Cytotoxic effect of the crude extracts of the locally Isolate Lactococcus lactis on AMN-3 tumor cell line

Abstract

This project was conducted to study the activity of secondary metabolites produced by one of a human microflora which is Lactococcus lactis on AMN-3 tumour cell line in vitro. Twenty samples of dairy products (bucolic sour yoghurts, pasteurized milk and raw milk) were collected; nine isolates of Lactococccus were isolated by propagating in MRS broth medium followed by subjecting the isolates to microscopic, cultural, physiological and biochemical tests. The results showed the presence of four isolates belonged to the genus Lactococcus sp. lactis. the isolates were grown in three broth production media, which were MRS, VVM and BHI at 37ºC for 6 h. followed by extraction of crude extracts using ammonium sulphate saturation ratio which was 80% for each medium confidentially. The overall result was three crude extracts (one from each medium), followed by estimation the concentrations of extracted proteins depending on standard curve of bovine serum albumin. The cytotoxic activity of different concentrations for each crude extract was studied on AMN-3 tumour cell line for three incubation periods (24,48,72) hrs in addition to normal rabbit embryo fibroblast (REF) cell line for 72 hr only. The result illustrated a clear cytotoxic activity of these crude extracts with high significances on this tumour cell line during the three incubation periods, suggesting that the cytotoxic effect of these crude extracts is a dose and time dependent, but on REF cell line, there is no significant effect of these crude extracts was reported, suggesting also, that may be the active compound of L. lactis possess some specificity in cytotoxicity on cancer cells but not on normal cells.