Abstract
On paper chromatogram of phenolic substances in red clover leaves, three major components were found, besides free p-coumaric and caffeic acids. One of them was similar to chlorogenic acid in its colour reactions and UV-absorption spectra, although there was some doubt compared with authenic specimens of chlorogenic and isochlorogenic acids in RF value, and the second to p-coumaroylquinic acid. The third component, which probably reacted in the browning of red clover leaves, was not identified.
The effects of p-coumaric, caffeic and chlorogenic acids on digestion of leaf protein were studied with pepsin. Since the acetone powder of fresh leaves of red clover contained about 34% of protein and showed polyphenoloxidase activity, it was used as protein substrate. The digestibility of the leaf protein decreased when the acetone powder was incubated with buffer solution (pH: 3_??_8) and phenolic acid at 37°C for 3 hrs. before proteolytic digestion. Among three acids, caffeic acid was most effective.
