Aristolochic acid II (AAII), one of the major components of the carcinogenic plant extract aristolochic acid, is known to be mutagenic and to form DNA adducts in vitro and in vivo,
AAII shows more carcinogenic risk than aristolochic acid I, and this may be, at least partly, the result of its increased levels in kidney and plasma.[1,2]
Aristolochic acid exhibit significant toxicity, and the short-term toxicity of aristolochic acid-II and aristolochic acid is similar to each other, renal but not hepatic failure induced by aristolochic acid could be prevented by pentoxifylline.[3]

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[1] Pfau W, Schmeiser H H, Wiessler M. Cheml Res Toxicol, 1991, 4(5):581-6.
[2] Xing G, Qi X, Min C, et al. Mutat Res-Fund Mol M, 2012, 743(1-2):52-8.
[3] Yeh Y H, Lee Y T, Hsieh H S, et al. Food Chem Toxicol , 2008, 46(3):1157-63.
[4] Zhu G, Wang Z, Wang Q, et al. China Pharmacy, 2006, 17(18):21-4.