The antioxidant activity of capsaicin, as compared to BHT and melatonin, was determined by the direct measurement of lipid hydroperoxides formed upon linoleic acid autoxidation initiated by AIBN. The formation of four isomeric lipid hydroperoxides was detected after reverse-phase HPLC separation. Data from three detectors, UV absorption, glassy carbon electrode electrochemical detection, and po...

H and C NMR spectra were recorded with Bruker DPX-400, AVANCE-400 and DRX-500. The numbering of the protons relate to the numbering chosen in Fig. 1. High resolution mass spectra were obtained with a Micromass LCT via loop-mode injection from a Waters (Alliance 2695) HPLC system. Alternatively a Micromass Q-TOF in combination with a Waters Aquity Ultraperformance LC system was employed. Ionizat...

Ethanol and dichloromethane extracts of a Brazilian green propolis from Baccharis dracunculifolia were analyzed by HPLC-APCI-MS and GC-MS, respectively. The HPLCAPCI-MS technique, at the positive mode, furnished a complete and unequivocal chemical composition of the green propolis sample. It serves as fi ngerprint for different propolis samples. The composition of the ethanol extract consisted ...

About 30% of the polyphenols in wort and beer derive from hop, but little is yet known about their nutritional impact. The recent discovery of trans-resveratrol and piceid isomers in hop opens new doors to understanding beer health benefits. In the present work, resveratrol was quantified by HPLC-APCI-MS/MS in pellets from 9 different cultivars. Concentrations ranging from 4 to 9 mg/kg trans-pi...

Seven prenylated stilbenes were identified by combined HPLC-PAD-APCI/MSn analysis of an extract of mucilage isolated from peanut (Arachis hypogaea L.) root tips. The principal constituent was assigned the structure 4-(3-methyl-but-1-enyl)-3, 5-dimethoxy-4'-hydroxy-trans-stilbene. The common name mucilagin A is proposed for this novel compound. Its concentration in the mucilage was estimated at ...

The lyophilized venom of the spider Paracoelotes birulai (Araneidae: Amaurobiidae) has been analyzed. A no. of acylpolyamines were found and sepd. By online coupled high-performance liq. chromatog. and atm.-pressure chem.-ionization mass spectrometry, the structures of the three most abundant compds. PB 490 (N-(16-guanidino-4-hydroxy-4,8,12-triazahexadecyl)-2-(4-hydroxyindol-3-yl)acetamide), PB...

Quantitative analysis of triacylglycerols (TGs) in plant oils and animal fats by normalization of peak areas can lead to erroneous results due to the large response differences with common HPLC detectors between the various TGs. The charged aerosol detector (CAD), that generates an almost universal response for non-volatile compounds, was combined with non-aqueous reversed-phase HPLC (NARP-HPLC...