HerbalGram. 2003; 58:75-76 American Botanical Council
by Dennis V.C. Awang, Ph.D., F.C.I.C.
PDR for Herbal Medicines, 2nd edition, edited by
Joerg Gruenwald, Ph.D., Thomas Brendler, Christof Jaenicke, M.D. Medical Economics
Co.: Montvale, NJ; 2000. 858 pp. hardcover $59.95 ISBN 1-56363-361-2
When the late Prof. Varro E. (Tip) Tyler, reviewed the first
edition of this work in HerbalGram 46, he made a number of criticisms
of it, as well as suggestions for its improvement. The German editors, given
the opportunity to comment on Prof. Tyler’s review, promised to implement
his suggestions in a timely fashion "wherever possible and appropriate."
Salient among Tyler’s criticisms of the volume was the uncritical character
of its monographs, omission of significant botanicals, and inclusion of a number
of toxic and clinically "insignificant" herbs. This from a book touted
as "The Information Standard for Complementary Medicine" and aimed
at physicians. He further advised that "The clinical utility of the PDR
for Herbal Medicines could have been greatly improved by judicious editing."
The second edition is similarly in need of expert scientific
editing – as well as proof reading. The carelessness evident in both areas
is prevalent enough to enervate knowledgeable herbal scientists. A number of
egregious examples will be provided later in this review, but the shoddiness
of editing is nowhere more evident than in the kava kava entry, where, under
the contraindications heading, two virtually identical sentences caution against
its use in patients with endogenous depression because of an increased risk
of suicide.
The number of entries in the second edition increased from
600 or so in the first to more than 700. While in their comments about the review
of the first edition the editors expected it "to steadily improve and expand,"
such a large expansion does not seem to be warranted given the rate of development
of new medicinal plant treatments. They have not eliminated any of the monographs
dealing with very toxic and clinically insignificant plants, and only one of
Tyler’s noted omissions (cat’s claw) has been included (Unicaria
[sic] tomentosa) in the Alphabetical Index which precedes the main
body of the text. Soybean is still represented as the wild species Glycine
soja instead of the commercial cultigen G. max. It would be interesting
to review the rest of the hundred or so new entries, roughly equal in number
to the herbs of major significance in North America.
Nevertheless, the second edition is considerably improved over
the first, including recent literature references and information on herb-drug
interactions such as those involving St. John’s wort (SJW). However, even
with these additions there is a lack of critical attention to published research
results, as in perpetuating the erroneous notion that SJW has potential for
reproductive toxicity, and promoting the long-discredited theory that hypericin
is the SJW principle responsible for its anti-depressant activity: "In
general a range of 200 to 1000 micrograms/day of hypericin is recommended for
treatment of depression (Anon, 1996)."
While much prominence is given to the judgments of the German
Commission E, these bulleted lists of abbreviated indications neglect the Commission’s
findings that some 600 plants did not have sufficient research to support safety
or efficacy recommendations. Occasional inaccuracies appear, such as in the
case of rosemary and yarrow: the PDR erroneously states that the Commission
E approved rosemary’s use for: blood pressure problems, loss of appetite,
rheumatism. However, the Commission cites rosemary leaf use only for dyspeptic
complaints, at least insofar as the monograph published in ABC’s The
Complete Commission E Monographs, for which Dr. Gruenwald was an associate
editor. Interestingly, Tyler wrote in Tyler’s Honest Herbal (Haworth
Herbal Press, 1999) that it is used to treat low blood pressure, while
the British Herbal Pharmacopoeia lists as indication: "headaches
migrainous or hypertensive." Also inexplicably, the PDR adds
to the Commission E approvals for yarrow: "Liver and gallbladder complaints,"
which are not listed in the ABC publication.
Regarding format, the second edition, sensibly, has altered
the vast majority of monograph headings to give priority to common names, inferiorly
listing Latin binomials in their accustomed italics. However, the binomials
are not italicized in the main text, as they ought to be. It also seems unnecessary
to retain the original heading entries in the main body of text since the Latin
binomials are available in the Alphabetical Index for those unfamiliar with
the respective common names. A final note regarding Latin binomials: No naming
authorities are given, nor are any synonyms. While this neglect is often inconsequential,
there are instances where confusion could occur with inexpert readers. For example,
in much of the European literature saw palmetto is referred to as Sabal serrulata
rather than the designation Serenoa repens common in North America.
Also, while German chamomile is currently widely represented as Matricaria
recutita, the earlier binomials M. chamomilla and Chamomilla recutita
are still occasionally encountered today.
There is a disconcerting situation respecting the literature
listings and textual references, when they occur. There are some monographs
with numerous literature listings that have no correlation with the monograph
text (e.g., 34 unreferenced literature listings under wormwood). The situation
is further confounded by the fact that a number of literature citations do not
include the title of the publication, and some are incorrect: in both the ginger
and wormwood monographs, a paper by Marles et al. is cited as being "In:
JNP 55: 1044-1056, 1992". However, the JNP paper included me as an author
and has a different author list than that cited. In any event, ginger was found
not to inhibit serotonin release from blood platelets, the scientific focus
of the subject bioassay – and there is no indication in the wormwood monograph
of any relation to such function. In the case of feverfew, there are two references
to "Groenewegen, 1986" in the monograph text but the literature listing
notes two publications attributed to Groenewegen in 1986, both without
titles.
In addition to annoying misspellings – notably "partholide"
repeatedly for parthenolide, which is particularly confusing to those unfamiliar
with feverfew chemistry, since secotanapartholide A is regarded as one of the
plant’s significant actives – more serious is the attribution of dominant
activity to parthenolide, especially regarding feverfew’s anti-migraine
effect. It is stated that "the usual standardization level is 0.2 percent
parthenolide content," but since 1996 it has been apparent that parthenolide
is not a significant contributor to feverfew’s migraine prophylactic effect.
In fact, the 0.2 percent parthenolide minimum was meant as an identity criterion,
established by the Canadian regulatory agency in an attempt to ensure similarity
to the clinically tested feverfew chemotype: at least two other feverfew sesquiterpene
lactone chemotypes contain no parthenolide. Finally, regarding feverfew drug
interactions, the statement that "there is a strong possibility that Feverfew
may interact with thrombolytics, anticoagulants and platelet aggregation"
is simply not supported by recorded experience: no case of a bleeding problem
has ever been associated with feverfew use. Such speculation is based entirely
on in vitro laboratory observation of an anti-platelet aggregation effect.
The heading Ginseng, Panax ginseng, (Asian Ginseng)is followed by a list of Trade Names, which include "Siberian Ginseng…American
Ginseng Root…Standardized Siberian Ginseng Root….Siberian Ginseng
Power Herb…Eleuthero Ginseng Root, Siberian Ginseng Root." A later
listing is Siberian Ginseng, Eleutherococcussenticosus. The American
Herbal Products Association wisely recognizes eleuthero as the preferred common
name for E. senticosus,acknowledging, as the U.S. Congress
has recently, that only Panax species may legitimately be claimed to
be ginseng.
Under Actions and Pharmacology are listed protopanaxadiol ginsenosides,
"protopanaxytriol" [sic] ginsenosides, and oleanolic acid ginsenosides.
No mention is made of the significant panaxatriol ginsenoside Rg2,
and mentioned as oleanolic acid derivatives are ginsenoside Ro, chikusetsusaponin—V
and Rb1, Rb2, Rc, Rd, Re
and Rg1: Rb1, Rb2, Rc and Rd
are protopanaxadiol glycosides, while Re and Rg1 are protopanaxatriol
derivatives. Ginsenoside Ro is the only oleanolic acid derivative
present in Asian and American ginsengs; it is identical with chikusetsusaponin-V,
first identified in Japanese ginseng (P. japonicus).
In summary, while this very substantial volume contains much
useful factual information on a vast array of medicinal plants, its striking
deficiencies and extensive errors of both commission and omission seriously
limit its usefulness while promoting an inaccurate appreciation of many of the
more important and commercially prominent herbal preparations.