Self-assembly of the monohydroxy triterpenoid lupeol yielding nano-fibers, sheets and gel: environmental and drug delivery applications

Lupeol is a medicinally important naturally abundant triterpenoid having a 6-6-6-6-5 fused pentacyclic backbone and one polar secondary -OH group at the C3 position of the A ring. It was extracted from the dried outer bark of Bombax ceiba and its self-assembly properties were investigated in different neat organic as well as aquous-organic binary liquid mixtures. The triterpenoid having only one polar -OH group and a rigid lipophilic backbone self-assembled in neat organic non-polar liquids like n-hexane, n-heptane, n-octane and polar liquids like DMSO, DMF, DMSO-H2O, DMF-H2O, and EtOH-H2O yielding supramolecular gels via formation of nano to micrometre long self-assembled fibrillar networks (SAFINs). Morphological investigation of the self-assemblies was carried out by field emission scanning electron microscopy, high resolution transmission electron microscopy, atomic force microscopy, optical microscopy, concentration dependent FTIR and wide angle X-ray diffraction studies. The mechanical properties of the gels were studied by concentration dependent rheological studies in different solvents. The gels were capable of removing toxic micro-pollutants like rhodamine-B and 5,6-carboxyfluorescein as well as the toxic heavy metal Cr(vi) from contaminated water. Moreover release of the chemotherapeutic drug doxorubicin from a drug loaded gel in PBS buffer at pH 7.2 has also been demonstrated by spectrophotometry.

Automated summary

Lupeol is a medicinally important triterpenoid that can self-assemble into supramolecular gels in various organic and aqueous-organic liquid mixtures. These gels exhibit capabilities in removing pollutants from water and releasing drugs, showcasing potential applications in environmental and pharmaceutical fields.