Two new 13-hydroxylated milbemycin metabolites from the genetically engineered strainStreptomyces avermitilisAVE-H39

Two new milbemycin metabolites, 13 alpha-hydroxymilbemycin beta(13)(1) and 26-methyl-13 alpha-hydroxymilbemycin beta(13)(2), were isolated from the fermentation broth of a genetically engineered strainStreptomyces avermitilisAVE-H39. Their structures were determined by the comprehensive spectroscopic data, including 1 D, 2 D NMR, MS spectral analysis and the comparison with data from the literature. Compounds1and2not only exhibited potent acaricidal activities againstTetranychus cinnabarinus, but also had nematocidal activity againstBursaphelenchus xylophilus.