(a) With H2O2
(b) With Al-maltol
(c) With Zn
(d) Dose response
Figure 3: The effect of essential oils on GT1–7 cells exposed with various cytotoxins. GT1–7 cells were treated with 20 μM H2O2 (a), 100 μM Al (b), or 25 μM Zn (c) without (aroma (—) in graph) or with 25 ppm of various essential oils. After 24 h, the viability was analyzed using the WST-1 method. The white bar shows the viability of GT1–7 cells treated with essential oil alone. Data are presented as the mean ± SEM (). (d) The dose dependency of the effects of essential oils on GT1–7 cell cytotoxicity. 10–25 ppm of essential oils was treated with 20 μM H2O2. After 24 h, the viability was analyzed using the WST-1 method. Data are presented as the mean ± SEM (). , versus the aroma (—) group. The abbreviated names of the essential oils used in the figure are shown in Table 1.