Robert T. Rosen

Antioxidant activity and phenolic compounds of Swiss chard (Beta vulgaris subspecies cycla) extracts

The antioxidant activity (radical scavenging and thiocyanate method), total phenolic contents (gallic acid equivalents) and phenolic composition (coulometric array detection) in methanol extracts of different parts and tissue types of hydroponically grown Swiss chard (Beta vulgaris subspecies cycla) were determined. Significant differences (P <0.01) in the antioxidant activity were found between leaves and stems. Phenolic content and composition of the leaves and the stems also were found to be different. A positive linear correlation (R=0.943) was demonstrated between radical scavenging activity and total phenolic content of each extract. The major phenolic acid and flavonoid in leaves of Swiss chard were syringic acid and kaempferol. Coulometric array detection showed good reproducibility (CV, 0.06–1.05%) and sensitivity (1 ng/ml, detection limit) for simultaneous detection of 13 phenolics. Our data indicates that Swiss chard has potential as a good dietary source of phenolic antioxidants.

Determination of Alkylphenol Ethoxylates and Their Acetic Acid Derivatives in Drinking Water by Particle Beam Liquid Chromatography/Mass Spectrometry

Abstract Particle beam liquid chromatography/mass spectrometry (PB/LC/MS) was used to analyze finished drinking water for non-volatile organic compounds. 500 liters of finished water were extracted with an on-line continuous liquid/liquid extractor with dichloromethane at pH 7.4. PB/LC/MS was an excellent tool to detect and identify ng/L concentrations of alkylphenol polyethoxylates (n = 3−8), materials which went undetected by on-column gas chromatography/mass spectrometry. In addition, alkylphenol polyethoxylate carboxylates with 2–7 degrees of ethoxylation could be detected without chemical derivatization.

Prospective, Multicenter, Randomized Phase II Trial of the Herbal Supplement, PC-SPES, and Diethylstilbestrol in Patients With Androgen-Independent Prostate Cancer

PURPOSE To evaluate the herbal combination, PC-SPES, and diethylstilbestrol (DES) in patients with androgen independent prostate cancer (AIPC). PATIENTS AND METHODS A randomized phase II study was conducted with cross-over design. Patients were randomly assigned to receive either three PC-SPES capsules orally three times a day or DES 3 mg orally once a day. Prophylactic warfarin was administered. At clinical or prostate-specific antigen progression, patients received the other therapy. The study closed prematurely after PC-SPES was withdrawn from the market. Chemical analyses were performed on multiple lots of PC-SPES. RESULTS Ninety patients were enrolled, of whom 85 were assessable for response. Prostate-specific antigen declines > or = 50% were noted in 40% (95% CI, 25% to 56%) with PC-SPES, and 24% (95% CI, 12% to 39%) with DES. Median response duration was not reached with PC-SPES, and was 3.8 months with DES. Median time to progression for randomly assigned patients was 5.5 months for PC-SPES and 2.9 months for DES. Common toxicities included mild fatigue, gynecomastia, and mastodynia. Five thromboembolic events occurred (one PC-SPES, four DES). Responses in the cross-over phase were inconclusive. Four lots of PC-SPES had measurable quantities of DES, ranging from 0.01% to 3.1% of the dose used in the DES arm. Ethinyl estradiol was also detected in PC-SPES lots. CONCLUSION PC-SPES and DES demonstrate activity in AIPC and are well tolerated. However, the synthetic estrogens, DES and ethinyl estradiol, were detected in various lots of PC-SPES, including those used in this trial. Clinical trials that utilize herbal therapies must account for issues of purity and consistency.

Chemical studies on antioxidant mechanism of tea catechins: analysis of radical reaction products of catechin and epicatechin with 2,2-Diphenyl-1-picrylhydrazyl

Tea catechins, an important class of polyphenols, have been shown to have wide spectrum of antitumor activity believed to be due mainly to their antioxidative effect. In this study, the radical scavenging behavior of catechins on 2,2-diphenyl-1-picrylhydrazyl (DPPH) was studied. Two reaction products of (+)-catechin, and two reaction products of (-)-epicatechin were purified and identified. Their structures were determined on the basis of detailed high-field 1-D and 2-D NMR spectral analysis. Structure elucidation of these products can provide insights into specific mechanisms of antioxidant reactions. A possible mechanism of the formation of reaction products is suggested.

Characterization of powdered turmeric by liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry

Five commercial powdered turmeric samples were analyzed to identify major and minor components. The developed HPLC method allows the separation of curcumin, demethoxycurcumin and bisdemethoxycurcumin, as well as three other major components and numerous minor components. The separation was accomplished on an octadecyl stationary phase using a mobile phase consisting of 50 mM ammonium acetate with 5% acetic acid and acetonitrile as the organic modifier. Thermospray mass spectra were obtained for all of the components. Particle beam EI-mass spectra were obtained for the curcuminoids, but could not be obtained for the other components due to the limitations of the particle beam interface when analyzing volatile and semi-volatile compounds. EI mass spectra for the volatile components were obtained by direct thermal desorption-gas chromatography-mass spectrometry (DTD-GC-MS).

Formation of Pyrazines from the Maillard Reaction of Glucose and Lysine-.alpha.-amine-15N

The contribution of amino and amide nitrogen atoms to pyrazine formation in both dry and aqueous systems was investigated. The 15N isotope labeled at the amide side chain of glutamine was chosen to react with glucose at 180 degrees C in the studies. Pyrazine, methylpyrazine, ethylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, 2,3-dimethylpyrazine, vinylpyrazine, and 2-ethyl-5-methylpyrazine were identified from heating the isotope-labeled glutamine with glucose in a dry system. Similar types of pyrazines were also found in an aqueous system. The exception was 2-vinyl-5-methylpyrazine, which was produced instead of 2-ethyl-5-methylpyrazine. These results demonstrated that deamidation did participate in pyrazine production and more than half of the nitrogen sources of pyrazines came from the amide side chains of glutamine. The yields of pyrazines from the dry system were higher than that from the aqueous system.

Determination of glucosinolates in domestic and wild mustard by high-performance liquid chromatography with confirmation by electrospray mass spectrometry and photodiode-array detection

A method has been developed to easily separate and quantify glucosinolates in mustard and winter cress plants using reversed-phase HPLC with volatile ion-pairing reagents to modify the mobile phase and enhance retention and selectivity. Volatile buffers are required for HPLC-electrospray mass spectrometry. Confirmation of identity was accomplished using both negative ion electrospray mass spectrometry and photodiode-array detection. This method provides a way to determine glucosinolates in Brassica and cruciferous vegetables, most of which are commercially unavailable. Glucosinolates were determined in various parts and sections of yellow and brown domestic mustards and winter cress (wild mustard). Results varied from 0.2 mg/g glucosinolate content in the roots of the plants to 26 mg/g in the seeds.

Chemical studies of the antioxidant mechanism of tea catechins: radical reaction products of epicatechin with peroxyl radicals

Tea catechins, an important class of polyphenols, have been shown to have antioxidant activity and are thought to act as antioxidants in biological systems. However, the mechanisms of their antioxidant reactions remain unclear. The objective of this study was to characterize the reaction products of epicatechin with peroxyl radicals generated by thermolysis of the azo initiator azo-bisisobutyrylnitrile (AIBN). Structural elucidation of these products can provide insights into specific mechanisms of antioxidant reactions. Eight reaction products were isolated and identified using high-field 1D and 2D NMR spectral analysis. The observation of these compounds confirmed that the B-ring is the initial site for formation of reaction products in the peroxyl radical oxidant system.

Chemical studies on antioxidant mechanism of garcinol: analysis of radical reaction products of garcinol with peroxyl radicals and their antitumor activities

Abstract Antioxidant actions of garcinol ( 1 ), a polyisoprenylated benzophenone, purified from Garcinia indica fruit rind, are believed to contribute to its chemopreventive activity. However, the mechanisms of its antioxidant reactions remain unclear. The objective of this study was to characterize the reaction products of garcinol with peroxyl radicals generated by thermolysis of the azo initiator azo-bis-isobutyrylnitrile (AIBN). Structure elucidation of these products can provide insights into specific mechanisms of antioxidant reactions. Four reaction products ( 2–5 ) were isolated and identified. Their structures were determined on the basis of detailed high field 1D and 2D spectral analysis. The identification of these products provides the first unambiguous proof that the double bond of the isopentenyl group is a principal site of the antioxidant reaction of 1 . The induction of apoptosis in human leukemia HL-60 cells, the inhibition of NO generation, and the inhibition of LPS-induced iNOS gene expression by Western blot analysis by 1 and its four oxidation products ( 2–5 ) were investigated.

Videofluoroscopic and scintigraphic analysis of dysphagia in the head and neck cancer patient

This paper presents two advances in the evaluation of swallowing function which better define the swallowing processes in the head and neck cancer patient. Videofluoroscopy, improved by computer‐assisted image analysis, provides more accurate information regarding oral and pharyngeal movement of structures. Radionuclide scintigraphy, a complementary technique, quantitatesbolus flow (transit times) and the degree of aspiration. Several cases demonstrate the advantages of the methods and their usefulness in evaluating the effects of cancer treatment. The improved techniques also provide opportunity for designing new strategies of medical and surgical rehabilitation.