Antimicrobial Substances from Rhizomes of the Giant Knotweed Polygonum sachalinense against the Fish Pathogen Photobacterium damselae subsp. piscicida
The antimicrobial compounds against the fish pathogen Photobacterium damselae subsp. piscicida were isolated from Polygonum sachalinense rhizomes. The structures of the antimicrobial compounds 1 and 2 were determined by 1H and 13C NMR, 2D-NMR (COSY, HSQC, HMBC and ROESY) and FAB-MS to be phenylpropanoid glycosides, vanicoside A and B, respectively. Both compounds have feruloyl and p-coumaroyl groups bonded to a sucrose moiety in their structures. Vanicoside A also has an acetyl group in the sucrose moiety. The MIC values for vanicoside A and B against Ph. damselae subsp. piscicida DPp-1 were 32 and 64 μg/ml, respectively. The antimicrobial activities of these vanicosides were modest, in contrast to higher activities (MICs at <4 μg/ml) of antibiotics, florphenicol, ampicillin and amoxicillin, which have been generally used for treating pasteurellosis. The activities of the vanicosides, however, were higher than those (MICs at 256 μg/ml) of ferulic acid and p-coumaric acid. It was suggested that the structure of phenylpropanoids esterified with sucrose was essential for higher antimicrobial activity of vanicosides and also acetylation of sucrose might affect the activity against the bacterium.
New sucrose phenylpropanoid esters from Polygonum perfoliatum.
Five diferuloyl esters of sucrose, 6'-acetyl-3,6-diferuloylsucrose (helonioside B) (1); 2',4',6'-triacetyl-3,6-diferuloylsucrose (2); 1, 2',4',6'-tetraacetyl-3,6-diferuloylsucro se (3); 1,2',6'-triacetyl-3, 6-diferuloylsucrose (4); and 2',6'-diacetyl-3,6-diferuloylsucrose (5), were isolated, along with the 1,3,6-tri-p-coumaroyl-6'-feruloylsucroses, vanicoside A and vanicoside B, from the whole plant of Polygonum perfoliatum by various chromatographic methods. The structures of these phenylpropanoid glycosides were determined on the basis of their NMR and mass spectroscopic data. Compound 1 is a known compound, but 2-5 are new members of this class.
Hydropiperoside, a novel coumaryl glycoside from the root of Polygonum hydropiper
Abstract From the methanol extract of the root of Polygonum hydropiper, a novel coumaryl glycoside hydropiperoside was isolated together with anthraquinone, ellagic acid 3,3′-di-O-methyl ether, gallic acid, two quercetin glycosides and an unidentified aromatic δ-lactone possessing antifertility activity. The structure of hydropiperoside was established as β- d -(1,3,6-tri-p-coumaryl)-fructofuranosyl-α- d -glucopyranoside by combination of extensive 1H NMR and 13C NMR spectra, and the FD/MS spectrum.