Structure determination of the extractives from the Taxus cuspidata fruits

초록

The fruits of Taxus cuspidata were collected, divided into seeds and fruits, and extracted with 95% EtOH. The extracts were evaporated under the reduced vacuum pressure, concentrated, then successively fractionated with a series of n-hexane, dichloromethane, ethyl acetate and water on a separatory funnel to get some freeze dried samples. A portion of the EtOAc (arils:1.65 g, seeds:1.04 g) and H<inf>2</inf>O (arils:7 g, seeds:10 g) soluble samples were chromatographed on a Sephadex column using MeOH-H<inf>2</inf>O (1:1, 1:3, 1:5, v/v), EtOH-hexane (3:1, v/v) mixture and 100% H<inf>2</inf>O as eluting solvents to isolate pure compounds from the fractions. The isolates were developed by cellulose TLC using t-BuOH-HOAc-H<inf>2</inf>O (TBA; 3:1:1, v/v/v) and 6% aqueous HOAc. Visualization was done under ultraviolet light and by spraying the vanillin-HCl-EtOH reagent (4.8:12:480, v/v/v). followed by heating. The structures of the isolates were characterized by 1H- and 13C-NMR, DEPT, 2D-NMR, LC/MS and EI-MS spectra. In addition to the NMR and MS spectra, acid hydrolysis and permethylation were used to determine the correct structure of the isolated sugar compound. Their structures were elucidated as (+)-catechin (1), (-)-epicatechin (2), (+)-gallocatechin (3), (-)-epigallocatechin (4) and β-D-fructofuranose-(2→4)-O-β-D- glucopyranose(1→4)-O-α-D-glucopyranose (1→2)-O-β-D- fructofuranose (5) on the basis of the above experimental evidences.

키워드