Yoshida K, Okamoto M, Umehara K, Iwami M, Kohsaka M, Aoki H, Imanaka H
J Antibiot (Tokyo). 1982 Feb;35(2):151-6. doi: 10.7164/antibiotics.35.151.
New vasodilators, designated WS-1228 A and B have been discovered in the culture filtrate of a strain of Streptomyces aureofaciens. The active compounds were purified by column chromatography with Diaion HP-20 and silica gel, and finally separated from each other by high performance liquid chromatography. They were obtained as pale yellow crystals and their molecular formulae were both C11H17N3O.