Complementary Analytical Platforms of NMR Spectroscopy and LCMS Analysis in the Metabolite Profiling of Isochrysis galbana

Abstract

This study was designed to profile the metabolites of Isochrysis galbana, an indigenous and less explored microalgae species. 1H Nuclear Magnetic Resonance (NMR) spectroscopy and Liquid Chromatography-Mass Spectrometry (LCMS) were used to establish the metabolite profiles of five different extracts of this microalga, which are hexane (Hex), ethyl acetate (EtOAc), absolute ethanol (EtOH), EtOH:water 1:1 (AqE), and 100% water (Aq). Partial least square discriminant analysis (PLS–DA) of the generated profiles revealed that EtOAc and Aq extracts contain a diverse range of metabolites as compared to the other extracts with a total of twenty-one metabolites, comprising carotenoids, polyunsaturated fatty acids, and amino acids, that were putatively identified from the NMR spectra. Meanwhile, thirty-two metabolites were successfully annotated from the LCMS/MS data, ten of which (palmitic acid, oleic acid, α-linolenic acid, arachidic acid, cholesterol, DHA, DPA, fucoxanthin, astaxanthin, and pheophytin) were similar to those present in the NMR profile. Another eleven glycerophospholipids were discovered using MS/MS-based molecular network (MN) platform. The results of this study, besides providing a better understanding of I.galbana’s chemical make-up, will be of importance in exploring this species potential as a feed ingredient in the aquaculture industry.

The Immunostimulant Effects of Isochrysis galbana Supplemented Diet on the Spleen of Red Hybrid Tilapia (Oreochromis spp.) Evaluated by Nuclear Magnetic Resonance Metabolomics

“…However, the increment measured was not significant, probably due to high variations between rep-licates. The increment of ethanol could be associated with glycolysis due to high glucose content in IG as reported previously in the relative quantification of metabolites identified [73]. Previous studies have proven the impact of ethanol on immunomodulatory properties [87,88].…”

“…In the present study, isoleucine is one of the metabolites with a significant increment in fish spleen cells after being fed with an IG-supplemented diet when compared to the commercial diet. The isoleucine increase could be related to its presence with other amino acids in IG which successfully identified via NMR in polar solvents as reported before [73]. A recent study found isoleucine enhanced growth performance and intestinal immunology of hybrid catfish.…”

Potential Anti-Cholinesterase Activity of Bioactive Compounds Extracted from Cassia grandis L.f. and Cassia timoriensis DC.

“…However, there is no information available in the literature about the spectrum data for this compound. The obtained data were compared to the related structure, arachidic acid fatty acid [ 46 ]. Hence, according to the NMR inspection, mass data, and literature data, the structure of 1 was confirmed as arachidyl arachidate, which is known as a one of the natural waxes found in plants and microorganisms [ 47 , 48 ].…”

Anti-Inflammatory and Anticancer Effects of Microalgal Carotenoids

“…This carotenoid is present in a variety of macroalgae, but also in a multitude of species of microalgae such as Isochrysis sp. (Haptophyta), Odontella aurita [54,55], Nitzschia laevis (formerly Nitzschia amabilis) [56], and Chaetoceros neogracili (formerly Chaetoceros gracilis) (Bacillariophyta), the coccolithophore Pleurochrysis carterae (Haptophyta, Coccolithophyceae) [57], Phaeodactylum tricornutum (Bacillariophyta) [46], and the microalga strain Pavlova sp. OPMS 30543 (Haprophyta) [58].…”