Enhancement of the apoptotic effects of Arctii Fructus extracts on cancer cells by the enzymatic bioconversion of lignans

The fruit of Arctium lappa L. (Arctii Fructus) is one of the most popularly used medicinal plant components in Asia. To enhance the functionality of Arctii Fructus extract, a bioconversion method was developed to produce arctigenin from arctiin. Treatment with β‐glucosidase increased the arctigenin content by >5 fold in Arctii Fructus extracts. The bioconversion products enhanced the apoptosis of cancer cells. The cell viabilities of gefitinib‐resistant lung cancer HCC827 (HCC827GR) cells and colon cancer cells (DLD1) were decreased by 40% and 35%, respectively. The bioconversion products also decreased anchorage‐independent growth of cancer cells. In addition, the increase of apoptosis in cancer cells by bioconversion was confirmed by the flow cytometry analysis. These results indicated that arctigenin exerts anticancer effects on lung and colon cancer cells and that Arctii Fructus can potentially function as a chemopreventive agent. In addition, bioconverted Arctii Fructus extract displayed higher anticancer activity than the same levels of purified arctigenin, indicating the advantage of consuming Arctii Fructus itself as a food or medicinal material.