ANTIOXIDATIVE AND FREE RADICAL SCAVENGING POTENTIALS OF CYCLOSORUS INTERRUPTUS (WILLD.) H. ITÔ AND PRONEPHRIUM NUDATUM (ROXB. EX GRIFF.) HOLTTUM

Objectives: The work aims to screen the antioxidative potentials of different crude extracts of the fronds of two medicinally important pteridophytes of Southern Assam, India, namely, Cyclosorus interruptus (Willd.) H. Itô and Pronephrium nudatum (Roxb. ex Griff.) Holttum. Methods: Frond extracts of the pteridophytes were prepared by Soxhlet hot extraction method. Total phenolic content (TPC) and total flavonoid content (TFC) of the hexane, ethyl acetate, acetone, and methanol extracts of the fronds of the plants were done by following standard protocol. In vitro assessment of the antioxidative behavior of the extracts was performed using standard 2,2-diphenyl-1-picrylhydrazyl scavenging assay, reducing power assay, metal chelating assay, hydroxyl, superoxide, and 2,2’- azino-bis (3-ethylbenzothiazoline - 6 – sulfonic acid) radical scavenging methods in different in vitro systems. Results: Preliminary phytochemical analysis implicated the presence of phenolic and flavonoid compounds in all the frond extracts. The methanol extract of the fronds of both the plants showed maximum phenolic and flavonoid contents in comparison to the other extracts, however, that of C. interruptus was found to be higher than P. nudatum. Antioxidative potentials of the said extracts were also found to be impressive and noteworthy. The decreasing order of the antioxidative efficacies of the extracts was found to be same as that of TPC and TFC of the extracts. Conclusion: It is pertinent to comment that the methanol extract of the fronds of both the plants may be treated as a potential source of natural antioxidants.