Extraction and liquid membrane preconcentration of rosmarinic acid from lemon balm (Melissa officinalis L.)

Liquid membrane separation technique was applied for the recovery and preconcentration of rosmarinic acid from aqueous extract of dried leaves of Balm lemon (Melissa officinalis L.). Among several studied organic solvents, diisopropyl ether and ethylacetate appeared to be appropriate membrane liquids for recovery and selective preconcentration of the acid. The difference in pH values between the two aqueous solutions was the driving force in this case. An integrated process coupling the extraction of rosmarinic acid from ground Melissa leaves with a simultaneous stripping of membrane and accumulation of the extracted solute was demonstrated using a laboratory bulk liquid membrane contactor. The process provided an almost complete (96 percent) exhaustion of the herbal mass and highly enriched final extract, containing 87 percent RA after strip solution drying.