Quercetin-albumin nano-complex as an antioxidant agent against hydrogen peroxide-induced death of spinal cord neurons as a model of preventive care study

Herein, the quercetin-human serum albumin (HSA) nano-complex was formulated and its capability to decrease H2O2-stimulated cytotoxicity against spinal cord neurons as a model of preventive care study was investigated by cellular assays. Quercetin molecules were first encapsu-lated into HSA as a shell and the loading efficiency along with drug release and different properties of formulated nano-complex were determined using TEM, SEM, and DLS approaches. Afterwards using CD spectroscopic method and theoritical analysis, the structural changes and binding redisues of HSA after interaction with quercetin were investigated, respectively. Finally, the antioxidant activity of quercetin-HSA nano-complex against H2O2 (200 mu M)-stimulated cytotoxicity in spinal cord neurons was explored by MTT, SOD and CAT activity, and morphological changes assays. It was shown that the fabrication of quercetin-HSA nano-complex resulted in the improved bioavailability of quercetin with an entrapment efficiency of 68.99% and percent yield of 53.19%. Also, molecular docking study showed that quercetin molecules spontaneously bind to HSA through hydrogen bonds and van der Waals interactions. Furthermore, CD data indicated that the quercetin did not change the secondary structure of HSA. Finally, cellular assays displayed that the pre-treatments of spinal cord neurons with quercetin-HSA nano-complex attenuated the H2O2-triggerd neuron mortality through a significant increase in the activity of SOD and CAT and prevention of morphological changes. In conclusion, it may be suggested that the formulation of quercetin into nano-complex can improve its medical properties and this new developed drug formulation may hold a great promise in the advancement of antioxidant compounds in preventive care services. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.