Absolute Configuration of (13R)- and (13S)-Labdane Diterpenes Coexisting in Ageratina jocotepecana

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• 作者：Edgar Garc铆a-S谩nchez ; C茅sar B. Ram铆rez-L贸pez ; Armando Talavera-Alem谩n ; Alejandra Le贸n-Hern谩ndez ; Rosa E. Mart铆nez-Mu帽oz ; Mauro M. Mart铆nez-Pacheco ; Mario A. G贸mez-Hurtado ; Carlos M. Cerda-Garc铆a-Rojas ; Pedro Joseph-Nathan ; Rosa E. del R铆o
• 刊名：Journal of Natural Products
• 出版年：2014
• 出版时间：April 25, 2014
• 年：2014
• 卷：77
• 期：4
• 页码：1005-1012
• 全文大小：386K
• 年卷期：v.77,no.4(April 25, 2014)
• ISSN：1520-6025

文摘

Chemical investigation of the hexanes extracts of Ageratina jocotepecana afforded (鈭?-(5S,9S,10S,13S)-labd-7-en-15-oic acid (1), methyl (鈭?-(5S,9S,10S,13S)-labd-7-en-15-oate (2), (+)-(5S,8R,9R,10S,13R)-8-hydroxylabdan-15-oic acid (3), and (鈭?-(5S,9S,10S,13Z)-labda-7,13-dien-15-oic acid (5). The coexistence of (13R)- and (13S)-labdanes in this member of the Asteraceae family was demonstrated by vibration circular dichroism measurements of ester 2 and methyl (+)-(5S,8R,9R,10S,13R)-8-hydroxylabdan-15-oate (4) in comparison to the DFT B3LYP/DGDZVP-calculated spectra. In addition, transformation of 1 and 3 with HClO₄ in MeOH yielded epimeric methyl (+)-(5S,10S,13S)-labd-8-en-15-oate (6) and methyl (+)-(5S,10S,13R)-labd-8-en-15-oate (7), respectively, confirming the presence of C-13 epimers in this plant. Diterpene 1 showed remarkable antibacterial activity against Bacillus subtilis (MIC 0.15 mg/mL) and Staphylococcus aureus (MIC 0.78 mg/mL), while diterpene 3 exhibited moderate activities against the same organisms.