Antimycotic Activity and Acute Toxicity of Benzopyranopyrans and Related Compounds
A series of 39 new benzopyranopyrans and related compounds were synthesised and their antimycotic activity in vitro was evaluated against 4 species of human pathogenic yeasts which were insensitive to miconazole, isoconazole and tolnaftate. The minimum inhibitory concentrations (MICs) of these commercial compounds ranged between 50 and 150 µg/ml. Of the new compounds, 15 were active against 5 strains of Cryptococcus neoformans, while 9 more were active against 3 of these strains with an MIC of 6 µg/ml or lower. Similar MICs were shown by 5 compounds which were active against Candida albicans and 3 which were active against Trichosporon cutaneum. All the active compounds were found to be less toxic than the 3 commercial antimycotics, as judged by their LD50 values in mice. A number of deductions were made regarding the structural variations which resulted in the heterogeneity of response shown by the strains of C. neoformans tested in this series.