Strepantibins A–C: Hexokinase II Inhibitors from a Mud Dauber Wasp Associated Streptomyces sp.

Two new p-terphenyls, strepantibins A and B (1 and 2), along with the first representative of a naturally occurring bisphenyltropone, strepantibin C (3), were characterized from a Streptomyces sp. associated with the larvae of the mud dauber wasp Sceliphron madraspatanum. Their structures were determined by high-resolution electrospray ionization mass spectrometry, NMR, and X-ray crystallography data interpretation. Strepantibins A–C inhibited hexokinase II (HK2) activity and displayed antiproliferative activity against hepatoma carcinoma cells HepG-2, SMMC-7721 and plc-prf-5. In SMMC-7721 cells treated with strepantibin A, the morphological characteristics of apoptosis were observed.