The hydrolysis of saponin-rich extracts from fenugreek and quinoa improves their pancreatic lipase inhibitory activity and hypocholesterolemic effect

Abstract

Saponins are promising compounds for ameliorating hyperlipidemia but scarce information exists about sapogenins, the hydrolyzed forms of saponins. Saponin-rich extracts and their hydrolysates from fenugreek (FE, HFE) and quinoa (QE, HQE), and saponin and sapogenin standards, were assessed on the inhibition of pancreatic lipase and interference on the bioaccessibility of cholesterol by in vitro digestion models. All extracts inhibited pancreatic lipase (IC₅₀ between 1.15 and 0.59 mg/mL), although the hydrolysis enhanced the bioactivity of HQE (p = 0.014). The IC₅₀ value significantly correlated to the saponin content (r = -0.82; p = 0.001). Only the hydrolyzed extracts showed a reduction of bioaccessible cholesterol (p < 0.001) higher than that of phytosterols (35% reduction). Sapogenin standards exhibited no bioactivities, protodioscin and hederacoside C slightly inhibited the lipase (around 10%) and protodioscin reduced the bioaccessible cholesterol (23% reduction, p = 0.035). The hydrolysis process of saponin-rich extracts enhances the bioactivity and allows developing multibioactive products against pancreatic lipase and cholesterol absorption simultaneously.

Keywords: Cholesterol; Cholesterol (PubChem CID: 5997); Diosgenin (PubChem CID: 99474); Fenugreek; Hederacoside C (PubChem CID: 11491905); Hydrolysis; In vitro digestion; Oleanolic acid (PubChem CID: 10494); Pancreatic lipase; Protodioscin (PubChem CID: 441891); Quinoa; Sapogenins; Saponins; β-Sitosterol (PubChem CID: 222284).