Identification of volatile compounds released by myxobacteria Sorangium cellulosum AHB103-1

Secondary metabolite ethyl acetate extract (EAME) produced by Sorangium cellulosum AHB103-1 had good antitumor bioactivity. The results of MTT assay showed that IC(50) value of EAME on human liver cancer cell line (HepG2), mouse melanoma cell line (B16), human breast cancer cell line (MDA-MB231) and human gastric cancer cells (SGC7901) were 5.29, 1.43, 8.77, 6.21 mu g/ml respectively. Moreover, the IC(50) value of EAME on normal mouse spleen cell was 278.87 mu g/ml. After treatment with the EAME, significant changes in morphology of HepG2 cells were observed, such as disappearance of microvilli and formation of apoptotic bodies, etc. The volatile compounds released by S. cellulosum AHB103-1 were analyzed by gas chromatography-mass spectrometry. The ratio of various volatiles at the end of fermentation (7 days) was listed as follows: esters 11.41%, alcohols 13.40%, ketones 16.36%, fatty acids 29.60%, aroma compounds 9.0% and miscellaneous ring compounds 20.22%. The formation of some volatile compounds including isoamyl acetate, acetic acid, benzaldehyde, 4-(benzoyloxy)-2H-pyran-3-one, 1-methyl-indan, methyl-pyrazine, geranylacetone and n-methyl-3-pyridinecarboxamide was related to anti-tumor substances. Acetic acid and 4-(benzoyloxy)-2H-pyran-3-one were the most important among the above compounds because of relatively higher content. The change of their content could be used as an indicator of fermentation control.