Sciadonic acid derived from pine nuts as a food component to reduce plasma triglycerides by inhibiting the rat hepatic Δ9-desaturase

Abstract

Sciadonic acid (Scia) is a Δ5-olefinic fatty acid that is particularly abundant in edible pine seeds and that exhibits an unusual polymethylene-interrupted structure. Earlier studies suggested that Scia inhibited the in vitro expression and activity of the Stearoyl-CoA Desaturase 1 (SCD1), the hepatic Δ9-desaturase involved in the formation of mono-unsaturated fatty acids. To confirm this hypothesis, rats were given 10% Scia in diets balanced out with n-6 and n-3 fatty acids. In those animals receiving the Scia supplement, monoene synthesis in the liver was reduced, which was partly attributed to the inhibition of SCD1 expression. As a consequence, the presence of Scia induced a 50% decrease in triglycerides in blood plasma due to a reduced level of VLDL-secreted triglycerides from the liver. In non-fasting conditions, results showed that Scia-induced inhibition of SCD1 led to a decrease in the proportions of 16:1n-7 and 18:1n-7 in the liver without impacting on the level of 18:1n-9, suggesting that only triglycerides with neosynthesized monoenes are marked out for release. In conclusion, this in vivo study confirms that Scia highly inhibits SCD1 expression and activity. The work was performed on normotriglyceride rats over six weeks, suggesting promising effects on hyper-triglyceridemic models. Sciadonic acid (Scia) is composed of an aliphatic chain with 20 carbons and 3 unsaturations (20:3Δ5,11,14). It is a Δ5-olefinic acid, a fatty acid (FA) group characterized by the presence of a polymethylene-interrupted double bond at C5, as distinct from the more common malonic structure. In the natural environment, Scia is specifically abundant in conifers, although it is also present in trace amounts with different other olefinic structures in slime molds 1 and certain marine invertebrates 2. Seven Δ5-olefinic acids are commonly found in gymnosperms and their composition profile provides a good marker of the plant phylogeny 3,4. Scia is particularly associated with the suborder Taxares, representing up to 26% of the total FA content in Podocarpus nagi 5. It is ubiquitously found in pine nuts, constituting up to 7% of the total FA in Pinus pinaster 6. As it is present in edible seeds and consumed as a nutrient, studies performed on rodent models have been carried out to determine its functional effect. Scia is incorporated in membranes when supplied to the cells and substitutes for arachidonic acid (20:4n-6) in phospholipids such as phosphatidylinositol 7. Consequently, this unusual FA integrates lipid metabolism resulting in the modulation of physiological functions. Scia supplemented to mammal cells induces synthesis of the uncommon 16:2n-6 (Δ7,10), which is subsequently elongated into linoleic acid (18:2n-6 or Δ9,12) 8,9. Scia then reduces the production of modulators causing inflammation that are derived from arachidonic acid 10-13. In rats fed with a Scia-enriched diet, triglyceride levels are lowered in the blood plasma and the liver 14-16. Previous work performed in vitro on hepatocytes showed that Scia inhibited ...

Ozone-enabled fatty acid discovery reveals unexpected diversity in the human lipidome

“…Among the identified fatty acids, twelve are non-methylene-interrupted fatty acids including sciadonic acid (FA 20:3 n −6,9,15 at 47 ± 8 nmol mL −1 ) and keteleeronic acid (FA 20:2 n −9,15 at 2.4 ± 0.4 nmol mL −1 ). Polyunsaturated fatty acids that exhibit a pattern of unsaturation other than the canonical methylene-interrupted or conjugated sequences of double bonds have not previously been reported in human plasma but have been observed in other biological systems including pine nuts 56 , sea urchins 18 , mangos 57 , marine food webs 58 , dairy 59 , seed oils 22 as well as human breast milk 60 . Prior identification of non-methylene-interrupted fatty acids in foodstuffs may point to these being present in reference plasma as a result of dietary intake.…”

OzFAD: Ozone-enabled fatty acid discovery reveals unexpected diversity in the human lipidome

“…Among the identified fatty acids, twelve are non-methylene interrupted fatty acids including sciadonic acid (FA 20:3 n -6,9,15 at 47 ± 8 nmol mL -1 ) and keteleeronic acid (FA 20:2 n -9,15 at 2.4 ± 0.4 nmol mL -1 ). Polyunsaturated fatty acids that exhibit a pattern of unsaturation other than the canonical methylene-interrupted or conjugated sequences of double bonds have not previously been reported in human plasma but have been observed in other biological systems including pine nuts, 45 sea urchins, 14 mangos, 46 marine food webs, 47 dairy 48 as well as human breast milk. 49 Prior identification of non-methylene interrupted fatty acids in foodstuffs may point to these being present in reference plasma as a result of dietary intake.…”

Fatty Acids of Echinoderms: Diversity, Current Applications and Future Opportunities

“…The anti-inflammatory and antioxidant effects of sciadonic acid, inhibiting the activity of phosphodiesterase and lipoxygenase-5, have been clearly demonstrated [ 144 ]. An in vivo study confirms that sciadonic acid markedly inhibits expression and activity of stearoyl-CoA desaturase 1, the hepatic Δ9-desaturase involved in the formation of MUFAs, which demonstrate promising effects on hyper-triglyceridemic models [ 145 ]. It has been shown that sciadonic acid can modify lipid metabolism in rats: when rats were fed sciadonic acid, the serum and liver triacylglycerol levels decreased [ 146 ].…”