Preparation and Properties of a Purified Ragweed Extract. ∗

Abstract

Summary

Absorption spectra of ragweed pollen extracts prepared by a new electro-phoretic preparative method and by extracting the pollen with methanol are reported. Two main absorption bands were observed for crude aqueous extracts at about 2600 Å and 3600 Å. The 2600 and 3600 Å bands may be correlated with an impurity. The main components separated electrophoretically by the preparative method still showed a marked absorption band at 2600 Å, but none at 3600 Å. Ninety percent methanol leached, lyophilized ragweed pollen extracts (MLL) show a marked depression of the 2600 Å and the 3600 Å bands. Biological activity of the essentially pigment-free preparation is identical with the preparation containing all of the pigment thus confirming our previous point of view that the pigments do not contribute substantially to the biological activity. Electrophoretic analysis reveals that a new substantially colorless major component is formed, on removal of the pigment, with an electric mobility of approximately 0.3 μ per second at pH 7.4.