Antimutagenic Activity of Ethanolic Extract of Roccella montagnei against Sodium Azide – An In Vitro Study

Abstract

Lichens are considered to be a potential source of active molecules as they produce a
variety of secondary metabolites in response to environmental stress conditions. The present
work was aimed at evaluating the possible mutagenic and antimutagenic activities of the
ethanolic extract of Roccella montagnei (EERM) against a potent mutagen, sodium azide
(NaN3). Ames test was performed using Salmonella typhimurium TA100 (MTCC Acc. No.
1252), a special strain designed to detect base-pair substitution. The extract was screened
for its antimutagenic activity at three concentrations (5.0, 10.0 and 20.0 μg/plate dissolved
in 10% DMSO) against NaN3 (1.0 μg/plate) in the absence and presence of mouse S9
fraction. The numbers of histidine revertant colonies (CFU/ plate) were counted. Each
experiment was conducted in triplicates and statistical analysis was done. The rate of
antimutagenicity was determined using the formula [(M-S1)/(M-S0)]×100. The observed
data confirmed the mutagenic potency of NaN3 both in the absence (412.7±35.6) and
presence of S9 fraction (569.5±41.3), which were found to be statistically significant
compared to the solvent control (p less than 0.001). There was no significant increase in the
number of revertants indicating that EERM did not induce base pair substation in the test
organism. EERM imparted the antimutagenic effect at the moderate level against NaN3
after its metabolic activation as indicated by decrease in the number of revertants (38.7%;
p less than 0.01). However, the antimutagenic potency of EERM was found to be weak against NaN3
without S9 fraction (22.0%). Thus, the ethanolic extract of R. montagnei, to some extent,
protects against NaN3-induced mutation after its metabolic activation.