Since many modern pharmaceuticals owe their origins to medicinal herbs, it may seem only logical to use those plants in lieu of drugs in the management of health conditions. Additionally, there is an assumption in the United States population that if something is "natural" it is safer than pharmaceutical medications. Unfortunately, herbal preparations often don't measure up to the claims insinuated by marketers. When this happens, consumers assume that plant medicines generally don't work. Thus, a powerful resource is discredited.
Medicinal Herb Potency Depends on Complex Factors
Several factors impact the efficacy of herbal materials in medicinal formulas. Reasons for ineffective medicinal herbs include:
- incorrect dosage
- incorrect cultivation and harvesting
- wrong parts used
- use of incorrect species
- faulty processing procedures
Incorrect Herbal Dosage
Medicinal herbs are often dosed at very low levels that will at best achieve a placebo effect. Often, manufacturers include only small amounts of an herb and blend it with others in a "proprietary formula." This allows them to state the herb is in the formula, but not disclose the exact amount of it. Expect this when an herbal material is rare or expensive. Sometimes herbal formulas are diluted down by the manufacturer out of legal concerns that the preparation will not be used properly by consumers. Expect this when working with strong materials known to exhibit adverse effects.
Cultivation and Harvesting Effects Herbal Potency
Plants are factories for special compounds called secondary metabolites. Secondary metabolites may have pharmacological effects and are the basis for many drugs. These chemicals are often used for defensive purposes, especially when the plant experiences adverse conditions. When conditions are optimal, the plant may not expend the energy required to make these compounds. Therefore, mass-cultivation of crops like ginseng and echinacea may possibly result in the loss of potency and biological effect.
Concentrations of chemicals are often unique to a plant species and vary with season, age, and part of plant used. Some compounds are only found in young leaves while others, in roots that are several years old. Processing procedures may further impact herbal potency. Grinding of plant materials may create heat that destroys volatile compounds. Some chemicals require water, or alcohol solvent extraction techniques to be effective, while others are used in crude form.
Incorrect Use of Species
Sometimes, similar species of an herb have different properties. One species may be substituted for the other out of ignorance or due to cost concerns. For example, spike lavender (Lavandula latifolia) is often substituted for English lavender (Lavandula angustifolia). This is important since while English lavender is considered calming, spike lavender is stimulating.
Considerations must be addressed in the creation of a working herbal formula. When these challenges are ignored, formulas don't work and give the industry a bad name.
Sources:
Peter Houghton and Pulok K. Mukherjee, Evaluation of Herbal Medicinal Products, 1st ed. (Pharmaceutical Press, 2009).
Se Yun et al., “Wild ginseng prevents the onset of high-fat diet induced hyperglycemia and obesity in icr mice,” Archives of Pharmacal Research 27, no. 7 (July 1, 2004): 790-796.
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