Selective increase in pinolenic acid (all-cis-5,9,12–18∶3) in Korean pine nut oil by crystallization and its effect on LDL-receptor activity
The aims of this study were to obtain concentrated pinolenic acid (5,9,12–18∶3) from dietary Korean pine (Pinus koraiensis) nut oil by urea complexation and to investigate its cholesteroi-lowering effect on the LDL-receptor activity of human hepatoma HepG2 cells. Pine nut oil was hydrolyzed to provide a low-pinolenic acid-containing FA extract (LPAFAE), followed by crystallization with different ratios of urea in ethanol (EtOH) or methanol (MeOH) as a solvent to produce a high-pinolenic acid-containing FA extract (HPAFAE). The profiles of HPAFAE obtained by urea complexation showed different FA compositions compared with LPAFAE. The long-chain saturated FA palmitic acid (16∶0) and stearic acid (18∶0) were decreased with urea/FA ratios (UFR) of 1∶1 (UFR1), 2∶1 (UFR2), and 3∶1 (UFR3). Linoleic acid (9,12–18∶2) was increased 1.3 times with UFR2 in EtOH, and linolenic acid (9,12,15–18∶3) was increased 1.5 times with UFR3 in MeOH after crystallization. The crystallization with UFR3 in EtOH provided the highest concentration of pinolenic acid, which was elevated by 3.2-fold from 14.1 to 45.1%, whereas that of linoleic acid (9,12–18∶2) was not changed, and that of oleic acid (9–18∶1) was decreased 7.2-fold. Treatment of HepG2 cells with HPAFE resulted in significantly higher internalization of 3,3′-dioctadecylindocarbocyanine-LDL (47.0±0.15) as compared with treatment with LPAFAE (25.6±0.36) (P<0.05). Thus, we demonstrate a method for the concentration of pinolenic acid and suggest that this concentrate may have LDL-lowering properties by enhancing hepatic LDL uptake.
high-pinolenic acid-containing FA extract
low-pinolenic acid-containing FA
minimum essential medium
unsaturated polymethylene-interrupted FA