Campechic Acids A and B: Anti-invasive Polyether Polyketides from a Soil-Derived Streptomyces

Campechic acids A (1) and B (2), two new polyketides, were isolated from the culture extract of Streptomyces sp., and their structures were determined by NMR and MS spectroscopic analysis. Campechic acids are polyether-polyketides functionalized by two tetrahydrofuran rings, an enolized 1,3-diketone, and multiple methyl substitutions. Absolute configuration of nine stereogenic centers in 1, except for four chiral centers in the cyclic ether moieties, was determined by the H-1 NMR anisotropy method in combination with chemical degradation. Campechic acids exhibited potent inhibitory effects on tumor cell invasion with IC50 values in the nanomolar to submicromolar range.