93074-04-5

Milbemycin A4 oxime, a derivative of milbemycin A4 and a component of milbemycin oxime, exhibits insecticidal and nematocidal activity. At 0.05 mg kg, it reduces microfilariae of the heartworm D. immitis in naturally infested dogs and inhibits the growth of C. glabrata clinical isolates with MIC80 values of 16 to >32 μg ml. At 2.5 μg ml, it blocks fluconazole efflux from C. glabrata clinical isolates (but not from strains lacking CgCDR1 and PDH1 efflux pumps) and reduces MICs of fluconazole and 4-nitroquinoline 1-oxide in wild-type C. glabrata. Furthermore, it enhances adriamycin-induced inhibition of cell growth, increases intracellular accumulation of adriamycin and the P-glycoprotein substrate rhodamine 123 in adriamycin-resistant, but not adriamycin-sensitive, MCF-7 breast cancer cells in a concentration-dependent manner.