The trypsin inhibitor content of 61 wild edible plant foods of Niger

In the western Sahel and many other regions of sub-Saharan Africa,wild edible plants contribute significantly to human diets, notonly during periods when cereal staples are scarce, but also whenthey are readily available. Although there have been publishedreports regarding the nutrient contents of these plant foods,little attention has been devoted to their content of antinutrientssuch as calcium chelators and inhibitors of the pancreas-derivedproteases, trypsin and chymotrypsin, which are required for theefficient digestion and absorption of dietary proteins. In thisstudy, aqueous extracts of 61 different leaves, seeds, fruits andflowers of edible plants gathered in the Republic of Niger wereanalyzed for their content of trypsin inhibitory substances using-N-benzoyl-DL-arginine-p-nitroanilide as the substrate andbovine trypsin as the enzyme source. Twelve of these plant foodscontained more antitrypsin activity than soybeans (1.34–8.18 vs.1.32 g trypsin inhibited/mg dry weight). Boiling for 3 mindid not inactivate the antitrypsin activity in most of the plantextracts. These data confirm that more than half of the wildedible plant foods widely consumed by various populations whoinhabit the western Sahel contain significant quantities of heat-stable trypsin inhibitor that could possibly compromise thebioavailability of proteins present in the diets of these populations.