A Structured Pine Nut Oil Has Hypocholesterolemic Activity by Increasing LDLR Gene Expression in the Livers of Obese Mice

Abstract

A structured pine nut oil (SPNO) is previously developed with pinolenic acid (PLA) evenly distributed at all sn positions on the glycerol backbone, whereas natural pine nut oil (NPNO) has PLA positioned mostly at the sn-3 position. This SPNO exhibited greater lymphatic PLA absorption than NPNO, although SPNO and NPNO contained equal amounts (approximate to 13wt%) of PLA. In this study, SPNO containing approximate to 13wt% PLA (SPNO13) and approximate to 44wt% PLA (SPNO44) is produced via Novozym 435-catalyzed esterification of glycerol with the free fatty acids containing approximate to 13wt% and approximate to 44wt% PLA from NPNO (from Pinus koraiensis Siebold & Zucc.). Five-week-old C57/BL6J mice are fed either a low- or high-fat diet (HFD) containing NPNO, SPNO13, or SPNO44 for 15 weeks. Supplementation with SPNO44, but not NPNO or SPNO13, significantly attenuates HFD-induced increases in final body weight, weight gain, and retroperitoneal and liver masses in diet-induced obese mice, without affecting food intake. SPNO44 also significantly reduces serum total and LDL cholesterol levels, as well as serum triacylglycerol levels and hepatic lipid accumulation. The hypocholesterolemic activity of SPNO44 is attributed to the greater hepatic accumulation of PLA from it causing increased SREBP2 levels and upregulation of LDL receptor gene expression in the livers of obese mice.Practical Applications: PLA has received much attention due to its anti-obesity and anti-dyslipidemia effects. NPNO is the sole source of PLA, but it can be converted into SPNO. The authors hypothesized that SPNO should improve PLA's health benefits due to the enhanced lymphatic absorption of PLA from SPNO. When compared to NPNO, SPNO44 may provide several advantages, such as enhanced anti-obesity and anti-dyslipidemia effects for food and nutraceutical applications. In future studies, the lymphatic absorption of SPNO44 and NPNO or SPNO13 should be compared. SPNO44, a structured pine nut oil containing approximate to 44wt% pinolenic acid (PLA) and an even distribution of PLA on the glycerol backbone, has hypocholesterolemic activity by increasing sterol regulatory element-binding protein 2 (SREBP2) levels and upregulating LDLR gene expression in the livers of obese mice.