Triglycerides Isolated from Streptomyces sp. ZZ035 and Their Nuclear Magnetic Resonance Spectroscopic Characters

Abstract

Streptomyces sp. ZZ035 isolated from a folk medicinal soil sample in China showed remarkable antimicrobial activities. During the isolation of secondary metabolites, a white crystal powder (1) was isolated from the broth of this strain. Its nuclear magnetic resonance (NMR) and infrared (IR) spectra indicated that it was a complex composed of triglycerides. Next, six C15-17 long- chain fatty acids derived from these triglycerides were respectively identified as n-pentadecanoyl, 12-methyltetradecanoyl, 14-methyl pentadecanoyl, palmitoyl, 15-methyl hexadecanoyl and 14-methyl hexadecanoyl using the gas chromatography-mass spectroscopy (GC-MS) technology. Finally, the 13C and 1H assignments of 1 were achieved through the analyses of NMR data. Based on above, their detailed NMR spectroscopic elucidation and meticulous 13C, 1H assignments, especially the split peaks and coupling correlation of protons attached on the glycerol carbons, were performed for distinguishing triglycerides from other glycerides and for the identification of the long-chain fatty acids, and which would be helpful to the qualitative and quantitative analyses of tri-, di-and mono-glycerides.