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We used a [.sup.1]H NMR-based metabonomics approach to examine the physiological effects of the seaweed Ascophyllum nodosum in a mammalian model, assess the dosage level required to elicit a response in the urinary profile, and identify potential toxic effects. Male Sprague-Dawley rats (n = 6/group) were fed a control or 5, 10, or 15% freeze-dried, ground A. nodosum diet for 4 wk. Urine samples were collected 3 times daily (0-4, 4-8, and 8-24 h) prior to feeding experimental diets and, at the end of the study, were profiled using [.sup.1]H NMR spectroscopy. Food intake, weight gain, and serum enzyme (alanine transaminase and aspartate transaminase) levels indicated that seaweed diets were well tolerated. The spectral data and principal component analysis (PCA) revealed that rats fed 5, 10, and 15% seaweed diets had increased urinary excretion of citrate, 2-oxoglutarate, succinate, trimethylamine (TMA), TMA-N-oxide, and malonate and decreased excretion of taurine, creatinine, and acetate compared with the controls. In addition, mannitol was detected in the 8- to 24-h urine samples from seaweed-fed rats. Metabolic responses related to ingestion of seaweed polyphenolics and fiber were not observed in the spectral profiles. Increased seaweed concentration in the diet did not increase the magnitude of the rats' response as detected by [.sup.1]HNMR. Visual analysis and PCA of the spectral data for serum samples collected at the end of the study did not show diet-related clustering. The lack of toxicity at 15% seaweed incorporation allows the use of this concentration in future A. nodosum intervention studies. J. Nutr. 139: 1487-1494, 2009.

Biosynthetic origins of the cyclic 13-desmethyl spirolide C were determined by supplementing cultures of the toxigenic dinoflagellate Alexandrium ostenfeldii with stable isotope-labeled precursors and measuring the incorporation patterns by (super 13)NMR spectroscopy. Results reveal that such cyclic toxins are polyketides and support the biosynthetic pathways, used for other polyether dinoflagellate toxins.

The isolation of six CD-spiro-triterpenoids from the bark extract of Ruptiliocarpon caracolito and their characterization are presented. The structure of the spirocaracolitones A-F was examined by a combination of proton and carbon N

Spirolides are marine phycotoxins produced by the dinoflagellates Alexandrium ostenfeldii and A. peruvianum. Here we report that 13-desmethyl spirolide C shows little cytotoxicity when incubated with various cultured mammalian cell lines. When administered to mice by intraperitoneal (ip) injection, however, this substance was highly toxic, with an LD50 value of 6.9 μg/kg body weight (BW), showing that such in vitro cytotoxicity tests are not appropriate for predicting the in vivo toxicity of this toxin. Four other spirolides, A, B, C, and 20-methyl spirolide G, were also toxic to mice by ip injection, with LD50 values of 37, 99, 8.0 and 8.0 μg/kg BW respectively. However, the acute toxicities of these compounds were lower by at least an order of magnitude when administration by gavage and their toxic effects were further diminished when administered with food. These results have implications for future studies of the toxicology of these marine toxins and the risk assessment of human exposure. [ABSTRACT FROM AUTHOR]

Extracts of the brown seaweed Ascophyllum nodosum have been used as a biostimulant to promote growth and productivity in a number of agricultural production systems. Although the extracts have been shown to improve seedling emergence and vigor in a variety of plants, including barley, the mechanism(s) of this growth-promoting effect is(are) largely unknown. In our study, A. nodosum extract induced amylase activity in barley seed-halves; a significant difference in amylase activity was observed in seeds without an embryo. The addition of activated charcoal to the treatment media negated the bioactivity of the extracts suggesting the organic nature of bioactive compounds in A. nodosum extracts. The extracts induced amylase activity in a gibberellic acid (GA)-deficient barley mutant ( grd2). LC-MS-MS analysis failed to detect the presence of GA3 in the extracts. ABA supplementation of the medium caused a significant reduction of amylase activity in GA-treated seeds compared with those treated with the A. nodosum extract. Taken together, our results suggest that the organic components of A. nodosum extract induce amylase activity independent of GA3 and might act in concert with GA-dependent amylase production leading to enhanced germination and seedling vigor in barley. Being derived from a renewable resource, the bioactive compounds from A. nodosum could be used to improve crop productivity in sustainable agricultural systems. [ABSTRACT FROM AUTHOR]

Betaines are a class of quaternary ammonium compounds found in marine algae that can act as osmolytes and/or affect gene expression, and therefore improve plant tolerance to stresses such as temperature extremes, drought, and salinity when applied to agricultural crops. In humans, glycine betaine acts as a methyl donor and has been shown to protect internal organs, improve vascular risk factors, and enhance sport performance. Here we describe a sensitive LC-MS-MS method for the baseline separation and quantification of four betaines found in algae, namely, glycine betaine, δ-aminovaleric acid betaine, γ-aminobutyric acid betaine, and laminine.

Phlorotannins are a class of polyphenols found in brown seaweeds that have significant potential for use as therapeutics, owing to their wide range of bioactivities. Molecular characterization of phlorotannin-enriched extracts is challenging due to the extreme sample complexity and the wide range of molecular weights observed. Herein, we describe a method for characterizing phlorotannins employing ultrahigh-pressure liquid chromatography (UHPLC) operating in hydrophilic interaction liquid chromatography (HILIC) mode combined with high-resolution mass spectrometry (HRMS).

Background: Ursolic acid and its cis- and trans-3-O-p-hydroxycinnamoyl esters have been identified as constituents of American cranberries (Vaccinium macrocarpon), which inhibit tumor cell proliferation. Since the compounds may contribute to berry anticancer properties, their content in cranberries, selected cranberry products, and three other Vaccinium species (V. oxycoccus, V. vitis-idaea and V. angustifolium) was determined by liquid chromatography-mass spectroscopy. The ability of these compounds to inhibit growth in a panel of tumor cell lines and inhibit matrix metalloproteinase (MMP) activity associated with tumor invasion and metastasis was determined in DU145 prostate tumor cells., Results: The highest content of ursolic acid and esters was found in V. macrocarpon berries (0.460-1.090 g ursolic acid and 0.040-0.160 g each ester kg(-1) fresh weight). V. vitis-idaea and V. angustifolium contained ursolic acid (0.230-0.260 g kg(-1) ), but the esters were not detected. V. oxycoccus was lowest (0.129 g ursolic acid and esters per kg). Ursolic acid content was highest in cranberry products prepared from whole fruit. Ursolic acid and its esters inhibited tumor cell growth at micromolar concentrations, and inhibited MMP-2 and MMP-9 activity at concentrations below those previously reported for cranberry polyphenolics., Conclusion: Cranberries (V. macrocarpon) were the best source of ursolic acid and its esters among the fruit and products tested. These compounds may limit prostate carcinogenesis through matrix metalloproteinase inhibition., (Copyright © 2011 Society of Chemical Industry.)

Our investigations into the stability of tincture preparations of milk thistle fruit [ Silybum marianum L. Gaertn. (Asteraceae)] have led to the characterization of a new flavonolignan 4-(4-hydroxy-3-methoxyphenyl)-7-[(2 R,3 R)-3,5,7-trihydroxy-4-oxochroman-2-yl]-1-oxo-1,3,3a,4,5,7a-hexahydro-2-benzofuran-5-carboxylic acid called silyamandin (1). Incubation of the tincture at 40 degrees C for 3 months resulted in an increase in the level of this compound, as observed in the LC/DAD silymarin profile.

1H-NMR (nuclear magnetic resonance)-based chemometric methods have been applied for the first time to investigate changes in the plasma metabolite profiles of Atlantic salmon Salmo salar as a result of exposure to Aeromonas salmonicida subsp. salmonicida, a Gram-negative bacterium that is the etiological agent of furunculosis. Plasma samples were obtained from salmon that survived 21 d post exposure to A. salmonicida, and from a control group maintained under similar conditions. 1D 1H-NMR spectra were acquired and principal components analysis (PCA) was used to assess differences between the spectral profiles of plasma from salmon that survived an A. salmonicida challenge, and non-infected controls. PCA enables simultaneous comparison of spectra, presenting a simplified overview of the relationship between spectral data, where spectra cluster based on metabolite profile similarities and differences; information regarding the metabolite variations can therefore be readily deciphered. The major metabolite changes responsible for the spectral differences were related to modification in the lipoprotein profile and choline-based residues, with minor changes in carbohydrates, glycerol, trimethylamine-N-oxide and betaine. These changes indicated that exposure to A. salmonicida induced a characteristic biochemical response which could be used to determine the health status of salmon. This study suggests that with further development this metabolite profiling technique may be a useful tool for diagnosis of disease states in salmon and could provide a better understanding of the host-pathogen relationship which at present is poorly understood for A. salmonicida and Atlantic salmon.