Botany session 11

© Copyright PCNM 2011
Botany and Pharmacognosy
Session 11

Review
Last session we covered:
• Ethnopharmacology, Part II
kettlemoraineacupuncture.com

This Session
During this session we will cover:
• Phytotherapy, Part I
mdholistichealth.com

Safety
• Phytotherapy has been used by humans for a very long time, and
has proven to be efficacious for many conditions. However it is vital
that when using phytotherapy to follow certain practices to minimise
any health risks.
www.yourdictionary.com

Safety
Correct identification
• As we have seen, different plants
contain different constituents, or
sometimes the same constituents but
in differing amounts. For an herbal
preparation to exert the expected
therapeutic effect it is essential that
the correct herbs are in that
preparation. An herb that has been
knowingly or unknowingly substituted
for a named plant in a preparation will
have different phytoconstituents which
at best may be ineffective and at worst
may be toxic.
www.shtfpreparedness.com

Misidentification
• Plants can be named in four different ways making it more difficult to
be certain the correct plant is being used.
• As an example, the Chinese herb dong quai is also known as
dong guai, danngui and tang kuei. Its botanical name is Angelica
polymorpha (formerly sinensis). Its common name is angelica.
Sometimes Radix Angelica is used to describe it. However, both
angelica and Radix angelica are also used to describe the
European species Angelica archangelica.
Left: Angelica
polymorpha
Right: Angelica
archangelica
medicinalherbinfo.org
jekkasherbfarm.wordpress.com

Misidentification
• From a medicinal point of view
these herbs are not
interchangeable, so it is
important to choose the correct
species.
• Black cohosh and blue
cohosh have very similar
names; however the plants
are not only from different
genera but different families. Above
Black
cohosh
Below:
Blue
cohosh
identifythatplant.com
www.finegardening.com

Misidentification
• Misidentification can result in erroneous associations being made.
This has clinical implications for that immediate herbal preparation
and for subsequent clinical uses. The misidentification may be made
at the time of the manufacturer’s bulk purchase of the herbal
material or it could be made earlier when the wild plants are picked

Misidentification
• It is therefore necessary to be able to correctly identify plants.
• To identify plants botanists use one of several keys which enable individual
plants to be correctly identified. The most common type of key used is a
dichotomous key. In a dichotomous key, successive choices between
contrasting statements are followed until the correct name is found by a
process of elimination. The dichotomous key is made up of paired choices.
Each half of the pair consists of a statement that is either true or false.
Choosing one of these statements leads to another pair of statements where
the correct one needs to be selected, and so on.
www.layers-of-learning.com

Misidentification
• Using a dichotomous key is like following
directions to a distant destination.
• Along the road there are junctions where
one of two paths must be followed. If the
roads are properly marked and the correct
choice made, the destination is finally
reached.
• A dichotomous key enables proper
identification of a plant’s family, species
and infraspecific taxon. Infraspecific taxa
in botany include subspecies, variety,
subvariety, form and subform.
• In zoology an animal can only be
identified down to sub species.
itsadeliverything.com

Dichotomous keys

More About Flowers
• This section requires the use of the
text: Chong SN. Basic morphology
of flowering plants.
• Angiosperm flowers vary widely in
their structure. To adequately
describe flowers so that they may
be identified many technical terms
have been developed. Terms have
been coined for both dicot and
monocot plants.
• Sections 7.1, provide an illustrated
glossary which will be worked
through.
www.studyblue.com

More About Flowers
• The gynoecium is the collective term for all the carpels in the
flower, therefore the carpels are the building blocks of the
gynoecium. Section 7.2, shows how to determine the number of
carpels in a flower.
• Section 7.3, illustrates how to describe an angiosperm flower using
diagrams of a longitudinal half flower and a cross-section of the
ovary of the flower.
www.byflugur.is

Floral formula
• The floral formula is a way to represent the structure of a flower
using specific letters, numbers and symbols. A general formula is
used to represent the flowers of a family rather than individual
species. The letters used may vary so this course will use the letters
and symbols depicted in the set text.
www.life.illinois.edu

Floral formula
• The formula begins with either
the sign for actinomorphy or
zygomorphy. This is followed by
a series of letters in the order K
for calyx, C for corolla, A for
androecium and G for
gynoecium. The number of parts
(sepals, petals, stamens and
carpels respectively) in each
whorl is shown by a number
following the appropriate letter. If
there are more than twelve of a
particular part then the symbol
for infinity is used, 8.
en.wikipedia.org

Floral formula
• If the parts are fused then the
number is bracketed, but if the
parts are free then they are
not enclosed in brackets. If the
parts are in distinct whorls or
groups this is indicated by
splitting the number
appropriately; e.g. in the
garden pea, Pisum sativum,
there are ten stamens. Nine of
these are fused and the tenth
is separate. This is
represented A(9)+1.
www.tutorvista.com

Floral formula
• If two whorls are united then the
representative symbols are joined by
a single bracket or arch over the two
symbols. For example, in the
primrose, Primula vulgaris, the
stamens are inserted on the corolla
tube.
• If the sepals and petals are
indistinguishable then K and C are
replaced by P representing the
perianth. Primrose
en.wikipedia.org

Floral formula
• The position of the ovary is
indicated by a line. In a superior
ovary the line is placed
underneath the number of
carpels, and in an inferior ovary
the line is placed above. If there is
no line above or below the
number of carpels this indicates a
half-inferior ovary.
• Please refer to the set text. Work
through these examples to gain
an understanding of the floral
formula
en.wikipedia.org

Floral diagram
• A floral diagram is a stylised, pictorial
representation of the structure of a
flower.
• The whorls of the floral parts are shown
as a series of concentric circles. All
floral segments arising at the same
level are placed in the same circle at
their correct relative positions.
• The order of arrangement is therefore
as in the flower; from the outside
inwards the order is calyx, corolla,
androecium and gynoecium. Fusion of
parts is indicated where necessary.
The ovary is represented in cross
section in the centre of the whorls.
www.countrysideinfo.co.uk

Floral diagram
• The bottom of the diagram represents the anterior side of the flower,
that is the side furthest from the axis of the inflorescence. This axis
is shown as a circle at the top or posterior side of the diagram. Any
bracts subtending the flower are inserted at the base of the diagram.
commons.wikimedia.org
www.excellup.com

Floral diagram
• It is usual to present a floral diagram in conjunction with a
longitudinal section through the centre of the flower.

Floral diagram
• Note the differing use of the symbol
representing ‘numerous’ in the floral
formula. In the floral diagram this
means a 2-lobed anther.
• Refer to the text, then attempt the
examples.
• Note that each of these descriptive
methods has its limitations. It is
useful then to show the half flower
diagram, the floral formula and the
floral diagram to give a complete
description of a flower.

Substitution
• Deliberate substitution is no less
dangerous than misidentification,
and it also implies malfeasance.
However this is not necessarily
the case. When raw materials are
being purchased there can be
unintentional adulteration.
• Adulteration is described as the
intentional substitution with
another plant species or
intentional addition of a foreign
substance to increase the weight
or potency of the product or to
decrease its cost.
mdholistichealth.com

Substitution
• In 1994 it was reported that young
women taking a Belgian slimming
preparation developed rapidly
progressing interstitial nephritis. It was
discovered that the herb Aristolochia
fangchi had been substituted for
Stephania tetranda. Aristolochia fangchi
contains aristolochic acid which is toxic
to the kidneys. Eighty cases were
identified; more than half of these
developed terminal renal failure. bethwelch.buzznet.com

Substitution
• There are documented cases of the cheaper Siberian ginseng,
Eleutherococcus senticosus or American ginseng, Panax
quinquefolium being substituted for the more expensive Korean
ginseng, Panax ginseng. Fortunately no adverse effects were
recorded, but there may well have been reduced efficacy of the
herbal preparation.
Eleutherococcus
senticosus
Panax ginseng
www.mdidea.com
www.herbs.org

Substitution
• Deliberate substitution is no less dangerous than misidentification,
and it also implies malfeasance. However, not all substitutions are
deliberate malpractice. When raw materials are being purchased
there can be unintentional adulteration. Unintentional adulteration
may be due to several reasons:
preventdisease.com

Substitution
• Name confusion. There may be
confusion over vernacular names. In
Chinese herbal medicine the vernacular
for Stephania tetranda is ‘Fang-jig’. This
can easily be confused with Aristolochia
fangchi, especially if only the species
name is used. In indigenous systems of
medicine there may be confusion
because of local dialects. In Ayurveda,
‘Parpatta’ refers to Fumaria parviflora. In
Siddha, ‘Parpadagam’ is taken to mean
Mollugo pentaphylla. These two are often
substituted one for the other, even
though they are distinctly different in
appearance. Fumaria has some
hepatoprotective applications whereas
Mollugo is used as an antifungal.
Fumaria parviflora
Fumaria parviflora

Substitution
• Lack of knowledge about the authentic source. ‘Nagkesar’ is an
important drug in Ayurveda. Its authentic source is Mesua ferrea.
However, Calophyllum inophyllum is also sold as Nagkesa. True
Nagkesar from Mesua is a heart tonic and emmenagogue, and is
used as an abortifacient. A preparation from Calophyllum
inophyllum is anti-inflammatory and used to treat eczema and
psoriasis.
Mesua ferrea Calophyllum inophyllumtamilnet.com medplants.blogspot.com

Substitution
• Similarity in morphology. Macuna
pruriens, the velvet bean, has long
been used in Ayurvedic medicine to
treat Parkinson’s Disease. It
contains L-DOPA, the precursor to
dopamine. However the seeds of
this plant are often confused with
very similar looking bean seeds that
do not contain L-Dopa so that the
innocent substitution leads to an
ineffective product.
Macuna pruriens seeds
www.indiamart.com

Substitution
• Lack of authentic plant. Hypericum
perforatum, St John’s wort, is very widely
used in European countries. In Asian
countries it is not easily available. However
the Indo-Nepal species, Hypericum patulum
is widely available and is sold as H.
perforatum. There are about 450 species in
the genus Hypericum but only H. perforatum
has been extensively studied. One
preliminary study found two constituents in H.
patulum that are not in H. perforatum, but
little else is known of the phytoconstituents. It
is thus not possible to know if the substitution
of H. patulum for H. perforatum is an
effective substitution.
Hypericum perforatum

Substitution
• Careless collection. Herbal collectors and suppliers need to take
great care to collect the correct species and not to mix species
from a particular genus. Unintentional adulteration may occur
when a collector harvests weed species growing alongside the
herb. Many suppliers are illiterate and are not aware of
differences between species and sub-species. Illiteracy may also
be the reason for name confusion and lack of knowledge about
the authentic plant.
www.gardenersworld.com

Substitution
Lack of knowledge may also result in inappropriate parts of the
plant being included in the collection. The World Health
organisation, in its publication on quality standards for medicinal
plant materials recommends rejecting any batch of raw material
which contains greater than 5% of any other plant part of the
same plant, such as stem in leaf collections, even though they
are derived from the authentic plant.
olliesyummyinyourtummy.blogspot.com

Contamination
• During growth and storage, crude
plant material can become
contaminated. This contamination may
be from pesticide residue, radioactive
substances or heavy metals,
especially lead, cadmium, mercury
arsenic and thallium. In 1996 there
was a report of five people in Britain
who were poisoned by lead in some
Asian traditional remedies. The herbal
preparations implicated contained 6-
60% w/w lead. Other heavy metals
found in these medicines included
mercury, arsenic, aluminium and tin.
mynutrametrix.transitionslifestyle.com

Contamination
• Some herbs may be
contaminated by micro-
organisms and toxins from
microbes, such as aflatoxin.
The Australian Code of Good
Manufacturing Practice
specifies detection of micro-
organisms but leaves the
estimation of other
contaminants to the discretion
of manufacturerswww.sloatgardens.com

Adulteration
• There have been reports of the intentional addition of
pharmaceutical substances to herbal preparations. Chinese herbal
medicine has featured in a number of recent cases. An anti-arthritic
preparation, Tung Shueh was reported to have caused renal failure,
loss of blood pressure control and peptic ulceration. The product
was found to contain mefenamic acid and diazepam but neither of
these were listed on the label. Mefenamic acid is a non-steroidal
anti-inflammatory drug, and diazepam is a sedative and anxiolytic.
In 1995 a Chinese herbalist in Victoria was prosecuted for adding a
steroid cream to a herbal preparation, causing severe facial
erythema in a patient.

Incorrect preparation or dosage
• How crude plant material is processed has
a major effect on the pharmacological
activity of the finished product. This
processing may be carried out by the
manufacturer, the practitioner or even the
patient. In 1994 a person in Western
Australia had a heart attack induced by
drinking a liquid preparation of aconite.
The herbalist who prescribed the aconite
had instructed the patient to boil the herb
in one and half litres of water for an hour,
and then to drink the decanted liquid. The
patient increased the recommended dose
and shortened the boiling time. The correct
boiling time changes the alkaloid
composition of the herb, reducing its
toxicity.
Aconite
www.abchomeopatia.com

Incorrect preparation or dosage
• It should be noted however, that
aconite is a restricted plant in
Australia and ingestion is NOT
recommended. According to the
British Herbal Pharmacopoeia the
therapeutic dose is so close to the
toxic level that this remedy is not
suitable for internal administration
Aconite
www.cambridge2000.com

Lack of standardisation
• The therapeutic and/or toxic components of plants vary depending:
• The part of the plant used
• The stage of ripeness
• Geographic area where the plant was grown
• Storage conditions

• This means that batch-to-batch reproducibility of plant material
should be assessed in the production of marketed products. In
practice, sampling has shown significant variation from one batch to
another. A study published in the Lancet in 1994 examined the
amount of ginsenoside in Panax ginseng preparations. Ginsenoside
is the glycosylated steroid which gives ginseng most of its biological
activity. Fifty commercial brands of ginseng were tested. The
amount of ginsenoside ranged from 0 to 9% w/w. One of these
samples contained no ginsenosides but did contain large amounts
of ephedrine. This was only discovered when an athlete was
accused of doping himself with ephedrine. The only product he had
consumed was a commercial ginseng. Upon investigation the
ephedrine content was discovered.

• Wild crafted versus farmed.
• As species face loss of habitat or overharvesting, there have been
new issues to deal with. When a previously wild crafted herb is
farmed the herb itself undergoes change.

Checkpoint!

Summary
During this session we covered:
• Phytotherapy, Part I

Next Session
We will cover:
• Phytotherapy, Part II

Preparation
Brief Notes
• Don’t forget to log on to the LMS and download and print off your
brief notes and handouts for the next session.

Botany session 11

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Botany session 11