1. Secondary Products III Glycosides

2. Glycosides  Sugar most commonly found is glucose  Non-sugar molecule known as the aglycone and may be amino acid derivatives steroids triterpenes

3. Glycosides Most common types  Saponins  Cardiac Glycosides (Cardenolides)  Cyanogenic Glycosides  Anthraquinone Glycosides  Glucosinolates (sometimes not included) Most glycosides function as deterrents to herbivores

4. Saponins Terpene glycosides  Steroid glycosides  Steroid-alkaloid glycosides  Triterpene glycosides Sapogenins Properties of saponins Effects of saponins on water

5. Useful saponins Saponins from yam - Disocorea spp. are the source of steroids used for human hormones  Birth control pills - most synthetic but some still use natural hormones  Anti-inflammatory steroids Licorice - Glycyrrhiza glabra produces saponins that possibly help gastric ulcers because they suppress prostoglandins

6. Cardiac glycosides Properties Distribution Best known are digitoxin and digoxin from Digitalis purpurea (foxglove) – 30 glycosides Other poisonous plants with cardiac glycosides  Oleander - Nerium oleander - oleandrin  Milkweed - Asclepias spp - asclepiadin  Lily of the Valley - Convallaria sp. – convallotoxin and convallarin Physiological Action

7. Foxglove Digitalis purpurea

8. Digitoxin

9. Sugars in digitoxin 2 molecules of digitose 1 molecule of 1-acetyl digitose 1 molecule of glucose Digitose

10. Oleander

11. Oleandrin

12. Milkweeds

13. Convallaria majalis

14. Convallotoxin

15. Cyanogenic glycosides Distribution Most derived from 4 amino acids (phenylalanine, tyrosine, valine, or isoleucine) or from nicotinic acid Cyanogenic glycosides are not toxic by themselves Two enzymes involved in toxicity   glycosidase releases the sugars  Hydroxynitrile lyase releases HCN Effects of HCN

16. Electron Transport System

17. Cyanogenic Glycosides Variability Cassava (Manioc esculenta) major food crop with cyanogenic glycosides Rosaceae (Rose Family) contains cyanogenic glycoside - amygdalin  Amygdalin from apricot pits source of Laetrile

18. Cassava

21. Amygdalin

22. Glucosinolates