Presence of Alkaloids and Cyanogenic Glycosides in Fruits Consumed by Sympatric Bonobos and the Nkundo People at LuiKotale/Salonga National Park, Democratic Republic of Congo and Its Relationship to Food Choice

Abstract

The importance of secondary compounds remains poorly studied in wild plants eaten by bonobos (Pan paniscus) and humans. As part of this study, alkaloids and cyanogenic glycosides (cyanide) were investigated in wild fruits consumed by bonobos at LuiKotale in Salonga National Park. In high concentrations, the two components can become toxic. Therefore, we investigated whether the bonobos and the Nkundo people avoid high concentrations of these components in their food. To analyze alkaloids and to detect the presence of cyanogenic glycosides, we used semi-quantitative methods. Of the 75 species of fruit analyzed, 28 species (37%) were revealed to have alkaloids at different proportions and 47 species (63%) were shown to be without alkaloids, 12 species (16%) with low concentrations (+), 14 species (19%) with moderate concentrations (++), and two species (3%) with high concentrations (+++). Of the 75 species, 60 were eaten, of which 46 were consumed only by bonobos, 13 were eaten by both bonobos and the Nkundo people, and one species (Piper guinensis) was eaten only by the Nkundo people. In total, bonobos ate 59 species and the Nkundo people 14 species. Of the 60 species consumed, the majority, i.e., 39 species (65%) did not show the presence of alkaloids, while 11 species (18%) showed a low concentration and 10 species (17%) moderate concentrations. As for cyanogenic glycosides (cyanide), this was detected in only three of the 75 species of fruit analyzed. Two species, Camptostylus mannii and Dasylepsis seretii, belong to the Achariaceae family, with Oncoba welwitschii in the Salicaceae family. The two species of Achariaceae both contain alkaloids and cyanogenic glycosides. No species eaten by the Nkundo contained cyanogenic glycosides. Hence, we infer that bonobos and the Nkundo people both avoid eating fruit species that contain high concentrations of alkaloids and cyanogenic glycosides, and this might have relevance linked to the evolution of seed dispersal.