title: Development of an efficient fractionation method for the preparative separation of sesquiterpenoids from Tussilago farfara by counter-current chromatography.
abstract: A novel application of counter-current chromatography (CCC) to enrich plant extracts using direct and continuous injection (CCC-DCI) was developed to fractionate sesquiterpenoids from the buds of Tussilago farfara L. In this study, an n-hexane-acetonitrile-water (HAcW) solvent system was separately pumped into the CCC column, and an extraction solution (45% acetonitrile) was directly and continuously injected into the CCC column. Since the extraction solution was used as a mobile phase in this method, solvent consumption could be greatly reduced. To enrich the extraction solution (315.9g/5.4L), only 4.2L water, 4.6L acetonitrile, and 1.2L n-hexane were used, including the extraction step. Finally, 6.8g of a sesquiterpenoid-enriched (STE) fraction was obtained from the crude extract (315.9g) of Tussilago farfara (1kg) in a single CCC run with a separation time of 8.5h. The sample injection capacity of CCC-DCI was greater than 300g; this amount of sample could not be handled in conventional CCC or other fractionation methods with the same column volume. Moreover, three major sesquiterpenoids (1: tussilagone, 2: 14-acetoxy-7β-(3'-ethyl cis-crotonoyloxy)-1α-(2'-methylburyryloxy)-notonipetranone, and 3: 7β-(3'-ethyl cis-crotonoyloxy)-1α-(2'-methylburyryloxy)-3, 14-dehydro-Z-notonipetranone) were purified from the STE fraction by CCC, and their chemical structures were elucidated by1H NMR and13C NMR. A quantification study was conducted, and the contents of compounds 1-3 in the CCC-DCI fraction were higher than those of conventional multi-step fractionations performed in series: solvent partitioning and open column chromatography. Furthermore, the average CCC-DCI recoveries were 96.1% (1), 96.9% (2), and 94.6% (3), whereas the open column chromatography recoveries were 77.7% (1), 66.5% (2), and 58.4% (3). The developed method demonstrates that CCC is a useful technique for enriching target components from natural products.
authors.affiliation: College of Pharmacy, Natural Products Research Institute, Seoul National University, Seoul 08826, South Korea.
authors.forename: Kwangho
authors.initials: K
authors.lastname: Song
authors.affiliation: College of Pharmacy, Natural Products Research Institute, Seoul National University, Seoul 08826, South Korea.
authors.forename: Kyoung Jin
authors.initials: KJ
authors.lastname: Lee
authors.affiliation: College of Pharmacy, Natural Products Research Institute, Seoul National University, Seoul 08826, South Korea. Electronic address: kims@snu.ac.kr.
authors.forename: Yeong Shik
authors.initials: YS
authors.lastname: Kim
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D003377:Countercurrent Distribution / Q000379:methods*; D006586:Hexanes / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry; D012717:Sesquiterpenes / Q000302:isolation & purification*; D012997:Solvents / Q000737:chemistry; D031207:Tussilago / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D006586:Hexanes; D010936:Plant Extracts; D012717:Sesquiterpenes; D012997:Solvents; D014867:Water; C026385:n-hexane; C054337:tussilagone; C032159:acetonitrile
keywords: Counter-current chromatography-direct and continuous injection; Efficient fractionation method; Sesquiterpenoids; Tussilago farfara