201
Recently, the presence of flavone glycoside thalassiolin B in significant concentrations from T. testudinum (partially characterized using 1H NMR and LC-MS)
was reported which was capable of inhibiting the growth of Labyrinthula sp.
(Vergeer and Develi 1997). Furthermore, various flavonoids such as luteolin, apigenin, luteolin-3'-glucuronide and luteolin-4-O-glucuronide have also been isolated
and characterized by HPLC/MS
n
and NMR from T. testudinum and Enhalus acoroides with anti-feedent and anti-larval activities against Spodoptera litura and Bugula
neritina larvae (Vergeer and Develi 1997). Luteolin from leaf tissues of T. testudinum has also been shown to inhibit the settlement of motile zoospores of the protist
Schizochytrium aggregatum.
The most abundant lipid classes defined in seagrass species are fatty acids, sterols and hydroxyl fatty acids. Free fatty acids and amides such as γ-linolenic acid,
myristic acid, palmitoleic acid, docosahexaenoic acid, 10,12,14-octadecatrienoic
acid, palmitic amide, oleamide and stearamide and steroidal compounds
β-sitosterol, campesterol and stigmasterol were identified in this study. However, it
should be noted that the extraction protocol in this study was not lipid specific and
hence the fatty acid and derivatives identified in this study may not be conclusive.
Many targeted and non-targeted GC-MS-based metabolomic approaches have
revealed fluctuations in fatty acid composition in marine plants exposed to various
biotic and abiotic stresses. An enhanced proportion of oleic acid and linoleic acid
with a parallel decrease in palmitoleic acid was observed in marine macrophyte
Gracilaria corticata and Ectocarpus siliculosus at hypersalinities in contrast to
hyposalinity (Kumar et al. 2016). Higher PUFAs accumulation was suggested as
an adaptive strategy to maintain greater membrane fluidity, to stabilize the protein
complexes of PSII and to control the physicochemical properties of membranes,
such as the increased activity of the Na
+
/H
+
antiporter system of the plasma membrane in order to cope with hypersalinity stress (Kumar et al. 2016). Phytosterols
play important role in plant adaptation to temperature and are also involved in the
regulation of temperature involved membrane dynamics (Ribeiro et al. 2014).
Sterols such as 24-ethylcholest-5-en-3β-ol, 24-ethylcholesta-5,22E-dien-3β-ol and
24-methylcholest-5-en-3β-ol have been previously reported from Z. muelleri
(Gillan et al. 1984).
9.4 Conclusion
In this study, we demonstrate the potential of MS-based metabolite profiling for
analysing a broad spectrum of metabolites in seagrasses. Information on metabolites is integral for linking genotype and phenotype and thus has a significant role
in the development of system biology approaches in marine systems. The metabolite information of Z. muelleri attained in this study can provide a better insight
into the biochemical composition of the species. However, it is highly likely that
results of metabolomics when integrated with allied omic platform such as
9 Gas and Liquid Chromatography-Mass Spectrometry-Based Metabolic Profiling…
Recently, the presence of flavone glycoside thalassiolin B in significant concentrations from T. testudinum (partially characterized using 1H NMR and LC-MS)
was reported which was capable of inhibiting the growth of Labyrinthula sp.
(Vergeer and Develi 1997). Furthermore, various flavonoids such as luteolin, apigenin, luteolin-3'-glucuronide and luteolin-4-O-glucuronide have also been isolated
and characterized by HPLC/MS
n
and NMR from T. testudinum and Enhalus acoroides with anti-feedent and anti-larval activities against Spodoptera litura and Bugula
neritina larvae (Vergeer and Develi 1997). Luteolin from leaf tissues of T. testudinum has also been shown to inhibit the settlement of motile zoospores of the protist
Schizochytrium aggregatum.
The most abundant lipid classes defined in seagrass species are fatty acids, sterols and hydroxyl fatty acids. Free fatty acids and amides such as γ-linolenic acid,
myristic acid, palmitoleic acid, docosahexaenoic acid, 10,12,14-octadecatrienoic
acid, palmitic amide, oleamide and stearamide and steroidal compounds
β-sitosterol, campesterol and stigmasterol were identified in this study. However, it
should be noted that the extraction protocol in this study was not lipid specific and
hence the fatty acid and derivatives identified in this study may not be conclusive.
Many targeted and non-targeted GC-MS-based metabolomic approaches have
revealed fluctuations in fatty acid composition in marine plants exposed to various
biotic and abiotic stresses. An enhanced proportion of oleic acid and linoleic acid
with a parallel decrease in palmitoleic acid was observed in marine macrophyte
Gracilaria corticata and Ectocarpus siliculosus at hypersalinities in contrast to
hyposalinity (Kumar et al. 2016). Higher PUFAs accumulation was suggested as
an adaptive strategy to maintain greater membrane fluidity, to stabilize the protein
complexes of PSII and to control the physicochemical properties of membranes,
such as the increased activity of the Na
+
/H
+
antiporter system of the plasma membrane in order to cope with hypersalinity stress (Kumar et al. 2016). Phytosterols
play important role in plant adaptation to temperature and are also involved in the
regulation of temperature involved membrane dynamics (Ribeiro et al. 2014).
Sterols such as 24-ethylcholest-5-en-3β-ol, 24-ethylcholesta-5,22E-dien-3β-ol and
24-methylcholest-5-en-3β-ol have been previously reported from Z. muelleri
(Gillan et al. 1984).
9.4 Conclusion
In this study, we demonstrate the potential of MS-based metabolite profiling for
analysing a broad spectrum of metabolites in seagrasses. Information on metabolites is integral for linking genotype and phenotype and thus has a significant role
in the development of system biology approaches in marine systems. The metabolite information of Z. muelleri attained in this study can provide a better insight
into the biochemical composition of the species. However, it is highly likely that
results of metabolomics when integrated with allied omic platform such as
9 Gas and Liquid Chromatography-Mass Spectrometry-Based Metabolic Profiling…