Inhibition of melanogensis by a novel origanoside from Origanum vulgare.
BACKGROUND
Natural and synthetic substances are becoming increasingly utilized as tyrosinase inhibitors of depigmentation and developed cosmetics industry. However, few have been employed as skin-whitening agents, primarily because of numerous safety concerns.


OBJECTIVE
A novel compound was found, and then its safe concentrations and inhibition effect of hyperpigmentation by the regulation of the tyrosinase family of proteins were examined.


METHODS
A novel phenolic glucoside, origanoside (1), was isolated from Origanum vulgare. The structure of the origanoside (1) was established on the basis of spectral evidence and the safe concentrations were determined by MTT assay. Skin-whitening capacity in skin fibroblast Hs68 and melanoma B16 cells and in vivo animal test for origanoside (1) were investigated.


RESULTS
Origanoside (1) is non-toxic in concentrations of 0-100 microg/ml in both cells. The ability of origanoside (1) to inhibit cellular tyrosinase and DOPA oxidase in B16 cells was investigated. Origanoside (1) significantly reduced expressions of microphthalmia-associated transcription factor (MITF), tyrosinase and tyrosinase-related proteins 2 (TRP-2) in vitro and in vivo, suggesting that origanoside (1) is responsible for the antimelanogenic effect. Smearing origanoside (1)-gel samples on 12 mice for 10 days increased L*, reduced a* and erythema-melanin (E/M), and b* was almost unchanged compared with those of samples and untreated groups, indicating that the skin lightened.


CONCLUSIONS
Experimental data demonstrate that origanoside (1) causes depigmentation and may be useful for novel food additives and skin-whitening cosmetics.
Liang
Chia-Hua
CH
Department of Cosmetic Science, Chia Nan University of Pharmacy and Science, Tainan, Taiwan.
Chou
Tzung-Han
TH
Ding
Hsiou-Yu
HY
D000818:Animals; D001104:Arbutin / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D005960:Glucosides / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D062385:Hydroxybenzoates / Q000302:isolation & purification / Q000494:pharmacology*; D008543:Melanins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D015394:Molecular Structure; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D031341:Origanum; D010936:Plant Extracts / Q000494:pharmacology*; D012880:Skin Pigmentation / Q000187:drug effects*
D005960:Glucosides; D062385:Hydroxybenzoates; D008543:Melanins; D010936:Plant Extracts; C549999:origanoside; D001104:Arbutin; D014442:Monophenol Monooxygenase; D001205:Ascorbic Acid