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.Keywords Renewable Á Triterpenoid Á Nano Á Self-assembly Á Plant secondary metabolite Electronic supplementary material The online version of this article (

Corosolic acid, a natural ursane-type 6-6-6-6-6 pentacyclic dihydroxy triterpenic acid, self-assembled in binary liquid mixtures yielding vesicles.

Terpenoids are a large and structurally group of natural products containing multiple five carbon containing isoprene units. Previously we have reported that irrespective of their acyclic or alicyclic nature, all the triterpenoids containing 30C’s have nano-metric lengths. In the current studies, detailed computations have been carried out with 120 naturally occurring mono- (C10), sesqui- (C15), di- (C20), sester- (C25), sesqua- (C35) and tetra- (C40) terpenoids using Gaussian 09 software with Gauss view 07 and molecular mechanics calculation using Serena software. The heat of formation and the calculated molecular lengths obtained by the two methods were compared. Interestingly, monoterpenoid to tetraterpenoid all the terpenoids (except three monoterpenoid and one sesqui-terpenoid) have molecular lengths above one nanometer making them useful as nano-sized building blocks.

Plant metabolites can serve as renewable chemicals for the development of a sustainable society. Terpenoids are the major component of over 500,000 plant secondary metabolites reported till date. Monoterpenoid (C10) to tetraterpenoid (C40) all the terpenoid have recently been shown to have nanometric lengths. Studies on the self-assembly of terpenoids, have drawn the attention of scientific community in recent years due to many of its potential and realized applications in medicine, drug delivery, pollutant capture, metal nanoparticle hybrid material, selective damage of cancer cells, etc. In this review, we have discussed the isolation of seven terpenoids from plants and their self-assembly properties in different liquids, even without functional transformation. The utilization of the resulting supramolecular architectures such as vesicles, spheres, flowers and fibrillar networks of nano- to micro-meter dimensions and gels have also been discussed paving the way for a green, renewable and sustainable world.