Bioactive secondary metabolites from acid mine waste extremophiles.

The extremophilic microbes of the Berkeley Pit Lake are a valuable source of new and interesting secondary metabolites. It is of particular interest that these acidophilic microbes produce small molecule inhibitors of pathways associated with low pH and high Eh. These same small molecules also inhibit molecular pathways induced by reactive oxygen species (ROS) and inflammation in mammalian cells. Low pH is a hallmark of inflammation and high Eh is one of ROS, so the suitability of this collection as a source of bioactive metabolites is actually quite biorational. Compound isolation was guided by inhibition of caspase-1 and matrix metalloproteinase-3, and active compounds were sent to the National Cancer Institute-Developmental Therapeutics Program and Memorial Sloan Kettering Cancer center for evaluation as either antiproliferative or cytotoxic agents.