Terpenoids
Terpenoids, or isoprenoids, are the largest group of natural compounds. Terpenoids consist of a highly non-polar terpene backbone with functional groups attached to it. Therefore terpenoids are mostly insoluble in water. Many terpenoids are biologically active and protect the organisms from parasites. Therefore they are promising candidates for novel pharmaceuticals.
Plant terpenoids are extensively used for their aromatic qualities. Well-known terpenoids include menthol, cannabinoids, artemisinin, citral and the curcuminoids found in turmeric and mustard seeds.
Terpenoids contribute to the scent of eucalyptus, the flavors of cinnamon, cloves and ginger, the yellow color of sunflowers and the red color in tomatoes.