Preparation, structural characterization and neuroprotective effects of polysaccharides from the pericarp of Zanthoxylum bungeanum Maxim against H2O2-induced oxidative damage in PC12 cells

The pericarp of Zanthoxylum bungeanum Maxim (PZM) is one of eight fascinating condiments and also used as a traditional herbal medicine to treat a variety of diseases. In this study, ultrasound-assisted extraction (UAE) was applied for the extraction of polysaccharides from PZM (PPZM) and the extraction conditions were optimized by response surface methodology (RSM). The obtained PPZM yield (2.60 +/- 0.06%) was closely agreed with the predicted value (2.58%), and the optimal extraction conditions obtained were: liquid to solid ratio of 32 mL/g, extraction time of 42 min, and extraction temperature of 61 degrees C. PPZM was determined to be composed of mannose (Man), rhamnose (Rha), galacturonic acid (GalA), glucose (Glu), galactose (Gal), arabinose (Ara) with a molar ratio of 4.93: 5.03: 71.01: 16.01: 24.87: 18.79, and the average molecular weight (Mw) of PPZM was 1.72 x 10(5) Da. Typical polysaccharide characteristics were determined by fourier transform infrared spectroscopy (FT-IR). PPZM exhibited remarkable antioxidant activities in vitro. More importantly, PPZM effectively protected adrenal phaeochromocytoma PC12 cells against H2O2-induced damage by inhibiting the release of lactate dehydrogenase (LDH) and malondialdehyde (MDA), increasing the level of superoxide dismutase (SOD), and inhibiting abnormal apoptosis. Further experiments indicated that the anti-apoptotic effects of PPZM were closely related to down-regulating the expressions of Bax and Caspase-3, and up-regulating the expression of Bcl-2. Therefore, PPZM can be used as the source of natural antioxidants and neuroprotective agents. (C) 2021 SAAB. Published by Elsevier B.V. All rights reserved.