Clerodane diterpene

The clerodane diterpenes are classified into four groups trans-cis (TC), trans-trans (TT), cis-cis (CC), and cis-trans (TC) based on the relative stereochemistry at the decalin junction (trans or cis) and the relative stereochemistry of the substituents at C-8 and C-9 (trans or cis). The absolute stereochemistry of the clerodanes is classified as neo (shown below) or ent-neo (enantiomeric to neo). The neo-clerodanes share the same absolute stereochemistry as clerodin. Approximately 25% of clerodanes have the 5:10 cis ring junction. The remaining 75% have a trans 5:10 ring junction. == Biosynthesis ==

They are structurally related to the bicyclic labdane diterpenes. Its biosynthesis in plants (mostly present in the families Lamiaceae and Asteraceae) takes place in the chloroplasts. Some forms can be useful intermediates in organic synthesis. Some clerodanes like clerodin (3-desoxy-caryoptinol) from the leaves of Clerodendrum infortunatum (Verbenaceae) have anthelminthic properties, others like are repellent to herbivore predators (mostly insects and their larvae) or have a very bitter taste, such as gymnocolin. Some examples for clerodanes are I to V extracted from bugleweeds like Ajuga remota, Ajuga ciliata, Ajuga decumbens, common skullcap (Scutellaria galericulata), and germanders (Teucrium sp.), cascarillin from Croton eluteria, from Jateorhiza columba, Jateorhiza palmata and guduchi (Tinospora cordifolia), gymnocolin from Gymnocolea inflata, hardwickiic acid from Hardwickia species (Fabaceae). Neo-clerodane diterpenes can have hallucinogenic properties such as salvinorin A, a trans-neoclerodane diterpene from Salvia divinorum. == See also ==