Extraction Of Polyphenols From Gastrodia Elata Bl.and Its Protective Effect On Hydrogen Peroxide Induced Oxidative Stress Injury Model In PC12 Cells

Tianma（Gastrodia elata Bl.）,a member of the orchid family,has been used medicinally for over two thousand years in China.Its dried rhizome has a number of affects including anticonvulsant,headache,dizziness,wind,and anticonvulsant.According to current research in medicinal chemistry,the rhizome of asparagus includes 80 different types of compounds,including phenols,phenolic glycosides,polysaccharides,organic acids,and sterols.Gastrodin,a phenolic glycoside with anticonvulsant,headache-relieving,anti-anxiety,anti-depressant,and other aspects of neuroprotective functions,has been named by the Chinese Pharmacopoeia as the distinctive pharmacological activity marker of Gastrodia elata Bl rhizome,with great potential for use.However,there is also scope for development and use of the remaining active components in Gastrodia elata Bl.Stability tests and in vitro antioxidant studies were performed in this research using dried G.elata rhizome as experimental materials to extract and purify polyphenols from G.elata.Finally,a model of oxidative stress injury in PC12 cells was built to research the protective qualities of pretreatment with G.elata polyphenols.The following were the major conclusions.1.G.elata polyphenols were extracted using an ultrasonic/microwave-assisted extraction technique,and the best ultrasonic power,material-to-liquid ratio,extraction temperature,and extraction time for these compounds were identified using a single-factor test with the yield of these compounds serving as the evaluation index.Under these conditions,the yield of polyphenols was 33.07±0.04 mg GAE·g^-1,and the crude extract was enriched and purified by AB-8macroporous adsorbent resin,and the purity of polyphenols reached 63.97±0.67%.2.Qualitative identification of the purified G.elata polyphenols using UV absorption spectroscopy,IR absorption spectroscopy and chemical identification showed that G.elata polyphenols had characteristic absorption peaks similar to gallic acid,and the infrared absorption spectrum of G.elata polyphenols had characteristic absorption peaks of polyphenols,which tentatively determined that the extracted purified products did contain polyphenolic compounds.The stability of G.elata polyphenols was evaluated,and the results showed that the stability of G.elata polyphenols was reduced by light,temperature over 40℃,strong acid and strong alkali environment,and treatment with hydrogen peroxide and sodium sulfite.3.In vitro antioxidant experiments were conducted with purified G.elata polyphenols to explore the scavenging ability of G.elata polyphenols on DPPH·radicals,·OH^-radicals,O₂^-radicals,ABTS·⁺radicals and the determination of Fe³⁺reduction ability,using Vc as a control,the results showed that G.elata polyphenols had good free radical scavenging ability in the four in vitro antioxidant tests within the selected concentration range,and The antioxidant effect increased with the increase of concentration,but the antioxidant capacity of asparagus polyphenols was lower than that of Vc.4.A model of oxidative stress injury was constructed using H₂O₂-induced PC12 cells with pretreatment intervention of G.elata polyphenols,and the results showed that G.elata polyphenols reversed H₂O₂-induced lipid peroxidation,LDH leakage,ROS production,IL-6,TNF-α,and NO inflammatory factor levels in PC12 cells,and improved mitochondrial membrane potential and attenuated cell oxidative stress damage by increasing the level of endogenous antioxidant enzymes,improving mitochondrial membrane potential and reducing apoptosis.