Fructose-amino acid conjugate and other constituents from Cyperus rotundus L.

Further phytochemical study on the aerial parts of Cyperus rotundus L. led to the isolation of a fructose-amino acid conjugate, N-(1-deoxy-alpha-D-fructos-1-yl)-L-tryptophan (16) and its tautomers, in addition to n-butyl-beta-D-fructopyranoside (1), ethyl-alpha-D-glucopyranoside (2), adenosine (3), (-)-(E)-caffeoylmalic acid (4), vitexin (5), isovitexin (6), orientin (7), epiorientin (8), myricetin 3-O-beta-D-galactopyranoside (9), luteolin 7-O-beta-D-glucuronopyranoside-6''-methyl ester (10), chlorogenic acid (11), luteolin 4'-O-beta-D-glucuronopyranoside (12), luteolin 7-O-beta-D-glucuronopyranoside (13), uridine (14) and ellagic acid (15). Their structures were elucidated on the basis of spectroscopic methods. Additionally, antioxidant and alpha-amylase inhibitory activities of some of the isolated phenolic compounds were carried out.