Palustric acid
Palustric acid is an organic compound with the formula. It is classified as a diterpenoid and a resin acid. Palustric acid is an isomer of abietic acid: the location of the two C=C bonds differ in these two compounds. It is a colorless solid that is soluble in polar organic solvents. In terms of biological function palustric acid protects its host trees, especially conifers, against insects, an example of plant [defense against herbivory]. It is biosynthesized from the C20 precursor geranylgeranyl diphosphate.