Further Insight into the Toxic Effects of Estragole, Methyleugenol, Myristicin, and Elemicin in V79 Cells

Alkenylbenzenes occur naturally in various herbs and spices, such as basil and nutmeg, and are therefore also found in various foods made from them, such as basil-containing pesto and plant food supplements. The alkenylbenzenes estragole and methyleugenol are well studied and known to induce severe toxic effects. In contrast, structurally closely related myristicin and elemicin are less well studied regarding their toxic potential. In order to address existing data gaps, we here studied the impact of estragole, methyleugenol, myristicin, and elemicin on cytotoxicity (determined via WST-1 assay) and on deoxyribonucleic acid (DNA) integrity (assessed by measurement of histone H2AX phosphorylation) in V79 cells in a comparative manner. We found that estragole, methyleugenol, myristicin, and elemicin induced cytotoxicity and impaired DNA integrity in a concentration-dependent manner in the absence and in the presence of microsomal S9 rat liver cell extract. The intensity of these effects varied among the tested compounds. The most intense effects on cytotoxicity and H2AX phosphorylation were observed for estragole and myristicin at 500 µM. Elemicin also significantly increased H2AX phosphorylation, whereas its cytotoxic impact was rather mild. Finally, methyleugenol induced only moderate effects on cytotoxicity and H2AX phosphorylation in V79 cells. Based on our findings, we concluded that the alkenylbenzenes examined in this study differ in their cytotoxic potential, which may be due to their structural properties. Moreover, mechanistic analysis assessing H2AX phosphorylation showed the tested alkenylbenzenes to induce DNA-destabilizing processes in V79 cells, which are indicative for potential genotoxic or proapoptotic effects in this experimental setting.