Two trimeric proanthocyanidins, cinnamtannin B-1 (1) and cinnamtannin D-1 (2), have been isolated from the bark of Cinnamomum cassia along with the known tetramer parameritannin A-1 (3) and a previously unreported tetramer, named cassiatannin A (4). The structures of 1-4 were elucidated on the basis of 1D and 2D NMR, MS, and CD analyses and compared to the reported data. Proanthocyanidins (1-4) possess significant in vitro inhibitory activity against cyclooxygenase-2 (COX-2) at micromolar concentrations.
Cranberry (Vaccinium macrocarpon) juice is traditionally used for the prevention of urinary tract infections. Human urine produced after cranberry juice consumption can prevent Escherichia coli adhesion, but the antiadhesive urinary metabolites responsible have not been conclusively identified. Adult female sows were therefore fed spray-dried cranberry powder (5 g/kg/day), and urine was collected via catheter. Urine fractions were tested for antiadhesion activity using a human red blood cell (A+) anti-hemagglutination assay with uropathogenic P-fimbriated E. coli. Components were isolated from fractions of interest using Sephadex LH-20 gel filtration chromatography followed by HPLC on normal and reversedphase sorbents with evaporative light scattering detection. Active urine fractions were found to contain a complex series of oligosaccharides but not proanthocyanidins, and a single representative arabinoxyloglucan octasaccharide was isolated in sufficient quantity and purity for full structural characterization by chemical derivatization and NMR spectroscopic methods. Analogous cranberry material contained a similar complex series of arabinoxyloglucan oligosaccharides that exhibited antiadhesion properties in preliminary testing. These results indicate that oligosaccharides structurally related to those found in cranberry may contribute to the antiadhesion properties of urine after cranberry consumption. a All protons appeared as overlapping multiplets unless otherwise indicated. b Numerical assignments are tentative due to signal overlap. c Approximate J value. d A reliable numerical J value assignment could not be made due to signal overlap.
Two new five-membered-ring peroxide acids, plakinic acid F (3) and epiplakinic acid F (4), and a new peroxide-lactone, plakortolide F (5), were isolated from a sponge of the genus Plakinastrella collected from Felicite Island, Seychelles. The structures were elucidated through spectral analysis. The free acids 3 and 4 exhibit moderate antifungal activity against Candida albicans with minimum inhibitory concentrations of 25 micrograms/mL (SDB) and 3.1 micrograms/mL (RPMI) for 3, and 25 micrograms/mL (SDB) and 6.25 micrograms/mL (RPMI) for 4, respectively. Both also showed moderate in vitro inhibition of Aspergillus fumigatus with IC90's of 25 micrograms/mL.
Cured meat pigment from cooked corned beef was isolated and completely characterized by IR and visible spectroscopies and shown to be identical with synthetic material that was further identified by fast atom bombardment mass spectrometry as the mononitrosyl species nitrosyliron(I1) protoporphyrin. The 'H
Two new compounds, a long chain ester 1 of p-coumaric acid and a prenylated isoflavone, senegalensin [5], 5,4'-dihydroxy-8-(gamma,gamma-dimethylallyl)-[5"-(hydroxyisopropyl ) (2",3":6.7)] isoflavone, in addition to a known long chain ester 2 of ferulic acid, have been isolated and characterized from the stem bark of the Cameroonian medicinal plant Erythrina senegalensis. Another known compound 3, a long chain ester of ferulic acid, was isolated from Erythrina excelsa. The structures of all the compounds were determined by spectroscopic techniques.
Introduction
Commercial cranberry supplements provide a low‐sugar alternative to juices and sweetened fruit consumed for health benefits, but their phytochemical composition and associated biological activity varies depending on the source material and post‐harvest processing. Proton nuclear magnetic resonance (1H‐NMR) is a rapid and environmentally friendly method of generating metabolic profiles of plant materials that may be used to authenticate cranberry products.
Objective
The 1H NMR‐based chemometrics were used to characterise variations in metabolic profiles of cranberry supplements in comparison to a whole cranberry powder reference standard.
Materials and Methods
The secondary metabolite profiles of nine commercial cranberry supplements were compared to a whole cranberry powder reference standard, using 1H‐NMR with Bruker AssureNMR software and principal component analysis (PCA). Content of selected triterpenoids and organic acids was determined by quantitative NMR. Total proanthocyanidins and anthocyanins were determined by established methods.
Results
PCA of 1H‐NMR spectra showed overlap between the cranberry standard and three supplements, but most products varied substantially in metabolic profile. Metabolites contributing to the observed variance include citric acid and cranberry peel constituents ursolic acid, oleanolic acid and hyperoside. Ursolic, oleanolic, citric, quinic and malic acids were readily determined by quantitative 1H‐NMR in the whole cranberry standard, but were below detection limits in many supplements. Proanthocyanidin and flavonoid content in several products was minimal or below detection limits.
Conclusion
The 1H‐NMR chemometrics found significant variation in composition of characteristic cranberry metabolites among commercial preparations, reinforcing the need for reliable industry standards
A new purine derivative microxine (1) was isolated from the Australian marine sponge Microxina sp. The compound was isolated via reversed-phase chromatography and its structure determined spectroscopically. Microxine was found to weakly inhibit cdc2 kinase activity with an IC(50) of 13 microM.
A deep-water sponge of the genus Spongosorites has yielded a bis-indole alkaloid which we have named dragmacidin G. Dragmacidin G was first reported by us in the patent literature and has recently been reported by Hitora et al. from a sponge of the genus Lipastrotheya. Dragmacidin G is the first in this series of compounds to have a pyrazine ring linking the two indole rings. It also has a rare N-(2-mercaptoethyl)-guanidine side chain. Dragmacidin G shows a broad spectrum of biological activity including inhibition of methicillin-resistant Staphylococcus aureus, Mycobacterium tuberculosis, Plasmodium falciparum, and a panel of pancreatic cancer cell lines.
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