title: New phenylpropanoid-substituted flavan-3-ols and flavonols from the leaves of Uncaria rhynchophylla.
abstract: Uncariols A (1) and B (2), two new phenylpropanoid-substituted flavan-3-ols, and (±)-uncariols C (3a/3b) and D (4a/4b), two pairs of new phenylpropanoid-substituted flavonol enantiomers, together with nine known compounds (5-13), were isolated from the leaves of Uncaria rhynchophylla. The structures of 1-4 were established primarily by NMR and HRESIMS experiments. The absolute configurations of the new ones were deduced via the circular dichroism (CD) and quantum chemical calculations of the electronic circular dichroic (ECD) spectra. In addition, all of the isolated compounds showed potent antioxidant activity in the DPPH radical scavenging test.
authors.affiliation: Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
authors.forename: Ruxin
authors.initials: R
authors.lastname: Li
authors.affiliation: Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
authors.forename: Jintang
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
authors.forename: Mengjiao
authors.initials: M
authors.lastname: Jiao
authors.affiliation: Institute of Materia Medica, Chinese Academy of Medical Sciences, and Peking Union Medical College, Beijing 100050, China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Guo
authors.affiliation: Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Chen
authors.affiliation: Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China. Electronic address: la62@163.com.
authors.forename: An
authors.initials: A
authors.lastname: Liu
mesh_terms: D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification; D044948:Flavonols / Q000737:chemistry* / Q000302:isolation & purification; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000302:isolation & purification; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry; D032070:Uncaria / Q000737:chemistry*
chemical_list: D005419:Flavonoids; D044948:Flavonols; D016166:Free Radical Scavengers; C404987:flavan-3-ol
keywords: (−)-epicatechin (PubChem CID: 72276); Antioxidant activity; Cinchonain Ia (PubChem CID: 10456516); Cinchonain Ib (PubChem CID: 442675); Cinchonain Ic (PubChem CID: 21676383); Cinchonain Id (PubChem CID: 21676382); Enantiomers; Flavan-3-ols; Flavonols; Methyl caffeate (PubChem CID: 689075); Quercetin (PubChem CID: 5280343); Quercetin-3-O-robinobioside (PubChem CID: 10371536); Rutin (PubChem CID: 5280805); Uncaria rhynchophylla