Structure and Biological Activity of Plant Growth Regulators Produced by Penicillium sp. No. 31f

A phenolic amide, N-p-coumaroyltyramine (1), was isolated as an α-glucosidase inhibitor from methanol extracts of Welsh onion (Allium fistulosum). The inhibitory activity of 1 against a yeast enzyme was as high as K_i 8.4 × 10^?7 m. From a structure-activity relationship study of 1 and its related compounds, the occurrence of α-glucosidase inhibitory activity required a p-coumaramide structure, with an amide hydrogen and alkyl or aralkyl substituent on the amide part.