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Application of HPLC-NMR in the identification of plocamenone and isoplocamenone from the marine red alga Plocamium angustum.

Timmers MA, Dias DA, Urban S - Mar Drugs (2012)

Bottom Line: A combination of on-line HPLC-NMR and off-line chemical investigations has resulted in the identification of the previously reported polyhalogenated monoterpene plocamenone, together with the new structural analogue isoplocamenone from the crude extract of the marine alga Plocamium angustum.On-flow and stop-flow HPLC-NMR analyses (including the acquisition of WET 2D NMR spectra) rapidly assisted in the identification of the major component plocamenone and in the partial identification of its unstable double bond isomer isoplocamenone.Conventional off-line isolation and structural characterization techniques were employed to unequivocally confirm both structures, leading to a structural revision for plocamenone, as well as to obtain sufficient quantities for biological testing.

View Article: PubMed Central - PubMed

Affiliation: School of Applied Sciences, Health Innovations Research Institute (HIRi), RMIT University, GPO Box 2476V, Melbourne, Victoria 3001, Australia. michael.timmers@rmit.edu.au

ABSTRACT
A combination of on-line HPLC-NMR and off-line chemical investigations has resulted in the identification of the previously reported polyhalogenated monoterpene plocamenone, together with the new structural analogue isoplocamenone from the crude extract of the marine alga Plocamium angustum. On-flow and stop-flow HPLC-NMR analyses (including the acquisition of WET 2D NMR spectra) rapidly assisted in the identification of the major component plocamenone and in the partial identification of its unstable double bond isomer isoplocamenone. Conventional off-line isolation and structural characterization techniques were employed to unequivocally confirm both structures, leading to a structural revision for plocamenone, as well as to obtain sufficient quantities for biological testing.

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(a) On-flow HPLC-NMR contour plot of the methanol fraction of P. angustum and (b) Stop-flow HPLC-NMR WET 1-D 1H NMR spectra of compounds (4) and (5) acquired using 70% CH3CN/D2O.
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marinedrugs-10-02089-f002: (a) On-flow HPLC-NMR contour plot of the methanol fraction of P. angustum and (b) Stop-flow HPLC-NMR WET 1-D 1H NMR spectra of compounds (4) and (5) acquired using 70% CH3CN/D2O.

Mentions: Plocamium angustum was extracted as outlined in the Extraction and Isolation section. Chemical profiling was conducted on the dichloromethane partitioned fraction employing HPLC-NMR in an attempt to identify the class of secondary metabolites present. HPLC-NMR profiling was achieved using two modes of operation (on-flow and stop-flow). On-flow HPLC analysis clearly indicated the presence of two structurally related secondary metabolites as shown in Figure 2. Given that the genus Plocamium is known to produce polyhalogenated monoterpenes, it was proposed that the compounds present in the crude extract were most likely of this structure class. This was also supported by the presence of the deshielded 1H NMR chemical shift at δ 4.44 which is characteristic of a halogenated methine.


Application of HPLC-NMR in the identification of plocamenone and isoplocamenone from the marine red alga Plocamium angustum.

Timmers MA, Dias DA, Urban S - Mar Drugs (2012)

(a) On-flow HPLC-NMR contour plot of the methanol fraction of P. angustum and (b) Stop-flow HPLC-NMR WET 1-D 1H NMR spectra of compounds (4) and (5) acquired using 70% CH3CN/D2O.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3475275&req=5

marinedrugs-10-02089-f002: (a) On-flow HPLC-NMR contour plot of the methanol fraction of P. angustum and (b) Stop-flow HPLC-NMR WET 1-D 1H NMR spectra of compounds (4) and (5) acquired using 70% CH3CN/D2O.
Mentions: Plocamium angustum was extracted as outlined in the Extraction and Isolation section. Chemical profiling was conducted on the dichloromethane partitioned fraction employing HPLC-NMR in an attempt to identify the class of secondary metabolites present. HPLC-NMR profiling was achieved using two modes of operation (on-flow and stop-flow). On-flow HPLC analysis clearly indicated the presence of two structurally related secondary metabolites as shown in Figure 2. Given that the genus Plocamium is known to produce polyhalogenated monoterpenes, it was proposed that the compounds present in the crude extract were most likely of this structure class. This was also supported by the presence of the deshielded 1H NMR chemical shift at δ 4.44 which is characteristic of a halogenated methine.

Bottom Line: A combination of on-line HPLC-NMR and off-line chemical investigations has resulted in the identification of the previously reported polyhalogenated monoterpene plocamenone, together with the new structural analogue isoplocamenone from the crude extract of the marine alga Plocamium angustum.On-flow and stop-flow HPLC-NMR analyses (including the acquisition of WET 2D NMR spectra) rapidly assisted in the identification of the major component plocamenone and in the partial identification of its unstable double bond isomer isoplocamenone.Conventional off-line isolation and structural characterization techniques were employed to unequivocally confirm both structures, leading to a structural revision for plocamenone, as well as to obtain sufficient quantities for biological testing.

View Article: PubMed Central - PubMed

Affiliation: School of Applied Sciences, Health Innovations Research Institute (HIRi), RMIT University, GPO Box 2476V, Melbourne, Victoria 3001, Australia. michael.timmers@rmit.edu.au

ABSTRACT
A combination of on-line HPLC-NMR and off-line chemical investigations has resulted in the identification of the previously reported polyhalogenated monoterpene plocamenone, together with the new structural analogue isoplocamenone from the crude extract of the marine alga Plocamium angustum. On-flow and stop-flow HPLC-NMR analyses (including the acquisition of WET 2D NMR spectra) rapidly assisted in the identification of the major component plocamenone and in the partial identification of its unstable double bond isomer isoplocamenone. Conventional off-line isolation and structural characterization techniques were employed to unequivocally confirm both structures, leading to a structural revision for plocamenone, as well as to obtain sufficient quantities for biological testing.

Show MeSH
Related in: MedlinePlus