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Evidence-Based Complementary and Alternative Medicine
Volume 2014, Article ID 259836, 11 pages
http://dx.doi.org/10.1155/2014/259836
Research Article

Inhibitory and Acceleratory Effects of Inonotus obliquus on Tyrosinase Activity and Melanin Formation in B16 Melanoma Cells

1College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun 130118, China
2Engineering Research Center of Edible and Medicinal Fungi, Ministry of Education, Jilin Agricultural University, Changchun 130118, China

Received 22 April 2014; Revised 19 June 2014; Accepted 30 June 2014; Published 13 August 2014

Academic Editor: Hyunsu Bae

Copyright © 2014 Zheng-Fei Yan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The aim of the present study is to preliminarily investigate the antimelanogenesis effect of Inonotus obliquus extracts by cell-free mushroom tyrosinase assay. It was found that petroleum ether and n-butanol extracts might contain unknown potential tyrosinase inhibitors, while its ethyl acetate extract might contain some unknown accelerators. Six compounds were isolated and their structures were identified by interpretation of NMR data and nicotinic acid was first discovered in Inonotus obliquus. In cells testing, betulin and trametenolic acid decreased tyrosinase activity and melanin content, while inotodiol and lanosterol significantly increased tyrosinase activity and melanin content, showing an of 9.74 and 8.43 μM, respectively. Nicotinie acid, 3β,22,25-trihydroxy-lanosta-8-ene, had a little or no effect on tyrosinase. Betulin exhibited a mode of noncompetitive inhibition with a of 0.4 μM on tyrosinase activity showing an IC50 of 5.13 μM and being more effective than kojic acid (6.43 μM), and trametenolic acid exhibited a mode of mixed inhibition with a of 0.9 μM, of 0.5 μM, and an of 7.25 μM. We proposed betulin and trametenolic acid as a new candidate of potent tyrosinase inhibitors and inotodiol and lanosterol as accelerators that could be used as therapeutic agent.