Plasma triglyceride-decreasing components of pine needles

An ultrafiltrate (M.W. < 10000) of 0.1 M acetic acid extract from Japanese red pine needles was treated with Sep-Pak Vac C18, and an absorbable fraction (pine aqueous components fraction, PAC) was obtained. Since the intraperitoneal administration of PAC to rats decreased plasma triglyceride in a screening test for bioactivity, we tried to further isolate the active substances with respect to this triglyceride-decreasing action. Active substances were precipitated by acid, and we then divided them into fractions using reversed phase HPLC. The active fractions were hydrolyzed, then the hydrolysate was re-separated by the same HPLC system. Negative ion mode FAB-LC/MS of the bioactive fractions of this hydrolysate revealed an [M-H] molecular ion peak at m/z 169 and 321. The 13C-NMR spectra were consistent with those of authentic gallic acid and galloyl gallic acid, a dimer of gallic acid. Authentic gallic acid also showed a triglyceride-decreasing action, and galloyl gallic acid even more markedly decreased triglyceride. These findings suggest that the triglyceride-decreasing action of Japanese red pine needles is due to these polyphenol compounds. In addition, amino acids were also detected in the hydrolysate of PAC, indicating that the components in Japanese red pine needles that decrease triglycerides are complexes of a hydrolyzable tannin, which contains gallic acid and galloyl gallic acid as components and peptides.