Two New Aristolochic Acid Analogues from the Roots of with Significant Cytotoxic Activity.

Twelve compounds, including two new aristolochic acid analogues with a formyloxy moiety (9-10) and 10 known aristolochic acid derivates (1-8 and 11-12), were obtained from the roots of . Their structures were elucidated using extensive spectroscopic methods. Their cytotoxic activity in human proximal tubular cells HK-2 was evaluated by the MTT method, which has been widely used to assess cell viability. Among these molecules, compounds and were found to be more cytotoxic. Furthermore, molecular modeling was used to evaluate, for the first time, the interactions of compounds and with the target protein organic anionic transporter 1 (OAT1) that plays a key role in mediating aristolochic acid nephropathy. Structure-activity relationships are briefly discussed.