Protease Inhibitors Purified from the Canola Meal Extracts of Two Genetically Diverse Genotypes Exhibit Antidiabetic and Antihypertension Properties

Abstract

Valorization of vegetable oil waste residues is gaining importance due to their high protein and polyphenol contents. Protease inhibitors (PIs), proteins from these abundantly available waste residues, have recently gained importance in treating chronic diseases. This research aimed to use canola meal of genetically diverse Brassica napus genotypes, BLN-3347 and Rivette, to identify PIs with diverse functionalities in therapeutic and pharmacological applications. The canola meal PI purification steps involved: native PAGE and trypsin inhibition activity, followed by ammonium sulfate fractionation, anion exchange, gel filtration, and reverse-phase chromatography. The purified PI preparations were characterized using SDS-PAGE, isoelectric focusing (IEF), and N terminal sequencing. SDS-PAGE analysis of PI preparations under native reducing and nonreducing conditions revealed three polymorphic PIs in each genotype. The corresponding IEF of the genotype BLN-3347, exhibited three acidic isoforms with isoelectric points (pI) of 4.6, 4.0, and 3.9, while Rivette possessed three isoforms, exhibiting two basic forms of pI 8.65 and 9.9, and one acidic of pI 6.55. Purified PI preparations from both the genotypes displayed dipeptidyl peptidase-IV (DPP-IV) and angiotensin-converting enzyme (ACE) inhibition activities; the BLN-3347 PI preparation exhibited a strong inhibitory effect with lower IC50 values (DPP-IV 37.42 µg/mL; ACE 129 µg/mL) than that from Rivette (DPP-IV 67.97 µg/mL; ACE 376.2 µg/mL). In addition to potential human therapy, these highly polymorphic PIs, which can inhibit damaging serine proteases secreted by canola plant pathogens, have the potential to be used by canola plant breeders to seek qualitative trait locus (QTLs) linked to genes conferring resistance to canola diseases.

Extraction, Isolation of Bioactive Compounds and Therapeutic Potential of Rapeseed (Brassica napus L.)

“…Preclinical studies show that these peptides exhibit glucose tolerance and high rates of insulin secretion. Thus, Brassica napus L. seeds have potential antidiabetic and antihypertensive properties [84].…”

“…The peptides present in rapeseed affect high levels of insulin secretion 680 µg/mL [84] Hypoglycemic action An extract derived from rapeseed significantly reduces serum triglyceride levels 3 g/kg [92] Atherosclerosis Rapeseed oil prevents atherosclerosis by lowering plasma triglyceride and cholesterol levels 20% [103] Antioxidant activity The methanol extract of rapeseed has an antioxidant effect 1000 µL [105] Antiviral activity An aqueous extract of rapeseed shows antiviral activity against the A/H1N1 influenza virus 0.5 mg/mL [110] Hepatitis C virus…”