A comparative study on the effects of rosmarinic acid and carnosic acid on the cell viability, ceramide metabolism and antioxidant enzyme responses in the Hep-G2 cancer cell line

Carnosic acid and Rosmarinic acid belong to a family of polyphenols found in Rosemary. In this study the effects of these two compounds were compared based on ceramide metabolism in cell line of Hep-G2. Hep-G2 cells were cultured in DMEM, supplemented with fetal bovine serum and antibiotics. Cells with double dilution were then cultured with Carnosic acid and Rosmarinic acid (with concentrations 0 to 70 µM for 24 h) and viability of cells was determined by MTT method. A spectrophotometer and HPLC assay was used to measure of caspase-3 activity and the level of ceramide. The activity of such enzymes as sphingomylinase, acid ceramidase, glucosylceramide synthase was also measured. Carnosic acid increased cell viability in Hep-G2 cells by reducing ceramide levels and the activity of the other enzymes such as caspse-3, sphingomylinase, glucosylceramide synthase and also by increasing the activity of the ceramidase enzyme acid. Rosmarinic acid in concentrations of up to 50 µM decreased cell viability by increasing ceramide levels and the activity of caspse-3, sphingomylinase and also by decreasing activity of enzymes such as acid ceramidese and glucosylceramide synthase. This substance also in concentrations of up to 40 µM caused increasing activity of caspase-3 enzyme. Although in most cases polyphenols resulted in induction of apoptosis and decreased cell viability, in some cases they affected inversely and caused cell growth.