Artichoke leaf extract for treating hypercholesterolaemia.
BACKGROUND: 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. OBJECTIVES: 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). SEARCH STRATEGY: 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containing artichoke extract and experts on the subject were contacted and asked to contribute published and unpublished material. SELECTION CRITERIA: 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 COLLECTION AND ANALYSIS: 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. MAIN RESULTS: 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. REVIEWER'S CONCLUSIONS: 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.