Richard Brooks, of Waimairi School, asks :-

What are some of the medicines made from bark and leaves of trees?

Murray Parsons, an ethnobotanist with Landcare Research, Lincoln, responded.

Plants have been used to provide medicines since the beginning of human time.

Today many medicines in pills and potions are extracted from plants or are similar chemicals manufactured in the laboratory. All parts of plants can be used for medicine; the leaves, flowers, wood, bark, fruits and seeds, although each part usually has different uses. One of the most familiar medicines is the antiseptic eucalyptus oil that relieves blocked noses and ears from colds and flu. It is extracted by steaming the leaves of a gum tree (Eucalyptus globulus).

Bark from the willow tree (Salix alba) is used for inflammation and joint pains. Aspirin was developed in the lab and resembles similar compounds found in willow. The delicious flavour of cinnamon is obtained from the bark of the tree Cinnamomum zelanicum and this has antifungal properties too. Quinine, important in the treatment and prevention of malaria, is obtained from the bark of Cinchona trees.

Traditionally Maori have used the leaves of the manuka (Leptospermum scoparium) for an antiseptic oil which is now being commercialised. The bark of kowhai (Sophora microphylla) has been used as a blood purifier; whereas the leaves of kawakawa (Macropiper excelsum) have been used for toothache, to relieve asthma and as a general tonic. I have chewed the top shoots of koromiko (Hebe stricta), also a Maori remedy, to stop diarrhoea effectively.