Structure–gelation property relationships of phenolic glycosides of pentose sugars: pH dependent controlled release of curcumin

Abstract

Herein, we explored a library of structurally simple phenolic glycopyranosides of pentose sugars as organogelators, with the objective of finding a correlation between the sugar configuration and gelation ability. Of the twenty eight compounds investigated, only four–two each from the β-arabino- and α-xylo-series – were found to be capable of acting as organogelators. Thorough characterization of supramolecular gels using techniques such as FESEM, AFM, rheology, FTIR spectroscopy and WXRD led to the identification of one arabinoside derivative as being able to form the most mechanically robust organogel at loadings of about 0.2–0.3% (w/v). The mechanism of self-assembly involved mainly H-bonding interactions as evidenced from FTIR spectroscopy, WXRD and theoretical studies, although some evidence of π–π stacking interactions was also observed. This gelator was then used to prepare a curcumin entrapped organogel in mustard oil that was explored for the pH dependent controlled release of a drug model – curcumin.