Today:

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Today

• Plant Medicines
• Some Practice 6 Questions
• Thursday
• Plant Medicines (cont.)
• Quiz 6!

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Plant Medicines Refer also to the Appendix in
your Reader Old, yet new pharmaceuticals
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Chemistry of Plant Medicines
A large of todays OTC and prescription drugs
have their origins in plant chemistry Examples
Aspirin, morphine, codeine, ephedrine, quinine,
digitalis, contraceptives
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Salicin and Aspirin
Salicin in willow bark (Salix)
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History of the Chemistry of Plant Medicines

• Native Americans
• Chinese herbal medicines
• Traditional medicine of India (Ayurveda)
• Many others

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Paracelsus, a Medieval Alchemistand Physician
around 1500
The dose alone makes the poison
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Dose
the quantity of an active substance taken in or
absorbed at any one time
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LD50
LD "Lethal Dose" LD50 is the amount of a
material, given all at once, which causes the
death of 50 of a group of test animals. It
measures the short-term poisoning potential
(acute toxicity) of a substance
Examples (Data from Merck Index) Aspirin oral,
rats LD50 1500 mg/kg Nicotine oral, rats
LD50 50 mg/kg Strychnine oral, rats 5.8 mg/kg
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How to obtain plant-derived pharmaceuticals

• A long procedure!
• Isolation of active compound(s) from plants
• Purification
• Structure determination Spectroscopy (IR, NMR,
  Mass Spectrometry )
• Testing of pharmaceutical activity
• Approval by FDA

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Pharmacologically Active Plant Compounds
Isolated in19th Century

• Isolation beginning 19th century
• Structure 1889
• Synthesis 1952
• Configuration 1952

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Pharmacologically Active Plant Compounds
Isolated in19th Century
Quinine, an antimalarial Tonic water
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Pharmacologically Active Plant Compounds
Isolated in19th Century
Atropa belladonna
Datura
Atropine
Scopolamine
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Pharmacologically Active Plant Compounds
Isolated in19th Century
a cardiac glycoside !
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• Some Practice 6 Questions
• Thursday
• Plant Medicines (cont.)
• Quiz 6!