Congolese edible caterpillars, valuable sources of bioactive compounds with human health benefits

Insects are part of the regular diet of more than two billion people around the world and are not only delicacies. Insects provide great opportunities to replace meals but can have important additional benefits as well. In the Democratic Republic of the Congo (DRC), caterpillars are the most consumed insects, and they are consumed by more than 70% of the population throughout the year. The aim of this research was to report the microscopic features, mineral micronutrients, chromatographic fingerprints, antioxidant activities and peroxidase inhibition of edible Congolese caterpillars of the genus Cinabra, Imbrasia and Gonimbrasia from DRC. Microscopic analysis showed the presence of characteristic features, specific to each host plant of caterpillars, such as palisade cells, stomata, trichomes, sclereids, fibres, vessels, pollen and starch grains. Phytochemical screening by chromatographic techniques revealed the presence of phenolic acids, flavonoids and terpenes as major secondary metabolites. Elemental analysis on dry matter showed that studied caterpillars are insects containing significant amounts of micronutrients such as copper, magnesium, manganese, selenium and zinc. Gonimbrasia belina had the highest selenium, magnesium and zinc content (0.12 g/100 g, 0.17 g/100 g and 0.011 g/100 g, respectively) than Cirina forda, Cinabra hyperbius, Imbrasia truncata and Imbrasia sp., C. forda and Imbrasia sp. had the highest copper content (0.003 g/100 g). C. forda had the highest manganese content (0.006 g/100 g). All aqueous extracts displayed high radical-scavenging activities with IC50 values ranging from 10 to 80 mu g/ml. Extracts showed the best cellular antioxidant activities on reactive oxygen species-induced chemiluminescence using L012 on human leucocytes 60 monocytes related to their IC50 values less than 0.5 mu g/ml. In specific immuno-extraction followed by enzymatic detection of myeloperoxidase assay, all extracts of caterpillars exhibited a dose-dependent inhibitory effect on myeloperoxidase activity in the range concentrations of 1 to 20 mu g/ml excepted extracts of Imbrasia epimethea, Imbrasia sp. and I. truncata. Our results showed that insects are not only valuable source of lipids, proteins and micronutrients such as selenium but also are sources of phytochemicals with therapeutic benefits.