Figure 3

Quenching of CTZ chemiluminescence by superoxide scavengers from Lepidium. CTZ was mixed with hypoxanthine at t = 12 s. This gave a background luminescence due to the presence of ambient oxygen. The superoxide yielding reaction was started by injection of xanthine oxidase to the assay mix at t = 48 s. Light output was quenched by an extract from Lepidium containing superoxide scavengers at t = 72 s (green line). The red line represents non-enzymatic scavenging of a heat-inactivated (30 min at 95°C) sample. The grey line is the control experiment with buffer injected. The steady state luminescence after starting the reaction with XOD (62 s < t < 72 s) was used to normalise the data.