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 valuesgiven are theintravenous 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
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 from Sigma Aldrich Where prices weregiven 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 (highlow) / Toxicity (highlow) / Cost (highlow)Drug / Molecular weight (g) / Drug / LD50 (mg/kg mice IV) / 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 / Capsaicin / 0.4 / Heroin / 692.00
Digoxin / 780.9 / Strychnine / 0.41 / Vincristine / 579.73
Tubocurarine / 609.7 / Colchicine / 1.7 / Reserpine / 390.34
Reserpine / 608.7 / Vincristine / 3 / Tetrahydrocannabinol / 123.65
Irinotecan / 586.7 / Topotecan / 7.5 / Vinblastine / 119.41
Topotecan / 421.4 / Digoxin / 7.7 / Taxol / 75.03
Diosgenin / 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 and find out about properties and prices at and
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
References
Plant-based drugs and medicine
Wong, K (2001) ‘Mother Nature’s Medicine Cabinet’, Scientific American
Shultz, J (2012) ‘Secondary Metabolites in Plants’, Biology Reference
Drug properties/information obtained from and
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:
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.