. 2021 Aug 22;22(16):9059. doi: 10.3390/ijms22169059

Table 1.

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

Source	Enzyme(s) Used	Substrate	Protein Hydrolysate	Peptide(s) Identified	Mechanism of Action	IC₅₀	Reference
Cow milk	Trypsin	Milk protein	Milk protein hydrolysates		Reduced blood plasma glucose level in vivo		[52]
Donkey milk	Pepsin and pancreatin		Milk protein hydrolysates		Improved damaged β-cells viability in vitro, reduced blood glucose level and improved insulin resistance in vivo		[53]
Goat milk	Flavourzyme	Casein	Casein hydrolysate	SDIPNPIGSE	Ameliorated insulin resistance in HepG2 cells		[54]
				NPWDQVKR
				SLSSSEESITH
				QEPVLGPVRGPFP
Goat milk	Trypsin and chymotrypsin	Casein	Casein hydrolysate	MHQPPQPL	Inhibited DPP IV in vitro	350.41 ± 4.1 μM	[55]
				SPTVMFPPQSVL		676.31 ± 12.6 μM
				VMFPPQSVL		Nd
				INNQFLPYPY		40.08 ± 5.0 μM
				AWPQYL		Nd
Camel milk	Alcalase, bromelain, and papain	Milk proteins	Milk protein hydrolysates	MPSKPPLL	Inhibited pancreatic α-amylase in vitro		[56]
Camel milk	Alcalase, bromelain, and papain	Milk proteins	Milk protein hydrolysates	KDLWDDFKGL	Inhibited pancreatic α-amylase in vitro		[56]
Camel milk	Trypsin	Milk proteins	Milk protein hydrolysates	FLQY	Inhibited DPP IV in vitro	>1000 μM	[57]
				FQLGASPY		>1000 μM
				ILDKEGIDY		347.8 ± 42.8 μM
				ILELA		721.1 ± 46.3 μM
				LLQLEAIR		177.8 ± 22.2 μM
				LPVP		87.0 ± 3.2 μM
				LQALHQGQIV		>1000 μM
				MPVQA		93.3 ± 8.0 μM
				SPVVPF		214.1 ± 16.7 μM
Gouda cheese	Microbial fermentation	Water-soluble extracts (WSEs)		LPQNIPPL	Reduced glucose level in vivo and inhibited DPP IV in vivo and in vitro	46 μM	[60]
				LPQ		82 μM
				VPITPTL		110 μM
				VPITPT		130 μM
Egg	Alcalase	Egg white protein	Egg white protein hydrolysates	RVPSLM	Inhibited α-glucosidase in vitro	23.07 μmol/L	[61]
				TPSPR		40.02 μmol/L
				DLQGK		>150.0 μmol/L
				AGLAPY		>150.0 μmol/L
				RVPSL		>150.0 μmol/L
				DHPFLF		>150.0 μmol/L
				HAEIN		>150.0 μmol/L
				QIGLF		>150.0 μmol/L
Egg	Pepsin	Egg yolk protein	Egg yolk protein hydrolysates	YINQMPQKSRE,	Inhibited DPP IV in vitro	222.8 μg/mL	[62]
Egg	Pepsin	Egg yolk protein	Egg yolk protein hydrolysates	VTGRFAGHPAAQ	Inhibited α-glucosidase in vitro	365.4 μg/mL	[62]
Turtle egg	Trypsin, pepsin, α-chymotrypsin, thermolysin, and GI enzyme	Egg yolk protein	Egg yolk protein hydrolysates	LPSW	Inhibited DPP IV in vitro and in silico	289.2 ± 11.85 μM	[63]
				WLQL		269.7 ± 15.91 μM
				LPLF		463.6 ± 5.52 μM
				VPGLAL		>2000
				LVGLPL		432.5 ± 40.31 μM
Chicken egg	Pepsin and trypsin	Myosin and lysozyme		ADF	Inhibited DPP IV in vitro and in silico	16.83 mM	[64]
				MIR		4.86 mM
				FGR		46.2 mM
Cooked meat (pork, beef, chicken, and turkey)	Amylase, pepsin and trypsin	Meat proteins	Meat protein hydrolysates	IPI	Inhibited DPP IV in vitro	3.5 μmol/L	[65]
				WL		44 μmol/L
				LPL		241 μmol/L
				WI		89 μmol/L
				FL		400 μmol/L
				LW		993 μmol/L
Cooked meat (Pork, chicken and turkey)				VL		74 μmol/L
				WM		243 μmol/L
				ML		91 μmol/L
Cooked meat (Pork and beef)				IP		150 μmol/L
				LP		712 μmol/L
				AL		882 μmol/L
Cooked meat (Chicken and turkey)				FP		363 μmol/L
Cooked meat (Pork)				IPM		70 μmol/L
Dry cured ham				KA	Inhibited DPP IV in vitro	6.27 ± 0.59 mM	[66]
				AA		9.40 ± 0.10 mM
				GP		9.69 ± 0.49 mM
				PL		>10 mM
				AAATP		6.47 ± 0.20 mM
				AAAAG		8.13 ± 0.48 mM
				ALGGA		>10 mM
				LVSGM		>10 mM
Chicken feet	Neutrase and protamex	Feet protein	Feet protein hydrolysates		Stimulated GLP-1 release in vivo and inhibited DPP IV in vitro	4.42 ± 0.1 μL	[67]
Chicken by product	Flavourzyme and corolase	Mechanical chicken deboning residue	Protein hydrolysates	TL	Promoted glucose uptake and inhibited DPP IV in vitro		[68]
				HT
				LA
				LADVEVDLL
				LL
				ETGKGEDGE
				FL
				LFFSMLLML
				LF

Nd—Not determined.