Studies On The Separation And Purification Methods Of Magnolol And Honokiol In Magnolia Officinalis Rehd ET Wils Bark

Magnolia officinalis Rehd et Wils is a popular and traditional medical herb in China. The main bioactive components of this plant are honokiol and magnolol. Deeply investigations of magnolol and honokiol showed them many important applications in disease therapys. Methods for preparation of magnolol and honokiol were developed, and most of them were based on chromatography processes. These chromatography methods were almost complicated and low effective.Recently a simple and convenient method for separation and purification of magnolol and honokiol from ethanol extracts of Magnolia officinalis Rehd et Wils bark was developed in our works. This method was based on selective extr-action, selective precipitation and crystalization without any chromatography. This method was described herein.The original residue from extraction of plant material with ethanol was extracted with weak polar solvent and gave a weak polar fraction, and then the weak polar fraction was dissolved in ethanol. A lot of components other than magnolol and honokiol precipitated from the solution when water was droped slowly into it. The filtrate was condensed to give a dry residue, and a crystal, crude magnolol was obtained from it after8h. The filtrate was extracted with aqueous ethanol solution. The extracts were condensed to give a dry residue. After8h, crystals formed in the residue. Then filtered, rough magnolol and honokiol were obtained. The pure magnolol and honokiol were obtained finally by recrystalization.Effects on prearation of magnolol and honokiol from Magnolia officinalis Rehd et Wils bark were disccused and led optimum processes. Plant material was extracted with cyclohexane (material:cycolhexane=1:6, w/v) for30min at60℃, and then gave an original residue, precipitatal sovent, water: ethanol=1:2(v/v); aqueous ethanol (ethanol:water=11:10) for extracting honokiol; aqueous ethanol (ethanol:water=16:10) for extracting magnolol; pure magnolol was obtained by recrystalizated with ethyl acetate; pure honokiol was obtained by recrystalizated with cyclohexane. Following these conditions,2.84g magnolol (98.57%pure) was obtained and0.97g honokiol (98.55%pure) was obtained from450g crude material (content of magnolol was1.71%, content of honokiol was0.68%). The recovery of pure magnolol was36.91%and the recovery of pure honokiol was31.55%respectively.In addition, the solubility of magnolol and solubility of honokiol in cyclohexane, petroleum ether and hexane at different temperature were measured respectively by equilibrium method. The solubility of magnolol and solubility fo honokiol elevated with temperature in these solvents. Magnolol and honokiol were the most dissolvability in cyclohexane, petroleum ether the second and hexane the third at the same temperature. The solubility of honokiol and solubility of magnolol showed a striking contraste in cyclohexane at60℃. It can provide theoretical reference for extraction and separation of magnolol and honokiol in industry.