NOVEL SQUALESTATINS PRODUCED BY BIOTRANSFORMATION

Microorganisms were screened for the ability to modify the squalene sy nthase inhibitor squalestatin 1. Biotransformation of 1 by two actinom ycetes, S15106 and S15138, yielded three products hydroxylated on the 4,6-dimethyl-oct-2-enoyl side chain either at the 6 position (5) or 7 position (4 two diastereoisomers), and lacking the acetyl ester from t he C-1 side chain. Many strains were found to hydrolyse the 4,6-dimeth yl-oct-2-enoyl or acetyl esters to yield squalestatins 2 or 3. The 3-m ethyl ester (6) of 1 was obtained using Fusarium sp. F13945. This fung us also produced a farnesoic acid derivative, possibly in response to inhibition of its squalene synthase by 1. The biotransformation produc ts of 1 all retained potent squalene synthase inhibitory activity.