The mutagenicity and anti-mutagenicity effect of aqueous leaves extract of Vinca rosea by bacterial system (Part one)

Abstract

This study was carried out in order to determine the toxic, mutagenic and anti-mutagenic effects
for aqueous extract of Vinca rosea dried leaves against the mutagenic effect of Methotrexate
(MTX) as a chemical mutagen and Ultra Violet rays (UV) as a physical mutagen. The effect was
studied in a bacterial system (G-system). The used system consisted of three wild isolates
G3Bacillus spp., G12Arthrobacter spp. and G27Brevibacterium spp., The study depended on
recording survival fraction (Sx) as an indicator for the induction of Streptomycin and Rifampic in
resistance mutants as a genetic marker. Aqueous extract was prepared from dried leaves, gradual
concentrations of plant aqueous extract was used to choose the suitable concentration which is
remembered the negative control, the optimum concentration of aqueous extract was 200 µl/ml
comparing with the negative control. The interactions included three types of treatments (premutagen, with-mutagen and post-mutagen) in order to determine the mechanisms of this plant
extracts in preventing or reducing the genotoxic effect of mutagen (MTX and UV).The results
showed that the interaction effect between the optimum concentration of aqueous extract and the
mutagen on survival fraction (Sx) increase the survival fraction value of the of G-system isolates to
reach normal value compare with positive control (MTX), the results of the interaction between
optimum concentration for extracts and the treatment with mutagen to induce resistance mutant
for streptomycin and rifampicin found that the MTX had no effect to induce resistance mutant
for these two antibiotics, for all types of treatment (pre-MTX, with-MTX, and post-MTX), the
aqueous extract suppress or repair mutant and give 100% protection for bacterial cells, while the
UV had some effects to induce resistance mutant for these two antibiotics for pre-UV and withinUV treatments and the aqueous extract showed suppressing or repairing mutant partially with
post-UV treatment and gave 100% protection for bacterial cells.