Peiwen Yang

1H and 13C NMR assignments of eight nitrogen containing compounds from Nocardia alba sp.nov (YIM 30243T)

An unprecedented new natural product named nocarsin A (1), 5H‐4a,6,7a‐triazacyclopenta[cd]indene‐5,7(6H)‐dione (1), together with seven known compounds lumichrome (2), cyclo (L‐Leu‐L‐Tyr) (3), cyclo (L‐Ala‐L‐Ile) (4), cyclo (L‐Ala‐L‐Leu) (5), cyclo (L‐Val‐L‐Ala) (6), 5‐methyluracil (7) and uracil (8), was isolated from Nocardia alba sp.nov (YIM 30243T), which was isolated from a soil sample collected from Yunnan Province, P. R. China. NMR techniques including COSY, HSQC, ROESY, and HMBC were used to elucidate the structures of these compounds. We report the unambiguous assignments of the 1H and 13C NMR spectra of the new compound nocarsin A (1). Copyright

Oligomycins A and C, major secondary metabolites isolated from the newly isolated strain Streptomyces diastaticus

During the screening program for fungicides, one actinomycete strain ECO 00047 was isolated with the potential activity against fungus. According to the morphology and analysis of the nucleotide sequence of the 16S rRNA gene (1500 bp) this isolate was identified as Streptomyces diastaticus. The active compounds were separated by silica gel column chromatography, Sephadex LH-20 gel filtration and then purified by flash chromatography on C18 (20–45 μm). The chemical structure of the bioactive compounds I and II were elucidated, based on the spectroscopic data of MS, IR, UV, 1H-NMR, 13C-NMR and X-ray single crystal diffraction analysis. Compounds I and II were identical with oligomycins A and C, the macrolide antibiotics which have been known to be produced by Streptomyces diastatochromogenes, S. libani and S. avermitilis. The two compounds exhibited a strong activity against Aspergillus niger, Alternaria alternata, Botrytis cinerea and Phytophthora capsici but no activity toward bacteria. Although the two above antibiotics were known, their isolation has so far not been reported from S. diastaticus.

Cytotoxic metabolites of Streptimonospora salina

Streptimonospora salina gen. nov., sp. nov. was found to produce three phenoxazinone antibiotics, 2-amino-3H-phenoxazin-3-one (1), 2-methylamino-3H-phenoxazin-3-one (2), 2-acetylamino-3H-phenoxazin-3-one (3), and one phenazine antibiotic, phenazine-1-carboxylic acid (4). The chemical structures of the compounds were determined using 1D and 2D NMR spectrometry and electrospray mass spectrometry (ESMS). Compounds 1-4 exhibited modest cytotoxicity against a human renal carcinoma cell line ACHN with IC50 values of 35.4, 12.4, 65.4, and 82.9 μM, respectively. Compound 2 was discovered for the first time from a biological origin.