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December 1, 2000

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The Whole Truth About Herbs


The Whole Truth About Herbs
by John Chen, Ph.D.

The rapid growth rate in the herbal industry presents many with the complexand confusing task of identifying and selecting high quality products. Whilethere are reputable companies providing quality herbs, there are also unethicalmanufacturers selling substandard products that generate negative press for thewhole profession. The therapeutic efficacy of an herbal product can only beguaranteed with tests to verify authenticity, potency, purity and safety.

Authenticity

In herbal medicine, one of the biggest challenges is to identify the correctspecies of each herb. In dried form, many herbs look, taste and smell alike,making identification difficult. One problem that arises for herb buyers is thatunethical suppliers will substitute inexpensive herbs in place of expensive orhard-to-obtain herbs. To avoid this type of error, the person in charge ofquality control must be fully trained in botany and biochemistry of plants toensure accurate identification and precise formulation of the finished products.While visual inspection of the herbs offers some assurance, it does notguarantee authenticity, especially if the end product is a tablet or a capsule.Other tests that can be performed on the herb include organoleptic exams toidentify the physical characteristics of the plants, such as look, smell, andtaste; microscopic inspection to identify the cellular structure of the plant(particularly beneficial if two plants possess the same physical similarities);and TLC and HPLC to dissect the molecular composition, which aids to confirm thecorrect identity of the herb.

Potency

Different preparations, such as raw herb, herbal extract, full-spectrumextract, and standardized-extract, have specific advantages and disadvantages.This can lead to a tremendous margin of inconsistency of quality amongst variousproducts, and confusion amongst most consumers.

Raw herb decoction (brewing a tea) is by far the oldest method foradministration of herbal supplements, but the undesired taste, smell and timerequired to prepare herbal decoctions limits regimen compliance. Raw herbtablets have evolved to fill this desire for plain herbs; the tablets are madeby grinding raw herb into powder and pressing the powder into tablets. However,a standard dosage regimen of six to eight tablets per day may not deliver atherapeutic dosage; furthermore, the potency of raw-herb tablets can becompromised by inactive materials such as fiber, substrate and fillers.

Standardized extract is one of the more commonly used form of herbs.Standardized extract is a more sophisticated manufacturing technique in which aplant is extracted using solvents to a particular marker compound level. Thisapproach mirrors that of making pharmaceutical drugs to have specificguidelines. But using a marker compound carries some disadvantages. First, aselected marker compound may not be the active ingredient. For example, ginsengroot (the most potent therapeutic part of the plant) contains the least amountof the marker compound ginsenosides, while the leaves (the least potent part)contain the most. A selected marker may even be ineffective; for example,anthroquinone is used by some companies as the marker for radix polygonummultiflorum. This marker is a strong laxative agent; using it only ensures therewill be this effect, not necessarily that other active components are includedat a therapeutic dose. Finally, the chemical solvents used can change the taste,smell and therapeutic properties of a plant.

A final extraction technique is full-spectrum extraction. This type ofextraction maintains all the active ingredients in their natural ratios; thepotency of the herb can be monitored by measuring the area under the curve (AUC)on an HPLC graph. This method of preparation is preferred by most herbalists asthe ideal way to process the herbs as both potency and efficacy can bepreserved.

Purity

Ensuring the purity of end products requires rigorous cleaning of raw herbsbefore extraction to remove unwanted materials such as sand, fungus, spores,sulfur and insect eggs. Purity is especially an issue with the products madefrom raw herbs. A simple purity test is to chew and taste products for a sandyor gritty texture in the end products. The presence of sand or grit is anindication of impurity.

Processing procedures that incorporate sugar as a binder, or alcohol (up to30% by weight) in tincture, may alter the action of the herbs and createunwanted side effects. The presence of sugar and alcohol may present problems inindividuals who have diseases such as diabetes, hypertension, elevatedcholesterol levels, and heart disorders. Some products may contain a largeamount of sugar to artificially improve solubility.

If the herb appears dark and has a burnt or overly bitter taste, it isover-cooked and the active ingredients may have been destroyed. It is similar tohow vegetables that are cooked for a long period of time under extreme heat losenutritional content. Many self-proclaimed "super-concentrates" aremade by over-cooking the herbs. Unfortunately, even if the concentrate has a10:1 ratio, the product is ineffective if the active ingredients were destroyedby heat.

Safety

Herbs are susceptible to a number of contaminants, ranging from pesticidesand herbicides to heavy metals. To ensure safety and efficacy, all productsshould be tested and have a certificate of analysis (C of A) available forquality control purposes. Once again, it is important that the C of A isperformed on every batch, not just on a random basis, to ensure the safety ofthe herbs.

Safety is also dependant on the accurate identification of the herbs used.For example, in the early 1990s, there was a weight-loss clinic in Belgium thatsold a weight-loss product that contained the herb stephania root. However, theclinic incorrectly substituted aristolochia root (toxic to the kidneys) for thecorrect (and safe) stephaniae root. As a result, 33 patients suffered fromkidney damage and subsequently required kidney transplant (Am J KidneyDiseases, 24(2):172-80, 1994).

The herbal industry in the United States has experienced a renaissance overthe past decade that has been characterized by rapid growth, followed by agradual decline. This mixed result is due in part to the confusion in the mindsof the consumers as to what constitutes a "safe and effective"product. Though there is not one single standard that governs the use of herbs, authenticity,potency, purity and safety are four issues one must consider whenchoosing an herbal product. It is vital for manufacturers and consumers to beeducated on these issues so the industry can continue to grow, and negativefactors such as confusion, fear and lack of confidence can be eliminated.

John Chen, Ph.D, Pharm.D., O.M.D., L.Ac., is a recognized authority onChinese herbal medicine and Western pharmacology. He is a member of the HerbalMedicine Committee for the American Association of Oriental Medicine (AAOM) andan herbal consultant for the California Association of Acupuncture and OrientalMedicine (CAAOM); this year he was selected as a member of the editorial boardfor Medical Acupuncture. He is the founder and president of Lotus Herbsand can be reached at (626) 916-1070.

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