EFFICIENT EXTRACTION OF POLYPHENOLICS FROM THE BARK OF TROPICAL TREE SPECIES

Abstract

MAKINO R, OHARA S & HASHIDA K. 2009. Efficient extraction of polyphenolics from the bark of tropical tree species. The objective of this study was to discover a method for extracting polyphenolics containing as few sugar components as possible. In this work, water extraction was carried out for the bark of several tropical tree species under various temperature conditions to compare the extractability of polyphenolics and sugar components. The yield and total polyphenolics content of the extracts increased with increase in extraction temperature. Total polyphenolics at 100 ˚C from Acacia mangium, Acacia auriculiformis, Rhizophora apiculata and Larix leptolepis were 14.2, 12.9, 8.0 and 5.3% respectively. Total sugar contents from A. mangium and L. leptolepis, which were determined using a slightly modified phenol–sulphuric acid method, were almost constant at 20–80 ˚C, but increased substantially at 100 ˚C. The same trend was observed with total reducing sugar contents from these two species. Our results suggest that water extraction at 80 ˚C from the barks of A. mangium and L. leptolepis is a good method for the extraction of polyphenolics with very few sugar components.