Optimization of extraction process for phenolic acids from black cohosh (Cimicifuga racemosa) by pressurized liquid extraction

An investigation to optimize the extraction of phenolic acids from black cohosh using a pressurized liquid extractor system was studied with the aim of developing a generalized approach for sample preparation of phenolic compounds from plant matrices. Operating parameters such as solvent composition, solid-to-solvent ratio, temperature, particle size distribution, and number of extraction cycles were identified as main variables that influence extraction efficiency. A mixture of methanol and water (60:40 v/v) was found to be the best solvent for total phenolics (TP) and individual phenolic acids. The four phenolic acids extracted from black cohosh were identified by HPLC and LC-MS as caffeic acid, ferulic acid, sinapic acid and isoferulic acid. Over 96% of the measured phenolics were extracted in first two cycles. The extraction efficiency for black cohosh with MeOH:H2O (60:40 v/v) was found to be maximum at a solid-to-solvent ratio of 80mg ml(-1). TP content of the extract was found to increase with temperature up to 90 degrees C. Particle size was found to have a large impact on extraction efficiency of TP. Samples with particle size between 0.25 mm. and 0.425 mm. provided optimum extraction of phenolics from black cohosh. Published in 2005 for SCI by John Wiley & Sons, Ltd.