*3.6. Antimutagenity Activity*

The aim was to investigate the mutagen and antimutagen activities of BBE by the bacterial reverse mutation assay in *Salmonella typhimurium* (*S. typhimurium*) strains. The antimutagenity of BBE against *S. typhimurium* TA 98 and TA 100, was tested by comparing the numbers of induced revertants and spontaneous revertants. According with Table 8, TA98 and TA100 strains increase in the number of revertant colonies compared with the negative control when the bacteria was treated with BBE at 5 mg/plate concentration, thereby indicating an antimutagenic activity. Thus, all extracts were antimutagenic to the frameshift TA98 or TA100 *S. typhimurium* strains.

To determine the potential antimutagen activity of the BBE to prevent DNA damage by 4-NPD/NaN3 (positive mutagen/carcinogen), BBE were incubated together with 4-NPD/NaN3. The results are presented in Table 8. The percentage of inhibition of mutagen activity of 4-NPD/NaN3 (antimutagenity) of the beech bark extracts ranged from 3.6 to 17.01% in *S. typhimurium* TA98 and from 15.47 to 16.33% in *S. typhimurium* TA100. The BBE1 had the highest value for antimutagen activity (17% for *S. typhimurium* TA98 and 16.33% for *S. typhimurium* TA100). The antimutagen effect is considered low when the inhibitory effect is less than 25%, moderate when the inhibitory effect is between 25%–40% and strong when the effect is more than 45% [26,34]. Thus, based on the literature data, beech bark extracts assayed in this study may be considered to have low or no antimutagen effects.


**Table 8.** Antimutagen properties of beech bark extracts (5 mg/plate) on *S. typhimurium* TA98 and TA100 bacterial strains.

Notes: <sup>a</sup> BBE1—extracts obtained with water 100%, BBE2—extracts obtained with ethanol–water 50:50, BBE3—extracts obtained with ethanol–water 80:20; <sup>b</sup> Values expressed are means <sup>±</sup> SD of three replications; <sup>c</sup> 4-NPD and NaN3 were used as positive controls for *S. thyphimurium* TA98 and TA100 strains, respectively.
