Regulatory Issues on Herbal Medicines!
Some plants contain extremely potent pharmacological substances, and these obviously are controlled in most countries. For example digitalis, rauwolfia, belladonna, poppy, coca etc. are all strictly controlled by national agencies similar to the Food and Drug Administration (FDA) in the USA.
Similarly, other national agencies have lists and tight control on growing, purchasing, holding or marketing of plants that have highly toxic constituents e.g. nux vomica beans (which contains strychnine).
Apart from these classes of plants, generally most herbal medicines are not subjected to legislative control and have been freely available as ‘over-the- counter’ herbal supplements for centuries. It is only in recent years that scientists have begun to carry out detailed phytochemical, pharmacological, safety, efficacy, and clinical studies on some of the more commonly used herbal medicines.
There are numerous problems in the enactment of laws controlling the use of herbal medicines.
Firstly, it is claimed that these herbs have long history of safety, since they have been used in traditional folklore medicine over many millennia.The counter argument is that folk medicines have moved a long way from its original use in family groups or small villages to herbal shops in urban areas.
Now modern, often more concentrated preparations are marketed by herbal industries. The traditionally used herbal preparations (e.g. infusions) were probably of low potency, but contained a finely balanced mixture of plant constituents acting in synergy to cure or manage minor ailments.
Secondly, the herbal companies are marketing more concentrated semi-purified extracts, and some claim that such ‘refinements’ may be removing some of the beneficial plant constituents in the extraction process. It therefore seems prudent to carry out some phytomedical efficacy and safety testing on these modern ‘herbal extracts’, since it is clear now that the use of herbal medicines is not entirely risk-free.
However, legislative control of such multi-component mixtures is difficult, particularly if more than one of the plant constituents are active, or if all these constituents act in synergy. Requiring herbal industries to carry out the detailed testing that is now necessary for newly developed single-component modern synthetic drugs would be too cost-prohibitive.
In a recent review, Canigueral et al., (2008) makes the point that, quote “we should not disregard the legacy of traditional wisdom because ethno pharmacology and knowledge provided by existing clinical trials (be they open, observational studies or small, double-blind investigations) is a source of invaluable insight into the safety and efficacy of herbal medicines”, unquote.
Despite this view, most scientists now believe that the production of herbal medicines nowadays has reached a level of sophistication where quality and standardised products are available, and such products can be subjected to some of the rules regulating clinical research of synthetic drugs.
At the very least, national regulatory agencies need to provide some detailed guidelines for the herbal industries, since the safety and efficacy of the modern quality standardised herbal medicines are readily evaluable by methods of modern clinical pharmacology.
At present most of the phytochemical, safety and efficacy research is carried out by academic researchers.
If the associations of the herbal industries were to fund more of this type of academic research, the data generated on every aspect of the production of herbal medicines, from plant selection, processing, extraction, standardisation, formulation (Fig. 25.1), right up to some safety and efficacy studies, would be extremely useful in providing scientific backing to the use of traditional herbal medicines.
The actual regulations of herbal medicines vary from country to country.
In some countries where herbs have a widespread use (e.g. China and India), national agencies have compiled detailed monographs, which set out limits of active constituent(s), and provide information on quality control and standardisation procedures, and therefore information on dosage (RDD, recommended daily dosage) can be obtained from such databases.
Most herbal medicines in Europe are under strict guidelines of individual member countries of the European bloc countries, and European guideline should be looked upon as a model for production of good quality standardised herbal medicines.
In the United States, herbal medicines are marketed as ‘dietary supplements’, and it is left largely to the manufacturers to ensure that such supplements are safe and labelled appropriately.
Thus US FDA can only take action to restrict the use of an herbal product after it has been shown to be unsafe.
The US FDA has proposed guidelines for current good manufacturing practice rules for dietary supplements, but no strict regulations have yet been enacted. It is disheartening to read a report in the year 2008 entitled “Why the United States Still Needs Improved Dietary Supplement Regulation and Oversight”.
Numerous publications have in recent years reviewed the current regulation of herbal medicines in different countries, but it is the detailed WHO guidelines that hopefully will ultimately lead to some global harmonisation of the regulations on herbal medicine production and use, as well as rules for some form of risk-monitoring system.