Natural triterpenoids as renewable nanos

Plant metabolites are the most significant source of renewable chemical feedstocks for a sustainable future. Among various plant secondary metabolites, triterpenoids are a large and structurally diverse 30-carbons subset of the major component terpenoids. Whereas the acyclic triterpene squalene can exist in many different conformations, the cyclic triterpenoids are more rigidified and largely chiral. The tetra and pentacyclic triterpenoids are more abundant than other triterpenoids and molecules having ten chiral centers are common. We show that acyclic and mono-cyclic to fused pentacyclic triterpenes are all nano-sized molecules having varied rigid and flexible lengths. Monte-Carlo investigation of their conformational space revealed that the nanometric lengths are maintained even in the folded conformers rendering all the triterpenoids useful as renewable nanos.