Aristolochic Acids\nand Aristoloxazines Are Widespread\nin the Soil of Aristolochiaceae Herb Cultivation Fields

The cancer risk associated with aristolochic acid (AA)\nexposure\nthrough the consumption of AA-containing herbal medicine has received\ntremendous attention in the past decades. However, environmental exposure\nroutes from the associated medicinal herb cultivation fields have\nreceived little attention. We reveal through liquid chromatography-tandem\nmass spectrometry analysis of over 400 soil samples collected from\nthree different Aristolochiaceae herb cultivation fields that AAs,\nwhich are nephrotoxic and carcinogenic, and aristoloxazines (AXs),\na family of recently identified neurotoxic and genotoxic AA analogues,\nare widespread pollutants in these areas. In particular, aristoloxazine\nC was detected for the first time in the environment and was found\nin 318 out of 320 soil samples, at concentrations as high as 2.8 mg/kg,\nfrom an Asarum heterotropoides cultivation\nfield. We show that in fact AXs are ecotoxic, inhibiting plant growth\nand significantly reducing the soil microorganism population. With\nthe extensive cultivation of Aristolochiaceae herbs in order to meet\ntheir market demand, we believe our study points to an important environmental\nhazard that may place food crops and non-AA/AX-producing medicinal\nherbs at risk of AA/AX contamination. While previous research focused\nprimarily on the health risks associated with exposure to AAs, this\nstudy uncovers environmental exposure as a new human exposure pathway\nthat warrants the attention of both the general public and regulatory\nagencies.