Antioxidant activity and free radical scavenging capacity of phenolic extracts from Helicteres isora L. and Ceiba pentandra L.

In the present study, antioxidant activities of the phenolic extracts from H. isora fruits and C. pentandra seeds were investigated by employing established in vitro systems, which included reducing power, OHau, DPPHau, ABTS(au+), linoleic acid emulsion, metal chelation and antihemolytic activity. The extracts of C. pentandra contained relatively higher levels of total phenolics and flavonoids than those of H. isora. All the extracts showed dose dependent reducing power activity and moreover, they were well correlated with the total phenolic substances. A similar dose dependant trend has also been observed for hydroxyl radical scavenging activity and DPPHau radical scavenging activity. Further, addition of 250 mu g of extracts to the reaction mixture produced 41.3-54.6% peroxidation inhibiting activity during 60 h of incubation. The potential of multiple antioxidant activity of samples can be further evidenced by inhibition of reactive oxygen mediated erythrocyte cell lysis and metal ion chelating activity.