The Extraction And Purification Of Solanesol And The Interaction Of Solanesol With HSA

Solanesol is one of the trisesquiterpenoid alcohol which mainly exists in tobaccoleaves. It is an important intermediate of some valuable medical substances such ascoenzyme Q10and vitamin K2. A preparation process of solanesol including extraction,saponification, crystallization and purificationwere built using waste and inferior to-bacco leaves as raw material. The extraction rate and purity of solanesol were used toinvestigate the result of extraction. The results single factor experiments showed thatthe appropriate conditions of extracting solanesol from the tobacco leaves: extractionsolvent n-hexane, liquid-soild ratio14:1(ml:g), extraction temperature50℃, extrac-tion time3h, shaker frequency175rpm and radium of tobacco particle20-40mesh.The extraction rate result was91.42%, and purity of crude solanesol was18.05%.The result is better than literature values. In order to improve the extraction efficiencyof solanesol, we used ultrasound assisted extraction and ammonia leaching pretreat-ment assisted extraction. The results showed that the extraction time was significantlyshorten than the heat extraction.The saponification of crude solanesol using NaOH and lipase were studied. Theresult showed that after NaOH saponification the purity of solanesol was improvedfrom18%to28.14%. The28.14%crude solanesol was then recrystallized usingmethanol as solvent by four times,65.96%of the purity in two times and91.85%infour times. After purification by macroporous resin the purity of solanesol improvedfrom65.96%to83%, it can be used in organic synthesis.After we obtained high purity solanesol, UV–vis absorption, fluorescence and cir-cular dichroism (CD) spectroscopies were employed to reveal the mechanism of thebinding between solanesol and human serum albumin (HSA) under physiologicalconditions (pH=7.4). The binding parameters have been calculated by fluorescencequenching method. The thermodynamic parametersindicatedthat the enthalpy–drivenbinding process was spontaneous, and the main binding forces between solanesol andHSA were hydrogen bonds and Van der Waals forces. The competitive experi-mentsusing different site markers indicated that subdomains IIA (site I) of HSA wasthe primary binding site for solanesol. The average binding distance (r) between HSA and solanesol was4.29nm, which was estimated according to the F rster’s theory ofnon–radiation energy transfer. The CD spectra, UV–vis absorption data showed theslight conformational changes of HSA in the presence of solanesol. The interactionmechanism of coenzyme Q10(CoQ10) and HSA was investigated using the same spec-troscopic methods. The bindingmechanism, thebindingdistance, thethermodynamicparameters, the main binding forceandbinding sites of CoQ10-HSA system were thesame to orsimilar with solanesol-HSA system, these results demonstrated that the pol-yisoprene side chainof CoQ10had significant influence on its binding to HSA.