. 2020 Apr 24;20(1):173–185. doi: 10.3892/etm.2020.8687

Table II.

Tyrosinase inhibitors from natural sources and characterization of the active compounds.

		Mode of action
Structure type	Source	Mechanism	IC50	(Refs.)
Anthraquinones
Hydroquinone	Coffee, cranberries and blueberries.	Alternative substrate	75 µM^a	(74,75)
Arbutin	Cranberries, blueberries, wheat and pears	Alternative substrate	0.17 µM^a; 4.0 µM^b	(76,77)
Flavonoids
Epigallocatechin gallate	Tea	Copper chelation	-	(80)
Quercetin	Sophora japonica	Competitive inhibition	30.8 µM^a	(81)
Aloesin	Aloe vera	Competitive inhibition, Dopa oxidation	0.17 mM^a	(82,83)
Glabridin, semilicoisoflavone B, allolicoisoflavone B	Glycyrrhiza	^^^^	0.43 µM^a; 0.25 µM^a; 0.80 µM^a	(87,88)
Anthocyanosides	Black soya bean, red grapes	Scavenging free radicals	-	(96)
Flavonoid compounds and ferulic acid	Spiranthes sinensis	Copper chelation	0.21 mg/ml^a	(95)
2,4,2',4'-Hydroxycalcone	Morus australis	Competitive inhibition	0.21 µM^a	(93)
Fleminchalones A-C	Flemingia philippinensis	Competitive inhibition	1.28 µM^a	(92)
Baicalin	Scutellaria baicalensis	Inhibition of tyrosinase expression and activity	-	(97)
Soybean extracts	Soybean	Inhibition of tyrosinase expression and activity	-	(91)
Carthamus yellow	Carthamus tinctorius	Competitive inhibition	1.01 mg/ml^a	(94,100)
Coumestrol	Medicago sativa	Inhibition of tyrosinase expression	-	(98)
Resveratrol analogs
Resveratrol	Grape, Polygonum cuspidatum	Alternative substrate	54 µM^a; 250 µM^b	(85,86)
Phenylpropanoids
Ferulic acid	Tetragonia tetragonioides, Angelicae Gigantis Radix	Inhibition of tyrosinase expression		(103)
Cinnamic acid esters	Origanum vulgare	-	16.13 µM^a	(102)
Benzaldehyde	Cinnamon oil, bitter almond oil	Partial noncompetitive inhibition	31.0 mµM^a	(101)
Olefinic unsaturated compounds
Astaxanthin, astaxanthin esters	Green alga Haematococcus pluvialis	Inhibition of tyrosinase expression	-	(104,105)
Curcumin	Curcuma aromatica Salisb.	Inhibition of tyrosinase expression	0.18 mM^a	(106)
Others
Kojic acid	Aspergillus solid culture	Copper chelation	6.2 µM^a; 250 µM^b	(107,108)
Bis(4-hydroxybenzyl)sulfide	Rhizome of Gastrodia elata	Copper chelation	0.53 µM^a	(114)
Methyl gentisate	Radix gentianae	Copper chelation	11.2 µM^a; 30.9 µM^b	(109,110)
Ganodermanondiol	Ganoderma lucidum	Inhibition of tyrosinase expression	-	(111,112)
10-Hydroxy-2-decenoic acid	Royal jelly	Inhibition of tyrosinase expression	-	(113)
S. japonicus extracts	Stichopus japonicus	Inhibition of tyrosinase expression	-	(66)

^aKinetics study on mushroom tyrosinase;

^bkinetics study on melanocyte or melanoma cell cultures.