Flower- and Grass-like Self-Assemblies of an Oleanane-Type Triterpenoid Erythrodiol: Application in the Removal of Toxic Dye from Water

摘要

Erythrodiol (3β-olean-12-ene-3, 28-diol) (C_(30)H_(50)O_(2)) 1 is a nanosized oleanane-type fused 6-6-6-6-6 pentacyclic triterpeneoid extractable from the dried leaves of olive (Olea europia ). One step reduction of oleanolic acid extracted from Lantana camara also yields the same compound. The triterpenoid has one secondary ?OH group attached at C3 of the “A” ring and one primary ?OH group at C28 present at the junction of the “D” and “E” rings. Here, we report the spontaneous self-assembly of erythrodiol in different neat organic liquids and aqueous-organic liquid mixtures. The nanosized dihydroxy triterpenoid having an oleanane-type lipophilic rigid skeleton self-assembled in liquids, yielding nanosized fibrils, microsized flowers, and grass-like architectures via formation of densely assembled fibrils and petals or 2D sheets. The microstructures of the self-assemblies have been characterized by different techniques like optical microscopy, electron microscopy, atomic force microscopy, FTIR, and wide angle X-ray diffraction studies. The porous self-assemblies having a large surface area obtained from 1 were capable of adsorbing toxic fluorophores like rhodamine-B, rhodamine-6G, methylene blue, and crystal violet (CV). Moreover, removal of the aforementioned toxic pigments has also been demonstrated from their aqueous solutions by using UV–visible spectrophotometry and epifluorescence microscopy.