Fructan biosynthesis in transgenic plants. (1/19)

Data from plants transformed to accumulate fructan are assessed in the context of natural concentrations of reserve carbohydrates and natural fluxes of carbon in primary metabolism: Transgenic fructan accumulation is universally reported as an instantaneous endpoint concentration. In exceptional cases, concentrations of 60-160 mg g(-1) fresh mass were reported and compare favourably with naturally occurring maximal starch and fructan content in leaves and storage organs. Generally, values were less than 20 mg g(-1) for plants transformed with bacterial genes and <9 mg g(-1) for plant-plant transformants. Superficially, the results indicate a marked modification of carbon partitioning. However, transgenic fructan accumulation was generally constitutive and involved accumulation over time-scales of weeks or months. When calculated as a function of accumulation period, fluxes into the transgenic product were low, in the range 0.00002-0.03 nkat g(-1). By comparison with an estimated minimum daily carbohydrate flux in leaves for a natural fructan-accumulating plant in field conditions (37 nkat g(-1)), transgenic fructan accumulation was only 0.00005-0.08% of primary carbohydrate flux and does not indicate radical modification of carbon partitioning, but rather, a quantitatively minor leakage into transgenic fructan. Possible mechanisms for this low fructan accumulation in the transformants are considered and include: (i) rare codon usage in bacterial genes compared with eukaryotes, (ii) low transgene mRNA concentrations caused by low expression and/or high turnover, (iii) resultant low expression of enzyme protein, (iv) resultant low total enzyme activity, (v) inappropriate kinetic properties of the gene products with respect to substrate concentrations in the host, (vi) in situ product hydrolysis, and (vii) levan toxicity. Transformants expressing bacterial fructan synthesis exhibited a number of aberrant phenotypes such as stunting, leaf bleaching, necrosis, reduced tuber number and mass, tuber cortex discoloration, reduction in starch accumulation, and chloroplast agglutination. In severe cases of developmental aberration, potato tubers were replaced by florets. Possible mechanisms to explain these aberrations are discussed. In most instances, the attempted subcellular targeting of the transgene product was not demonstrated. Where localization was attempted, the transgene product generally mis-localized, for example, to the cell perimeter or to the endomembrane system, instead of the intended target, the vacuole. Fructosyltransferases exhibited different product specificities in planta than in vitro, expression in planta generally favouring the formation of larger fructan oligomers and polymers. This implies a direct influence of the intracellular environment on the capacity for polymerization of fructosyltransferases and may have implications for the mechanism of natural fructan polymerization in vivo.  (+info)

Artichoke cultivars (var. "Blanca de Tudela") under elevated ozone concentrations. (2/19)

Ozone concentrations rise to phytotoxic levels from spring to autumn at western Mediterranean basin coastal sites, where artichoke is one of the most important crops. Simultaneously, from year to year and especially since the early 1980s, resprouting of the stumps has been decreasing in Valencian Community artichoke plantations. To see if ozone might be playing a role in this decrease, a number of plants were exposed to different levels of ozone. Results of the ozone treatments showed reduced biomass in the offshoots of plants exposed to the highest ozone treatment. The exposure to ambient ozone during the stump-establishment period, when compared to filtered-air conditions, resulted in a reduction in yield when plants were transplanted in the field under ambient ozone concentrations. And when plants were exposed to acute short picks, typical ozone visual injury appeared in the older leaves.  (+info)

Efficacy of artichoke leaf extract in the treatment of patients with functional dyspepsia: a six-week placebo-controlled, double-blind, multicentre trial. (3/19)

BACKGROUND: This study aimed to assess the efficacy of artichoke leaf extract (ALE) in the treatment of patients with functional dyspepsia (FD). METHODS: In a double-blind, randomized controlled trial (RCT), 247 patients with functional dyspepsia were recruited and treated with either a commercial ALE preparation (2 x 320 mg plant extract t.d.s.) or a placebo. The primary efficacy variable was the sum score of the patient's weekly rating of the overall change in dyspeptic symptoms (four-point scale). Secondary variables were the scores of each dyspeptic symptom and the quality of life (QOL) as assessed by the Nepean Dyspepsia Index (NDI). RESULTS: Two hundred and forty-seven patients were enrolled, and data from 244 patients (129 active treatment, 115 placebo) were suitable for inclusion in the statistical analysis (intention-to-treat). The overall symptom improvement over the 6 weeks of treatment was significantly greater with ALE than with the placebo (8.3 +/- 4.6, vs. 6.7 +/- 4.8, P < 0.01). Similarly, patients treated with ALE showed significantly greater improvement in the global quality-of-life scores (NDI) compared with the placebo-treated patients (- 41.1 +/- 47.6 vs. - 24.8 +/- 35.6, P < 0.01). CONCLUSION: The ALE preparation tested was significantly better than the placebo in alleviating symptoms and improving the disease-specific quality of life in patients with functional dyspepsia.  (+info)

Flavonoids from artichoke (Cynara scolymus L.) up-regulate endothelial-type nitric-oxide synthase gene expression in human endothelial cells. (4/19)

Nitric oxide (NO) produced by endothelial nitric-oxide synthase (eNOS) represents an antithrombotic and anti-atherosclerotic principle in the vasculature. Hence, an enhanced expression of eNOS in response to pharmacological interventions could provide protection against cardiovascular diseases. In EA.hy 926 cells, a cell line derived from human umbilical vein endothelial cells (HUVECs), an artichoke leaf extract (ALE) increased the activity of the human eNOS promoter (determined by luciferase reporter gene assay). An organic subfraction from ALE was more potent in this respect than the crude extract, whereas an aqueous subfraction of ALE was without effect. ALE and the organic subfraction thereof also increased eNOS mRNA expression (measured by an RNase protection assay) and eNOS protein expression (determined by Western blot) both in EA.hy 926 cells and in native HUVECs. NO production (measured by NO-ozone chemiluminescence) was increased by both extracts. In organ chamber experiments, ex vivo incubation (18 h) of rat aortic rings with the organic subfraction of ALE enhanced the NO-mediated vasodilator response to acetylcholine, indicating that the up-regulated eNOS remained functional. Caffeoylquinic acids and flavonoids are two major groups of constituents of ALE. Interestingly, the flavonoids luteolin and cynaroside increased eNOS promoter activity and eNOS mRNA expression, whereas the caffeoylquinic acids cynarin and chlorogenic acid were without effect. Thus, in addition to the lipid-lowering and antioxidant properties of artichoke, an increase in eNOS gene transcription may also contribute to its beneficial cardiovascular profile. Artichoke flavonoids are likely to represent the active ingredients mediating eNOS up-regulation.  (+info)

Antispasmodic activity of fractions and cynaropicrin from Cynara scolymus on guinea-pig ileum. (5/19)

This study describes the antispasmodic activity of some fractions and cynaropicrin, a sesquiterpene lactone from Cynara scolymus, cultivated in Brazil, against guinea-pig ileum contracted by acetylcholine. The dichloromethane fraction showed the most promising biological effects, with an IC(50) of 0.93 (0.49-1.77) mg/ml. Its main active component, the sesquiterpene lactone cynaropicrin, exhibited potent activity, with IC(50) of 0.065 (0.049-0.086) mg/ml, being about 14-fold more active than dichloromethane fraction and having similar potency to that of papaverine, a well-known antispasmodic agent. The results confirm the popular use of artichoke for the treatment of gastrointestinal disturbances, and encourage new studies on this compound, in order to obtain new antispasmodic agents.  (+info)

Evaluation of the relaxant action of some Brazilian medicinal plants in isolated guinea-pig ileum and rat duodenum. (6/19)

PURPOSE: The present study aimed to evaluate the possible antispasmodic activity in vitro of methanolic extracts (ME) of six Brazilian medicinal plants. METHODS: The extracts were evaluated on isolated guinea-pig ileum and rat duodenum preparations. RESULTS: Rubus imperialis, Maytenus robusta, Ipomoea pes caprae and Epidendrum mosenii did not inhibit the contractile response elicited by acetylcholine on guinea-pig ileum. On the other hand, ME from Calophyllum brasiliense and Cynara scolymus exhibited significant inhibitory activity for the contractile response elicited by acetylcholine on guinea-pig ileum and on rat duodenum in a noncompetitive and concentration-dependent manner. CONCLUSIONS: The current study suggests that, of the six medicinal plants evaluated, only the ME of Calophyllum brasiliense and Cynara scolymus show probable antispasmodic activity, confirming and justifying their use in folk medicine for the treatment of intestinal disorders.  (+info)

In vitro and in vivo survival and transit tolerance of potentially probiotic strains carried by artichokes in the gastrointestinal tract. (7/19)

The ability of potentially probiotic strains of Lactobacillus plantarum and Lactobacillus paracasei to survive on artichokes for at least 90 days was shown. The anchorage of bacterial strains to artichokes improved their survival in simulated gastrointestinal digestion. L. paracasei IMPC2.1 was further used in an artichoke human feeding study involving four volunteers, and it was shown that the organism could be recovered from stools.  (+info)

Daily polyphenol intake in France from fruit and vegetables. (8/19)

The objective of this study was to create a French database on the polyphenol content of fruit and vegetables as uncooked fruits and vegetables and then to evaluate polyphenol intake through fruit and vegetable consumption in France. To achieve this, we used the Folin-Ciocalteu method adapted to fruit and vegetable polyphenol quantitation (1). Vegetables with the highest polyphenol concentration were artichokes, parsley, and brussels sprouts [>250 mg of gallic acid equivalent (GAE)/100 g fresh edible portion (FEP)]; fruits with the highest concentrations were strawberries, lychees, and grapes (>180 mg of GAE/100 g FEP). Conversely, melons (Cantaloupe cv.) and avocados had the lowest polyphenol concentration for fruits and vegetables, respectively. Based on fruit consumption data, apples and strawberries are the main sources of polyphenols in the French diet, whereas potatoes, lettuces, and onions are the most important vegetable sources. Total polyphenol intake from fruit is about 3 times higher than from vegetables, due to the lower polyphenol concentration in vegetables. The calculation of polyphenol intake, based on both assessment methods used [(Societe d'Etudes de la Communication, Distribution et Publicite (SECODIP) and Supplementation en Vitamines et Mineraux Antioxydants (SUVIMAX)], showed that apples and potatoes provide approximatively half of the total polyphenol intake from fruit and vegetables in the French diet.  (+info)

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