Artichoke Leaf Extract Research Articles

Artichoke Leaf Extract Reduces Symptoms of Irritable Bowel Syndrome and Improves Quality of Life in Otherwise Healthy Volunteers Suffering from Concomitant Dyspepsia: A Subset Analysis

Artichoke Leaf Extract Reduces Symptoms of Irritable Bowel Syndrome and Improves Quality of Life in Otherwise Healthy Volunteers Suffering from Concomitant Dyspepsia: A Subset Analysis

Flavonoids from Artichoke (Cynara scolymus L.) Up-Regulate Endothelial-Type Nitric-Oxide Synthase Gene Expression in Human Endothelial Cells

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.

Commercial and laboratory extracts from artichoke leaves: estimation of caffeoyl esters and flavonoidic compounds content

Artichoke leaf extracts are widely used alone or in association with other herbs for embittering alcoholic and soft drinks and to prepare herbal teas or herbal medicinal products. Despite this wide diffusion, the European Pharmacopoeia does not report an official method for the determination of the active principles of artichoke leaf extracts. This work reports a quali-quantitative determination by HPLC/DAD and HPLC/MS techniques of both cynnamic acids and flavonoids present in some artichoke leaf commercial extracts (Com) compared with two different laboratory extracts (Lab). Most of the commercial extracts showed a similar quali-quantitative pattern with a single exception having five–six times higher value. The quantitative data from the Italian Pharmacopoeia(IP) official method does not evaluate the flavonoidic fraction and showed an overestimation of the caffeoyl esters with respect to the HPLC/DAD results. The proposed HPLC/DAD method was able to completely characterize and quantify this matrix and represents a contribution to better quality control of these herbal extracts.

Validated method for the determination of six metabolites derived from artichoke leaf extract in human plasma by high-performance liquid chromatography–coulometric-array detection

A validated method was developed for the simultaneous determination of the hydroxycinnamates caffeic (CA), dihydrocaffeic (DHCA), ferulic (FA), dihydroferulic (DHFA), and isoferulic acid (IFA) and the flavonoid luteolin (LUT) in human plasma as metabolites derived from artichoke leaf extract. The method involves sample preparation followed by separation using high-performance liquid chromatography on reversed-phase material with a polar endcapping (Aqua-C 18, 250×4.6 mm). Selectivity and sensitivity towards the target compounds were achieved by electrochemical array detection (CoulArray). Calibration curves were constructed in the ranges 2.1–51.7 ng mL −1 (CA), 2.0–76.7 ng mL −1 (DHCA), 2.2–53.7 ng mL −1 (FA), 2.1–79.2 ng mL −1 (DHFA), 1.1–52.6 ng mL −1 (IFA) and 2.1–258.6 ng mL −1 (LUT). Linearity could be shown for all target compounds over the entire calibration range. Values for within-day and between-day precision and accuracy were in accordance with the international guidelines for validation of bioanalytical methods. It is concluded that this newly developed method is appropriate for analysing samples from bioavailability and pharmacokinetic studies after oral administration of artichoke leaf extract.

Artichoke leaf extract and pectin may lower serum cholesterol

Artichoke leaf extract and pectin may lower serum cholesterol

Prevention of taurolithocholate-induced hepatic bile canalicular distortions by HPLC-characterized extracts of artichoke (Cynara scolymus) leaves.

The effects of water-soluble extracts of artichoke (Cynara scolymus L.) leaves on taurolithocholate-induced cholestatic bile canalicular membrane distortions were studied in primary cultured rat hepatocytes using electron microscopy. Artichoke extracts at concentrations between 0.08 and 0.5 mg/ml were able to prevent the formation of bizarre canalicular membrane transformations in a dose-dependent manner when added simultaneously with the bile acid. However, prevention also occurred when the hepatocytes were preincubated with the extracts, indicating that absorption of the bile acid to components of the extracts was not involved. These results demonstrate that artichoke leaf extracts exert a potent anticholestatic action at least in the case of taurolithocholate. This effect may contribute to the overall hepatoprotective influence of this herbal formulation.

Isolation, characterization and determination of minor artichoke (Cynara scolymus L.) leaf extract compounds

Artichoke (Cynara scolymus L.) and artichoke leaf extracts (ALE) have a long history as a traditional part of the Mediterranean diet as well as in folk medicine for the treatment of dyspeptic disorders. Although several biological mechanisms of action have been suggested, e.g. increased biliary secretion leading to an increased cholesterol elimination and/or inhibition of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity resulting in a decreased cholesterol biosynthesis, convincing and conclusive human studies investigating the blood cholesterol lowering properties of artichoke or ALE are currently limited. The aim of the present study was to isolate, characterize and determine minor artichoke compounds with regard to their blood cholesterol lowering potential, bitter taste sensation and antioxidant potential. Liquid chromatographic isolation techniques (Sephadex LH-20) in combination with analytical methods (HPLC-DAD-MS and HPLC-DAD) were successfully employed to separate, characterize, and quantify minor artichoke compounds. In commercially available ALE the following compounds were identified: 8-deoxy-11-hydroxy-13-chlorogrosheimin, cryptochlorogenic acid, chlorogenic acid, neochlorogenic acid, cynarin, cynaratriol (tentatively), grosheimin, 8-deoxy-11,13-dihydroxygrosheimin, luteolin-7-O-rutinoside, luteolin-7-O-glucoside, and cynaropicrin. Most of these compounds were liquid chromatographically described for the first time. The concentration of essential ALE compounds, namely chlorogenic acid, cynarin, and luteolin-7-O-glucoside, was in the range of 0.35–18.34, n.d.-1.02, 0.04 – 10.65 mg/g ALE, respectively. Cynaropicrin, the predominant bitter ALE principle, was present at concentrations between <0.06 and 22.6 mg/g ALE. Rancimat assay revealed an equivocal picture with respect to the antioxidant (AOX) properties of ALE dissolved in sunflower oil: four extracts showed a effect, while three ALE had an antioxidative effect and one extract showed no effect at all at concentration between 500 and 4000 mg/kg (compared to refined sunflower oil). However, all investigated individual artichoke compounds – chlorogenic acid, cynarin, luteolin, luteolin-7-O-glucoside – showed a remarkable antioxidative effect, chlorogenic acid being the strongest AOX compound. Moreover, chlorogenic acid showed a strong, dose-dependent linear HMG-CoA reductase inhibitory effect at concentrations between 5 and 50 mg/ml. Luteolin and luteolin-7-O-glucoside showed an even stronger inhibitory effect at 10 mg/ml (relative HMG-CoA reductase activity: 2.4% and 6.5%, respectively compared to 26.5% activity after chlorogenic acid treatment). All studied commercially available ALE showed a moderate inhibitory effect at 10 mg/ml.

Artichoke leaf extract for treating hypercholesterolaemia.

Hypercholesterolaemia is directly associated with an increased risk for coronary heart disease and other sequelae of atherosclerosis. Artichoke leaf extract (ALE), which is available as an over-the-counter remedy, has been implicated in lowering cholesterol levels. Whether ALE is truly efficacious for this indication, however, is still a matter of debate. To assess the evidence of ALE versus placebo or reference medication for treating hypercholesterolaemia defined as mean total cholesterol levels of at least 5.17 mmol/L (200 mg /dL). We searched MEDLINE, Embase, Amed, Cinahl, CISCOM and the Cochrane Controlled Trial Register. All databases were searched from their respective inception until June 2001. Reference lists of articles were also searched for relevant material. Manufacturers of preparations containing artichoke extract and experts on the subject were contacted and asked to contribute published and unpublished material. Randomized controlled trials of ALE mono-preparations compared with placebo or reference medication for patients with hypercholesterolaemia were included. Trials assessing ALE as one of several active components in a combination preparation or as a part of a combination treatment were excluded. Data were extracted systematically and methodological quality was evaluated using a standard scoring system. The screening of studies, selection, data extraction and the assessment of methodological quality were performed independently by two reviewers. Disagreements in the evaluation of individual trials were resolved through discussion. Two randomised trials including 167 participants met all inclusion criteria. In one trial ALE reduced total cholesterol levels from 7.74 mmol/l to 6.31 mmol/l after 42 +/- 3 days of treatment whereas the placebo reduced cholesterol from 7.69 mmol/l to 7.03 mmol/l (p=0.00001). Another trial did state that ALE significantly (p<0.05) reduced blood cholesterol compared with placebo in a sub-group of patients with baseline total cholesterol levels of more than 230 mg/dl. Trial reports and post-marketing surveillance studies indicate mild, transient and infrequent adverse events. Few data from rigorous clinical trials assessing ALE for treating hypercholesterolaemia exist. Beneficial effects are reported, the evidence however is not compelling. The limited data on safety suggest only mild, transient and infrequent adverse events with the short term use of ALE. More rigorous clinical trials assessing larger patient samples over longer intervention periods are needed to establish whether ALE is an effective and safe treatment option for patients with hypercholesterolaemia.

Choleretic activity and biliary elimination of lipids and bile acids induced by an artichoke leaf extract in rats.

The therapeutic properties of artichoke (Cynara scolymus L.) preparations have been known since ancient times. The traditional use of artichoke leaf extract (ALE) in gastroenterology is mainly based upon its strong antidyspeptic actions which are mediated by its choleretic activity. The aim of this study was to investigate the effects of ALE on bile flow and the formation of bile compounds in anaesthetised Wistar rats after acute and repeated (twice a day for 7 consecutive days) oral administration. A significant increase in bile flow was observed after acute treatment with ALE as well as after repeated administration. The choleretic effects of ALE were similar to those of the reference compound dehydrocholic acid (DHCA). Total bile acids, cholesterol and phospholipid were determined by enzymatic assays. There was a strong ALE-induced increase in total bile acid concentration over the entire experiment. With the highest dose (400 mg/kg), a significant increase was obtained after single and repeated administration. The bile acids-increased effects of ALE were much more pronounced than those of reference (DHCA). No significant differences in cholesterol and phospholipid content could be found.

Artichoke leaf extract reduces symptoms of irritable bowel syndrome in a post-marketing surveillance study

Irritable bowel syndrome (IBS) is a problem reported to affect 22% of the general population. It is characterized by abdominal pain and altered bowel habit, but has so far defied elucidation of its pathogenesis and proved difficult to treat. There is a growing body of evidence which indicates therapeutic properties for artichoke leaf extract (ALE). Dyspepsia is the condition for which the herb is specifically indicated, but the symptom overlap between dyspeptic syndrome and IBS has given rise to the notion that ALE may have potential for treating IBS as well. A sub-group of patients with IBS symptoms was therefore identified from a sample of individuals with dyspeptic syndrome who were being monitored in a post-marketing surveillance study of ALE for 6 weeks. Analysis of the data from the IBS sub-group revealed significant reductions in the severity of symptoms and favourable evaluations of overall effectiveness by both physicians and patients. Furthermore, 96% of patients rated ALE as better than or at least equal to previous therapies administered for their symptoms, and the tolerability of ALE was very good. These results provide support for the notion that ALE has potential value in relieving IBS symptoms and suggest that a controlled trial is justified.

Activity of artichoke leaf extract on reactive oxygen species in human leukocytes

Artichoke leaf extract was studied in human leukocytes for activity against oxidative stress using flow cytometry and dichlorofluorescin diacetate as a fluorescence probe. It produces a concentration-dependent inhibition of oxidative stress when cells are stimulated with agents that generate reactive oxygen species (ROS): hydrogen peroxide, phorbol-12-myristate-13-acetate (PMA), and N-formyl-methionyl-leucyl-phenylalanine (FMLP). Cynarin, caffeic acid, chlorogenic acid, and luteolin, constituents of artichoke leaf extract, also show a concentration-dependent inhibitory activity in the above models, contributing to the antioxidant activity of the extract in human neutrophils.

Artichoke leaf extract — Recent findings reflecting effects on lipid metabolism, liver and gastrointestinal tracts

In various molecular, cellular and in vivo test systems, artichoke (Cynara scolymus L.) leaf extracts show antioxidative, hepatoprotective, choleretic and anti-cholestatic effects as well as inhibiting actions on cholesterol biosynthesis and LDL oxidation. Recently, active ingredients responsible for the main effects have been identified. Thus, luteolin seems to be of crucial importance for the inhibition of hepatocellular de novo cholesterol biosynthesis. The anti-dyspeptic actions ware mainly based on increased choleresis. Regarding clinical data, lipid-lowering, antiemetic, spasmolytic, choleretic and carminative effects have been described, along with good tolerance and a low incidence of side effects. Due to its specific mechanisms of action, the future use of artichoke leaf extract for the prevention of arteriosclerosis can be expected.

Long‐term treatment with artichoke leaf extract in dyspeptic syndrome

Long‐term treatment with artichoke leaf extract in dyspeptic syndrome