title: Antioxidant caffeic acid derivatives from leaves of Parthenocissus tricuspidata.
abstract: Five caffeic acid derivatives; methyl ester of caffeoylglycolic acid (1), dimethyl ester of caffeoyltartaric acid (2), dimethyl ester of caffeoyltartronic acid (3), monomethyl ester of caffeoyltartronic acid (4), methyl ester of caffeic acid (5), and some other secondary metabolites including; quercetin, quercetin 3-O-beta-D-glucuronide methyl ester, kaempferol, 3,5,7,4'-O-tetramethylkaempferol, beta-sitosterol glucoside, 2alpha-hydroxyursolic acid and 2,24-dihydroxyursolic acid, have been isolated and characterized. All the isolated compounds were characterized with the help of NMR spectroscopy and mass spectrometry. Structure of compound 3 was also confirmed by a single X-ray crystallographic technique. Isolates were evaluated for antioxidant activities and most of the tested compounds were found to be potent in DPPH free radical scavenging (IC50 = 4.56-14.17 microg/mL) and superoxide anion scavenging (IC50 = 0.58-7.39 microg/mL) assays.
authors.affiliation: Medicinal Chemistry Research Center, Division of Life Sciences, Korea Institute of Science and Technology, PO Box 131, Cheongryang, Seoul 130-650, Korea.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Saleem
authors.forename: Hyoung Ja
authors.initials: HJ
authors.lastname: Kim
authors.forename: Changbae
authors.initials: C
authors.lastname: Jin
authors.forename: Yong Sup
authors.initials: YS
authors.lastname: Lee
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002109:Caffeic Acids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002417:Cattle; D016166:Free Radical Scavengers / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D018515:Plant Leaves; D010946:Plants, Medicinal; D013481:Superoxides / Q000378:metabolism; D027844:Vitaceae
chemical_list: D000975:Antioxidants; D002109:Caffeic Acids; D016166:Free Radical Scavengers; D010936:Plant Extracts; D013481:Superoxides; C040048:caffeic acid