Enhancement of a pentacyclic tyrosine kinase inhibitor production in Cladosporium cf. cladosporioides by Cladosporol

The binaphthyl derivative cladosporol A was supplied from 60 to 200 mg l−1 to shaken cultures of Cladosporium cf. cladosporioides. Compared to blank, fungal biomass was not affected by adding cladosporol till 100 mg l−1: it rather increased at higher ratios between 150 and 200 mg l−1. The production of the major pentacyclic metabolite 1, a cytokine production and tyrosine kinase inhibitor, was enhanced tenfold when cladosporol was supplied at the highest ratio (200 mg l−1) to shaken growing cultures of the fungus. The bioconversion of cladosporol to cladosporol D through reductive cleavage of the epoxide group was also observed. Interest in this kind of metabolites lies in their potential activity vs DNA topoisomerase I.