1.
Herbal preparations for obesity: are they useful?
Heber, D
Primary care. 2003;(2):441-63
Abstract
The opportunities for additional research in this area are plentiful. Unfortunately, there has been relatively limited funding for research on herbal supplements compared with the amount of funding that is available for research on pharmaceuticals. Botanical dietary supplements often contain complex mixtures of phytochemicals that have additive or synergistic interactions. For example, the tea catechins include a group of related compounds with effects that are demonstrable beyond those that are seen with epigallocatechin gallate, the most potent catechin. The metabolism of families of related compounds may be different than the metabolism of purified crystallized compounds. In some cases, herbal medicines may simply be less purified forms of single active ingredients, but in other cases they represent unique formulations of multiple, related compounds that may have superior safety and efficacy compared with single ingredients. Obesity is a global epidemic, and traditional herbal medicines may have more acceptance than prescription drugs in many cultures with emerging epidemics of obesity. Several ethnobotanical studies found herbal treatments for diabetes, and similar surveys, termed bioprospecting, for obesity treatments may be productive. Beyond increasing thermogenesis, there are other biological rationales for the actions of several different alternative medical and herbal approaches to weight loss. For example, several supplements and herbs claim to result in nutrient partitioning so that ingested calories will be directed to muscle, rather than fat. These include an herb (Garcinia cambogia), and a lipid which is the product of bacterial metabolism (conjugated linoleic acid). Moreover, a series of approaches attempt to physically affect gastric satiety by filling the stomach. Fiber swells after ingestion and has was found to result in increased satiety. A binding resin (Chitosan) has the ability to precipitate fat in the laboratory and is touted for its ability to bind fat in the intestines so that it is not absorbed. In double-blind studies, however, this approach was found to be ineffective. There are two key attractions of alternative treatments to obese patients. First, they are viewed as being natural and are assumed by patients to be safer than prescription drugs. Second, there is no perceived need for professional assistance with these approaches. For obese individuals who cannot afford to see a physician, these approaches often represent a more accessible solution. Finally, for many others, these approaches represent alternatives to failed attempts at weight loss with the use of more conventional approaches. These consumers are often discouraged by previous failures, and are likely to combine approaches or use these supplements at doses higher than are recommended. It is vital that the primary care physician is aware of the herbal preparations that are being used by patients so that any potential interaction with prescription drugs or underlying medical conditions can be anticipated. Unfortunately, there have been several instances where unscrupulous profiteers have plundered the resources of the obese public. Although Americans spend $30 billion per year on weight loss aids, our regulatory and monitoring capability as a society are woefully inadequate. Without adequate resources, the FDA resorted to "guilt by association" adverse events reporting, which often results in the loss of potentially helpful therapies without adequate investigation of the real causes of the adverse events that are reported. Scientific investigations of herbal and alternative therapies represent a potentially important source for new discoveries in obesity treatment and prevention. Cooperative interactions in research between the Office of Dietary Supplements, the National Center for Complementary and Alternative Medicine, and the FDA could lead to major advances in research on the efficacy and safety of the most promising of these alternative approaches.
2.
PC-SPES: herbal formulation for prostate cancer.
Marks, LS, DiPaola, RS, Nelson, P, Chen, S, Heber, D, Belldegrun, AS, Lowe, FC, Fan, J, Leaders, FE, Pantuck, AJ, et al
Urology. 2002;(3):369-75; discussion 376-7
Abstract
PC-SPES is a potent eight-herb formulation sold directly to consumers; it has promising efficacy in the treatment of prostate cancer (CaP). The product induces a castrate status in most, if not all, men, resulting in a 50% or greater prostate-specific antigen reduction in the great majority of men with androgen-dependent CaP and in more than one half of the men with androgen-independent CaP. The duration of response is not yet clear. The efficacy of PC-SPES appears to exceed that of androgen ablation alone, but is not necessarily separate from an estrogenic effect. Common side effects include gynecomastia, nipple tenderness, loss of libido, and impotency; uncommon side effects include a 4% incidence of thromboembolic phenomena, but also two reports of bleeding diatheses. The mechanisms of action may involve downregulation of the androgen receptor, induction of apoptosis by way of inhibition of the bcl-2 gene, and increased expression of p53. Two marker compounds in PC-SPES are baicalin and oridonin, both of which exhibit antiproliferative effects in CaP cell lines. Thousands of men are currently obtaining this nonprescription medicine, and physicians should ask patients specifically about its use. PC-SPES is of great interest in men with androgen-independent CaP, an area in which future research should be primarily directed.
3.
Herbs and atherosclerosis.
Heber, D
Current atherosclerosis reports. 2001;(1):93-6
Abstract
It is now widely accepted that atherosclerosis is a complex multicellular process involving oxidation of cholesterol and the intracellular accumulation of oxidized cholesterol. This accumulation causes a cascade of inflammatory processes, resulting in an unstable atherosclerotic plaque that ultimately bursts, causing myocardial infarction. Botanical dietary supplements (herbs) can ameliorate this process and prevent cardiovascular disease at many steps in the process. Many herbs have antioxidant activity and can reduce low-density lipoprotein oxidation. Some phytosterols found in botanicals can inhibit cholesterol absorption. After a brief review of herbs being promoted for achieving and maintaining healthy cholesterol levels, the evidence and future prospects for Chinese red yeast rice, the main component of dietary supplements with HMG-CoA reductase inhibiting activity, are discussed in detail. Initial phase II clinical trials are highly encouraging. This herb is likely to be able to directly impact the process of atherosclerosis, but large-scale clinical trials are needed to assess the public health potential of this herbal supplement.