- Bioactive tigliane diterpenoids from the latex of Euphorbia fischeriana
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Latex is a type of sticky endogenous fluids derived from diverse plants including Euphorbia fischeriana, and is of great scientific and commercial values. In the current study, it was demonstrated that the latex extracted from E. fischeriana strongly respelled the growth of cotton bollworm, Helicoverpa armigera. Using spectroscopic methods, HPLC, and GC-MS analyses, six aliphatic tigliane diterpenoids were isolated from the latex of E. fischeriana, among which three compounds (2, 3, and 5) were new. Two major compounds (1 and 4) exhibited remarkable antifeedant activity against H. armigera, with EC50 values at 2.59 and 15.32 μg/cm2, respectively. In addition, the quantification analysis of diterpenoids in different organs indicated that 4 was the most abundant constituent and was highly accumulated in the latex. Collectively, the current study highlighted that the diterpenoids in latex of E. fischeriana had a considerable antifeedant function against H. armigera, which might be employed for the future development of natural insecticides for organic farming.
- Deng, Yan-Yan,Qu, Bo,Zhan, Zhong-Lang,Wang, An-Qi,Zhou, Wei,Jia, Ming-Yue,Hua, Juan,Luo, Shi-Hong
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supporting information
p. 179 - 187
(2021/01/12)
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- 2-Methoxylated FA Display Unusual Antibacterial Activity Towards Clinical Isolates of Methicillin-Resistant Staphylococcus aureus (CIMRSA) and Escherichia coli
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The naturally occurring (6Z)-(±)-2-methoxy-6-hexadecenoic acid (1) and (6Z)-(±)-2-methoxy-6-octadecenoic acid (2) were synthesized in 7–8 steps with 38 and 13% overall yields, respectively, by using an acetylide coupling approach, which made it possible to obtain a 100% cis-stereochemistry for the double bonds. In a similar fashion, the acetylenic analogs (±)-2-methoxy-6-hexadecynoic acid (3) and (±)-2-methoxy-6-octadecynoic acid (4) were also synthesized in 6–7 steps with 48 and 16% overall yields, respectively. The antibacterial activity of acids 1–4 was determined against clinical isolates of methicillin-resistant Staphylococcus aureus (ClMRSA) and Escherichia coli. Among the series of compounds, acid 4 was the most active bactericide towards CIMRSA displaying IC50s (half maximal inhibitory concentrations) between 17 and 37?μg/mL, in sharp contrast to the 6-octadecynoic acid, which was not bactericidal at all. On the other hand, acids 1 and 3 were the only acids that displayed antibacterial activity towards E. coli., but 1 stood out as the best candidate with an IC50 of 21?μg/mL. The critical micelle concentrations (CMCs) of acids 1–4 were also determined. The C18 acids 2 and 4 displayed a five-fold lower CMC (15–20?μg/mL) than the C16 analogs 1 and 3 (70–100?μg/mL), indicating that 4 exerts its antibacterial activity in a micellar state. None of the studied acids were inhibitory towards S. aureus DNA gyrase discounting this type of enzyme inhibition as a possible antibacterial mechanism. It was concluded that the combination of α-methoxylation and C-6 unsaturation increases the bactericidal activity of the C16 and C18 FA towards the studied bacterial strains. Acids 1 and 4 stand out as viable candidates to be used against E. coli and CIMRSA, respectively.
- Carballeira, Néstor M.,Montano, Nashbly,Morales, Christian,Mooney, Joseph,Torres, Xiomara,Díaz, Dakeishla,Sanabria-Rios, David J.
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p. 535 - 548
(2017/06/07)
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- Phosphonium Iodide in Organic Synthesis
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Phosphonium iodide is found useful in the stereospecific conversion of some vicinal diols to olefins.Synthesis of cis-hexadec-9-enolide has been achieved.
- Chatterjea, J. N.,Majee, R. N.,Mukherjee, S. N.
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p. 733 - 735
(2007/10/02)
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