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(13)C, (15)N CPMAS NMR and GIAO DFT calculations of stereoisomeric oxindole alkaloids from Cat's Claw (Uncaria tomentosa)

AbstractOxindole alkaloids, isolated from the bark of Uncaria tomentosa [Willd. ex Schult.] Rubiaceae, are considered to be responsible for the biological activity of this herb. Five pentacyclic and two tetracyclic alkaloids were studied by solid-state NMR and theoretical GIAO DFT methods. The (13)C and (15)N CPMAS NMR spectra were recorded for mitraphylline, isomitraphylline, pteropodine (uncarin... READ MORE

New A-type Trimeric and Tetrameric Procyanidins from Peanut Skins

AbstractPeanut skins constitute up to 4% w/w of peanuts and are a unique source of A-type procyanidins. Methanol extract of the skins was purified by Centrifugal Partition Chromatography (FCPC Kromaton, Roussel Robatel; France) and RP HPLC to afford pure procyanidins. They contain both epicatechin (EC) and catechin (C) subunits, which are joined through 4β–8 or 4α–6 bonds. The extract contai... READ MORE

Presence of 1-(2,4,6-trihydroxyphenyl)-3-(3,4-dihydroxyphenol)-propanol-2 in Grape Seed Extract indicates involvement of anaerobic bacteria in the production stages

AbstractForty six samples of Grape Seed Extract from domestic and international producers were analyzed chromatographically by RP HPLC and by NMR to evaluate chemical diversity. In six samples a prominent peak of an unknown phenolic substance reaching up to 2 % was found and was subsequently attributed to 1-(2,4,6-trihydroxyphenyl)-3-(3,4-dihydroxyphenol)propanol-2 (TDP). TDP is known to be produc... READ MORE

Four A-type procyanidin trimers are main flavanol components of Cinnamomum burmanii

AbstractCinnamon spice is derived from bark of several Cassia and Cinnamomum genera. Depending on the origin, there are distinctive differences between composition of the water-soluble procyanidins, which are mainly consisting of A-type procyanidins, attributed with anti-diabetic activity. Trimers are dominant group, while tetramers are at ca. 20% of the trimer content and other oligomeric DPs con... READ MORE

Honey, Bees, and Hepatotoxis Alkaloid Echimidine

AbstractEchimidine (1) is the main pyrrolizidine alkaloid of Echium plantagineum L, (Jane’s Salvation, Patersons Curse), endemic to Australia[1]. The plant is a great attractant for bees and as a result echimidine finds its way into honey. Because of its hepatotoxicity, echimidine became a target of new EU regulation requiring testing of imported honey. Under normal RP HPLC conditions echimidine... READ MORE

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