Isolation, structure elucidation and biological activity of angucycline antibiotics from an epiphytic yew streptomycete.

In the course of study of epiphytic microorganisms occurring on the surface of roots of Taxus baccata L. a new strain Streptomyces sp. AC113 was isolated.

Enniatins produced by Fusarium dimerum, an endophytic fungal strain.

Cyclohexadepsipetides enniatin B, B1 and G were isolated from the cultivation broth of Fusarium dimerum Penzig, an endophyte of Magnolia x soulangeana. Their production was about 350 mg l(-1) after 96 h of submerged cultivation in Sabouraud maltose medium. Isolated enniatins inhibited growth of selected microorganisms and activity of 12-lipoxygenase with IC50 = 0.

Biosynthesis and biological activity of enniatins.

Enniatins are N-methylated cyclohexadepsipeptides (CHDPs), composed of three units each of N-methylated branched-chain L-amino acid and D-2-hydroxy acid arranged in an alternate fashion. These low-molecular secondary metabolites are produced by Fusarium species, typical mycotoxin producing fungi. Enniatins are known for their ionophoric, phytotoxic and anthelmintic effect, antibiotic activity and recently their potent cytotoxic activity against cancer cell lines was shown.

Identification of the configuration of neosartorin by long-range nuclear Overhauser effect measurements.

The relative configuration of the two xanthene units of neosartorin, a new ergochrome biosynthesised by the soil mould Neosartorya fischeri, was determined using a 1D double-pulsed field gradient spin-echo NOESY experiment. It was found that both units have the same relative stereochemistry. Long-range nonbonding interactions between the substituents of different xanthene units stabilise the nonplanar configuration of the two aromatic rings A and A' connecting both monomer units of neosartorin.