Figure 5. Partial biochemical characterization of the coral extracellular antioxidant activity, expressed as a pseudo first order-decay constant k_CSW.

(A). Filtration through 0.2 µm had no significant effect (p>0.05, student's t-test) on the coral antioxidant activity. (B). Storage of the CSW in the lab for 22 hrs resulted in a loss of the antioxidant activity to background levels (FSW). (C). Heating at 90°C for 20 min resulted in a loss of the antioxidant activity to background levels (FSW). For both B and C, the⁻ decay in CSW prior to storage or heating was significantly higher than the other treatments (p<0.001, one way ANOVA). (D). Steady-state O₂ ⁻ concentrations measured over time in FSW and CSW in which O₂ ⁻ was continuously produced by the Xanthine-Xanthine Oxidase system. Throughout the experiment the coral antioxidant activity maintained significantly lower O₂ ⁻ concentrations as compared with FSW (p<0.001 student's t-test), possibly showing that this activity is regenerated rather than saturated.