*3.4. Hydrogen Peroxide (H2O2)*

Salt stress increased hydrogen peroxide content significantly in centella. The highest hydrogen peroxide was obtained at 100 mM NaCl (5.1 μmol g−<sup>1</sup> FW) followed by 75 mM NaCl. The lowest hydrogen peroxide content was found in the control and were comparable to 25 mM NaCl content. At 50 mM NaCl, the hydrogen peroxide in the centella leaf was 4.1 μmol g−<sup>1</sup> FW (Figure 3). There was also a significant relationship between H2O2 content and Na<sup>+</sup> content (Table 3).

**Figure 3.** Hydrogen peroxide of *Centella asiatica* L. as affected by different salinity levels. The experiment was carried out in triplicate. Different letters represent significant differences at the *p* < 0.05.
