Optimization Of Extraction Process And In Vitro Activity Of γ-aminobutyric Acid From Different Parts Of ‘Zijia 1’ Acanthopanax Senticosus

’Zijia 1’ was a new intraspecific variety of Acanthopanax senticosus with novelty,consistency and stability bred by our research group through artificial domestication of wild Acanthopanax senticosus in Mojiang County,Yunnan Province,because its tender stems and leaves were purple.With the improvement of recognition of ’Zijia 1’,in the existing component research,the attention of researchers is mainly on the tender stem and leaf and rhizome,where the tender stem and leaf is commonly used as a fresh food,and the overgrowth(apical dominance)branch is between the tender stem and leaf and the old stem and leaf,and the stem and leaf part and root bark that are often trimmed and discarded are often used as a medicinal part.Studies have shown that leaves of Acanthopanax senticosus contain a variety of amino acids,of which the precursor glutamic acid content of γ-aminobutyric acid(GABA)is high,and GABA has good water solubility,thermal stability and edible safety.In order to improve the comprehensive utilization of ’Zijia 1’ and provide a reliable production source of GABA,the extraction process,isolation,preparation and in vitro activity of GABA from different parts of ’Zijia 1’ were studied by response surface methodology,in order to provide a reference for expanding the drug source and the application range of each part of ’Zijia 1’ and effectively utilizing the resources.The main findings are as follows:1.Using ultrasound assisted water extraction,it was found that the feed to liquid ratio,ultrasonic temperature,and ultrasonic time had a large effect on GABA extraction through a single factor test.In response surface optimization tests,the ’Zijia 1’ GABA extraction was significantly affected by the feed to liquid ratio,sonication temperature,and sonication time,and the optimal extraction process was as follows: feed to liquid ratio 1:25(g/m L),sonication temperature 50 °C,and sonication time 40 min,’Zijia 1’ the mass concentration of GABA in the tender stem and leaf was 0.0864 mg/m L,which was close to the model theoretical value of 0.0884.The mass concentration of GABA in the long(apical dominance)branch was0.0848 mg/m L,which was close to the model theoretical value of 0.0860,under a feed to liquid ratio of 1:15(g/m L),sonication temperature of 50 °C,and sonication time of 50 min.With a material to liquid ratio of 1:15(g/m L),an ultrasonic temperature of 40 °C,and an ultrasonic time of 40 min,the mass concentration of ’Zijia 1’ root bark GABA was 0.0305 mg/m L,which was close to the model theoretical value of 0.0309.2.Activated carbon was selected as decolorizing agent and 732 cation exchange resin as adsorbent to purify the decolorizing separation medium of GABA.In the static adsorption test,the optimal adsorption time of GABA in tender stems and leaves is 60 min,and the optimal sampling flow rate is 3 m L/min and the optimal sampling p H is 3.5 in the dynamic adsorption test.The best adsorption time of GABA in the long(apical dominance)branch is 60 min,the best sampling velocity is 3 m L/min,and the best sampling p H is 2.5.The best adsorption time of GABA in root bark is 60 min,the best sampling velocity is 4 m L/min,and the best sampling p H is 2.5.The purity of GABA purified by silica gel column purification,methanol:dichloromethane fractionation and reversed-phase silica gel column(C18 packing)can reach more than 95% of the standard of nuclear magnetic resonance popper detection.3.The structure of the purified product ’Zijia 1’ was analyzed by NMR,and it was determined to be GABA.4.In vitro antioxidant and anti-inflammatory assay results showed that the crude extracts and purifications of GABA from different parts of ’Zijia 1’ exhibited antioxidant and anti-inflammatory capacities,but the scavenging of 1,1-diphenyl-2-trinitrophenylhydrazine(DPPH)radical,the scavenging of 2,2’-Azinobis-(3-ethylbenzthiazoline-6-sulphonate)(ABTS)radical,as well as the antioxidant capacities(ferric ion reduction/antioxidant capacity method(FRAP))and 5-lipoxygenase(5-LOX)inhibition ratio,weaker than vitamin C(Vc).In this study,the extraction and purification process of GABA from ’Zijia 1’ and its antioxidant and anti-inflammatory abilities in vitro were systematically studied.The structure of purified product ’Zijia 1’ was confirmed to be GABA by NMR pop.In the antioxidant and anti-inflammatory activity tests,GABA purified product and crude extract were introduced and compared,which more intuitively reflected the importance of purification for studying the biological activity of GABA.