Hierarchical Self-Assembly of a Renewable Nanosized Pentacyclic Dihydroxy-triterpenoid Betulin Yielding Flower-Like Architectures

Abstract

Betulin, a naturally occurring 6-6-6-6-5 pentacyclic dihydroxy-triterpenoid, is extractable from the bark of white birch (Betula papyrifera). We report the first self-assembly properties of betulin in different liquids. The molecule spontaneously self-assembled in different media, yielding flower-like architectures of nano- to micrometers diameters via the formation of fibrillar networks. The self-assemblies have been characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, FTIR, and X-ray diffraction studies. The porous microstructure of the self-assemblies has been utilized for the entrapment of fluorophore such as rhodamine-B and the anticancer drug doxorubicin. Moreover, the removal of toxic dyes such as rhodamine 6G, crystal violet, methylene blue, and cresol red has also been demonstrated.

Self‐assembly of Renewable Nano‐sized Triterpenoids

“…To find out whether the amphiphilic molecule with a rigid nano‐sized lypophilic backbone along with uniquely positioned hydroxyl groups can self‐assemble in liquids, we carried out self‐assembly studies in different neat organic liquids as well as aqueous solvent mixtures. Interestingly, the dihydroxy triterpenoid self‐assembled in aromatic liquids as well as aqueous solvent mixtures yielding soft solid‐like materials in some of the liquids . For example, an opaque gel was formed instantly in DMSO‐water (1:1) at 1% w/v.…”

Evolution of Vesicular Self‐Assemblies of the Salts of a Natural Triterpenoid Arjunolic Acid into Superstructured Ambidextrous Gels and Study of Their Entrapment Properties

“…Among various supramolecular building blocks from natural resources, the pentacyclic triterpenoid molecules have gained a significant attention of the scientific community in recent years because these nano‐sized chiral triterpenoid molecules possess a rigid backbone along with different functional groups at different positions and orientations . Because of this structural uniqueness of these triterpenoid molecules, they can even self‐assemble without any structural modification yielding diversified self‐assembled structures like fibers,, vesicles,,,,, flowers,, etc. which have been exploited as drug delivery vehicle, dye removing agent, template for the synthesis of organic‐inorganic advanced hybrid material for using it as recyclable heterogeneous catalyst, etc.…”

Triterpenoid‐Based Self‐Healing Supramolecular Polymer Hydrogels Formed by Host–Guest Interactions

“…These features not only endow them with pharmacological properties, but also make them ideal building blocks for self‐assembling versatile supramolecular structures . Since the first supramolecular organogel based on a pentacyclic triterpenoid was reported by Bag and co‐workers in 2005, a series of pentacyclic triterpenoid‐based small molecules have been designed and synthesized to study their supramolecular gelation behavior . For example, Mezzenga et al.…”

“…[10][11][12][13] Since the first supramolecular organogel based on ap entacyclic triterpenoid was reported by Bag and co-workers in 2005, [14] as eries of pentacyclic triterpe-noid-based smallm olecules have been designed and synthesized to study their supramolecular gelation behavior. [15][16][17][18][19][20][21][22][23][24] For example, Mezzenga et al reported that the right-handedf ibrillar networks in the hydrogel of glycyrrhizic acid could be utilized as scaffolds for hybrid nanomaterials in heterogeneous catalysis. [15] We foundt hat ap yridinium-tailored glycyrrhetinic acid amphiphile could transfer and magnify its chirality at the supramolecular level,a nd consequently result in the formation of helical nanofibers.…”