Untreated A549 cells (a), astersk-nucleus, arrow-cytoskeleton, rectangle-fusiform cell shape. A549 cells treated with IC50 value of silymarin (b and c), arrow-shrunken (circular shaped) cells, arrow head-holes on cytoskeleton, circle-nuclei with condensed chromatin and A549 cells treated with IC50 value of silymarin-loaded SLN (d, e and f) for 24 h; circle-cells with fragmented cytoskeleton, arrow-pyknotic nucleus, asterisk-chromatin condensation, arrow head-holes on cytoskeleton.