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Three new compounds, milbemycin β15 (I), seco-milbemycins E (IIa), and F (IIb) are isolated from the fermentation broth of S.

Two novel cyclic pentapeptides, bingchamides A (1) and B (2), have been isolated from the organic extracts of the mycelium of Streptomyces bingchenggensis. The structures of 1 and 2 were elucidated on the basis of extensive 1D and 2D NMR, as well as HRESI-MS, electrospray ionization-MS, UV and IR spectroscopic data analysis. Bingchamides A (1) and B (2) exhibited in vitro cytotoxicity toward human colon carcinoma cell line HCT-116 with the IC(50) values of 14.1 and 18.0 microg ml(-1), respectively. The bingchamides A (1) and B (2) scaffolds are probably promising structures for the development of new antitumor agents.

Two new beta-class milbemycins from Streptomyces bingchenggensis, named milbemycin beta(13) and beta(14), have been isolated and characterized. The producing organism has been deposited at the China General Microbiology Culture Collection Center (Accession No: CGMCC1734). On the basis of detailed spectroscopic analysis and comparison with reported data, their structures were determined to be the hydroxyl derivatives at C-27 of milbemycin beta(3) and 25-ethylmilbemycin beta(3), respectively. Milbemycins beta(13) and beta(14) possess potent acaricidal and nematocidal activity. The discovery of these two compounds plays an important role in understanding and perfecting the proposed pathways of milbemycins.

Isolation and identification of new macrocyclic lactones from a genetically engineered strain Streptomyces bingchenggensis BCJ60

A novel macrolide compound from Streptomyces bingchenggensis : fermentation, isolation, structure elucidation and biological properties

Two new seco-milbemycins have been isolated and characterized from the Streptomyces bingchenggensis. On the basis of detailed spectroscopic analysis and comparison with the reported data of milbemycin beta(14), their structures were established to be the seco-milbemycins of milbemycin beta(14). However, milbemycin beta(14) and the two new seco-milbemycins were not converted to each other during purification by silica gel column or storage in the MeOH extract at room temperature. The two new seco-milbemycins are the first discovered from milbemycin-producing microorganisms. They may play an important role in understanding and perfecting the proposed biosynthesis pathways of milbemycins.

Three new alpha-class milbemycins from Streptomyces bingchenggensis, named milbemycins alpha28, alpha29 and alpha30, have been isolated and characterized. On the basis of detailed spectroscopic analysis and comparison with reported data, their structures were determined to be the 22alpha-hydroxy, 23beta-O-(2-methylbutanoyl) milbemycin alpha9, 22alpha-hydroxy, 23beta-O-(2,4-dimethylpentanoyl) milbemycin alpha9 and 22alpha-hydroxy, 23beta-O-(2-methylbutanoyl) milbemycin A4, respectively. Milbemycins alpha28 and alpha29 are the first reported milbemycins that possess both C-26 and C-23 substituents. These three new milbemycins possess potent acaricidal and nematocidal activity.