Description_x000D_ Application_x000D_ The effect of Ascochlorin on MMP-9 was compared with that of Silibinin in MCF-7 human breast carcinoma cells._x000D_ Biochem/physiol Actions_x000D_ Ascochlorin is an isoprenoid antibiotic produced by Verticillium hemipterigenum, initially identified as an antiviral and antitumor agent. Research also indicates that ascochlorin inhibits the Qi and Qo quinone binding sites of the mitochondria cytochrom bc1 complex. Moreover, ascochlorin activates p53, probably as a result of its inhibitory effect on mitochondrial respiration. In addition, ascochlorin has the ability to suppress the nuclear subscription enzyme protein-1, a nuclear transcription factor activator, which leads to suppression of the extra-cellular enzyme, matrix metalloproteinase-9 (MMP9). The regulation of MMP is implicated in renal development, macrophage differentiation, atherosclerosis, inflammation, rheumatoid arthritis, and tumor invasion. Ascochlorin was also found to be effective against Mx-1, an estrogen lacking breast cancer cell line.