Inhibitors of recombinant protein-tyrosine phosphatase 1B (PTP1B) from Khaya senegalensis: Towards a strategic target for therapeutic intervention in trypanosomiasis

•Protein-tyrosine phosphatase is an important regulator of trypanosome differentiation and, as such, a promising therapeutic target for trypanosomiasis.•In an active fraction of Khaya senegalensis stem bark, potent inhibitors of recombinant human protein-tyrosine phosphatase (PTP1B) were discovered.•Three of the seven compounds in the active fraction (n-tridecanoic acid, n-hexadecanoic acid, and 14-pentadecenoic acid) were analogs of myristic acid with the general formula R-(CH2)n-COOH.•These are PTP1B inhibitors that are both potent and naturally occurring, with a low inhibitor binding constant (Ki).