Isovitexin (homovitexin or saponaretin) is a flavonoid, namely the apigenin-6-C-glucoside. In this case, the prefix 'iso' does not imply an isoflavonoid (the position of the B-ring on the C-ring), but the position of the glucoside on the flavone, in comparison to vitexin.
The compounds of every Wikipedia article carrying a Chembox or a Drugbox, refreshed daily, with the values their infoboxes give. The pages need JavaScript; the API does not.