Complementary analytical platforms of NMR spectroscopy and LCMS analysis in the metabolite profiling of Isochrysis galbana

• Main Authors: Ahamad Bustamam, Muhammad Safwan, Pantami, Hamza Ahmed, Azizan, Awanis, Shaari, Khozirah, Chong, Chou Min, Abas, Faridah, Nagao, Norio, Maulidiani, Maulidiani, Banerjee, Sanjoy, Sulaiman, Fadzil, Ismail, Intan Safinar
• Format: Article
• Published: Multidisciplinary Digital Publishing Institute 2021
• Online Access: http://psasir.upm.edu.my/id/eprint/96482/; https://www.mdpi.com/1660-3397/19/3/139
• Institution: Universiti Putra Malaysia

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.