Effect of different solvents on nisin ZP potential as anticancer agent against MG-63 osteosarcoma cells

Nisin, a known food preservative, has antimicrobial and anticancer properties. Nisin is a polycyclic polypeptide with five internal rings; a feature that strongly influence the choice of solvent to attain effectivity of the compound for all cell culture experiments. Previous studies used a number of solvents but comparison between these to identify the best solvent have not been reported. Aim: To investigate the effect of nisin ZP (NZP) when dissolved in four different solvents on the viability of MG63 osteosarcoma cells. Materials and methods: MG-63 cells were incubated overnight at 37°C, 5% CO2 and treated with increasing concentration of dimethyl sulfoxide (DMSO), methanol and acetic acid to observe the cytotoxic effects of these chemicals onto the cells via MTS assay. NZP was then dissolved in distilled water and the three solvents in increasing concentrations and applied to the cultured cells. Cell viability and morphology were documented. Results: Acetic acid, DMSO and methanol at 0.05% maintained more than 90% viability of MG-63. NZP precipitated at higher concentrations (≥ 800µg/ml) when dissolved in DMSO, methanol and distilled water which interfered with the measurement of formazan density in the cell viability assay. Increasing doses of NZP in 0.05% acetic acid showed the least interference with the desirable reduction of the cancer cell viability. Microscopically, as concentration of NZP increases, cell shrinkage and apoptotic bodies were more visible. In addition, brown precipitates were abundantly observed. Conclusion: Acetic acid provides the optimal solubility of NZP and the best solvent to use in experiments involving MG-63 cells.