Table 1.

Classes of natural α-glucosidase inhibitor compounds and their IC₅₀ (Half-maximal inhibitory concentration) values.

Classes of Compound	Chemical Structure	IC50 Value	Reference
Alkaloids
Vasicine		125 µM (0.8 µM)	[24]
Piperumbellactam B		43.8 µM (426 µM)	[25]
Piperumbellactam C		29.6 µM (426 µM)
Flavonoids
Quercetin		7 µM	[26]
Luteolin		21 µM
Cyanidin		4 µM
Baicalein		0.26 µM (0.02 µM)a	[27]
Quercitrin (quercetin-3-O-α-l-rhamnopyranoside		~0.5 mM (0.90 mM)	[28]
Isoquercetin		64.1 ± 3.3 µM (1.50 ± 0.14 µM) Maltase 42.5 ± 1.2 µM (2.38 ± 0.02 µM) Sucrase	[29]
Cyanidin-diglucoside		14.7 µg/mL	[30]
Pelargonidin-3-rutinoside		64.5 µg/mL
Epicatechin-(4β,8)-Epicatechin gallate		0.31 µM (5.3 µM)	[31]
Epicatechingallate		0.71 µM (5.3 µM)
Terpense
22α-hydroxychiisanoside		819.7 µM (788.6 µM)	[32]
7β-acetoxy-6β-hydroxyroyleanone		108.2 µM (131.2 µM)	[33]
Spicatanol		34.1 µM (23.8 µM)	[34]
Lupeol		7.18 µg/mL (9.68 µg/mL)	[35]
Phenols
p-hydroxycinnamic acid		90.8 µg/mL (230.4 µg/mL)	[36]
Protocatechuic acid		85.1 µg/mL (230.4 µg/mL)
Trans-N-(p-Coumaroyl)tyramine		4.47 µM (168.95 µM)	[37]
2,4-dimethoxy-6,7-dihydroxyphenanthrene		0.40 mM (3.52 mM)	[38]
Ferulic acid		4.9 mM (1.7 mM)	[39]
Ellagic acid		18.4 µg/mL	[30]
Umbelliferone		7.08 µg/mL (9.68 µg/mL)	[34]
Iminosugars
N-(9′-methoxynonyl)-1-deoxynojirimycin		0.015 µM	[40]
N-(6′-4″-azido-2″-nitrophenylamino) hexyl-1-deoxynojirimycin		0.017 µM

Values in parentheses are those of positive controls in references. ^a Concentration of a positive control showing 100% inhbition.