Tyrosinase is a key enzyme for melanin biosynthesis, and hyperpigmentation disorders are associated with abnormal accumulation of melanin pigments, which can be improved by treatment with depigmenting agents. In the present study, piperlonguminine from Piper longum was discovered to inhibit melanin production in melanoma B16 cells stimulated with alpha-melanocyte stimulating hormone (alpha-MSH), 3-isobutyl-1-methylxanthine or protoporphyrin IX, where the compound exhibited stronger depigmenting efficacy than kojic acid. However, piperlonguminine did not affect 1-oleoyl-2-acetyl-sn-glycerol-induced melanogenesis and did not affect protein kinase C-mediated melanin production. Surprisingly, piperlonguminine did not inhibit the catalytic activity of cell-free tyrosinase from melanoma B16 cells but rather suppressed tyrosinase mRNA expression. This effect was attributed to the inhibitory action of piperlonguminine on alpha-MSH-induced signaling through cAMP to the cAMP responsive element binding protein that in turn regulates the expression of the microphthalmia-associated transcription factor, a key activator of the tyrosinase promoter. This study demonstrates that piperlonguminine is an efficient depigmenting agent with a novel mechanism of action.

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Skin hyperpigmentations such as melasma, freckles and senile lentigines can be subjectively treated by depigmenting agents. In our ongoing study to find melanogenesis inhibitors from natural sources, Piper longum L (fruits, Piperaceae) was discovered to have an inhibitory effect on alpha-melanocyte-stimulating hormone (alpha-MSH)-induced melanogenesis in melanoma B16 cells. Piperlonguminine has been identified as the melanogenesis inhibitor from P. longum by activity-guided extraction and isolation. The compound showed dose-dependent inhibitory effects with 85.1 +/- 4.9% inhibition at 25 microM, 62.1 +/- 6.1% at 12.5 microM, 36.4 +/- 4.6% at 6.3 microM and 18.4 +/- 5.1% at 3.1 microM on alpha-MSH-induced melanogenesis, showing an IC50 value of 9.6 microM. As a positive control, kojic acid exhibited an IC50 value of 44.6 microM on the melanogenesis. As to the mode of action, piperlonguminine showed an inhibitory effect on alpha-MSH-induced tyrosinase synthesis, documented by Western immunoblot analysis. However, piperlonguminine did not show an inhibitory effect on tyrosinase activity or a direct depigmenting effect of melanin.

Objective : This study was performed to investigate the effect of Needle-Embedding Therapy on peripheral facial paralysis.Method : We investigated 60 cases of patients with peripheral facial paralysis, and devided patients into two groups : We treated one group by complex korean medical treatment with Needle-Embedding therapy, and did the other group by complex korean medical treatment without Needle-Embedding therapy. Yanagihara grading system at baseline and final were used for evaluating the effect of the treatment.Results : 1. In Needle-Embedding therapy group and non Needle-Embedding therapy group, compared with baseline, at final, Y score was significantly increased. 2. At final, there was significant difference in improvement between Needle-Embedding therapy group and non Needle-Embedding therapy group. Conclusions : Needle-Embedding therapy seem to be effective to improve symptoms of peripheral facial paralysis. Further studies will be needed to identify the beneficial of Needle-Embedding therapy on peripheral facial paralysis.

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