Three New Chromone Derivatives Produced by Phomopsis sp HNY29-2B from Acanthus ilicifolius Linn.

Three new chromone derivatives, phomochromenones A-C (1-3), and one known chaetocyclinone B (4) were obtained from the cultures of Phomopsis sp. HNY29-2B isolated from the mangrove Acanthus ilicifolius Linn., which was collected from the South China Sea. Their structures were determined by the analysis of D-1 NMR and D-2 NMR as well as mass spectroscopic data. The absolute configurations of 1 and 2 were assigned by quantum chemical calculations of the electronic circular dichroism (ECD) spectra. Compound 3 is the third example of alkaloids possessing the unique chromeno [3,2-c] pyridine nucleus. In the bioactivity assay, compound 4 showed cytotoxicity against human prostate cancer cell lines (PC-3 and DU145 cells) with the IC50 values of 8.13 and 3.59 mu mol/L, respectively.