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5. SUMMARY AND CONCLUSIONMedicinal plants are widely used to treat various diseases and most of them are commonly used in popular medicine in many countries allover the world.The use of these plants by the general population is an old and still widespread practice, which makes studies of their mutagenicity are essential. Although, most of the synthetic drugs in use are in their pure and active form, many of these compounds are known to have some adverse effects on heart and many other organs of the body. Looking for an alternative therapy, natural medicinal plants have been tried. Certain indigenous drug preparations with neutrally occurring plants have been in use for many decades for the treatment of certain diseases. So, the use of medicinal plant extracts instead of synthetic drugs in the treatment of some diseases is in progressive increase.Many investigators made trials to test the mode of action, toxicity, physiology and cytology of some plants extract effects.Therefore, the present study was planned to investigate the mutagenic action of Damsissa plant (Ambrosia maritima L.) through three model of assays, each has a different end point.The following results could be drawn:A .Model of bacterial assay:1. A.maritima L.extract has a slight toxicity to P.aeruginosa bacterial cells strain Pu 17 at concentration 15%. By adding 15% of the plant to each concentration of the ethylene imine as a mutagen agent, the survival percent has been enhanced up to 47.4%. Damsissa plant appears to have an effect against the toxic activity of ethylene imine.2. The results of the prophage induction assays clearly showed that A.maritima L.has no mutagenic activity. The same conclusion has been obtained upon using ascorbic acid as anti-oxidant agent in a negative control in this investigation.3. Low yield of transductants was observed using different concentrations of Damsissa indicating that this plant extract has no mutagenic activity specially when comparing these results with the results of the negative and positive control.4. Damsissa extract did not increase the rate of host DNA fragmentation hence number of transducing particles did not increase and this resulting in slight increase in transduction frequency of streptomycin resistance gene to the anti-oxidant agent, ascorbic acid did not significantly increase the transduction frequency.5. The mutagenic agent, ethylene imine, as a positive control has the ability to induce a serious damage to host DNA. This resulting in increasing the rate of DNA fragmentation allowing increasing the number of transducing particles which result in a great increase in transduction frequency. These results showed that transduction analysis could be used as a bacterial tool in detecting the mutagenicity of compounds beside the known bacterial tools. Since a correlation in the results of the two assays was observed.6. A remarkable decrease in phage induced and number of transductants has been observed by adding 15% of A.maritima L.to the different concentrations of ethylene imine. It seems that this plant may have an antimutagenic activity .So, Damsissa extract can be used as a natural source for the anti-oxidant compounds.7. The assessment of Damsissa against ethylene imine has been carried in prophage induction and transduction processes. The active ingredients of Damsissa may affect the process of prophage F116 induction by altering one or more of the enzymatic steps in the complex of reactions referred to SOS repair.B. Model of A.cepa L.plant assay:1. The mitotic index of A.cepa L.root tip cells has been decreased in each exposure period to A.maritima L.extract and it seems that mitotic index is not dose-dependence.2. The results indicated that Damsissa extract had affected the relative frequency of mitotic phases as compared to the control.3. The total number of cells with chromosomal aberrations did not increased during 6 and 12 hr., only after 24 hr. at high concentration an increased in the number of chromosomal aberrations has been detected. The types of aberrations were fragment, laggard, and bridge.4. The number of cells containing binucleate cells has increased in each soaking period. The binucleate cells were possibly originated as a consequence of inhibition of cytokinesis.5. The number of cells containing micronuclei has also been increased with maximum number up to 73 after also 24 hr. at 15%. Two types of micronuclei has been detected, compact and non-compact ones .The compact was dose dependent in each exposure time. The high frequency of compact micronuclei indicated that Damsissa extract is capable of inducing clastogenic effects. The induction of micronuclei indicates that Damsissa extract has a mutagenic effect, which may lead to loss of genetic material.C. Model of bone marrow assay:1. Damsissa extract has no significant effect at the mitotic index of rat bone marrow cells.2. Damsissa extract has a remarkable increase but not significant in percent of abnormal cells especially after 24 hr .3. The percent of chromatide type aberrations has also been increased for all treatments, but was not significant .4. However, no chromosome type aberrations have been detected after 24 hr. they only observed after 72 hr.and 7 days especially at high concentrations .As a general conclusion for this investigation as follow :1. The first model, the bacterial assay included the prophage induction and transduction assays and both of them proved that, A. maritima has no mutagenic activity. However, the statistical analysis using X2 -test showed a positive effect in the other two models, Allium cepa L. root tips and rat bone marrow.2. This may be due to the differences in exposure time that has been used in the three models, or to the sensitivity of the type of assay that has been used. Whether the assay based on bacterial, plant, or mammalian cells, this could affects the induction of the mutagenicity (El-Gorashi et al., 2002 and Kirkland and Marzin, 2003).3. Moreover, the detection of mutagens would depend mainly up on the sensitivity of the indicator organism (s) (Sayed Ahmed and Hegab, 2000).4. So, the results of this study may reflect a clastogenic mechanism.5. Moreover, the mutagenic response may depend on the strain that has been used in the bacterial assay.6. The plant showed an anti-mutagenic activity against ethylene imine in prophage induction of bacteriophage F116 and in transducing streptomycin, since the plant may have some anti-oxidant activity.7. The contradictory results between the three models that has been observed in the present investigation has been reported previously.So, it may be used as a natural source for these valuable substances, which protect DNA against the oxidative activity. But, results of the present investigation needs more and further studies to be able to detect the proper mutagenic activity of this plant.
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