this screen we found that most of our hits defined as conferring survival to at least 20 of the nematodes after five days were from the saponin family of natural compounds these natural products identified in the primary screen were retested and confirmed fig1 table 1 of the twelve saponins identified six of the compounds a7 a8 a24 a20 a17 and a21 had no precedent in the literature regarding their structure or biological activity however in some cases related analogs have been described moreover although the antifungal effects of some of these saponins have been reported sata et al biosci biotechnol biochem 62 1904 1911 1998 ohtani et al phytochem 33 83 86 1993 their efficacy against candida spp has not been studied after confirmation of these hits dose response experiments were conducted to determine the concentration that provided maximum nematode survival the compounds conferred a range of nematode survival from 27 compound a6 to 93 compounds a2 a7 a24 and a25 however with the exception of a6 all compounds conferred a nematode survival over 65 fig1 several representative members of the saponin family of natural products compounds a8 a11 a16 a20 and a24 fig1 had similar chemical structures and conferred a high degree of worm survival fig1 compounds a8 and a24 are.