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

Perilla frutescens is an annual herb belonging to the mint family, listed as one of the plant resources which could be used as foods and medicines in China by National Health Commission of PRC. Perilla seeds are nutrition powerhouses with abundant fibers, mineral elements, oils and polyphenols. Majority of the phenolics remained in the seed residues after oil extraction through cold-press process, including 3,4-Dihydroxyphenylethanol, caffeic acid-3-O-glycoside, caffeic acid, luteoloside, rosemarinic acid and rosemary acid-3-O-glycoside etc. These phenolics are potential phytonutrients, possessing antioxidant, anti-inflammatory, anti-bacterial and radical-scavenging activities. However, further studies concerning the structure activity relationship (SAR) and the assessment of contributions of the phenolic compound to the total antioxidant activities were limited because of a lack of controlled substances for caffeic acid-3-O-glycoside. Therefore, the objective of the present study is to optimize the extraction, enrichment and purification procedure for caffeic acid-3-O-glycoside, so as to provide controlled substances in further studies. Data and conclusion are summarized as following:(1) Controlled substances of caffeic acid-3-O-glycoside were prepared from the cold-pressed perilla seed residues through alkaline hydrolysis extraction, ODS chromatography and HPLC preparation chromatography purification. The structure of the controlled substance was confirmed based on the 1H NMR and 13C NMR data, which will facilitate further studies concerning perilla seeds and phenolic compounds.(2) The alkaline concentration, processing temperature and time were optimized through single factor and response surface analysis to get the optimal conditions for the extraction of caffeic acid-3-O-glycoside:2 M NaOH as hydrolysis solvent, extracted for 1.5 h at 70℃.(3) Macroporous resin was used to enrich caffeic acid-3-O-glycoside from the raw extracts of Perilla seed residues. Based on static the absorption and desorption tests, the type of macroporous resin suitable for the enrichment of caffeic acid-3-O-glycoside was optimized and then the elusion solvent was optimized based on dynamic desorption tests. The results revealed that HPD 300 was the best type of macroporous resin for the enrichment and 10% methanol as elute solvent could lead to high yields and high purification.