Optimization For Extraction And Enrichment Of Rosmarinic Acid-3-O-glucoside From Cold-pressed Perilla Frutescens Seed Residues

Perilla frutescens (L.) Britt. is an annual plant belonging to the mint family, Lamiaceae, traditionally used as medicines and edible resources in China. Abundant polyphenols remain in the cold-pressed seed residues after oil extraction, including rosmarinic acid-3-O-glucoside, rosmarinic acid, caffeic acid and caffeic acid-3-O-glucoside, etc. However, standards of rosmarinic acid-3-O-glucoside was almost not available currently, which limited the related studies such as structure-activities relations of rosmarinic acid and their varieties.In the present study, cold-pressed perilla seed residues were extracted with organic solvent, and then was subject to ODS column chromatography to purify the rosmarinic acid-3-O-glucoside, after which its structure was confirmed by 1H-NMR and 13C-NMR. Based on the standard isolated, the extraction method was optimized through single factor and response surface analysis. Finally, the optimal macroporous resin type and elution solvent for the enrichment of rosmarinic acid-3-O-glucoside was achieved after static and dynamic absorption and desorption tests. The main results and conclusions were as following.(1) The seed residues were extracted with acetone and then subjected to liquid-liquid extraction with ethyl acetate after concentration. Finally, rosmarinic acid-3-O-glucoside was purified by ODS chromatography and its structure was confirmed by H-NMR and C-NMR, which could be used as standards for the following studies.(2) Single factor experiment revealed that the acetone concentration, temperature and extraction time are important factors affecting the yields of rosmarinic acid-3-O-glucoside. The optimal extraction condition of rosmarinic acid-3-O-glucoside is reflux extraction with 50% acetone in the solid-liquid ratio 1:25 at 80℃ revealed by response surface methodology.(3) The static absorption experiment showed that HPD400 macroporous resin had the best absorption and desorption efficiency for acid-3-O-glucoside, and the best sample concentration is 25%. The dynamic desorption experiment illustrated that 10% methanol as elusion solvent showed the bestelution performance.