Lipase-Catalyzed Synthesis Of Capsinoids In Organic Media

Capsiate has been extracted from a nonpungent cultivar of red pepper, CH-19 sweet,and shown to be acapsaicin analogue called capsinoid that has an ester bond instead of the amide bond between the vanillylmoiety and fatty acid chain. Despite non-pungency, capsiate shares certain biological activities with capsaicin.As the development of Nonaqueous Enzymology, the lipase-catalyzed synthesis of bioactive substances inorganic solvent gained increasing interest.It is possible that capsiate could be a preferable medical or nutritional application over capsaicin.On thisbasis,the aim of this work was to study the direct enzymatic biotransformations of capsaicin truns intocapsiate in laboratory scale.And the kinetic model of lipase-catalyzed transesterification of vanillyl nonanoatewas constructed. The results as follows:Firstly,vanillyl nonanoate,the analogue of natual capsinoids,was synthesized in organic media catalyzedby lipase.The results indicated that lipase Novozym 435 showed the highest activity for the reaction.Theoptimization of reaction as follows: 50 mM vanillyl alcohol and 75 mM methyl nonanoate in 1 mL of acetoneusing 20 mg of Novozyme 435 at 30℃for 10h,the conversion yields was 65.9%. After purifying theproducts by silica gel column chromatography, confirmed the structures by UV,IR,NMR and MSmeasurements.Secondly, under the aboved conditions,natural capsaicin was converted to natural capsinoids by thecombinations of chemical-enzymatic pathway.After purifying the products by silica gel columnchromatography, detected the residual capsaicin by HPLC measurement and confirmed the structures byGC-MS measurements.Thirdly, the synthesis of vanillyl nonanoate by immobilized Candida lipase was primary studied,includingthe method of strain culture,the condition of produting lipase,the immobilizati-on method of the lipase andthe synthesis condions. It indicated the conversion yields were 0.23% and 0.33% using crystallitic celluloseand active carbon as the carrier, respctively.Finally, Kinetics of lipase-catalyzed trasesterification of vanilly alcohol and methyl nonanoate have beeninvestigated.The reaction rate could be described in terms of the Ping-Pong Bi-Bi mechanism.The kineticparameters were computed as: V_m= 44.84mmol/ (min·g); K_mA=1.022mmol/L; K_mB=0.056mmol/L.