Nature's Plus Ultra Isoflavone 100 with Genistein, 60 tablets Information on the health benefits of plant-derived substances called flavonoids has been accumulating among the vast number of flavonoids, one family of naturally occurring plant chemicals stands out, the isoflavones. Nature's Plus Ultra Isoflavone 100 is an isoflavone complex that has many times the isoflavone content of its closest competitor. In addition, Ultra Isoflavone 100 is the only major isoflavone complex on the market to offer puerarin, an intensively-studied, naturally derived isoflavone.