Talosins A and B: new isoflavonol glycosides with potent antifungal activity from Kitasatospora kifunensis MJM341. II. Physicochemical properties and structure determination.

In our screening program for new antifungal agents from microbial secondary metabolites, two new isoflavonol glycosides, with potent antifungal activity, talosins A and B, were isolated from the culture broth of Kitasatospora kifunensis MJM341. Talosins A and B were determined to be genistein 7-alpha-L-6-deoxy-talopyranoside and genistein 4',7-di-alpha-L-6-deoxy-talopyranoside, respectively, by spectroscopic studies. They are the first flavonoid glycosides incorporating 6-deoxy-talose as a sugar component.