Wellcome uses cookies.

Read our policy
Wellcome Collection homepage
All
Stories
Images
Catalogue
Events

Images

  • Catharanthus roseus (L.)G.Don Apocynaceae. Madagascar Periwinkle Distribution: Madagascar. It is the source of vincristine and vinblastine, which impair cell multiplication by interfering with microtubule assembly, causing metaphase arrest and are effective medications for leukaemias, lymphomas and some solid tumours. The mortality from childhood leukaemia fell from 100% to 30% once it was introduced - not a drug that could ethically be tested by double-blind trials. These chemicals were initially discovered by investigators in 1958 who were looking for cures for diabetes so tested this plant which was being used in the West Indies to reduce blood sugar levels. There are 70 different alkaloids present in this plant, and some - catharanthine, leurosine sulphate, lochnerine, tetrahydroalstonine, vindoline and vindolinine - lower blood sugar levels. However, the toxicity of this plant is such that this is not a plant to try at home for diabetic management. The vincristine content of the plant is 0.0003%, so two kilograms of leaf are required to produce sufficient vincristine for a single course of treatment for a child (6gm). Fortunately it is a vigorous weed and easy to grow in the tropics. Artificial synthesis has now been achieved. Photographed in the Medicinal Garden of the Royal College of Physicians, London.
  • Euphorbia milii Des Moul. Euphorbiaceae. Crown of Thorns - so called because of its very spiny stems. Distribution: Madagascar. The latex contains a copper-containing amine oxidase, a lectin, lipase, peroxidase, and a diamine oxidase. In vitro the latex is synergistic with ketoconazole against Candida albicans (thrush). All Euphorbia have a toxic white latex, and in Europe this has been used as a folk remedy to treat warts. It can cause skin allergies and the smoke from burning them is toxic. the genus named for Euphorbus (fl. circa 10 BC – 20 AD), the Greek physician to the Berber King Juba II (c. 50 BC – 23 AD) of Numidia, Euphorbia milii is one of the tropical spurges, with fierce, cactus-like spines, grown as a house plant. The sap of spurges is used in folk medicine for treating warts (not very effective), and, historically, as a purgative - the word spurge being derived from the French word for purgation. The sap (probably dried) was administered inside a fig because it is so corrosive that it would otherwise burn the mouth and oesophagus – a technique used today, rather more subtly, with ‘enteric coated’ medications. The sap contains a potential anti-leukaemic chemical, lasiodoplin, and is also used in drainage ditches to kill the snails which carry the parasitic trematode which causes fasciolaris. It does not kill the fish. Photographed in the Medicinal Garden of the Royal College of Physicians, London.
All images (2)

Catalogue

All works (6)