title: Carboxymethyl flavonoids and a chromone with antimicrobial activity from Selaginella moellendorffii Hieron.
abstract: Five new carboxymethyl flavonoids named 5-carboxymethyl-3', 4', 7-trihydroxyflavone (1), (2S)- 5-carboxymethyl-3', 4', 7-trihydroxyflavonone (2a), (2R)-5-carboxymethyl-3', 4', 7-trihydroxyflavonone (2b), (2S)-5-carboxymethyl-4', 7-dihydroxyflavonone (3), 5- carbomethoxymethyl-4', 7-dihydroxyflavone (4), and a new chromone named 5-carboxymethyl-7-hydroxychromone (5), together with two known compounds 5-carboxymethyl-4'-hydroxyflavone-7-O-β-d-glucopyranoside (6), 5-carboxymethyl-4', 7-dihydroxyflavone (7) were isolated from Selaginella moellendorffii Hieron. Their structures including absolute configuration were elucidated by extensive spectroscopic methods and experimental electronic circular dichroism (ECD) spectra. What's worth mentioning is that a carboxymethyl substituent appeared at the C-5 position of all isolated compounds, only recently discovered in genus Selaginella. Compounds 2a and 2b were identified as a pair of chiral isomers; compound 5 was discovered as the first chromone comprising a carboxymethyl side chain. Furthermore, all compounds were evaluated for their antibacterial activities against various Gram-positives and Gram-negatives, and compared to the reference drugs amoxicillin and norfloxacin. As a result, compounds 3 and 4 exhibited as potent antimicrobial agents with a broad spectrum, and compound 5 appeared as the most promising one to combat Gram-positives.
authors.affiliation: School of Pharmaceutical Sciences, Central South University, Changsha 410013, PR China; Xiangya Hospital of Central South University, Changsha 410008, PR China.
authors.forename: ZhenXing
authors.initials: Z
authors.lastname: Zou
authors.affiliation: Xiangya Hospital of Central South University, Changsha 410008, PR China.
authors.forename: PingSheng
authors.initials: P
authors.lastname: Xu
authors.affiliation: Medical School of Hunan University of Chinese Medicine, Changsha 410208, PR China.
authors.forename: CanRong
authors.initials: C
authors.lastname: Wu
authors.affiliation: School of Pharmaceutical Sciences, Central South University, Changsha 410013, PR China.
authors.forename: WeiXing
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Central South University Xiangya School of Medicine Affiliated HaiKou Hospital, Haikou 570208, PR China.
authors.forename: GangZhi
authors.initials: G
authors.lastname: Zhu
authors.affiliation: Central South University Xiangya School of Medicine Affiliated HaiKou Hospital, Haikou 570208, PR China.
authors.forename: XiaoAi
authors.initials: X
authors.lastname: He
authors.affiliation: Xiangya Hospital of Central South University, Changsha 410008, PR China.
authors.forename: GuoGang
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Xiangya Hospital of Central South University, Changsha 410008, PR China.
authors.forename: JianZhong
authors.initials: J
authors.lastname: Hu
authors.affiliation: Xiangya Hospital of Central South University, Changsha 410008, PR China.
authors.forename: Shao
authors.initials: S
authors.lastname: Liu
authors.affiliation: Xiangya Hospital of Central South University, Changsha 410008, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zeng
authors.affiliation: School of Pharmaceutical Sciences, Central South University, Changsha 410013, PR China. Electronic address: xukp395@csu.edu.cn.
authors.forename: KangPing
authors.initials: K
authors.lastname: Xu
authors.affiliation: School of Pharmaceutical Sciences, Central South University, Changsha 410013, PR China; Xiangya Hospital of Central South University, Changsha 410008, PR China.
authors.forename: GuiShan
authors.initials: G
authors.lastname: Tan
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000302:isolation & purification; D002867:Chromones / Q000737:chemistry* / Q000302:isolation & purification; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry; D032503:Selaginellaceae / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D002867:Chromones; D005419:Flavonoids; D010936:Plant Extracts
keywords: Antibacterial activity; Carboxymethyl flavonoids; Selaginella; Selaginella moellendorffii Hieron