Melanin is the phenolic biopolymer that is responsible for pigmentation. Although melanin plays a crucial role in absorbing free radicals from the cytoplasm and shielding from UV light, the overproduction and accumulation of melanin in the skin could be a serious skin disorder. 1) Current therapies for skin pigmentation disease are unsatisfactory. Thus the search for natural and synthetic chemical agents to modulate the metabolism of pigmentation is of great interest. 2)Melanin biosynthesis occurs in a cascade of enzymatic and spontaneous reactions that convert tyrosine to melanin pigments.3) The initial and rate-limiting step in melanin synthesis, the hydroxylation of tyrosine to dihydroxyphenylalanine (DOPA), is controlled by tyrosinase that is the key enzyme in the process. 4) Since the 1980s, skin cancer researchers have studied the melanin biosynthetic pathways, which led to the development of whitening cosmetics and medicines.5) Arbutin, kojic acid, hydroquinone and its derivatives were developed in 1980s.6) However, the clinical effects of those chemicals are unsatisfactory because of their low activity and cell toxicity. 7) Therefore there is a need for safe and effective whitening agents.Kaempferia pandurata ROXB. is a perennial herb of the Zingiberaceae family mainly cultivated in tropical countries, including Indonesia and Thailand. The fresh rhizome has been used as a food ingredient and as a folk medicine for the treatment of colic, dry cough, rheumatism, musle pain, and as an aphrodisiac.8) Several studies reported various activities of K. pandurata, including antiinflammatory, antitumor, antidiarrhea, antidysentery, antiflatulence, and antiepidermophytid effects. 9) Isopanduratin A and 4-hydroxypanduratin A (Fig. 1) are the typical chalcone compounds found in K. pandurata. Chalcones belong to a group of phenolic compounds in the flavonoid family and widely occur in nature as pigments. This category of flavonoids has a broad bioactive spectrum such as anticancer, antibacterial, antifungal activities, etc. [10][11][12] In previous studies, chalcone compounds in K.pandurata showed anticancer, antioxidative, antimutagenic, and antibacterial activities. [13][14][15] However, their depigmenting effect has not yet been examined. Therefore we focused on evaluating the inhibitory effects of chalcone compounds isolated from K. pandurata on melanin biosynthesis and tyrosinase. Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, South Korea: and c R&D Center, Amore-Pacific Corporation; 314-1, Bora-dong, Kiheung-gu, Yongin-si, Kyounggi-do 449-729, South Korea. Received April 11, 2007; accepted July 20, 2007 This study was carried out to investigate the in vitro effects of isopanduratin A and 4-hydroxypanduratin A isolated from Kaempferia pandurata ROXB. on melanin biosynthesis and tyrosinase activity. Two chalcone compounds, isopanduratin A and 4-hydroxypanduratin A, were isolated from the ethyl acetate fraction of ethanol extract as the active principles. Compared with phenylthiourea (IC 50 ‫3.4...

Hyperpigmentation disorders are associated with abnormal accumulation of melanin pigments, thus melanin synthesis inhibitors have been of great interest as target molecules for cosmetic and medicinal purposes. The aim of this study was to investigate the in vitro inhibitory effect of panduratin A, isolated from Kaempferia pandurata Roxb., on melanogenesis and its related enzymes such as tyrosinase, tyrosinase related protein-1 (TRP-1) and tyrosinase related protein-2 (TRP-2) in melan-a murine melanocytes. The IC(50) values of panduratin A for melanogenesis and tyrosinase were 9.6 μm and 8.2 μm, respectively, while those of arbutin as a positive control were 990 μm and 660 μm, respectively. In western blot analysis, panduratin A also significantly decreased tyrosinase, TRP-1 and TRP-2 protein levels. These results indicate that panduratin A effectively inhibits melanin biosynthesis, thus creating the possibility of developing a new skin-whitening agent.

329 Background: As indication for endoscopic resection for gastric neoplasms have been expanded, patients receiving multiple times of endoscopic resection for metachronous or synchronous lesions have been increasing. We aimed to compare clinicopathologic characteristics of patient with gastric neoplasm in a single location and multifocal lesions of three or more. Methods: From January 2006 to December 2021, 255 patients underwent endoscopic resection for three or more of multifocal lesions at tertiary medical institution were reviewed retrospectively and 8667 patient showed no recurrence after endoscopic resection for single lesion. The clinicopathologic characteristics of index gastric lesions were compared. Results: The male ratio was higher in multifocal lesions group than single lesion group (83.9% vs. 68.4%, P < 0.001). Diabetes mellitus was significantly more in multifocal lesions group than single lesion group (20.4% vs. 18.4%, P = 0.046), however hypertension, cardiovascular disease, kidney disease, and hepatitis showed no significant difference between the two groups. Smoking rate was significantly higher in the multifocal lesions group (current smoker 31.0% vs. 25.4%, and ex-smoker 24.7% vs. 24.8%, P = 0.028). In rapid urease test for Helicobacter pylori infection, the multifocal group showed significantly higher positives (54.9% vs. 40.8%, P < 0.001). Tumor depth, lymphovascular invasion, and perineural invasion showed no significant differences. Conclusions: Patients with multifocal early gastric neoplasms showed higher male ratio, higher rate of diabetes mellitus, and smoking rate compared with single lesion group. In addition, Helicobacter pylori infection was also significantly higher in patients with multifocal gastric neoplasm.