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Milbemycin R, a novel spiro-heterocycle milbemycin, was obtained from the metabolites produced by the mutant strain S. bingchenggensis BCJ60B11. Its structure was determined by spectroscopic and sp...

Two undescribed milbemycin derivatives, milbemycin P (1) and milbemycin Q (2), were isolated from a culture of the genetically engineered strain Streptomyces bingchenggensis BCJ60. Their structures were elucidated through the interpretation of NMR and HR-ESI-MS spectroscopic data, as well as comparison with previous reports. Their acaricidal and nematocidal activities against Tetranychus cinnabarinus and Bursaphelenchus xylophilus were tested. The results showed that compounds 1–2 possessed potent acaricidal and nematocidal activities.

Two new milbemycin derivatives, milbemycin M (1) and milbemycin N (2), were isolated from the culture of a genetically engineered strain Streptomyces bingchenggensis BCJ60. Their structures were elucidated through the interpretation of NMR and HR-ESI-MS spectroscopic data, as well as comparison with previous reports. The acaricidal and nematicidal activities of them against Tetranychus cinnabarinus and Bursaphelenchus xylophilus were tested. The results showed that compounds 1-2 possessed potent acaricidal and nematocidal activities.

Two new milbemycin derivatives, 27-methoxylmilbemycin α31 (1) and 27-oxomilbemycin α31 (2), were isolated from the genetically engineered strain Streptomyces bingchenggensis BCJ60. Their structures were determined by 1D NMR, 2D NMR and HR-ESI-MS spectral analysis, and comparison with previous reports. 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.

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.

Milbemycin oxime has been commercialized as effective anthelmintics in the fields of animal health, agriculture, and human infections. Currently, milbemycin oxime is synthesized by a two-step chemical reaction, which involves the ketonization of milbemycins A3/A4 to yield the intermediates 5-oxomilbemycins A3/A4 using CrO3 as catalyst. Due to the low efficiency and environmental unfriendliness of the ketonization of milbemycins A3/A4, it is imperative to develop alternative strategies to produce 5-oxomilbemycins A3/A4. In this study, the atmospheric and room temperature plasma (ARTP) mutation system was first employed to treat milbemycin-producing strain Streptomyces bingchenggensis, and a mutant strain BC-120-4 producing milbemycins A3, A4, B2, and B3 as main components was obtained, which favors the construction of genetically engineered strains producing 5-oxomilbemycins. Importantly, the milbemycins A3/A4 yield of BC-120-4 reached 3,890 ± 52 g/l, which was approximately two times higher than that of the initial strain BC-109-6 (1,326 ± 37 g/l). The subsequent interruption of the gene milF encoding a C5-ketoreductase responsible for the ketonization of milbemycins led to strain BCJ60 (∆milF) with the production of 5-oxomilbemycins A3/A4 and the elimination of milbemycins A3, A4, B2, and B3. The high 5-oxomilbemycins A3/A4 yield (3,470 ± 147 g/l) and genetic stability of BCJ60 implied the potential use in industry to prepare 5-oxomilbemycins A3/A4 for the semisynthesis of milbemycins oxime.

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

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

In the continuing study of the chemical compositions of the strain Streptomyces bingchenggensis, three new milbemycin derivatives, milbemycin alpha(31) (1), secomilbemycins C (2), and D (3), were isolated. Their structures were established on the basis of extensive spectroscopic analysis.

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.

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.