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 13, were isolated from the culture broth of Kitasatospora kifunensis MJM341. Talosins A and B were determined to be genistein 7-alpha-L-6-deoxytalopyranoside and genistein 4',7-di-alpha-L-6-deoxytalopyranoside, respectively, by spectroscopic studies. They are the first flavonoid glycosides incorporating 6-deoxy-talose as a sugar component.