Sphingolipid has a unique physiological function in animal cells such as cell growth and apoptosis. In this study, we investigated the properties and physiological effects of plant glucosylceramides (GlcCer). The major sphingoid bases of GlcCer from soybean, maize, and rice bran were trans-4, cis or trans-8-sphingadienine. However, the major sphingoid base in wheat and rye grains were 8sphingenine mainly with the cis-configuration (more than 60%). Examination was made of the apoptosis-inducing activity of sphingoid bases from plant and fungal sphingolipids. Sphingoid bases from plant and fungi were found to bring about apoptosis in Caco-2 human colon cancer cells. In differentiated Caco-2 cells, the model for normal intestine cells, no apoptosis by sphingoid bases was noted to occur. For clarification of physiological effects of dietary plant and fungal sphingolipids on colon cancer in vivo, investigation was made to determine the manner in which dietary maize and yeast GlcCer affect 1, 2-dimethylhydrazine (DMH) -induced aberrant crypt foci (ACF) formation in mice large intestine. At 10 weeks of maize and yeast GlcCer feeding and DMH administration, ACF formation was found to be significantly suppressed in all large intestines of the mice. The daily ingestion of these com-pounds should thus serve to suppress colon carcinoma in humans.

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The acyl groups of β-keto esters are activated by introducing the aryl group at the α-position. The activated acyl groups are effectively transferred to N-, O-andS-nucleophiles. Especially, amines quantitatively cause the transacylation under mild conditions without forming any by-products since this reaction proceeds via pseudo intramolecular process. When arylated diethyl 3-oxopentanedioate (diethyl acetonedicarboxylate) is employed as the substrate, unsymmetrical malonic acid derivatives such as amide ester are readily prepared. Furthermore, the chemoselective acylation of diamines and aminoalcohols are also performed by using high sensitivity of the present reaction to the bulkiness of the nucleophiles, in which no modification of the functional group and no additive are not necessary.

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