Euscaphinin, a New Ellagitannin Dimer from Euscaphis japonica (THUNB.) KANITZ

Abstract

NotesRecent studies on plant polyphenols have revealed various biological activities for ellagitannins.1,2) Distribution of ellagitannins in plants is relatively limited compared with that of condensed tannins (proanthocyanidins).3) In this study, we proposed to find new plant sources of functional polyphenols and examined the leaves, bark and wood of 39 plant samples belonging to 32 genera of 29 families, distributed in the Nagasaki region of Japan, by thin-layer chromatography (TLC) and high performance liquid chromatography (HPLC). Plants belonging to the Elaeocarpaceae, 4) Myricaceae, 5) Anacardiaceae, 6) Juglandaceae, 7) Stachyuraceae,8) and Fagaceae [9][10][11] families were shown to contain high concentrations of polyphenols, substances that have already been studied chemically. Unexpectedly, our study disclosed accumulation of ellagitannins in the leaves of Euscaphis japonica (THUNB.) KANITZ (Staphyleaceae). E. japonica is a deciduous tree distributed in western Japan, and little is known about the phenolic constituents of this plant. [12][13][14][15][16] Presence of ellagitannins in Staphyleaceae has not yet been reported. This paper describes the isolation and structural determination of two ellagitannins, including a new dimeric ellagitannin. Results and DiscussionAn aqueous acetone extract of the fresh leaves of E. japonica was subjected to a combination of Diaion HP20SS, Sephadex LH-20, and Chromatorex ODS column chromatography to furnish two major phenolic compounds. One of the products was identified as 1(b)-O-galloyl pedunculagin (1) 17,18) by comparisons of 1 H-NMR spectral data, HPLC retention time and UV absorption with those of an authentic sample.Compound 2 was isolated as a white amorphous powder and produced a dark-blue coloration upon reaction with FeCl 3 and a brown coloration upon reaction with NaNO 2 -AcOH reagent, 19) suggesting this compound is an ellagitannin. The Rf value on silica gel TLC was much smaller than that of 1 and the matrix-assisted laser desorption/ionizationtime-of-flight (MALDI-TOF) MS showed a [MϩNa] ϩ peak at m/z 1893, indicating that 2 is a dimeric ellagitannin. This was supported by appearance of signals attributable to two sugar anomeric protons [d 6.16 (1H, d, Jϭ8.5 Hz, Glc-1), 6.06 (1H, d, Jϭ8.7 Hz, Glc-1Ј)] in the 1 H-NMR spectrum.The sugar was confirmed to be D-glucose by the HPLC analysis of the thiocarbamoyl-thiazolidine derivative of the acid hydrolysis products.20) The chemical shifts (d 3.7-6.2) and the large coupling constants of the sugar proton signals were similar to those of 1 and indicated that the anomeric positions were b-configurations and that all the hydroxyl groups of the pyranose ring were acylated. In the aromatic region of the spectrum, nine singlets [d 7.16, 6.66, 6.65, 6.51, 6.50, 6.47, 6.46, 6.33, 6.33] and two mutually coupled doublets [d 7.30, 6.84 (each d, Jϭ1.9 Hz)] were observed. The hetero-nuclear multiple-bond connectivity (HMBC) correlations (Fig. 2) of these aromatic protons indicated that all of the protons are attached t...

Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles

“…Peak 3 yielded a [M-H]ion at m/z 447 (corresponding to an aglycone) and a major fragment ion at m/z 284 due to the loss of a hexose unit, and was identified as kaempferol-3-O-glucoside. These results were confirmed by comparisons with MS data in previous reports [63][64][65]. Previous studies showed that flavonoids quercetin-3-O-glucuronide and kaempferol-3-O-glucoside exhibited antibacterial activity by reducing the fluidity of the inner and outer layers of bacterial membranes, inhibiting DNA and RNA synthesis, and deterring energy metabolism [66].…”

Screening for melanogenesis-controlled agents using Sudanese medicinal plants and identification of active compounds in the methanol extract of Terminalia brownii bark

“…NMR data for these compounds were completely the same to previous reports [10][11][12][13][14][15][16][17].…”

“…1) [10][11][12][13][14][15][16][17]. Among the isolated compounds, 2 and 3 were identified as a/b(3/2)-punicalagin (2) and a/b(3/2)-terchebulin (3).…”

Selection and evaluation of reference genes for qRT-PCR analysis in Euscaphis konishii Hayata based on transcriptome data

“…Euscaphis has been widely used in traditional Chinese medicine. Several chemical compounds have been isolated from Euscaphis , such as triterpene compounds [ 26 – 29 ], phenolic acid compounds [ 30 , 31 ], flavonoid compounds [ 27 , 31 ] and others [ 31 – 33 ], however, no molecular and gene expression data has been reported in Euscaphis .…”