Cornus officinalis Methanol Extract Upregulates Melanogenesis in Melan-a Cells

Abstract

Cornus officinalis is widely distributed in Korea, and its fruit has been used to make as herbal drug for traditional medicine in Korea, Japan, and China because of its tonic, analgesic, and diuretic properties. However, the effects of C. officinalis methanol extract (COME) on melanogenesis remain poorly understood. We evaluated the melanogenic capability of COME in melan-a cells, which are immortalized mouse melanocytes. COME increased melanin synthesis in a dose-dependent manner. Treatment with 12.5 μg/mL of COME significantly increased melanin content by 36.1% (p < 0.001) to a level even higher than that (31.6%) of 3-isobutyl-1-methyl-xanthine, a well-known pigmentation agent. COME also upregulated tyrosinase activity and its messenger RNA and protein expression. In addition, COME upregulated the expression of tyrosinase-related proteins 1 and 2 and microphthalmia-associated transcription factor-M messenger RNA expression. These results imply that COME may be appropriate for development as a natural product to treat hair graying.

Keywords: Cornus officinalis; Hair graying; Melan-a cells; Melanogenesis; Tyrosinase activity.

Fig. 1.. Total polyphenol and flavonoid content of Cornus officinalis methanol extract (COME). Values are means ± standard deviation (SD) of three measurements.

Fig. 2.. Electron-donating capabilities of 2,6-di-tert-butylate hydroxytoluene (BHT) and Cornus officinalis methanol extract (COME). Values are means ± SD of three measurements.

Fig. 3.. Cell viability of melan-a cells treated with 3-isobutyl-1-methylxanthine (IBMX) and Cornus officinalis methanol extract (COME). Values are means ± SD of three measurements.

Fig. 4.. Effect of Cornus officinalis methanol extract (COME) on the synthesis of melanin in melan-a cells. Values are means ± SD of three measurements. C: control, IBMX: 3-isobutyl-1-methylxanthine. Values with different superscripts are significantly different (p < 0.001) with analysis of variance and Duncan’s multiple range test. *p < 0.05 compared with the control group.

Fig. 5.. Effect of Cornus officinalis methanol extract (COME) on tyrosinase activity in melan-a cells. COME was added to melan-a cells, and intracellular tyrosinase activity was measured after 60 min. COME was added to the cell extract and cell-extracted tyrosinase activity was measured after 60 min. Values are means ± SD of three measurements. C: control, IBMX: 3-isobutyl-1-methylxanthine. Values with different superscripts are significantly different (p < 0.001) with analysis of variance and Duncan’s multiple range test.

Fig. 6.. Effect of Cornus officinalis methanol extract (COME) on melanogenic gene expression in melan-a cells. COME upregulated tyrosinase (A) and microphthalmia-associated transcription factor-M (MITF-M; D) gene expression but did not affect tyrosinase-related protein 1 (TRP-1; B) and TRP-2 (C) gene expression. Values are means ± SD of three measurements. C: control, IBMX: 3-isobutyl-1-methylxanthine. Values with different superscripts are significantly different (p < 0.001) with analysis of variance and Duncan’s multiple range test.

Fig. 7.. Effects of Cornus officinalis methanol extract (COME) on melanogenic protein expression in melan-a cells. COME upregulated tyrosinase (A), tyrosinase-related protein 1 (TRP-1; B), and TRP-2 (C) protein expression. Values are means ± SD of three measurements. C: control, IBMX: 3-isobutyl-1-methylxanthine. Values with different superscripts are significantly different (p < 0.001) with analysis of variance and Duncan’s multiple range test.