Quality of Natural Product Clinical Trials: A Comparison of Those Published in Alternative Medicine Versus Conventional Medicine Journals
Center for Drug Information and Evidence-Based Practice, Creighton University, Omaha, Nebraska 68178, USA. Journal of Dietary Supplements
06/2011; 8(2):135-43. DOI: 10.3109/19390211.2011.561823
To compare the quality of natural product clinical trials published in alternative medicine journals versus those published in conventional medicine journals.
Systematic search and review of the literature. Randomized controlled trials of natural products were included if they were published in English between 2003 and 2008. Articles were categorized by their journal of publication (alternative medicine versus conventional medicine). Two independent reviewers evaluated study quality using guidelines from the Cochrane Collaboration. The results with respect to the primary outcome (positive or negative) were also assessed.
Thirty articles were evaluated, 15 published in alternative medicine journals and 15 in conventional medicine journals. Of articles published in alternative medicine journals, 33.33% (n = 5) were considered low quality, and none were considered high quality. Of articles published in conventional medicine journals, 26.67% (n = 4) were considered low quality and 6.67% (n = 1) were considered high quality. Two thirds of all trials reviewed were of unclear quality, due to inadequate reporting of information relating to the study's methodology. Similar proportions of positive and negative primary outcomes were found in alternative and conventional medicine journals, and low-quality articles were not more likely to report a positive primary outcome (Fisher's exact test, two-tailed p = .287).
The quality of natural product randomized controlled trials was similar among alternative and conventional medicine journals. Efforts should be made to improve the reporting of natural product clinical trials for accurate determinations of study quality to be possible.
Available from: Yu Zong Chen
- "Natural products (NP) have been traditional sources of drug discovery and there are renewed interests in them for new drug discovery , , , . In particular, NP combinations have been extensively studied , , tested in clinical trials , , , and widely used in traditional, folk and alternative medicines , . Their novel multi-targeted mechanisms , ,  or molecular scaffolds  may be valuable sources for developing multi-targeted therapeutics . "
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ABSTRACT: There have been renewed interests in natural products as drug discovery sources. In particular, natural product combinations have been extensively studied, clinically tested, and widely used in traditional, folk and alternative medicines. But opinions about their therapeutic efficacies vary from placebo to synergistic effects. The important questions are whether synergistic effects can sufficiently elevate therapeutic potencies to drug levels, and by what mechanisms and at what odds such combinations can be assembled. We studied these questions by analyzing literature-reported cell-based potencies of 190 approved anticancer and antimicrobial drugs, 1378 anticancer and antimicrobial natural products, 99 natural product extracts, 124 synergistic natural product combinations, and 122 molecular interaction profiles of the 19 natural product combinations with collective potency enhanced to drug level or by >10-fold. Most of the evaluated natural products and combinations are sub-potent to drugs. Sub-potent natural products can be assembled into combinations of drug level potency at low probabilities by distinguished multi-target modes modulating primary targets, their regulators and effectors, and intracellular bioavailability of the active natural products.
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