Subcritical water extraction of polysaccharides from Gastrodiae Rhizoma : optimization, characterization and in vitro hepatoprotective activity

AbstractSubcritical water extraction (SWE) is an efficient and eco-friendly technology that rapidly extracts valuable compounds from natural materials. In this study, response surface methodology (RSM) was utilized to determine the optimal extraction conditions for Gastrodiae Rhizoma using SWE (GRP-S). The optimum conditions were found to be 161 °C extraction temperature, 41 min extraction time, and a solid-to-liquid ratio of 1.55 mg/mL. Under these optimal conditions, the experimental yield of GRP-S was 66.32% ± 0.10% (n = 3), demonstrating a significant increase compared to hot water reflux extraction (HWE) in the extraction yield of polysaccharides. Characterization studies employing SEM, FT-IR, and HPAEC-PAD confirmed the differences between GRP-S and GRP-H (GRP obtained by HWE). Furthermore, both GRP-S and GRP-H exhibited a significant ability to protect HepG2 cells from ethanol-induced damage, with GRP-S showcasing a superior effect. The widespread adoption of SWE technology can lead to high GRP content in extracts and promote the green and sustainable development of natural products extraction processes.Keywords: Subcritical water extractiongastrodiae rhizomapolysaccharidesoptimizationcharacterizationhepatoprotective activity Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingThe work was supported by the National Natural Science Foundation of China (No. 82073954), Key R&D Program of Shandong Province, China (2021CXGC010508), the new innovative team of Jinan (202228020) and the Taishan Scholars Program of Shandong Province (X. Wang).