Study On The Mechanochemical Assisted Extraction Of Bioactive Compounds From Eleutherococcus Senticosus

Natural plant contains a diverse group of bioactive substances with a broad range ofapplications in medicine, healthcare product and cosmetic. China is rich in medical herbresources, but has a weak market share (less than 5%) for plant extract in the world market.At present, heat or heat reflux extraction with conventional organic solvents such as ethanol,methanol and acetone is widely used in the industrial-scale production of herb extracts inChina. This method with limitations such as high cost and complex procedures required hasgreatly decreased the production efficiency and profits. Moreover, the requirements forhazardous organic solvents which is inflammable-explosive could also increase theprobability of safety risks in production and environmental contamination. Therefore,environmental friendly and industry-ready technique with low cost and enhanced efficiency isrequired in order to accelerate the development of herb extract industry in China.The present study was focused on the mechanochemical assisted extraction (MCAE) ofisofraxidin and total flavone from Eleutherococcus senticosus with water as solvent. First, thechemical reagent was selected according to the yield of target compounds by MCAE; Second,a preliminary investigation was conducted on the interaction of the target compound-chemicalreagent. Different pretreatment was compared with respect to their effects on the plantmaterial morphology as well as the target compound yield. Finally, the MCAE process wasoptimized based on both orthogonal and one-factor experiment, and was compared withconventional heat reflux extraction.Preliminary investigation showed that isofraxidin and lutin could possibly be neutralizedby Na₂CO₃, Na₂CO₃ & Na₂B₄O₇ respectively, and certain complexes may have been formedbetween lutin and hydroxypropyl-β-cyclodextrin (HP-β-CD) after the solid grinding process.The yield of MCAE treated samples (extracting with water) was significantly improved (P＜0.05) comparing with physical mixing and superfine grinding samples. Both particleanalysis and scanning electron micrographs suggested that the plant cell wall could be brokenup after the mechanochemcal treatment.The optimum parameters for MCAE of isofraxidin were as follows: Na₂CO₃ content, 3%(w/w); particle size, D₉₅≤37μm; extraction solvent, water (0% v/v, aqueous ethanol);liquid/solid ratio, 1:30 g:ml. The optimum parameters for MCAE of total flavone were as follows: (1) alkali reagent.Na₂CO₃ & Na₂B₄O₇ content, 6% (w/w); particle size, D₉₅≤37μm; extraction solvent, 20%v/v aqueous ethanol; liquid/solid ratio, 1:60 g:ml. Aqueous ethanol was replaced by water,and no significant difference in yield was observed with other optimized parameters settings.(2) HP-β-CD reagent. HP-β-CD content, 13% (w/w); circulating water temperature, 60℃;milling period, 25 min.Under the optimized parameters determined herein, significant enhancement such asimproved yield, shorter time and more simplified procedures over heat-reflux extraction wasobserved, which makes MCAE (a combination of physical and chemical method) a potentialconvenient tool for isofraxidin and total flavone extraction from Eleutherococcus senticosus.Moreover, the favorable solvent is water, making MCAE a less expensive and eco-friendlytechnique.