Inhibition of digestive enzymes by commercial powder extracts of Hoodia gordonii

Abstract

Ethnopharmacological evidence supporting the inhibitory effect of appetite and weight loss Hoodia gordonii (Apocynaceae) native to Africa and sold worldwide for the treatment of obesity. However, such effects have been demonstrated only by its active ingredient, the glycoside P57. There are no studies related to the presence of compounds such as enzyme inhibitors, in commercial samples of the plant, which may participate or even be responsible for the proposed effects. The objective of this study was to test the inhibition of digestive enzymes with commercial samples of H. gordonii powder (PHG). Analysis was performed, inhibition of the enzymes α-amylase, α and β-glycosidases, lipase and trypsin in the presence and absence of a simulated gastric fluid. Inhibitions were detected (expressed in units of enzyme inhibited, UEI) only the α and β glucosidases, with differences between samples. For α-glycosidase inhibition was greater in the presence (50.5 and 29.8) in the absence (10.4 and 16.7) of gastric fluid samples for HA and HB, respectively. As for β-glycosidase inhibition was not detected (25.5 and 12.9) in the absence of gastric fluid, for both samples. The results indicate that the samples PHG are only able to inhibit the digestive enzymes α and β glycosides in satisfactory levels according to the literature, especially for the first one. The presence of this inhibitory activity may therefore explain part of the slimming effect of the PHG, attributed so far only the action of the active glycoside P57. Despite the inhibition assays have shown the same answers qualitatively for the two samples, quantitative differences are found, raising questions about the standardization of commercial extracts.