Medicinal Chemistry
But First – Some Flowers
15th Century Turkish Tulip
Semper Augustus Tulip
Triumph Tulips
Queen of the Night Tulip
Rosa alba – White Rose of York –
England pre-16th Century
Madame Hardy Rose – bred 1832
Modern Hybrid Tea Rose
Medicinal Chemistry
• Medicinal chemistry is the chemical study
of chemical substances useful in medical
treatments
Diospyros lycioides – source of
chewing sticks in Namibia
Ceanothus americanus – Native
American chewing stick
Modern Chewing Sticks
• Most chewing stick
plants have a wide range
of antibacterial activity
against a number of
odontopathic bacterial
species, and many also
contained healing and/or
analgesic compounds
Bloodroot – Sanguinaria canadensis
Rhizome of Bloodroot
Bloodroot extracts to treat
dental plaque
• Bloodroot extracts have been identified as
potentially valuable in controlling plaque
• Blood root has many alkaloids, known as
sanguinaria alkaloids, and sanguinarine in
particular, is thought to be a potential problem
limiting the usefulness of blood root as a dental
medicine
• There is an indication that sanguinarine may
provoke glaucoma in predisposed humans and
cats.
Double Blind Testing
• A key component of western testing is to do
double-blind testing, so neither healer nor patient
knows what the patient is receiving.
• Such tests often involve the use of a real substance
and a placebo.
• The test for the placebo effect assumes that
patients are not expecting the substance to have
certain effects.
• If patients do expect certain effects, it renders
placebo testing difficult or impossible.
Dwarf ginseng – Panax trifolium
Medicinal properties of Ginseng
• There are many claims that ginseng (Panax sp. –
F. Araliaceae – the arums) increases sexual
functioning, has anti-cancer properties, boosts the
immune system, and even increases ability to
perform in stressful situations.
• Difficult to test because ginseng preparations
differ in their composition.
• Many of the chemicals produced by ginseng have
counteractive effects. Isolated compounds work
well in vitro, but simple ginseng preparations in
vivo do not seem to have the benefits originally
claimed. How ginsenosides are absorped,
transported, degraded, and excreted is poorly
known in humans.
Opium poppy – Papaver somniferum
Plant chemical composition changes
with development
• The opium poppy Papaver somniferum is a good
example of changes in metabolites during
development. The seeds are free of alkaloids.
After germination, the plant produces narcotine
within 3 days. When the seedling is about 7 cm
tall, the plant begins to produce codeine,
morphine, and papaverine. Total alkaloid content
slowly increases until flowering and then there is a
sharp increase in alkaloids until the floral leaves
fall off the plant.
Poison hemlock – Conium maculatum
Poison hemlock in the wild
Water hemlock – Cicuta virosa
Poison Hemlocks
• Poison hemlock and the water hemlocks are the
most poisonous plants in North America. The
active ingredient in poison hemlock is the alkaloid
coniine. It is a central nervous system stimulant
that affects the body like a nicotine overdose;
paralysis creeps from the lower limbs upward.
Death is due to the paralysis of the diaphragm and
subsequent respiratory failure. Water hemlocks
are toxic due to an alcohol, cicutoxin. It produces
violent convulsions and death.
Alkaloid content varies during the day
• In poison hemlock, the amount of coniine varies
during the day. The fruits are very high in coniine
at 4 a.m. (226 micrograms) and low in coniine by
4 p.m. (8 micrograms). The amount of coniine
varies with amount of sun as well. Another
relative, wild parsnip (Pastinaca sativa) is toxic to
the skin and is more toxic during bright sun than
in cloudy weather or at night.
Wild parsnip – Pastinaca sativa
Wild parsnip in the field
Teonanacatl – The Flesh of the Gods
Psilocybe mushrooms
Dr. Albert Hoffman – Swiss Chemist
Conocybe – also produces psilocin
Panaeolus – also produces psilocin,
may be toxic
Stropharia – also produces psilocin,
may be toxic
Chemical structures of several
hallucinogenic substances
Drug Similarities
• Interestingly, the drug Visken, used to treat
hypertension was developed as an analog to 4hydroxyindole, the phenolic nucleus of psilocybin and
psilocin, from chemicals in Albert Hoffman’s lab.