| Schisandra chinensis is a plant of the genus Schisandra of Magnoliaceae,which can be used as medicine and health food.It is a valuable medicinal and food homology.The main components of Schisandra chinensis include lignans,volatile oil,organic acids,and polysaccharides,among which lignans are the main components of Schisandra chinensis,which have anti-inflammatory,antioxidant,anti-tumor,liver protection and enzyme lowering effects.At present,the extraction of Schisandra chinensis mainly focuses on the study of alcohol extracts,and there is no research on effective extraction and separation using more efficient extraction methods.Therefore,this paper took Schisandra chinensis as the research object,extracted and purified five lignans contained in it,and used them as reducing agent and stabilizer to prepare silver nano-materials.Taking the lignans content as the index,the lignans of Schisandra chinensis were extracted by microwave assisted deep eutectic solvent extraction(DESs),and the extraction process was optimized,and the content was analyzed by HPLC.Schisandrin A(SLA),Schisandrol B(SLB),Schisandrin A(SNA),Schisandrin A(SDA),Schisandrin B(SDB)were enriched and purified by macroporous adsorption resin.Finally,the silver nano-materials were prepared by hydrothermal synthesis,and characterized by ultraviolet visible absorption spectrum(UV-Vis),transmission electron microscope(TEM),fourier transform infrared spectroscopy(FTIR),thermogravimetry(TG),X-ray diffraction spectrum(XRD)and X-ray photoelectron spectroscopy(XPS).Finally,the bacteriostasis of Schisandra chinensis extract-silver nano-materials was preliminarily studied by the inhibition circle(ZOI)test,the minimum inhibition concentration(MIC)and the minimum bactericidal concentration(MBC)test.1.Firstly,HPLC method was established to analyze the contents of five active components in Schisandra chinensis.Chromatographic conditions:chromatographic column: Diamonsil C18 column,(250 mm×4.6 mm);Mobile phase: 0.1% formic acid aqueous solution(A)-acetonitrile(B);Column temperature: 30℃;Flow rate: 1.0 m L/min;Detection wavelength: 254 nm;Injection volume: 20 μL.Elution condition: 0-35 min,40-75%(B);35-45 min,75-80%(B).2.Combined with the results of single factor experiment,the process conditions of extracting SLA,SLB,SNA,SDA,SDB from Schisandra chinensis by microwave assisted low eutectic solvent were studied by response surface method(RSM),and the optimum process conditions were determined as follows: Choline chloride:glycolic acid=1:4;The water content is 30%,the solid-liquid ratio of SLA,SLB and SNA is 1:25,the extraction temperature is 50℃,and the extraction time is 40 min,the solid-liquid ratio of SDA and SDB is 1:20,the extraction temperature is 70℃,and the extraction time is 20 min.Under this condition,the extraction rates of the five active ingredients were 10.89 mg/g、8.616 mg/g、4.019 mg/g、4.893 mg/g and 5.318 mg/g.3.The extraction solution of Schisandra chinensis was separated and enriched by macroporous adsorption resin.The separation and enrichment of lignans from Schisandra chinensis by D-101,AB-8 and NKA-9 were investigated.The AB-8 resin had the highest recovery rate,78.23%,80.09%,77.07%,84.25% and 81.16%,respectively.4.The purified Schisandra chinensis extract was used as the reducing and stabilizing agent to prepare Schisandra chinensis extract-silver nanocomposites using a hydrothermal synthesis method.The optimum conditions for the preparation of the silver nanomaterials were optimised in this experiment,and the optimum synthesis conditions were: p H 9.0,addition of0.6 m L of 1% silver nitrate solution at 140°C for 4 h.The formation of silver nanoparticles was determined by the characteristic absorption peaks in UV-Vis of the synthesis solution.XRD indicated that the composite had a face-centred cubic crystal structure.FTIR showed the moieties of the Schisandra extract and the silver composite,indicating that the extract and the surface of the particles contained similar chemical compositions.XPS determined that elemental Ag was present in the silver nanocomposite as singlet silver.Antibacterial activity tests showed that the silver nanoparticles modified with Schisandra chinensis extract showed significant inhibition of Escherichia coli(E.coli),Staphylococcus aureus(S.aureus)and Candida albicans(C.albicans).In this study,we have developed a new and facile method to extract the active ingredient from Schisandra chinensis using a novel,non-polluting and degradable green solvent and to synthesise silver nanoparticles using Schisandra chinensis extract,which is fast,cheap and environmentally friendly and does not use any harmful reagents in the synthesis process.The preparation of Silver nanoparticle through Schisandra chinensis is economical and efficient.It has high antibacterial activity against bacteria and fungi,and is expected to develop into a new type of antibacterial agent. |
PDF Full Text Request