Present study reports on the general bioactivity of strictosamide and on its effects on Na+,K+-ATPase and Mg2+-ATPase activities of Charles River male mouse. Strictosamide is the main glycoalkaloid of Sarcocephalus; latifolius (Rubiaceae) leaves and roots, used as medicinal plant in folk medicine. In this work, we studied the in vitro effects of various concentrations of strictosamide (0.25, 0.5, 1 or 2 mg/mL) and the in vivo effects of single doses (50, 100 or 200 mg/kg, i.p.) of this compound on kidney and brain Na+,K+-ATPase and Mg2+-ATPase activities. Results of general study showed that strictosamide is slightly toxic to Charles River mouse (LD50 = 723.17 mg/kg), producing CNS depression and kidney toxicity, but the exact mechanism of these effects could not be defined. Strictosamide inhibited the in vitro and in vivo Mg2+-ATPase activity an kidney but had nonsignificant effect on brain. Furthermore, strictosamide had nonsignificant in vitro and in vivo effect on kidney Na+,K+-ATPase activity but produced an in vivo increase of Na+,K(+)ATPase activity of brain, these findings suggesting that strictosamine may be related to the induction of alpha(2) isoform of Na+,K+-ATPase and may account for the folk use of Sarcocephalus latifolius root infusion on hypertension. (c) 2008 Elsevier Ireland Ltd. All rights reserved.