Exploitation of polyphenol-rich pine barks for potent antioxidant activity

Abstract

The phenolic composition of pine bark from a variety of Pinus species was estimated by measuring Klason lignin, acid-soluble lignin, and a 1% NaOH extract. Polyphenol contents of hot water extracts from pine bark were determined by the Folin-Ciocalteu assay and the vanillin-H2SO 4 assay. Among the pine bark varieties investigated, Pinus radiata bark showed the highest polyphenol content and potent antioxidant activity. Pinus rigida bark was also a usable polyphenol-rich source, whereas Pinus densiflora bark had a low yield (5.1%) of hot water extract, although it showed potent antioxidant activity. Correlations between proanthocyanidin content in pine bark and antioxidant activity were observed. The results suggested that proanthocyanidin was the crucial contributor to potent antioxidant activity in pine bark. © 2007 The Japan Wood Research Society.