IN-VITRO ANTIFUNGAL AND FUNGICIDAL ACTIVITIES AND ERYTHROCYTE TOXICITIES OF CYCLIC LIPODEPSINONAPEPTIDES PRODUCED BY PSEUDOMONAS-SYRINGAE PV SYRINGAE

Recent increases in fungal infections, the few available antifungal dr ugs, and increasing fungal resistance to the available antifungal drug s have resulted in a broadening of the search for new antifungal agent s. Strains of Pseudomonas syringae pv, syringae produce cyclic lipodep sinonapeptides with antifungal activity, The in vitro antifungal and f ungicidal activities of three cyclic lipodepsinonapeptides (syringomyc in E, syringotoxin B, and syringostatin A) against medically important isolates were evaluated by a standard broth microdilution susceptibil ity method, Erythrocyte toxicities were also evaluated, All three comp ounds showed bread antifungal activities and fungicidal actions agains t most of the fungi tested. Overall, the cyclic lipodepsinonapeptides were more effective against yeasts than against the filamentous fungi, Syringomycin E and syringostatin A had very similar antifungal activi ties (2.5 to >40 mu g/ml) and erythrocyte toxicities. Syringotoxin B w as generally less active (0.8 to 200 mu g/ml) than syringomgcin E and syringostatin A against most fungi and was less toxic to erythrocytes. With opportunities for modification, these compounds are potential le ad compounds for improved antifungal agents.