Table 3.

Antidiabetic action of peptides and protein hydrolysates identified from plant food sources.

Source	Enzyme(s) Used	Substrate	Proteins Hydrolysate	Peptide(s) Identified	Mechanism of Action	IC50	Reference
Soy bean				ASCNGVCSPFEMPPCGSSACRC IPVGLVVGYCRHPSG (aglycin)	Enhanced insulin receptor signalling pathway and enhanced glucose uptake in vivo		[85]
Soy bean				VSCNGVCSPFEMPPCGSSACR CIPYGLVVGNCRHPSG (vglycin)	Enhanced insulin signalling by activating the insulin receptor (IR)/Akt signalling pathway		[86,87]
					Restored impaired insulin signalling, glucose tolerance and pancreatic function in vivo
Soy bean		β-conglycinin		YPFVV (soymorphin-5)	Improved glucose and lipid metabolism via activation of the adiponectin and PPARα system- in vivo		[88]
Soy bean	Pepsin and pancreatin	Germinated soybeans	Protein hydrolysates		Inhibited DPP IV, α-amylase and α-glucosidase in vitro	DPP-IV inhibition- 1.49 mg/mL)	[89]
						α-amylase inhibition- 1.70 mg/mL
						Maltase and sucrase activities of α-glucosidase 3.73 and 2.90 mg/mL
Lupin bean				LTFPGSAED	Inhibited DPP IV in situ	207.5 µM	[90]
Soy bean				IAVPTGV		223.2 µM
Fermented soy bean - Natto		Water soluble extract		KL	Inhibited DPP IV in vitro	41.40 ± 2.68 μg/mL	[96]
				LA		598.02 ± 18.35 μg/mL
Black bean	Proteinase K, pepsin, trypsin, papain, alcalase, flavourzyme, themolysin, and chymotrypsin		Protein hydrolysates	EGLELLLLLLAG	Inhibited DPP IV in vitro and in silico		[97]
				AKSPLF
				FEELN
				TTGGKGGK	Inhibited α-glucosidase in vitro and in silico
				AKSPLF
				WEVM	Inhibited α-amylase in vitro and in silico
Pinto beans	Protamex		Protein hydrolysates	PPHMLP	Inhibited α-amylase in vitro	1.97 mg/mL	[98,99]
				PLPTGAGF		8.96 mg/mL
				PPHMGGP		14.63 mg/mL
				PLPLHMLP		18.45 mg/mL
				LSSLEMGSLGALFVCM		20.56 mg/mL
Common beans	Pepsin, and pancreatin		Protein hydrolysates		Lowered blood glucose level by inhibiting α-glucosidase		[100]
Bambara bean	Alcalase and thermolysin		Protein hydrolysates		Inhibited DPP IV in vitro	1.73 mg/mL	[101]
Cow pea			Peptides		Activated the insulin signalling pathway in vivo		[102]
Chickpea	Pepsin, pancreatin and bromelain		Protein hydrolysates	PHPATSGGGL	Inhibited DPP IV in vitro	245 μg/mL	[103]
				YVDGSGTPLT
Oats	Pepsin, trypsin, pancreatin, and alcalase	Globulin		LQAFEPLR	Inhibited DPP IV in vitro	103.5 μM	[106]
				EFLLAGNNK
Wheat	Debitrase HYW20	Gluten	Gluten hydrolysates	VPL WL	Inhibited DPP IV in vitro		[107]
Quinoa	Pepsin and pancreatin		Protein hydrolysates	GEHGSDGNV	Inhibited DPP IV and α-glucosidase in vitro		[109]
				IQAEGGLT	Inhibited DPP IV and α-glucosidase in vitro
				DKKYPK	Inhibited α-glucosidase in vitro
Quinoa	Papain, ficin and bromelain	Seed storage proteins		MAF	Inhibited DPPIV in vitro		[110]
				NMF
				HPF
				MCG
Amaranthus	Alcalase	Albumin and globulin	Protein hydrolysates		Inhibited DPP IV in vitro and in vivo	0.12 ± 0.01 mg/mL	[111]
Amaranthus	Pepsin and pancreatin		Protein hydrolysates	FLISCLL	Inhibited α-amylase and DPP IV in vitro		[112]
				SVFDEELS
				DFIILE
				NRPET
				HVIKPPS
Walnut	Alcalase, Trypsin, Neutrase, Protamex and Flavourzyme		Protein hydrolysates	LPLLR	Inhibited both α-glucosidase and α-amylase in vitro		[115,116]
Cumin seeds	Protamex		Seed protein hydrolysates	FFRSKLLSDGAAAAKGALLPQYW	Inhibited porcine pancreatic α-amylase in vitro		[119]
Basil seeds	Alcalase		Seed protein hydrolysates	ACGNLPRMC	Inhibited α-amylase activity in vitro		[118]
				ACNLPRMC
				AGCGCEAMFAGA