Isolation and Structural Elucidation of Functional Components in Coix larcryma-jobi var. ma-yuen

Coix lacryma-jobi var. ma-yuen (Rom. Caill.) Stapf. is a valuable food resource in Asian countries, and is exploited as a food-industry ingredient because of its high carbohydrates and protein content. Recent research has shown that coix contain a variety of ingredients, including starch, coix oils, vitamin derivatives, phytosterol, polyphenol, flavonoids, lignan, lactam ring, and spiroenone. However, the research on the alkaloid component of the coix is at an unprecedented level. In an effort to provide the contents of alkaloids in Korean food, we investigated the alkaloids from coix cultivated in Korea and in result, we isolated spermidine-type alkaloids; N¹-acetyl-N<SUP>6</SUP>,N<SUP>10</SUP>-(E)-di-p-coumaroyl-spermidine (1), N¹,N<SUP>5</SUP>-di-(E)-p-coumaroyl-spermidine (2), N<SUP>5</SUP>,N<SUP>10</SUP>-di-[(E)-p-coumaroyl]-spermidine (3), and N,N&quot-dicoumaroylputrescine (DCP) (4). Interestingly, the spemidine alkaloids (1-4) isolated in this investigation showed the splitting ¹H and 13C NMR signals because of the central nitrogen’s sterically hindered umbrella inversion effect. Besides alkaloids, americanol A (5) belonging to the neolignan class and two macrolides, (10Z,12E,14R)-14-pentyloxacyclotetradeca-10,12-dien-2-one (6) and (10E,12E)-14-pentyloxacyclotetradeca-10,12-dien-2-one (7), were isolated and elucidated.