Supercritical fluid extraction and identification of isoquinoline alkaloids from leaves of Nelumbo nucifera Gaertn.

摘要

Isoquinoline alkaloids from leaves of Nelumbo nucifera (N. nucifera) were extracted using supercritical CO2. The effects of the parameters such as the dynamic extraction time, temperature, pressure, various modifiers, and flow rate of the modifier on the yield of nuciferine and the ratio of total isoquinoline alkaloids to the total extract were investigated. Nuciferine content of the extract was determined by high-performance liquid chromatography (HPLC). The results indicated that the yield of nuciferine increased with increases in the dynamic extraction time, pressure, temperature, and flow rate of the modifier. The highest nuciferine yield of 325.54 mug/g was obtained when the extraction was carried out for 2 h at 70 degrees C under 30 MPa, with 10% (v/v) diethylamine and 1% (v/v) water in methanol as the modifier which kept a flow rate of 1.2 mL/min. The ratio of total isoquinoline alkaloids to the extract was 49.85% at the highest nuciferine yield. Five kinds of isoquinoline alkaloids extracted from N. nucifera leaves were identified by high-performance liquid chromatography combined with ion trap/time-of-flight mass spectrometry (LC/MS-ITTOF). They were dehydronuciferine, N-nornuciferine, O-nornuciferine, nuciferine, and roemerine in the order of retention time. (c)Springer-Verlag 2010.