Glycyrrhizic acid (GA) \I;as tested for inhibition of arylamine N-acetyltransferase (NAT) activity in a human colon tumour (adenocarcinoma) cell line (colo 205), Two assay systems were performed, one with cellular cytosols (9000 fi supernatant), the other with intact colon tumour cell cultures. The NAT activity in a human colon tumour cell line was inhibited by GA in a dose-dependent manner in both types of systems examined, The data also indicated that GA decreased the apparent values of K-m and V-max of NAT enzymes from human colon tumour cells in both examined systems. The DNA-2-aminofluorene adduct formation in human colon tumour cells were inhibited by GA. This report is the first to demonstrate that GA does inhibit human colon tumour cell NAT activity and DNA adduct formation. (C) 2000 Elsevier Science Lid All rights reserved.
