Isolation and identification of antioxidant compounds from Ligularia fischeri.
The plant Ligularia fischeri var. spiciformis Nakai, a well-known edible medicinal herb in Korea, has been used to treat maladies such as jaundice, scarlet fever, rheumatoid arthritis, and hepatic function failure. In this research, 4 major antioxidant compounds were detected from this plant's leaves using an on-line high-performance liquid chromatography (HPLC)-ABTS screening system, which can determine the antioxidant activity based on a decrease in absorbance at 734 nm after postcolumn reaction of HPLC-separated antioxidants with the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radicals (ABTS(*)). In order to isolate these active compounds, a preparative HPLC was applied and their chemical structures were identified as 5-O-caffeoylquinic acid (5-CQA), 3,4-di-O-caffeoylquinic acid (3,4-DCQA), 3,5-di-O-caffeoylquinic acid (3,5-DCQA), and 4,5-di-O-caffeoylquinic acid (4,5-DCQA) by ESI/MS(n) and (1)H NMR. These 4 isomers comprised over 10% of the dried leaves, with 3,5-DCQA being the most abundant compound. The radical scavenging activity of each isomer was also evaluated simultaneously through the on-line HPLC-ABTS method, which showed 94% antioxidant activity of the ethanol extract derived from caffeoylquinic acids. Among these isomers, 3,4-DCQA contained the most strong antioxidant activity while 3,5-DCQA accounted for the highest radical scavenging capacity due to having the highest content.
Shang
Ya Fang
YF
Natural Product Research Center, KIST Gangneung Inst., Daejeon-dong, Gangneung, Gangwon, Republic of Korea.
Kim
Sang Min
SM
Song
Dae-Geun
DG
Pan
Cheol-Ho
CH
Lee
Won Jong
WJ
Um
Byung-Hun
BH
D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification*; D019659:Asteraceae / Q000737:chemistry*; D052160:Benzothiazoles / Q000737:chemistry; D002726:Chlorogenic Acid / Q000031:analogs & derivatives / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D055808:Drug Discovery; D007202:Indicators and Reagents / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D055670:Medicine, Korean Traditional; D015394:Molecular Structure; D009005:Monosaccharides / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D011801:Quinic Acid / Q000031:analogs & derivatives / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D021241:Spectrometry, Mass, Electrospray Ionization; D013451:Sulfonic Acids / Q000737:chemistry; D053719:Tandem Mass Spectrometry
C500585:3,5-di-O-(E)-caffeoylquinic acid; C500583:4,5-di-O-(E)-caffeoylquinic acid; D000975:Antioxidants; D052160:Benzothiazoles; D007202:Indicators and Reagents; D009005:Monosaccharides; D010936:Plant Extracts; D013451:Sulfonic Acids; D011801:Quinic Acid; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D002726:Chlorogenic Acid; C478100:3,4-di-O-caffeoylquinic acid