Plant-Derived Drug Essay

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CHAPTER 19 – Study guide

Morphine was isolated from opium poppy in 1806

Salicylic acid is an active ingredient in a number of plants known for their pain-relieving qualities – bark of willow tree was the precursor to aspirin - first synthesized in 1853, aspirin is the most widely used synthetic drug

25% of prescriptions in the U.S. contain plant derived ingredients (if fungal included then 50%)- more if consider those based on ingredients isolated from plants

Secondary plant products have many important functions – discourage herbivores, inhibit bacterial and fungal pathogens. Two major categories of these compounds are alkaloids and glycosides:


Mostly in herbaceous dicots such as the legume family, nightshade family, coffee family

Mostly affect the nervous system

Some alkaloids are medically important and some are hallucinogenic or poisonous

Difference between medicinal and toxic effect is often dosage

Examples of alkaloids: caffeine, nicotine, cocaine, morphine, quinine, ephedrine

Glycosides – sugar molecule attached

Cyanogenic glycosides: They release HCN upon breakdown e.g. Cassava, contains HCN that must be removed before consumption

Seeds, pits and bark of rose family (apple, pear, almonds, apricots, cherries, peaches, plums) contain a cyanogenic glycoside

Pits of apricots are rich in one glycoside that releases HCN only in the presence of tumor cells and selectively destroys them – potential for cancer therapy

Cardioactive glycosides have a steroid molecule as the active component – can effect contraction of heart muscle – can treat heart failure

Digitalis (foxglove) – leaves contain 30 glycosides – primary treatment for heart disease in the U.S.

Milkweed and oleander contain toxic levels of this glycoside

Saponins – have steroid molecule – less useful medically and highly toxic

One useful saponin comes from yams – precursor for the synthesis of various hormones such as progesterone and cortisone

Other Medicinal Plants

Treatment of malaria - Fever Bark tree (coffee family) – native to Andes Mountains - alkaloid quinine kills the parasite in the blood stream. The value of quinine brought about the development of tonic water by the British.

Artemisinin is a toxin found in glandular trichomes on the leaves and