New macrocyclic lactones with acaricidal and nematocidal activities from a genetically engineered strain Streptomyces bingchenggensis BCJ60

Two new macrocyclic lactones, 4,25-diethyl-4,25-demethyl-milbemycin β₃ (1) and 27-formaldehyde-milbemycin β₁₄ (2), were isolated from a genetically engineered strain Streptomyces bingchenggensis BCJ60. Their structures were determined on the basis of spectroscopic analysis, including 1D and 2D NMR techniques as well as ESI-MS and comparison with data from the literature. The acaricidal and nematocidal capacities of compounds 1 and 2 were evaluated against Tetranychus cinnabarinus and Bursaphelenchus xylophilus, respectively. The results showed that the two new macrocyclic lactones 1 and 2 possessed potent acaricidal and nematocidal activities.