Unlike pharmaceutical products which usually contain a single active entity, herbal products contain a complex mixture of ingredients, many of which have not even been identified. Some of these ingredients may work synergistically to enhance the pharmacological effect, while others may antagonise the toxic effects of some of the ingredients.
Often, the biologically active ingredients have not been ascertained yet except for well-documented herbs such as Ginkgo biloba, Panax ginseng, Milk thistle, Echinacea purpurea and Hawthorn. Due to the high cost and difficulty in identifying the exact amount and type of active ingredients, no specification for active ingredients are set by the Drug Control Authority in Malaysia. As a result, some health supplement manufacturers and marketeers have taken advantage of this loophole to manufacture products containing only a minute amount of the active ingredients which will not be able to produce the desired effect or result.
Wrong species or parts of plant used
In a herb, the biologically active ingredients may be concentrated in the leaves, fruits, flowers, roots, etc. Cheaper parts of the plant may be substituted intentionally to produce an inferior quality product. In addition, different species of the herb may be used, e.g. Echinacea purpurea, Echinacea angustifolia and Echinacea pallida.
A Chinese herbal preparation used for slimming caused severe kidney damage to 105 persons in Belgium and 18 cases of cancer. Investigations revealed that one of the herbs, Stephania tetrandra, was unintentionally substituted with Aristolochia fangchi as both of the herbs have the common name of fangchi in Chinese. Animal studies have shown that Aristolochia fangchi causes kidney damage and cancer.
Intentional adulteration with drugs
To achieve a quick therapeutic response, some unscrupulous manufacturers intentionally adulterate the herbal preparation with pharmaceutical drugs. Toxic effects of Chinese herbal preparations have been found to be adulterated with steroids, painkillers, muscle relaxants, tranquilisers and diabetic drugs. A Chinese slimming product (Slim 10) was found to contain the banned pharmaceutical substance fenfuramine last year.
A report by the Health Ministry Malaysia stated that almost 95% of the unregistered traditional herbal preparations in the local market have been found to contain steroids. In addition, about 37% of the 5,000 renal problems in Malaysia may be attributed to the chronic use of substandard traditional herbal preparations.
Environmental and microbial contamination
Herbs may be contaminated with toxic metals such as lead, mercury and arsenic due to the soil or stream contamination in the herb’s natural habitat. Cases of lead and arsenic poisoning have been reported due to the ingestion of herbal preparations.
Furthermore, herbs, being natural products, are susceptible to microbial contamination if they are not dried or processed properly. To circumvent the problem, some manufacturers subjected their products to gamma irradiation to reduce the microbial level.
High cost of quality
Many herbal product manufacturers do not have their in-house quality control laboratories to test their in-coming raw materials and finished products due to the high cost of acquiring the necessary equipment as well as qualified personnel for running them. They depend on outside laboratory for testing.
Naturally, the frequency and extent of sampling and testing are reduced to the minimum to cut cost. But the onus of ensuring the quality, safety and efficacy of the products rests with the manufacturer. It is quite obvious that the damaging effect of recalling substandard products and loss in business far outweigh the additional investment in quality.
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