Carboxymethyl flavonoids and a chromone with antimicrobial activity from Selaginella moellendorffii Hieron

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• 作者：ZhenXing Zou^a ; ^b ; PingSheng Xu^b ; CanRong Wu^c ; WeiXing Zhu^a ; GangZhi Zhu^d ; XiaoAi He^d ; GuoGang Zhang^b ; JianZhong Hu^b ; Shao Liu^b ; Wei Zeng^b ; KangPing Xu^a ; ^{xukp395@csu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; GuiShan Tan^a ; ^b ;
• 关键词：Selaginella ; Selaginella moellendorffii Hieron ; Carboxymethyl flavonoids ; Antibacterial activity
• 刊名：Fitoterapia
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：111
• 期：Complete
• 页码：124-129
• 全文大小：714 K

文摘

Five new carboxymethyl flavonoids named 5-carboxymethyl-3′, 4′, 7-trihydroxyflavone (class="boldFont">1), (2S)- 5-carboxymethyl-3′, 4′, 7-trihydroxyflavonone (class="boldFont">2a), (2R)-5-carboxymethyl-3′, 4′, 7-trihydroxyflavonone (class="boldFont">2b), (2S)-5-carboxymethyl-4′, 7-dihydroxyflavonone (class="boldFont">3), 5- carbomethoxymethyl-4′, 7-dihydroxyflavone (class="boldFont">4), and a new chromone named 5-carboxymethyl-7-hydroxychromone (class="boldFont">5), together with two known compounds 5-carboxymethyl-4′-hydroxyflavone-7-O-β-class="smallcaps">d-glucopyranoside (class="boldFont">6), 5-carboxymethyl-4′, 7-dihydroxyflavone (class="boldFont">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 class="boldFont">2a and class="boldFont">2b were identified as a pair of chiral isomers; compound class="boldFont">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 class="boldFont">3 and class="boldFont">4 exhibited as potent antimicrobial agents with a broad spectrum, and compound class="boldFont">5 appeared as the most promising one to combat Gram-positives.