Effect of Isothiocyanates on the Activity of Lactobacillus Plantarum Exposed to Irradiation

摘要

Two isothiocyanates, sulforaphane (SFA) and sulforaphene (SFE), are suggested to be used as an alternative chemopreventive diet. This study was focused on the effect of SFA and SFE on Lactobacillus plantarum, which has been subjected to the irradiation (2-50 Gy). Cultures were grown in de Man, Rogosa and Sharpe (MRS) broth or in tryptone soya broth (TSB); they were compared in terms of physiological activity of bacteria under tested conditions. Broth composition noticeably influenced parameters of bacteria growth kinetics as well as culture response to oxidative stress. Activity of L. plantarum cells after irradiation was evaluated by their dehydrogenase (DHA) and quinone-reductase (QR) activities. The enzyme activity was quantified in living cells. Bacterial cultures in MRS and TSB broth demonstrated contrasting characteristics in their enzyme activities. The MRS-grown cells did not show any QR activity, whereas the TSB-grown cells showed a nonlinear response towards gamma-irradiation with maximum inhibition at 10 Gy. Addition of SFA or SFE in concentration of 1 ?g/mL to cultures before irradiation exposure recovered the QR activity from 23 % in the non-amended variant up to 102 % (SFA) and 121 % (SFE). The non-irradiated non-amended variant is taken as 100 %.