Tyrosinase inhibitory activity

A large number and diverse classes of compounds have been reported to possess tyrosinase inhibitory activities to various extents from the millimo-lar to nanomolar concentration ranges. From our laboratory we have also reported a large variety of tyrosinase inhibitors and for some of them we have performed molecular modeling as well. Among them there are several alkaloids, and nitrogen-containing molecules are also present. 

Fig. 3 Molecular structures of the synthesized sildenafil (3) and some of its analogues (4-7) which exhibited promising tyrosinase inhibitory activities [43]...

Table 1 The tyrosinase inhibitory activities of compounds 3-7, as compared to the standard inhibitors (kojic acid and L-mimosine) [43]...

Table 2 Tyrosinase inhibitory activities of the diterpenoid and napelline type alkaloids and their derivatives [49]...

Selenoureas are prepared by reaction of isoselenocyanates with amines, or by reaction of carbodiimides with a mixture of LiAlH4/Se and by reaction of cyanamides with LiAlH4/Se.267 272 The tyrosinase inhibitory activity and superoxide radical scavenger effect of selenoamides and selenoureas have been investigated (Scheme 84).273 275... 

Gandia-Herrero, F, Jimenez, M, Cabanes, J, Garcia-Carmona, F, Escribano, J. 2003. Tyrosinase inhibitory activity of cucumber compounds enzymes responsible for browning in cucumber. J Agric Food Chem 51(26) 7764-7769. 

New 3-amino-5-ethenylcyclopentenones, myrothenones A 292 and B 293, were isolated together from the marine algicolous fungus of genus of Myrothecium. Compounds 292 exhibited a tyrosinase inhibitory activity with IC50 values of 6.6 pM, which is more active than kojic acid... 

Mulberroside F (104) showed moderate inhibitory effects on tyrosinase activity and on the melanin formation of melan-a cells. It also exhibited superoxide scavenging activity that is involved in the protection against auto-oxidation [62]. The geranylated stilbenes 81 and chlorophorin from Chlorophora excelsa [51], prenylated ones 4-prenyloxyresveratrol and artocarbene (72) from Artocarpus incisus [528] all demonstrated tyrosinase inhibitory activity (ICso 96, 1.3, 0.66 and 2.45 //M, respectively). 

Artogomezianol (527) and andalasin A (543) from the roots of Artocarpus gomezianus showed moderate tyrosinase inhibitory activity [274]. Resveratrol oligomers from dipterocarpaceae plants were also reported to have inhibitory effects on murine tyrosinase activity. The SARs revealed that the double bond in the stilbene skeleton was critical for the inhibition, and also that with increased molecular size, the inhibitory potency decreased [529]. 

For the development of a skin-whitening agent, Sophora flavescens was examined for tyrosinase inhibitory activity. The ethanol extract and dichloromethane fraction from S. flavescens showed significantly their inhibi-... 

Fig. 29 Prenylated flavonoids with tyrosinase inhibitory activity from Sophora flavescens and kojic acid (a control) (126)...

Garcinia subelliptica Merr. (leaves) Biflavanones-. (2/ ,35)-I-5,7,4, ll-5,7,3, 4 -heptahydroxy-(I-3,II-8)-flavanone-flavone(164) GB2a(172). Tyrosinase inhibitory activity. Masuda et al., 2005 [202]. 

Fig. 4 Molecular structures of NdV-unsubstituted selenourea derivatives exhibiting tyrosinase inhibitory activities [44]...

Table 2. Tyrosinase Inhibitory Activity of Acyclic Terpene Alcohol at 100 gg/ml...

Khanom, F, H. Kayahara, and K. Tadasa. 2000. Tyrosinase inhibitory activity of Bangladeshi indigenous medicinal plants. Biosci. Biotechnol. Biochem. 64(9) 1967-1969. 

Liu et al. [34] synthesized a series of dihydropyrimidinone and rhodanine derivatives and tested their tyrosinase inhibitory activity. The results showed that some of the S5mthesized... 

Recently, it was foimd that kojic add-tripeptide amides showed similar tyrosinase inhibitoiy activities to those of kojic add-tripeptide free adds but exhibited superior storage stability than those of kojic acid and kojic add-trip>eptide free acids (Noh, 2007). To find further kojic acid derivatives with higher tyrosinase inhibitory activity, stability, and synthetic effidency, a library of kojic add-amino acid amides (KA-AA-NH2) prepared and screened for their tyrosinase inhibitoiy activities. It was also confirmed that the kojic add-phenylalanine amides reduced the amount of dopachrome production during the melanin formation. It was suggested that a tyrosinase inhibition mechanism of KA-AA-NH2 based on the possible hydrophobic interadions between the side chain of KA-AA-NH2 and tyrosinase active site by a docking program (Noh, 2009 Kim, 2004). 

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