Ethyl ferulate was transesterified with Enova Oil (a soy-based vegetable oil containing 80-85% diacylglycerol) using Novozym 435 at 60 °C. The resultant feruloylated vegetable oil reaction product produced a precipitate (96.4 g, 4.02 wt%) after 7 d of standing at room temperature. Preliminary characterization of the precipitate identified the natural phenylpropenoids 1,3-diferuloyl-sn-glycerol (F2G) and 1-feruloyl-sn-glycerol (FG) as the major components. A flash chromatography method was developed and optimized (e.g., mass of sample load, flow rate, binary solvent gradient slope, and separation run length) using a binary gradient of hexane and acetone mobile phase and silica gel stationary phase to separate and isolate F2G and FG. The optimized parameters afforded F2G (1.188 ± 0.052 g, 39.6 ± 1.7%) and FG (0.313 ± 0.038 g, 10.4 ± 1.3%) from 3.0 g of the transesterification precipitate, n = 10 trials. Overall, all flash chromatography separations combined, F2G (39.1 g, 40.6%) and FG (9.4 g, 9.8%) were isolated in a combined yield of 48.5 g (51.4%), relative to the 96.4 g of transesterification precipitate collected. The optimized flash chromatography method was a necessary improvement over previously reported preparative HPLC and column chromatography methods used to purify milligram to low gram quantities of F2G and FG to be able to process ~100 g of material in a timely, efficient manner.
Keywords: diferuloyl glycerol; feruloyl glycerol; flash chromatography; transesterification.