Quercetin binding to Spatholobus parviflorus lectin: Promise of a macromolecular, specific-compound carrier for drug.

Glycan recognition is the most attractive defining feature of lectins, and also they exhibit specific phytochemical interactions at distinct sites without interfering the glycocode recognition capability. These additional sites may be viewed as potential drug carrying sites that could be exploited for targeted drug delivery. The pharmacological effects of quercetin (QN) have already been studied. However, its molecular mechanism of interactions with lectin has not yet been addressed. The extending novelty provokes us to unravel the binding profile of QN with Spatholobus parviflorus lectin (SPL) using a combination series of biophysical and computational approaches. The UV absorption studies revealed an intense SPL-QN complex formation, indicating a hyperchromic effect. The fluorescence spectroscopic analysis using sugar-free SPL and sugar saturated SPL (ssSPL) revealed that QN binding significantly quenched the intrinsic fluorescence of SPL. The thermodynamic parameters maintained uniformity with the binding stoichiometry (n = 4) of both SPL and ssSPL, hence it may be assumed that the sugar binding onto the SPL would not have been influenced with QN binding. The molecular docking analysis also maintained consistency with the in vitro results. It could be concluded from SPL-QN interactions without altering unique carbohydrate specificities, leave SPL unrestricted for other molecular recognition events.