박科植物 種子油의 脂肪酸 組成

Studies on the Fatty Acid Composition of Lipids from Some Seeds of the Cucurbitaceae Family

Levels of total, neutral and polar lipids from the seeds of eight species of the Cucurbitaceae family, Cucurbita moschata, Lufa cylindrica, Citrullus vulgari, Cucumis melo var. makuwa, Cucmis satvus, Lagenaria leucantha, Trichosanthes kirilowii and Momordica charatia, were determined, and their fatty acid compositions were also analyzed by gas-liquid chromatography. The results were summarized as follows : Lipid contents of the seeds range from 21.9 to 50.7%, which contained 98% up of neutral lipids. In the fatty acid composition of total lipids from the seeds of Cucurbita moschata, Lufa cylindrica, Citrullus vulgari, Cucumis melo var. makuwa, Cucumis sativus and Lagenaria leucantha, linoleic acid is the most predominant component(56.8~84.0%) followed by oleic acid(5.7~22.2%) and palmitic acid(6.1~14.0%) with a trace amount of α―linolenic acid(below 0.6%). On the contrary, the seed oils of Trichosanthes kirilowii and Momordica charantia are characterized by presence of considerable amounts of conjugate trienoic acid such as punicic acid (9c,11t,13c-C18:3) and α-eleostearic acid (9c,11t,13c-C18:3). For example, the total lipids of T. kirilowii seeds were mainly composed of linoleic acid(40.5%) and punicic acid(34.9%) in the fatty acid composition, while those of M. charantia seeds predominantly comprised α-eleostearic acid as a main component(66.9%), accompanied by oleic acid(11.7%) and linoleic acid(10.4%). In this oil β-eleostearic acid(9c,11t,13c-C18:3) was checked as a trace. Fatty acid profiles of neutral lipids bear a close resemblance to those of total lipids in all the seed oils, but are different from those of polar lipids. In particular, conjugate trienoic acids including punicic acid and α-eleostearic acid which are occupied as the most abundant component in both neutral lipids of T. kirilowii and M. charantia seed oils, are present in a extremely small amount in both polar lipids. The fatty acid distribution in the polar lipids of all the samples except for T. kirilowii and M. charantia seed oils, showed a tendency of considerably increased level of saturated fatty acids(25.0~29.4%) compared with that in the neutral lipids(9.9~20.6%). The results obtained in this experiment suggest us that the seed oils of the Cucurbitaceae family could be divided into high-linoleic acid class and high-conjugate trienoic acid class.