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| Ginkgo Biloba: blending ratio of active components important for standardisation |
A plenary session on complementary medicine was held on September 13 and chaired by Dr Steven Kayne (visiting lecturer in complementary medicine, University of Strathclyde, Glasgow) for a second year. Dr Kayne reminded the audience that complementary medicine took a holistic view of the patient, a perspective that was usually lacking in randomised controlled trials
Finished, labelled medicinal products that contained plant materials as active
ingredients or plant material which might be crude or processed were regarded
as herbal medicines, according to Professor Sami Khalid (University of Khartoum,
Sudan).
Professor Khalid said that herbal medicines might contain excipients in addition
to the active ingredients and differed from conventional drugs in several ways.
For example, the concept of synergy between herbal constituents was an important
component in phytotherapy-medicinal plants containing a diverse range of chemical
constituents and it was important to study herbs in their entirety. The chemical
complexity of herbal medicines made it difficult to determine their pharmacodynamic
and pharmacokinetic properties, as well as their potential for interactions
with conventional drugs.
Herbal market
Moving on to marketed herbal proprietary products, Professor Khalid referred
to survey data, from 16 countries, which had revealed that in Germany there
were almost 2,500 herbal proprietary products on the market (comprising around
500 single- and 2,000 multi-ingredient products), whereas in the United Kingdom,
there were only around 430 such products in total. The trade in medicinal plants
was vast, Professor Khalid said. Around 10,000 plant species were used medicinally
worldwide, and China alone produced around 1.6 million tonnes of plant material
for medicinal use per year.
In the United States, the annual turnover of plant-derived pharmaceuticals was
US$10 billion.
Phytopharmaceuticals
Professor Khalid listed several quality standards for phytopharmaceuticals which
required the application of good manufacturing practice, including:
Standardisation of botanical products on active constituent(s) or marker substances
was highly important. Parameters affecting standardisation could be divided
into botanical aspects, such as the plant species, geographical area and time
of collection of plant material, drying and storage conditions (which all influence
the chemical composition of the material), and chemical aspects, such as the
nature of the active constituents and the blending ratio of the various active
components (eg, flavonoids:terpenoids in Ginkgo biloba). Quality, said Professor
Khalid, needed to be assured for the crude plant material as well as for the
plant preparation (extract) and the finished product.
The need for a critical approach when considering the historical use of herbs
was
discussed by Dr John Crellin (department of History of Medicine, Memorial University
of Newfoundland, Canada).
Dr Crellin challenged the way that the phrase “it’s been around a
long time” was commonly used to bolster claims of herbal safety and effectiveness.
It was often stated that the historical record supported modern day uses of
herbal products, which was far from correct. For example, it was sometimes claimed
that the historical record of St John’s wort (Hypericum perforatum) supported
its use in depression. According to Dr Crellin, this was not the case (although
there was, of course, reliable evidence from randomised controlled trials for
the efficacy of St John’s wort in mild-to-moderate depression). “All
too often, historical pedigrees are created by mining old books for positive
statements about herbal use, and ignoring negative information”, he remarked.
Dr Crellin went on to explain that various social forces encouraged the belief
that the histories of herbs contained much sound empirical knowledge. He expressed
concern that many modern scientific authorities also promoted the view that,
if a herb had been around for a long time, it was probably safe. He noted that,
with some exceptions, such views were rarely critiqued. A particular concern
was the paucity of historical expertise in, for example, Canada’s Health
Protection Branch (seemingly the same elsewhere), when designating a herb a
“traditional medicine”.
In an attempt to provide a constructive solution to the problem, Dr Crellin
outlined a systematic approach to critical appraisal of the historical records
of herbs. This responded to certain queries, such as whether recommended uses
had been based on now outdated theories, or why many herbs were discarded during
the heyday of herbal usage. In the absence of sufficient scientific data and
clinical trials to support the efficacy of most herbs, the historical record
remained an important information resource for the foreseeable future.
Concluding, Dr Crellin suggested that societies such as the British Society
for the History of Pharmacy might consider developing teaching modules on the
historical appraisal of herbs.
Evaluating isopathy
Dr Neil Beattie (chairman of Ayr, Prestwick and Troon local health care co-operative,
Scotland) discussed the use of patient outcome measures to determine whether
or not homoeopathic medicine was effective. He presented data from a study that
had explored the use of isopathy in the treatment of allergies.
Isopathy involved the administration of homeeopathically prepared remedies derived
from the material responsible for causing a diseased state. They were thus given
on the basis of “same to treat same” rather than on the classical
homoeopathic principle of “like to treat like”. According to Dr Beattie,
there was evidence from work carried out at Glasgow Homoeopathic Hospital (GHH)
that isopathic treatment prescribed for allergic conditions did have a beneficial
and reproducible effect.
The study involved patients attending the GHH allergy clinic in response to
a referral from their GP. Patients underwent skin testing using a standard Bencard
skin testing kit. If the test was positive, the patient’s weals were measured
and the various allergens ranked in order of severity. Isopathic treatment was
commenced using a remedy prepared from the allergen that caused the most severe
reaction.
To date, 171 patients had been screened, of whom 117 provided suitable skin
test results. These patients were randomly allocated to one of three treatment
groups: Regimen X, one powders three times daily of the appropriate allergen
in the 30C potency; Regimen Y, one powder three times daily of the appropriate
allergen in the 200C potency; Regimen Z, one dose of the appropriate allergen
in the 30C potency twice daily for one month.
Measuring outcomes
Outcome measures used in the study included:
Fifteen per cent of participants defaulted during their treatment. Of the remainder, 87 per cent reported that their allergic symptoms were substantially improved or cured. According to Dr Beattie, regimen Z was significantly better (p = 0.001) than regimens X and Y. Despite the lack of a control group (patients were used as their own control) from these data Dr Beattie concluded that the effectiveness of using isopathic remedies in the treatment of allergies had been confirmed.
References
1. Reilly D, Taylor M, Beattie N et al. Is evidence for homceopathy
reproducible? Lancet 1994;344:1601-06.