera باستعمال المؤشرات الجزيئية والخلوية == Genotoxic Effect of Aloe Vera Extract Using Molecular And Cytogenetic Markers
Author name:
غيث منذر فاضل
Supervisor name:
نضال نعمة حسين
General topic:
Biology
Specific topic:
Plant - Genetics
Degree:
Master
University:
University of Baghdad - Ibn Al-Haytham College Of Education For Pure Sciences - Department Of Biology
Language:
Arabic
University location:
Baghdad
First pages:
24T2700 - p.pdf
Abstract:
نبات الصبار Aloe vera L. من النباتات المهمة والتي تستعمل حاليا بشكل واسع في مجال صناعة الادوية ويضاف هلام الصبار الى اغلب مستحضرات التجميل مع بعض المواد الغذائية في جميع انحاء العالم, لذا تم دراسة التاثيرات السمية الخلوية والوراثية لتراكيز مختلفة من المس | Aloe vera L. is one of the important plants in the world.It is currently and widely used in pharmaceutical industry, and its gel in some time added to some foods all over the world. Therefore, the present study was conducted to evaluate the cytotoxic and genetic effects of crude, alcohol and aqueous extracts of Aloe vera gel toward the onion(Allium cepa L.) roots (as a biological system) exposure at different periods. Onions roots were treated with different concentrations of the extracts : 2% , 5%, 10%, 20% and 40% (v/v)of the crud extract , 5%, 10%, 20% 30% and 50% (v/w) of alcohol extract and the concentration 25%, 50%, 100%, 150% and 200%(v/w) of aqueous extract of Aloe vera gel exposed for different period (24, 48 and 72) hour. The investigation were focused on the effect of these extracts on onions roots length rate and some cellular properties (mitotic index, phase index, the percentage and type of chromosome aberrations, as well as a genetic study using Random Amplified Polymorphic DNA (RAPD) of onions roots treated with different concentration of this extracts. Results showed that all Aloe vera gel extracts had inhibit activity toward onion roots length rate. The inhibition associated positively with the increasing concentration. The effective concentration (EC50%) were 10% of the crude extract, 20% of the alcoholic extract and 100% of aqueous extract, indicating the effectiveness of the crude extract followed by alcoholic extract and then the aqueous extract. Cytological study showed that all Aloe vera gel extract revealed a significant decrease in mitotic index (MI%) of the onion roots cells compared with the control group, and the effect was positively associated with the increasing concentrations of the extract. However, the effect was independent on the exposure period. The concentrations 10%, 20% and 150% of the crude, alcohol and aqueous extract respectively indicated a reduction of the mitotic index to almost 50% of the control treatment. Therefore, this concentrations considered as sub - lethal concentrations for this extracts respectively while the higher concentrations than 30%, 50% and 200% of the crude, alcohol and aqueous extract which reduced the mitotic index to almost 22% of the control treatment were considered as lethal concentrations. The results also showed a significant decreases in prophase and an increase in metaphase in onion roots cells treated with extracts comparison with control treatment. Many of chromosomal abnormalities were appeared due to the treatments of the onion roots with different concentration of the extracts, the percent abnormalities was increased with the increasing concentration of the extract and exposure period. The most frequent of chromosome abnormalities were chromosomal stickiness, disturbed chromosome, chromosomal bridges, C - mitosis, vagrant chromosomes in addition to the other chromosomal abnormalities star telophase. The toxicity effect of Aloe vera gel were studded on molecular level by using random amplification polymorphism of DNA(RAPD). Ten random primers were used, seven of them gave polymorphic bands in all the studied samples and their molecular weights were ranging from 100 to 1600 base pair. The results of Random Amplified Polymorphic DNA (RAPD) showed significant difference in the number of DNA band and their molecular weight of the onion roots treated with Aloe vera extracts compare to control treatment. The high concentrations(higher than EC50%) of extracts were showed to be more effective on the DNA through the appearance or disappearance of larger number of DNA band in comparison with control. The genetic template stability (% GTS) was significantly decreased in DNA of onions root treated with high concentrations (higher than EC50%) of Aloe vera extracts, therefore the high concentrations of Aloe Vera extracts were considered to be genetically toxic. The genetic dendrogram was obtained using Jaccard factor of genetic divergence and the result showed segregation of the samples treated with heights concentrations (%40 200% and 50%) of crude, alcohol and aqueous extract from other samples and control treatment. Therefore, the RAPD method can be considered as an efficient method in detecting for assessment of genotoxicity of crude, alcohol and aqueous extract of Aloe vera gel.
