Yew Trees that cure tumours

Yew Taxus baccata.
Photo: Håkan Tunón.

The National Cancer Institute in the USA started a big project in the 1960s to study the effects of various plant extracts on cancer cells cultivated in test tubes. More than 30,000 extracts from various plants were examined. One of these was the Pacific Yew, the Taxus brevifolia. It showed promising effects and in 1969 a substance was isolated that was named taxol after the Latin term for yew trees, Taxus. The substance was later renamed paclitaxel. In 1993 – twenty-four years later – it was registered in Sweden as a new drug, for use, among other things, for treating cancer of fallopian tubes and breasts.

A big problem arose during work with paclitaxel. Yew trees grow slowly and in order to satisfy the American market at the beginning of the 1990s, there was a need for around 25 kg of paclitaxel a year, which corresponds to approximately 38 000 fully grown yews. From a one hundred year old tree it is possible to extract 1 g of paclitaxel, enough for half a course of treatment. There was a risk of exterminating yews. Consequently scientists started searching for alternative methods of producing paclitaxel. It can be synthesised but it takes time and besides, it is extremely expensive. Other varieties of yews can possibly be used as a source of this substance since closely related species often contain similar chemical substances.

Yew, Taxus baccata, has been found to contain substances which form the first stages of taxol and which can be chemically changed to paclitaxel or similar compounds for drug development. The structure of paclitaxel has also been arousing interest. Are all the 112 atoms in the molecule really necessary or can parts of the substance be used for treatment? It is possible that one could make a smaller molecule with similar properties. In that case, it would be easier to develop a method of producing the drug synthetically more cheaply. Even when a drug has been produced, researchers continue to develop it further for a new generation of drugs.

Suggested reading:
Nicolau, K. C., Guy, R. K., and Potier, P. 1996. Taxoids: New weapons against cancer. Scientific American. (June):84-88.

Coffee – rat poison or miracle medicine?

The red berries, or, erroneously, coffee
beans of the coffee bush are rich in
caffeine and are roasted and used in
a rather bitter drink.
Photo: Fredrik Karlsson.

Coffee came to Sweden for the first time, somewhere around 1674. Only a small amount arrived, but that was just the beginning. Nowadays people in Sweden consume on average 11 kg coffee per person every year and this is only surpassed by the Finns who consume 12.8 kg.

In 2005 the world production of coffee was 7.7 million tons and Brazil produced more than a quarter of this. There are around seventy different kinds of coffee but the most important beans come from the bush Coffea arabica, which has 70% of the market.

Coffee breaks – an intellectual activity
Coffee houses began to appear in big cities, most significantly London, during the 17th and 18th centuries. They became the meeting places of men with intellectual interests. At that time coffee breaks were an all-male event. Coffee houses were important for spreading news. Politics, literature and science were discussed over a cup of coffee. Many radical thinkers, great philosophers and famous authors made their breakthroughs at these places.

At home Linnaeus considered himself a Turk!
Linnaeus realised that you had to behave like a Frenchman at the Royal Swedish Court, “but when we are at home, we live like Turks: a long and wide dressing gown, loose slippers, a big and white cap, we smoke our tobacco just like Turks; so that the Turks have taught us to dress at home and to drink coffee.”

The team leader of
Sweden’s first clinical trial
never saw the result of his

In general, Linnaeus considered that coffee was good for you and a bracing drink as long as it was taken in moderation and not too near bedtime. However, he also pondered over a French doctor’s declaration in 1715 that coffee shortened a man’s life. In this connection it can be noted that according to a story the King Gustav III should have carried out an experiment on two identical twins who were serving life sentences. He gave one of them three pots of coffee a day and the other tea, in order to see if the drinks affected their lifespan. This is jokingly referred to as the first Swedish clinical trial. Sadly Gustav III did not live to see the final result of his experiment, but the first twin died at the age of 83. The one who drank tea! The authenticity of the story has been questioned.

Coffee against sleep 
Coffee beans contain between 0.8 and 2.5% of the alkaloid caffeine. Studies have shown that coffee awakens one’s thoughts with lively associations and an increased ability to see combinations. The feeling is clearest when you are most tired. These are mainly subjective judgements but similar results have been obtained from more objective measurements. Coffee affects the heart by increasing the heart beat. It has been proved scientifically that it can take longer to go to sleep after having drunk coffee or taken caffeine. In addition it has been shown that the intake stimulates the acidity of the stomach. Nobody has been able to prove that coffee causes stomach ulcers although it can make existing ones worse. The tannic acids that are often found in coffee can be disguised with the help of milk. It is not just the diluting effect that leads to a more pleasant taste, it is also because the proteins in the milk bind the tannin. Both coffee and caffeine are potent diuretics.


Tea leaves contain more
caffeine than coffee
Photo: Gunnar Samuelsson.

Tea, in general, is a drink that consists of a hot water infusion of mainly leaves and flowers from various trees and herbs, but it can more specifically be from the leaves of the special tea tree, Camelia sinensis (previously Thea sinensis). Having been harvested, the leaves are dried. When crushed and fermented, enzymes are released that oxidise the tannic substances that occur in the tea leaves which become blackened. The caffeine content of the tea leaf is higher than in coffee beans: between 2.5 and 4.5%. In the actual drink, there is nearly twice the amount of caffeine in coffee as in tea. In addition, tea contains 0.02-0.04% theaflavin and about 0.05% teobromine.

Is black and bitter the main thing?

The root of chicory, or
serpent garlic, was earlier
used assurrogate coffee
in times of crises.
Photo: Håkan Tunón.

If you are not looking for the stimulating effects of caffeine, but you do want to drink something bitter and hot during your breaks, then there are local alternatives. Roasted roots of chicory, or serpent garlic, has a history of being a coffee substitute and was not unusual during the Second World War. Acorns and dandelion roots have also been used for similar purposes. In recent years health food stores have begun to sell chicory as a caffeine-free alternative to coffee.

Last modified: 2021-11-08