The results (Fig. 2) indicate that the scavenging activity
of seaweed extracts were concentration dependent. However,
the positive control (a-tocopherol) did not show dose
dependency and had a DPPH and hydroxyl radical scavenging
activities about 95% and 78%, respectively. The
scavenging activity was found to increase with increasing
concentration of extract in both the DPPH and deoxyribose
assay and corroborated well with earlier reports
(Ismail and Hong, 2002; Kuda et al., 2005). However, themethanol extracts showed a relatively low DPPH scavenging
activity (Fig. 2) as compared to standard antioxidant
(a-tocopherol). This present finding corroborates well with
earlier reports in other higher plants including brown/red
seaweeds (Kuda et al., 2005; Kumaran and Karunakaran,
2007). Further, methanol extracts of all the three brown
seaweeds showed higher hydroxyl radical scavenging activity
compared to standard antioxidant (Fig. 2).Director, CMFRI, Kochi (India), for support in collection
of seaweeds. Thanks to Director, CFTRI, for the encouragement
and permission to publish this work.