The Healing Power of Plants - Reviewed by Grant Winton

Did you know that 80% of the world's medicine supplies are derived from plants? Also 50% of NHS medicines are plant-based.

Timothy Walker came to St John's to talk to Year 7 and Year 8 about how important plants are for medicine in the modern world. Boys from St Martin's and Merchant Taylors' also attended.

Timothy started the lecture by talking about deep vein thrombosis (DVT)and an extremely fruity way to avoid it whilst travelling by aeroplane or other vehicles. DVT is a condition where the blood forms clots in your legs, particularly the calf muscles. A chemical called bromolane helps prevent the clots forming. A ready made supply of bromolane is found in the fruit of the pineapple. So to avoid DVT all you have to do is chew on some pineapple during your flight.

We were told that many rare plant species may be found today in the Botanic Gardens in Oxford. The Botanic Gardens were founded by Sir Henry Danvers who paid £5,000 alone for walls and arches. The garden opened in 1734. The oldest tree there that is still standing is an English Yew. It has been standing for 300 years. The English Yew is one of the only sources of a drug called Taxol. Taxol is a highly effective treatment for breast cancer.

Timothy explained that if a drug with medicinal properties was identified from a plant there were several methods to get hold of it. Firstly, you could contact a pharmaceutical company and ask if they could supply it. This won't work for new compounds though, as the companies won't know what they are! Secondly, you could grow the plant from seed and extract the drug. This might be okay if the plant is relatively fast growing - but what if it is slow? The third technique is to use GM technology. You could find the gene that makes the drug in the plant and then transfer it to a suitable micro-organism, such as yeast. The yeast would then be tricked into making the drug for you. This is used, for example, to make yeast (a fungus) to produce insulin (an animal hormone) so that diabetics can treat themselves. The GM technique is helpful to preserve endangered plants. Sometimes the GM method just doesn't work, in which case scientists hunt for other (possibly related plants) that could also contain the compound required. Finally, and most drastically, the wild plants could be harvested and the drug extracted. This, however, can cause enormous damage to habitats and risks extinction of the plant itself.

We should try to conserve plant species as they may be used for future disease cures. In 1992 all but six countries signed a Treaty called the Convention on Biological Diversity. This stated that:

1. All plants must be conserved wisely.
2. All countries must make sure that certain plants do not become extinct
3. All countries have their own plans to conserve plant life specific to its own country

The countries that didn't sign up to the Treaty are: Andorra, Brunei, Somalia, the Vatican, Iraq and the USA.

All the boys enjoyed a informative and entertaining lecture. Many thanks to Mr Walker for coming!

For more information about the Oxford University Botanic Gardens try this site: