Study on the difference and correlation between the contents and toxicity of aristolochic acid analogues in Aristolochia plants.

ETHNOPHARMACOLOGICAL RELEVANCE

The nephrotoxicity and carcinogenicity induced by traditional Chinese medicines (TCMs) containing aristolochic acids (AAs) and related compound preparations have greatly limited their clinical application. While the toxicity of AA-I and AA-II is relatively clear, there are marked differences in the toxic effects of different types of aristolochic acid analogues (AAAs). Thus, the toxicity of TCMs containing AAAs cannot be evaluated based on the toxicity of a single compound.

AIM OF THE STUDY

To systematically investigate the toxicity induced by Zhushalian (ZSL), Madouling (MDL) and Tianxianteng (TXT) as representative TCMs derived from Aristolochia.

MATERIALS AND METHODS

AAA contents in ZSL, MDL and TXT were determined using HPLC. Subsequently, mice were treated for 2 weeks with high (H) and low (L) dosages of TCMs containing total AAA contents of 3 mg/kg and 1.5 mg/kg, respectively. Toxicity was evaluated using biochemical and pathological examination and was based on organ indices. Correlations between AAA contents and induced toxicity were analysed using multiple methods.

RESULTS

Of the total AAA content, ZSL contained mainly AA-I and AA-II (>90%, of which AA-I accounted for 49.55%). AA-I accounted for 35.45% in MDL. TXT mainly contained AA-IVa (76.84%) and other AAAs accounted for <10%. Short-term toxicity tests indicated that ZSL and high-dose MDL induced obvious renal interstitial fibrosis and gastric injury, whereas TXT (high and low dosages) caused only slight toxicity. Correlation analysis suggested that AA-I might be the critical hazard factor for toxicity.

CONCLUSIONS

The toxicity of TCMs containing AAAs cannot be generalised. The toxicity of TXT is relatively low compared with those of ZSL and MDL. The toxicity of Aristolochia depends mainly on the AA-I content; therefore, control of AA-I levels in TCMs and related compound preparations is required to reduce the risk of toxicity associated with the use of Aristolochia herbs in clinical settings.