Xanthoquinodins, new anticoccidial agents produced by Humicola sp. Production, isolation and physico-chemical and biological properties.

Humicola sp. FO-888, a soil isolate, was found to produce a series of new anticoccidial compounds. Five active compounds, designated xanthoquinodins A1, A2, A3, B1 and B2 were isolated from the fermentation broth of the producing strain by solvent extraction and HPLC. Xanthoquinodins inhibited the growth of Eimeria tenella in an in vitro assay system using BHK-21 cells as a host. No schizont in the cells was observed at concentrations of 0.02-0.2 micrograms/ml for xanthoquinodins A1, A3, B1 and B2 and at 0.02 micrograms/ml for xanthoquinodin A2.