Simultaneous quantitative analysis of 12 methoxyflavones with melanogenesis inhibitory activity from the rhizomes of Kaempferia parviflora

Abstract

A methanol extract from the rhizomes of Kaempferia parviflora Wall. ex Baker (Zingiberaceae) has shown inhibitory effects against melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells (IC50 = 9.6 μg/mL). Among 25 flavonoids and three acetophenones isolated previously (1-28), several constituents including 5-hydroxy-7,3',4'-trimethoxyflavone (6, IC50 = 8.8 μM), 5,7,3',4'-tetramethoxyflavone (7, 8.6 μM), 5,3'-dihydroxy-3,7,4'-trimethoxyflavone (12, 2.9 μM), and 5-hydroxy-3,7,3',4'-tetramethoxyflavone (13, 3.5 μM) showed inhibitory effects without notable cytotoxicity at the effective concentrations. Compounds 6, 7, 12, and 13 inhibited the expression of tyrosinase, tyrosine-related protein (TRP)-1, and TRP-2 mRNA, which could be the mechanism of their melanogenesis inhibitory activity. In addition, a quantitative analytical method for 12 methoxyflavones (1, 2, 4-11, 13, and 14) in the extract was developed using HPLC. The optimal condition for separation and detection of these constituents were achieved on an ODS column (3 μm particle size, 2.1 mm i.d. × 100 mm) with MeOH-0.1 % aqueous acetic acid solvent systems as the mobile phase, and the detection and quantitation limits of the method were estimated to be 0.08-0.66 ng and 0.22-2.00ng, respectively. The relative standard deviation values of intra- and interday precision were lower than 0.95 and 1.08 %, respectively, overall mean recoveries of all flavonoids were 97.9-102.9 %, and the correlation coefficients of all the calibration curves showed good linearity within the test ranges. For validation of the protocol, extracts of three kinds of the plant's rhizomes collected from different regions in Thailand (Leoi, Phetchabun, and Chiang Mai provinces) were evaluated. The results indicated that the assay was reproducible, precise, and could be readily utilized for the quality evaluation of the plant materials.

3‐O‐Glyceryl‐2‐O‐hexyl ascorbate suppresses melanogenesis by interfering with intracellular melanosome transport and suppressing tyrosinase protein synthesis

“…B16 cells (8 × 10 3 cells/well) were seeded into 48‐well plates in DMEM. After preculture with samples (100 μmolL −1 ) and theophylline (1 mmolL −1 ) for 72 hours, melanin contents in cells were measured according to the protocol described previously …”

Characterization of phenolic compounds from normal ginger (Zingiber officinale Rosc.) and black ginger (Kaempferia parviflora Wall.) using UPLC–DAD–QToF–MS

“…Thailand is recognized as a center of diversity, and distribution to different region of Asia [22]. In previous studies, 25 methoxyflavones and their glycosides were identified and quantified as predominant flavonoids from rhizome extracts (Supplementary Table 2) [23][24][25][26]. The presence of these compounds contributed to a wider range of medicinal effects such as antiinflammatory [27], antioxidant [28,29], antiproliferative activity [30], hepatoprotective effect [31], and anticancer [32].…”

Aromatase Inhibitory Activity of Geranylated Coumarins, Mammeasins C and D, Isolated from the Flowers of <i>Mammea siamensis</i>

“…[1][2][3][4][5][6][7][8][9][10] Several coumarins, [1][2][3][4][5][6][7] xanthones, 8,9) triterpenoids, 10) and steroids 10) have been isolated from the flowers, 1,2,6,7,10) seeds, 3,9) twigs, 4,8) and bark 5) of this plant. In the course of our characterization studies on bioactive constituents in Thai natural medicine, 1,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] we reported that the methanol extract of the flowers of M. siamensis and its coumarin constituents showed inhibitory effects on nitric oxide production in lipopolysaccharide-activated RAW264.7 cells.…”

“…In the course of our characterization studies on bioactive constituents in Thai natural medicine, 1,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] we reported that the methanol extract of the flowers of M. siamensis and its coumarin constituents showed inhibitory effects on nitric oxide production in lipopolysaccharide-activated RAW264.7 cells. 1) Further studies revealed that the methanol extract inhibited enzymatic activity against aromatase.…”