The influence of acid and alkaline hydrolysis on the phenolic content and antioxidant activity of Terminalia catappa L. leaves were evaluated in this study. Polyphenolic content was determined using total phenolic, total flavonoid and total tannin assays. Four in vitro antioxidant assays such as DPPH, ABTS, Ferric Reducing Antioxidant Potency (FRAP) and total antioxidant capacity assays were followed to determine the antioxidant potency of the extracts and the values were expressed as mg vitamin C equivalent antioxidant capacity (VCEAC)/g extract. The results of this study indicated that acid hydrolysed and alkaline hydrolysed extracts possess fewer amounts of polyphenolic constituents in comparison with non hydrolysed extract. Even the VCEAC values of non hydrolysed extract in antioxidant assays were significantly higher (p<0.05) than acid and alkaline hydrolysed extracts. Moreover, the UV-visible spectral study also showed the absence of some of the absorption peaks of polyphenolic constituents in acid and alkaline hydrolysed extracts and hence, it supported our in vitro results. A strong correlation was observed for polyphenolic content and antioxidant activities of these extracts ensuring the involvement of polyphenolic content for the antioxidant activity. However, the results of this study may not be generalised for all plants as different plants possess different phytoconstituents in varying quantities.
H.V. Annegowda, C. Ween Nee, M.N. Mordi, S. Ramanathan and S.M. Mansor, 2010. Evaluation of Phenolic Content and Antioxidant Property of Hydrolysed Extracts of Terminalia catappa L. Leaf. Asian Journal of Plant Sciences, 9: 479-485.