Isolation of Eicosanol Ferulic Acid Ester from Linseed Oil and Rapeseed Oil

Abstract

Having previously found that the corn (maize) -germ oil contains an inhibitor in determining the tocopherol content by the method of Emmerie-Engel reaction, the authors isolated the dihydro-β-sitosterol ferulic acid ester, C39H60O4, mp 156157°C, [α] D+13.1°, ε231mμ max. 12270, ε290.5mμ max. 18380, ε314.5mμ max. 21460 from the oil. And also dihydro-γ-sitosterol ferulic acid ester, C39H60O4, mp 155156°C, [α] D+13.6°, ε231mμ max. 13040, ε290.5mμ max. 18440, ε314.5mμ max. 21460 has been isolated from the wheat-germ oil.It is interesting that such water insoluble lipid as sterol exists in the vegetable oil as a hydrophilic ferulic acid ester, and that the esters are a new state of sterols existing in nature. As to ferulic acid ester in vegetable oil, Kaneko and Tsuchiya had found it from rice-bran oil and named it “oryzanol”, reporting that it has such actions as furtherance of growth, recovery from fatigue and cure of aged disturbances. As the alcoholic components of oryzanol, cycloartenol and 24-methylene-cycloartanol were confirmed by Ota and Shimizu. Thus, it was found that ferulic acid esters are contained in few kinds of vegetable oil, and ferulic acid is similar to lignin etc. in its structure. Therefore its ester might be widely distributed in vegetable oils.In this work, the authors examined 5 kinds of vegetable oil : soy bean oil, linseed oil, sesame oil, rapeseed oil and safflower oil. Alkali carbonate and caustic alkali solutions have been adapted for separation and phenolic concentrate was obtained from those oils, and then refined repeatedly by chromatography and recrystallization (Fig. 1, curve AD). As a result, the authors could not confirm the presence of ferulic acid ester in soy-bean oil, sesame oil and safflower oil, but succeeded in isolating the eicosanol ferulic acid ester from linseed oil (content in the soap stock was 0.006%). The ester, C30H50O4 with mp 5354°C was positive in the Emmerie-Engel reaction and colored green with ferric chloride and yellow with potassium hydroxide, UV in heptaneε231mμ max. 14621, ε290.5mμ max. 17421, ε314.5mμ max. 20317 (Fig. 1, curve D), IR of the film showed phenolic OH (at 2.84μ), ester (at 5.73μ and 9.69μ), asymmetrical 3 substitute bond of benzene (at 11.80μ and 12.17μ) and methylenic chain (at 13.83μ) (Fig. 2). Eicosanol with mp 6566°C, IR : 9.44μ (OH), 13.84μ [- (CH2) n-] (the acetate : mp 3637°C) and ferulic acid with 167169°C (Emmerie-Engel reaction, UV, no depression with pure sample in mp) were obtained by hydrolysis of this substance. Then the authors separated a mixture of ferulic acid esters from rapeseed oil (Fig. 3) and further confirmed eicosanol as a conponent by examining the hydrolytic products of the mixture. Therefore the presence of eicosanol ferulic acid ester in rapeseed oil was found (content of the mixture in the soap stockwas 0.007%).