Anthocyanin rich extract from Aronia meloncarpa E induces a cell cycle block in colon cancer but not normal colonic cells

Abstract: Anthocyanin-rich extracts, potent antioxidants and commercially available food coloring agents, have been re-ported to inhibit growth of various cancer cell lines. We in-vestigated the effect of semipurified anthocyanin-rich extract from fruits of Aronia meloncarpa, on normal colon and colon cancer cell lines. A 24-h exposure to 50 µg monomeric anthocyanin/ml of Aronia extract resulted in 60 % growth in-hibition of human HT-29 colon cancer cells. The treated cells showed a blockage at G1/G0 and G2/M phases of the cell cy-cle. The cell cycle arrest coincided with an increased expres-sion of the p21WAF1 and p27KIP1 genes and decreased expres-sion of cyclin A and B genes. Prolonged exposure to the extract resulted in no further change in the cell number, indi-cating a cytostatic inhibition of cell growth. NCM460 normal colon cells demonstrated <10 % growth inhibition at the highest concentration of 50 µg/ml extract. A 35 % decrease in the cyclooxygenase-2 gene expression was observed within 24 h of exposure of HT-29 cells but did not translate into de-creased protein levels or protein activity. These results sup-port the need for further research to identify the specific com-ponent(s) in this extract that suppress cancer cell growth and the genes affected by these natural compounds