Showing papers in "Phytochemistry in 1997"

TL;DR: The secondary metabolites isolated from Piper species for the period 1907 to June 1996 have been reviewed in this paper, where nearly six hundred chemical constituents belonging to different classes of bioactive compounds are listed together with their source(s) and references.

TL;DR: A structure model for the active site of tyrosinases is proposed using hemocyanin structure as a template by comparing its structure with respect to enzymes, domain structure, Cu binding sites, maturation mechanism and activation mechanism.

TL;DR: This review, with 350 references, gives information on the chemical study of 234 naturally occurring tetraoxygenated xanthones in 12 families, 53 genus and 182 species of higher plants, and two which are described as fungal and lichen metabolites.

TL;DR: Biochemical properties which may contribute to these allelochemical activities were analysed and berberine and palmatine were most active at the alpha 2-receptor, and sanguinarine intercalate DNA, inhibit DNA synthesis and reverse transcriptase.

TL;DR: In this paper, five hop compounds were isolated from the resin part of the female inflorescences of Humulus lupulus, together with four known hop flavonoids, i.e. xanthohumol, 2.

TL;DR: Investigation in tomato seedlings found copper was found to be the most unfavourable for plant growth and lipid metabolism, and the possible mechanisms by which heavy metals, especially Cu, induce a strong lipid shift are discussed.

TL;DR: The results indicate that the removal of tannins from plant extracts prior to screening for receptor activities may result in missing biologically active compounds with specificity of action.

TL;DR: Comparison with the essential oils obtained from plants collected from the same localities in mid-summer shows noticeable differences in the total oil content and the concentration of the four main oil components.

TL;DR: The essential amino acids lysine, threonine, methionine and isoleucine are synthesised in higher plants via a common pathway starting with aspartate through the regulation of the pathway, and the properties of the key enzymes described.

TL;DR: The structures of the new saponins were elucidated on the basis of spectroscopic analyses, including two-dimensional NMR techniques, and chemical reactions.

TL;DR: A compilation of the triterpenoids isolated during the period 1990-1994 along with their occurrence, physical data, spectroscopy and X-ray analysis used for their characterization, is included.

TL;DR: In this paper, an anthocyanin-type pigment, vitisidin A, was found in small amounts in some red wines and at trace levels in stored grapes.

TL;DR: In this article, freeze-dried materials of cider apple pulp and skin were submitted to three successive solid-liquid extractions and the results revealed that they were a mixture of highly polymerized procyanidins mainly constituted of (−)-epicatechin units.

TL;DR: There have been major advances in the folate biochemistry of animal, bacterial, fungal and plant systems, including the refinement of methods for folate isolation and characterization and the detailed characterization of proteins that catalyze the generation and utilization of one-carbon substituted folates.

TL;DR: Naringenin, the first intermediate of the flavonoid pathway, displayed growth inhibition of Xanthomonas strains and spore germination of P. oryzae, while no such inhibition was found with Rhizoctonia solani.

TL;DR: A range of flavanols and proanthocyanidin dimers were identified and identified from Lotus pedunculatus as discussed by the authors, and their chemical constitution was studied by 13C NMR and by acid-catalysed degradation in the presence of excess phloroglucinol.

TL;DR: The melatonin concentration remained low or undetectable during the light period and increased during the darkness reaching a maximum at hours 4–6 of the dark period before rapidly decreasing.

TL;DR: It is suggested that increasing salinity in the growth medium increases the degree of fatty acid saturation and, hence, reduces the fluidity and permeability of the microalgal membranes.

TL;DR: In this paper, an ion series (up to trimer) was detected by mass spectrometry in the model solution, and the structure showed that oxidation does not affect catechin directly, but tartaric acid, to give glyoxylic acid, which then reacts with two flavanol units.

TL;DR: Five known and three new dihydroisocoumarins were isolated from different fungi and the absolute configuration of these secondary metabolites was confirmed by CD measurements and in two cases by X-ray structure analysis.

TL;DR: A rapid analytical screening by high-performance liquid chromatography combined with enzyme-linked immunosorbent assay specific for N6-(meta-hydroxybenzyl)adenine and its 9substituted derivatives revealed several regions of immunoactivity in extracts of mature poplar leaves (Populus × canadensis Moench., cv. Robusta) as mentioned in this paper.

TL;DR: The extraction procedure prevents rapid GABA accumulation during the sampling of tissue for analysis and removes over 95% of pigments absorbing at 340 nm which otherwise reduce the sensitivity of the spectrophotometric coupled enzyme assay.

TL;DR: 22 beta-Acetoxylantic acid showed antimicrobial activity against Staphylococcus aureus and Salmonella typhi and this compound and 22 beta-dimethylacryloyloxy lantanolic acid also showed antimutagenic activity.

TL;DR: In this paper, the authors analyzed the proanthocyanidins in the bark of several European conifer and broad-leaved tree species by thiolysis and gel permeation chromatography.

TL;DR: Two new acylated anthocyanins were isolated from the storage root of Ipomoea batatas and these compounds were identified as the 3-O-(6-O-trans-caffeyl-2-O -beta-glucopyranosyl-beta- glucobyranoside)-5- O - beta-Glucoside of cyanidin and peonidin.

TL;DR: The continuous accumulation of the cyclohexenone derivatives, especially blumenin, seems to correlate with the establishment of a functional barley mycorrhiza.

TL;DR: A methanol extract of hops of Humulus lupulus showed inhibitory activity against rat liver diacylglycerol acyltransferase (DGAT), and two chalcones were isolated, one of which was identified as xanthohumol and the other was found to be a new product designated xanthOHumol B.

TL;DR: The effectiveness of induced defence responses depends on their rapid initiation, development and accumulation and suggests a possible correlation between the timing and intensity of lignin-like polymer accumulation and resistance/tolerance of G. hirsutum seedlings against V. dahliae.

TL;DR: In a chemotaxonomic survey of 57 Pelargonium species, leaf exudate flavonoids were detected in 35% of the sample, mostly in trace amounts, but chrysin and a related C-methylflavanone were identified as major leaf surface constituents of P. quercifolium.

TL;DR: Although the variety ‘Parkin’ showed no clubroot symptoms, it is described as tolerant not resistant to clubroot disease, and the potential role of different glucosinolates in plant-pathogen interactions is discussed.