Medicines and drugs from plants: ‘trumps’ card
game
Teaching Notes
Introduction and context
Throughout human civilisation the plant world has provided a rich source of medicinal and
recreational drugs. In the past 100 years many of the active compounds in these folk remedies
have been purified, identified, studied and, in some cases, synthesised to provide effective
treatments. This resource uses a ‘trumps’ card game format to provide a fun and informative way
for Post-16 students to learn about some of these plant-derived pharmaceuticals.
Teaching Notes
This resource includes a set of 25 ‘trumps’ cards featuring plant-derived drugs. Each card
includes the name of the drug, source plant name and photo, the drug’s structure, molecular
weight, toxicity and cost.
The cards should be printed out on card or heavyweight paper beforehand. You can print out one
set for the whole class or a set for each pair/group of students.
How to play
1. Deal out the cards between all the players. Each player should hold their cards in a pile,
face down, without looking at them.
2. The first player takes the uppermost card from their stack. They read aloud the name of
the drug and the plant the drug comes from. They then choose a category (e.g. toxicity)
and state the value of that category for the card (e.g. 3.4).
3. The other players then pick the uppermost card from their stacks. Each one reads aloud
the name of the drug and the source plant, and then the value of the selected category.
4. The person with the highest value for that category is the winner, and claims their
opponents’ cards. These cards are then put to the bottom of the winner’s card pile.
5. This is repeated, with the winner of each round choosing the next category.
6. The game continues until one person holds all the cards and is declared the winner.
The ‘players’ could be individuals or groups of students. For all categories you could play either
highest value or lowest value wins.
Categories
Molecular weight: weight in grams (g) of 1 mole of the substance.
Toxicity: For ease of comparison the values given are the intravenous LD50 for mice as this
value was available for all the drugs except diosgenin, where the oral LD50 is given. LD50 stands
for ‘Lethal Dose 50%’ and is the dose needed to kill 50% of the mice in a test study. It is usually
expressed in mg of drug per kg of body weight. Although it is a flawed measure (results can be
variable and mice can react very differently to drugs than humans) it is a useful way of comparing
toxicity. NB. The higher the number, the less toxic the drug
Science & Plants for Schools: www.saps.org.uk
Medicines and plants from plants: p. 1
This document may be photocopied for educational use in any institution taking part in the SAPS programme.
It may not be photocopied for any other purpose. Revised 2012.
Cost per 100mg: The price of obtaining the drug legally through a pharmaceutical supplier has
been estimated based on cost of the pure drug or a derivative from http://www.drugbank.ca/ or
from Sigma Aldrich http://www.sigmaaldrich.com/. Where prices were given in USD they were
converted into GBP at 1USD = 0.642GBP.
Molecular formula: The molecular formula could also be used as a category e.g. number of
carbon or hydrogen atoms per molecule.
Background information
Why do plants produce these chemicals?
The fact that many plant molecules make effective drugs is a happy coincidence – the plants
certainly don’t produce them for our benefit! These molecules are known as secondary
metabolites. They are not essential for the basic life processes like photosynthesis or respiration.
However, secondary metabolites are important to the plant and help ensure its long term survival
in other ways. Secondary metabolites include scents and pigments, which are involved in
attracting pollinators and seed dispersers, and waxes for protective coatings, as well as the
compounds we use as drugs.
Although the natural functions of some of these chemicals is still being investigated it seems that
most of the ‘drugs’ are produced to help the plant defend itself. Plants are under constant attack
from herbivores, insects and micro-organisms but, unlike animals, they can’t run away and they
don’t have an immune system for protection. Plants have evolved a variety of ways to protect
themselves from an attack - these include physical barriers like spines as well as chemical
defences.
Many of the secondary metabolites produced by plants have a very unpleasant bitter taste, so
that grazing animals will soon go elsewhere. Lots of these chemicals are also poisonous (as you
can see from the toxicity data on the cards) - nicotine, for example, is such an effective
insecticide that it has been used in agriculture, as well in nature. Certain compounds are involved
in strengthening the plant cell wall to help it resist microbial attack. Some molecules, like salicylic
acid, have a role in regulating plant development or cell signalling, and others absorb UV light so
may provide a ‘sunscreen’ to prevent UV damage.
Humans have worked out how to make many of these biologically-active chemicals synthetically
in the lab but others, typically the more complex molecules, are impossible to produce meaning
they are extracted from plant tissues or grown in cell culture. Drugs produced from living tissues
are more expensive.
Drugs data
These tables show the drugs sorted by molecular weight, toxicity and cost.
Molecular weight (highlow)
Drug
Molecular
weight (g)
Toxicity (highlow)
LD50
(mg/kg
Drug
mice IV)
Cost (highlow)
Drug
cost per
100mg (£)
Taxol
853.9
Tubocurarine
0.13
Topotecan
23042.66
Vincristine
824.9
Nicotine
0.3
Irinotecan
1336.00
Vinblastine
810.9
Heroin
692.00
Capsaicin
0.4
Science & Plants for Schools: www.saps.org.uk
Medicines and plants from plants: p. 2
This document may be photocopied for educational use in any institution taking part in the SAPS programme.
It may not be photocopied for any other purpose. Revised 2012.
Digoxin
780.9
Strychnine
0.41
Vincristine
579.73
Tubocurarine
609.7
Colchicine
Reserpine
608.7
Vincristine
1.7
Reserpine
390.34
3
Tetrahydrocannabinol
Irinotecan
586.7
123.65
Topotecan
7.5
Vinblastine
119.41
Topotecan
Diosgenin
421.4
Digoxin
7.7
Taxol
75.03
414.6
Taxol
12
Capsaicin
62.40
Colchicine
399.4
Vinblastine
15
Digoxin
28.91
Heroin
369.4
Cocaine
16
Colchicine
19.68
Strychnine
334.4
Reserpine
21
Morphine
14.77
Quinidine
324.4
Heroin
21.8
Tubocurarine
7.92
Quinine
324.4
Tetrahydrocannabinol
42
Cocaine
4.39
Tetrahydrocannabinol
314.5
Quinidine
53.6
Theophylline
3.17
Capsaicin
305.4
Codeine
54
Quinine
1.66
Cocaine
303.4
Caffeine
62
Caffeine
1.25
Codeine
299.4
Quinine
68
Diosgenin
0.74
Morphine
285.3
Ephedrine
74
Nicotine
0.73
Caffeine
194.2
Irinotecan
132
Strychnine
0.65
Theobromine
180.2
Morphine
135
Codeine
0.53
Theophylline
180.2
Theophylline
136
Quinidine
0.10
Ephedrine
165.2
Aspirin
184
Theobromine
0.07
Nicotine
162.2
Theobromine
837
Ephedrine
0.03
Aspirin
138.1
Diosgenin
>8000
Aspirin
0.03
Further Investigations
Create your own cards: Challenge your students to add to the card set by researching other
plant-derived drugs. You can get a long list of drugs on The Rainforest Database http://rainforestdatabase.com/plants/plantdrugs.htm and find out about properties and prices at
http://www.drugbank.ca/ and http://chem.sis.nlm.nih.gov/chemidplus/
Extracting caffeine from tea: Now you know all about caffeine, why not see what it looks like? A
SAPS resource on extracting and purifying caffeine from tea is also available.
Plants Fight Back: If you or your students would like to know more about why plants produce
these chemicals why not try this SAPS resource available at
http://www.saps.org.uk/secondary/teaching-resources/118-plants-fight-back-an-article-for-post16-students
References
Plant-based drugs and medicine
http://rainforest-database.com/plants/plantdrugs.htm
Wong, K (2001) ‘Mother Nature’s Medicine Cabinet’, Scientific American
http://www.scientificamerican.com/article.cfm?id=mother-natures-medicine-c
Shultz, J (2012) ‘Secondary Metabolites in Plants’, Biology Reference
http://www.biologyreference.com/Re-Se/Secondary-Metabolites-in-Plants.html
Science & Plants for Schools: www.saps.org.uk
Medicines and plants from plants: p. 3
This document may be photocopied for educational use in any institution taking part in the SAPS programme.
It may not be photocopied for any other purpose. Revised 2012.
Drug properties/information obtained from http://www.drugbank.ca/ and
http://chem.sis.nlm.nih.gov/chemidplus/
Acknowledgements
This resource was created by Dr Sarah McLusky, lecturer in biochemistry at Newcastle College
and freelance science education consultant.
Drug structures are available on Wikimedia Commons. Plant photographs were sourced from
Flickr. All structures/images were in the public domain or made available under Creative
Commons licenses.
Science & Plants for Schools: www.saps.org.uk
Medicines and plants from plants: p. 4
This document may be photocopied for educational use in any institution taking part in the SAPS programme.
It may not be photocopied for any other purpose. Revised 2012.