Antioxidative collagen-derived peptides in human-placenta extract.

Human-placenta extract (PLx), has been widely used in clinical and cosmetic fields, and is known to possess marked antioxidant activity. We have attempted to identify the antioxidative components in PLx. Initially, we purified PLx using Sephadex G-10 column. The first eluted peak which had optical density at 280nm and exhibited approximately 20 per cent of antioxidant activity of the applied PLx, did not contain uracil, tyrosine, phenylalanine, or tryptophan which are the previously identified antioxidants from PLx. This fraction was further purified by reverse-phase high performance liquid chromatography. All eluted peaks containing antioxidant activity exhibited optical density at 280nm. Six separate fractions of eluent having antioxidant activity were analyzed by an amino acid sequencer, and each turned out to contain Glycine(G)-XY amino acid repeats, which appear to be derived from collagen. These results suggest that peptides produced from collagen are also antioxidative components of PLx.