 | Skullcap
Scutellaria lateriflora |
Safety Considerations Substitution of Scutellaria lateriflora (Skullcap) was a prominent issue in 2002 due to an Australian product being implicated in the death of a patient. The product contained Kava and two other herbs, one of these was meant to be Skullcap. However when the product was analyzed by the TGA (Australian equivalent of the FDA) it was found not to contain Skullcap. For this reason the TGA initiated a safety recall on this product and other Skullcap products from that same doctor-only company. In addition, they also recalled other Skullcap products on the market. This is significant because substitution of Skullcap with the hepatotoxic herb Germander (Teucrium spp.) is well known and has been implicated in cases of liver damage in literature.
MediHerb became aware of this problem many years ago and established stringent quality procedures to ensure that our Skullcap products would always be authentic. In his capacity as a member of TMEC (Traditional Medicines Evaluation Committee) the forerunner of CMEC (Complementary Medicines Evaluation Committee), Kerry Bone alerted the TGA to the potential harm that could arise from this substitution. As a result the TGA took action in the 1990s to ensure that manufacturers only used authentic Skullcap. They conducted widespread testing of Skullcap products and found many products did not contain Skullcap as claimed. The fact that this substitution may have arisen again, particularly in the context of the case of liver damage, is cause for serious concern.
Our stringent testing regimes guard against substitution, adulteration and poor quality The substitution of Stephania tetrandra with Aristolochia spp. has been widespread in the herbal market with safety alerts being issued by the FDA, TGA (Australia) and MHRA (England). This followed the more than 70 cases of renal failure in Belgium associated with a weight-loss product that mistakenly contained a species of Aristolochia instead of Stephania. This inadvertent substitution is believed to have been due to the similarity of the Chinese common name: Aristolochia fangchi (Guang Fang Ji) and Stephania tetrandra (Fang Ji). Stephania is an important herb with good anti-inflammatory activity, linked to the bisbenzylisoquinoline alkaloid known as tetrandrine. MediHerb research evaluated by HPLC eight samples of herb labelled as Stephania tetrandra. Of these samples only one was believed to be Stephania; five samples contained aristolochic acids and were more likely to be Aristolochia; the remaining two samples contained neither aristolochic acids or tetrandrine, and were probably either Clematis spp. or Akebia spp. Based on this survey, the risk involved in the commercially available Stephania herb was evaluated as being too high to warrant its inclusion in the product line.
Efficacy Through our research we have demonstrated that the alkylamide rich roots of Echinacea angustifolia and to a lesser extent E. purpurea have a modulatory effect on the immune system. However, when market surveillance was performed in October 2004 of 8 American professional products of Echinacea tablets and capsules, only one was found to have appropriate levels of alkylamides, but even then, the alkylamides were not of the most potent kind (2-ene). Echinacea is broadly used to describe all manner of preparations of the Purple Cone Flower plant: different plant parts and different species, but also different quality levels.
 Wild Yam
HPLC Trace |  | | This chart diagrams the levels of diosgenin, found only in Dioscorea villosa. Not the often substituted Dioscorea opposita (Chinese Yam Root). |
Commercial Wild Yam extracts available for use as raw materials are often not Dioscorea villosa but instead Dioscorea opposita (Chinese Yam Root) which has a different phytochemical profile and therefore a different clinical action. In addition to species substitution, it is widely misconstrued that Dioscorea villosa contains diosgenin and many products have this as a statement on their labels. However it does not contain diosgenin, but rather the diosgenin precursors. Traditionally Dioscorea villosa was believed to contain predominantly dioscin, however, the origin of this assignment is unclear (dioscin is a steroidal glycoside precursor of diosgenin). Research undertaken by MediHerb and Dr. James De Voss from the University of Queensland, Australia has found Wild Yam harvested traditionally contains only very small amounts of dioscin, not the predominance as previously thought. The major steroidal glycoside found was a diosgenin based compound that has an extra sugar molecule (either glucose or a similar sugar) to that of dioscin. Further research work continues. It is alarming that such a widely used herb is so misunderstood and substituted.
Cat's Claw Cat's Claw (Uncaria tomentosa) has two chemotypes, the preferred chemotype contains only pentacyclic oxindole alkaloids (POAs) speciophylline, mitraphylline, pteropodine, isomitraphylline and isopteropodine; the other chemotype, contains the tetracyclic oxindole alkaloids (TOAs) rhynchophylline and isorhynchophylline in addition to the POAs. Traditionally only the POA chemotype was used therapeutically. This preference for the POA chemotype of Cat's Claw has been backed up by scientific research. MediHerb tests each batch of Cat's Claw to determine only the preferred POA chemotype is used to manufacture our Cat's Claw products.
 | Golden Seal
Hydrastis canadensis |
Golden Seal Golden Seal (Hydrastis canadensis) is very expensive and has always been in short supply. As a result, substitution by other species is common. The herbs typically substituted are: Coptis chinensis, Indian Barberry (Berberis aristata), and Oregon Grape (Berberis aquifolium). These species do not contain hydrastine; they contain only berberine and berberine-related compounds. They do, however, produce an extract of the same color as Golden Seal. The berberine from Golden Seal and the herbs listed above is a potent antibacterial agent. However, it is the hydrastine that is believed responsible for the unique trophorestorative effects of Golden Seal upon mucous membranes. Similarly, the hair roots of Golden Seal, which have lower levels of hydrastine than the rhizome, are sold as the root and rhizome, which provides lower efficacy. The presence of hydrastine and the differentiation of adulterants is easily determined by HPLC. However, many companies do not have the necessary technology and often buy herbal ingredients without testing them. MediHerb only purchases cultivated Golden Seal, due to the report issued by CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) that the herb is endangered in its native habitat. This is a very common example of substitution of a less costly herb which greatly affects efficacy. |