radical directly.
H2O2 radical scavenging activity
The methanolic leaf extract of A. malaccensis showed
moderate scavenging effects with IC50 values at 80 μg/ml.
As shown in Figure 4, the extract demonstrated hydrogen
peroxide decomposition activity in a concentration
dependent manner. Scavenging activity of H2O2 by the
extract may be attributed to their phenolics, which can
donate electrons to H2O2 thereby neutralizing it into water
(Mathew and Abraham, 2006). Hydrogen peroxide is a
weak oxidizing agent and can inactivate a few enzymes
directly, usually by oxidation of essential thiol (-SH)
groups. It rapidly transverses cell membrane and once
inside the cell interior, H2O2 can probably react with Fe2+
and possibly Cu2+ ions to form hydroxyl radical and this
may be the origin of many of its toxic effects (Contreras-
Guzman and Strong, 1982). Thus, the removal of H2O2 is
very important for antioxidant defence in cell or food
systems.
NO scavenging assay
Figure 5 illustrates a significant decrease in the NO