Isolation of 1-O-trans-p-Coumaroyl-rβ-D-glucopyranose from Sweet Potato Roots and Examination of Its Role in Chlorogenic Acid Biosynthesis

摘要

1-O-trans-p-Coumaroyl-rβ-D-glucopyranose (p-coumaroyl-D-glucose) was isolated from slices of sweet potato root which had been incubated withtrans-cinnamic acid. Pre-loadedtrans-cinnamic acid efficiently trapped the radioactivity from L-U-14C-phenylalanine and reduced its incorporation into chlorogenic acid by 75of control values in disks of sweet potato root. In the root disks supplied withtrans-3-14C-cinnamic acid, the radioactivity was transferred first totrans-cinnamoyl- D-glucose, then top-coumaroyl-D-glucose, and subsequently to chlorogenic acid and isochlorogenic acid. These results support our earlier proposition thatp-coumaroyl-D-glucose is involved in the biosynthesis of chlorogenic acid as an intermediate adjacent in the pathway totrans-cinnamoyl-D-glucose in sweet potato roots