Antimalarial efficacy of a quantified extract of Nauclea pobeguinii stem bark in human adult volunteers with diagnosed uncomplicated falciparum malaria. Part 2: a clinical phase IIB trial - Mesia, K; Tona, L; Mampunza, M M; Ntamabyaliro, N; Muanda, T; Muyembe, T; Musuamba, T; Mets, T; Cimanga, K; Totté, J; Pieters, L; Vlietinck, A J (Planta Med, 2012)