Molluscs have provided medicinally useful products for many cultures around the world and their utility has been known for centuries. There are even reports on mussels used for therapy in ancient Crete. The present work was intended to assess the antioxidant properties of Indian green mussel Perna viridis by employing various in vitro assays. Antioxidant activities of ethyl acetate, methanol and aqueous/ethanol extracts of the mussel was evaluated using different in vitro assays (DPPH, hydroxyl, superoxide radical scavenging assays, reducing power and beta carotene bleaching activity) and compared with the standard compound BHT (Butylated Hydroxy Toluene). In the range of concentrations tested (0.15–6 mg/ml), the three extracts showed a dose dependent pattern in scavenging the DPPH radical and higher activity was detected for ethyl acetate extract with an IC50 value of 0.616 mg/ml. The P. viridis extracts showed stronger scavenging activity for hydroxyl radicals compared to the other free radicals tested. For superoxide anion, methanol extract displayed better scavenging activity than aqueous/ ethanol extract (IC50 2.79 and 3.88 mg/ml respectively). β-carotene- linoleic acid assay was found to be dose dependent for all the three extracts and they inhibited β-carotene oxidation with significant difference in absorbance at 492 nm compared to control. The results of the reducing power and hydroxyl radical scavenging activities implies that these extracts can also act as electron-donors, and as such can terminate radical chain reactions. Although ethyl acetate extract showed an overall better activity, (IC50 for OH-–0.782; DPPH- 0.616) it proved to be  slightly pro-oxidant against superoxide and hydroxyl radicals towards higher concentrations. It may be concluded that the extracts from P. viridis possess nontoxic antioxidant components, which render them suitable as potential therapeutics and good candidates for more detailed investigation. Further study is necessary to isolate active principles and elucidate the molecular structure of these compounds.

Perna viridis , DPPH, hydroxyl radical, superoxide radical scavenging assay