Potential exploitation of Shea press cakes in glycaemia regulation: Inhibition of α-amylase and α-glucosidase by protein and methanolic extracts

Shea (Vitellaria paradoxa) tree is integrally used in traditional medicine for the treatment of several health disturbances. Its kernels fat is widely exploited for food, medicinal and cosmetic purposes. Nevertheless germinated kernels are considered as waste, whereas shea germinative power would be very high. Their anti-diabetic ability was evaluated in vitro, in ordre to highlight their pharmacological benefits. Therefore, both proteins (crude, digested and dialysed ones) and hydroalcoholic extracts, were prepared from germinated and ungerminated shea seed press cakes. The anti-diabetic essay was carried out by evaluating extracts inhibiting power on both α-amylase and α-glucosidase activities. Proteins were quantified by spectrophotometry (214 nm). Results revealed that the protein content of the extracts from germinated seed cakes was 450 mg/100 g and that of the extracts from ungerminated shea seed cakes was 410 mg/100 g. The percentage of inhibition of α-amylase by the dialysed extracts of germinated shea seeds, in this case the external dialysate of germinated seed, presented the best rate of inhibition with 30.21 %. Contrary to the percentage of inhibition of α-amylase, the highest rates of inhibition of α-glucosidase were recorded with the crude protein extracts of sprouted seeds (82.02 %) and unsprouted seeds (62.32 %).  For methanolic extracts, the highest inhibition of α-amylase and α-glucosidase was recorded by the ungerminated seeds, with 42.61% for α-amylase and 97.47% for α-glucosidase. These results show that protein extracts of shea seed cakes may play a role in blood glucose regulation.