Abstract

Aristolochia longa L. (AL) (Aristolochiaceae) is used by Moroccan patients suffering from cancer during the course of their specific treatment. This practice has remained till date without scientific validation. To validate evidence for or against its continued use as antitumor product and afford data for further studies of this plant, the present investigation was carried out to evaluate the safety of an aqueous extract of A. longa by determining its potential of toxicity after oral administration in mice. To explain the mode of action of A. longa, the immunomodulatory activity test was equally carried out. For acute toxicity study, aqueous extract of A.longa given to adult ‘Swiss albinos’ mice in single dose of 2.5 g/kg/day did not produced any visible toxic signs or deaths. While in the sub-chronic toxicity study, the A. longa extract at doses of 1.25 and 2.5 g/kg/day for 3 and 6 weeks induced atypical locomotion, anorexia, asthenia, ataxia, diarrhea and urination for the higher dose used. The histopathological examination showed that A. longa extract at 1.25 g/kg was not toxic, while at 2.5 g/kg it caused a significant toxicity on the liver, intestine and kidney.  A gradual regression of hepatic and intestinal lesions was observed during 30 days recovery period. However, in the kidney tissue persistent interstitial nephritis was noted with no significant recovery. The high number of lymphocytes noted in the different organs indicated that it was an immune activity. In fact, when tested against SRBC, there was a statistically significant increase of “haemagglutinating antibody titer” and insignificant increase in “delayed type hypersensitivity” response in mice treated by the non toxic dose of A. longa (1.25 g/kg) compared to control group. We conclude that administration of the aqueous extract of A. longa at saturation limit dose (2.5 g/kg) produced severe and irreversible renal toxic effects in mice induced by a high immunostimulation activity.

Key words: Aristolochia longa L., animal toxicity, traditional medicine, immunomodulatory activity.