Angucyclinones with IDO and TDO inhibitory activities isolated from the actinomycetes Umezawaea beigongshangensis.

Four previously undescribed angucyclinones umezawaones A-D (1-4) were isolated from the liquid cultures of Umezawaea beigongshangensis. Their structures were determined by spectroscopic analyses, single crystal X-ray diffraction, quantum chemical 13C NMR and electronic circular dichroism calculations. All compounds displayed strong inhibitory activities against indoleamine 2,3-dioxygenase and tryptophan-2,3-dioxygenase in enzymatic assay, especially compound 2.

Epicoccanes A-D, Four Oxidative Dimers of Pyrogallol Analogues from Epicoccum nigrum.

Epicoccanes A-D (1-4) are four novel metabolites of an endophytic fungus Epicoccum nigrum. Their distinct unprecedented structures are hypothesized as oxidative dimers of pyrogallol analogues. Compounds 1 and 2 possess a novel spirobicyclo[3.2.1]octane-6,1'-cyclopentane or -cyclohexane core skeleton. Compound 3 is of a unique cage-like pentacyclic system, which unusually contained three continuous spiro-carbons. Compound 4 is a highly rearranged dimer with five contiguous chiral centers. The absolute structures of 1 and 2 were deduced by electronic circular dichroism (ECD) calculations, and those of 3 and 4 were determined by X-ray crystallography. Compounds 1 and 4 showed potential antiliver fibrosis activity.

Beetleane A and Epicoane A: Two Carbon Skeletons Produced by Epicoccum nigrum.

Two novel natural products, beetleane A (1) and epicoane A (2), were obtained from the metabolites of an endophytic Epicoccum nigrum. Compound 1 has a unique beetlelike structure that is constructed by the fusion and further fold of an unusual [5.5.5.6]trioxafenestrane with a cycloheptane ring. Compound 2 possesses a compact cagelike structure with a unique 6/5/5/5/6/6/5 heptacyclic ring system. Both 1 and 2 showed strong antiliver fibrosis activity in vitro.