Results showed that P. radiata bark was richer in total phenols and also in procyanidins, catechin always being the main unit, so terminal as extensional. For P. pinaster, epicatechin was the predominant extension unit. The mean degree of polymerization (mDP) was higher for the latter. Interestingly, opposite results were encountered for the corresponding OW fractions, where P. radiata showed a mDP of 2.9 vs. 2.3 of P. pinaster. It was also found that the higher the mDP the higher was the specific antiradical activity. The different procyanidin composition and specific antiradical activity of the two kinds of barks, and particularly their OW fractions, may lead to the design of efficient natural antioxidants with application in the food industry.

The composition and antiradical activity of procyanidins from the bark of two kinds of pine, Pinus pinaster and Pinus radiata, were compared. Both the total bark extract and the fraction soluble in both water and ethyl acetate (OW) were evaluated, because of their promising results in previous experiments.

We thank the Spanish Ministry of Science and Technology for Project No. PPQ2003-06602-C04, Subprojects 1 and 2.

5 pages, 4 tables.-- Printed version published Feb 2007.

Peer reviewed