Discovery Of Anticancer Constituent From Microorganism Metabolites

Cancer is a kind of disease that is very common and frequently encountered, which threatens human’s lives seriously. For the past few years over 5 million people have died of cancer in the world each year, the research on anticancer drugs is one of the subjects that arouse more and more attention. Soil microorganisms have been recognized as a prolific source of biologically active natural products,so it is significant to screen cytotoxic chemical constituent from metabolites of microorganism for the discovery of anticancer lead compounds. In this paper we described the details of the screening, fermentation, isolation and structure elucidation of cytotoxic compounds: N02ZA-0567 A、B、C and their anticancer activity in vitro.High throughput screening method using human breast cancer cell line MCF-7 and MTT chromatometry was firstly established for screening anticancer compounds from 4282 extracts of microorganism metabolites. The strain whose metabolites showed anticancer activity was defined to be a positive strain. The positive strain which picked out as a candidate was cultured in large scale and the culture broth was further isolated with the guide of bio-activity by solvent extraction, silica gel chromatography, Sephadex LH-20 , TLC and ODS HPLC to get pure compounds. On the basis of various modern spectroscopic analysis (UV, 1D and 2D NMR, ESI-MS etc.), the structures of the compounds were determined. The cytotoxic activities of the compounds against a panel of human cancer cell lines were evaluated in vitro.By the screening of 4282 extracts of microorganism metabolites one actinomycete strain named N02Z-0567 was selected for further chemical constituent research to get 3 active compounds: N02ZA-0567A, B and C. On the basis of various modern spectroscopic analysis the structures of the compounds were identified asγ-Naphthocyclinone(A),β-Naphthocyclinone epoxide(B) and 6’-deacetyl-γ-Naphthocyclinone(C) respectively. These 3 compounds showed specific cytotoxic activity against a panel of human cancer cell lines (human breast cancer cell line MCF-7, human colon tumor cell line Hct-15, human lung cancer cell line A549 and human leukemic cell line K562) with the IC50 ranging from 0.21μg/ml to 18.8μg/ml.The anticancer activities of the 3 compounds:γ-Naphthocyclinone (N02ZA-0567A),β-Naphthocyclinone epoxide (N02ZA-0567B) and 6’-deacetyl-γ-Naphthocyclinone (N02ZA-0567C) were first reported in this article. In the series of evaluations N02ZA-0567A、C showed stronger cytotoxic activities than N02ZA-0567B in vitro, the mechanism of the action was worth being studied and researched further.