| The polar head is a macrocyclic lactone ring containing nine amino acid residues, three of which have positive charges, whereas one has negative charge. |
| Tylvalosin is a new macrolide antibiotic based on a highly active lactone ring. |
| Luteic acid is the lactone and ellagic acid is the dilactone of hexahydroxydiphenic acid. |
| Another of these substances is ellagic acid C14H6O8, a double lactone of a hexa-hydroxy-diphenyldicarboxylic acid. |
| But by the 1970s it was known that the lethal chemical, first called qinghaosu and now artemisinin, had a structure never seen before in nature: In chemical terms, it is a sesquiterpene lactone with a peroxide bridge. |
| However, we reported in a previous study that santonin, a eudesmanolide sesquiterpene lactone, exerts no effects on the differentiation of leukemia cells. |
