Validation of an HPLC-method for an antiplasmodially active stem bark extract of Nauclea pobeguinii

Stem bark extracts of Nauclea pobeguinii (Rubiaceae) are widely used in African traditional medicine against malaria. Alkaloids, such as the major compound strictosamide, may be responsible for this activity [1,2]. An HPLC-method for the quantification of strictosamide in the stem bark extract of N. pobeguinii was developed. The method was validated according to the ICH guidelines. The response function of ajmalicine HCl, used as a secondary standard, was linear in a range from 4.2 to 21.2µg/mL. The method was shown to be precise in respect to the time (RSD of 2.2%, 3 days, n=6) and with respect to the concentration (RSD of 2.6%, 3 levels, n=6). The accuracy of the method was investigated by means of a recovery experiment (mean recovery of 92.2% and RSD of 9.4%).