Analysis Of Aristolochic Acids Inhouttuynia Cordataby Liquid Chromatography-Tandem Mass Spectrometry

Houttuynia cordata(H. cordata) is a popular vegetable in Asian countries and is also used extensively as herbal medicine in treating various diseases.H. cordatacontains aristolactams, which have a similar Chinese name as aristolochic acids (AAs); hence, an emerging concern in the greater China region has arisen about the potential linkage betweenH. cordataand aristolochic acid nephropathy (AAN). However, only a single study has tested for the presence of AAs inH. cordatasamples, and the analysis was limited by the analytical sensitivity of the method. Thus, further analysis of AAs inH. cordatausing analytical method of higher sensitivity is needed to alleviate public anxiety over the use of this popular vegetable. In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used to analyzeH. cordatasamples for the natural existence of aristolochic acid I (AA-I) and aristolochic acid II (AA-II), which are the most carcinogenic and nephrotoxic compounds in the AA family. After evaluating the method performance by fortifying blank samples with three concentrations of AAs, the validated method was applied to identify AA-I and AA-II in both fresh and sun-driedH. cordatasamples (n= 20) collected from different cities in China. The LC-MS/MS method achieved method detection limits (MDLs) as low as 2 ng/g of AAs inH. cordata. Analysis of the collected fresh and sun-driedH. cordatasamples revealed that AA-I and AA-II either do not exist naturally inH. cordataor exist at concentrations below the MDLs. Therefore, it is not very likely that consumption ofH. cordatawill result in AAN because AA-I and AA-II, the nephrotoxic and carcinogenic culprits of AAN, are not produced naturally in the plant or are produced at levels that do not pose a risk of AAN.