Contents lists available at ScienceDirect Phytochemistry journal homepage: www.elsevier.com/locate/phytochem NMR characterization and evaluation of antibacterial and antiobioflm activity of organic extracts from stationary phase batch cultures of fve marine microalgae (Dunaliella sp., D. salina, Chaetoceros calcitrans, C. gracilis and Tisochrysis lutea) M a José Iglesias a,∗ , Raquel Soengas a , Ian Probert b , Emilie Guilloud b , Priscillia Gourvil b , Mohamed Mehiri c , Yuly López d , Virginio Cepas d , Ignacio Gutiérrez-del-Río e , Saúl Redondo-Blanco e , Claudio J. Villar e , Felipe Lombó e , Sara Soto d , Fernando López Ortiz a,∗∗ a Área de Química Orgánica, Research Centre CIAIMBITAL, Universidad de Almería, Carretera de Sacramento s/n, Almería, 04120, Spain b Roscoff Culture Collection, FR2424 Station Biologique de Roscoff (Sorbonne Université / CNRS), 29680, Roscoff, France c Institut de Chimie de Nice, UMR CNRS 7272, Université Nice Sofia Antopolis, 06103, Nice, France d Barcelona Institute for Global Health (ISGlobal)-Hospital Clinic-Universitat de Barcelona, Carrer Rosselló 132, 08036, Barcelona, Spain e Research Group BIONUC, Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Principality of Asturias, Spain. IUOPA (Instituto Universitario de Oncología del Principado de Asturias), ISPA (Instituto de Investigación Sanitaria del Principado de Asturias), Spain ARTICLE INFO Keywords: Dunaliella Chaetoceros Tisochrysis NMR Metabolite identifcation Antibacterial Antibioflm ABSTRACT The chemical composition of fve marine microalgae (Dunaliella sp., Dunaliella salina, Chaetoceros calcitrans, Chaetoceros gracilis and Tisochrysis lutea) was investigated through nuclear magnetic resonance (NMR) spec- troscopic study of the soluble material obtained by sequential extraction with hexane, ethyl acetate (AcOEt) and methanol of biomass from stationary phase cultures. Hexane extracted the major lipids present in the microalgae during the stationary phase of growth, which correspond to storage lipids. Triacylglycerols (TGs) were the only storage lipids produced by Dunaliella and Chaetoceros. In contrast, T. lutea predominantly stored polyunsaturated long-chain alkenones, with sterols also detected as minor components of the hexane extract. The molecular structure of brassicasterol was determined in T. lutea and the presence of squalene in this sample was also unequivocally detected. Monogalactosyldiacylglycerols (MGDGs) and pigments were concentrated in the AcOEt extracts. C. calcitrans and D. salina constituted an exception due to the high amount of TGs and glycerol pro- duced, respectively, by these two strains. Chlorophylls a and b and β-carotene were the major pigments syn- thesized by Dunaliella and chlorophyll a and fucoxanthin were the only pigments detected in Chaetoceros and T. lutea. Information concerning the acyl chains present in TGs and MGDGs as well as the positional distribution of acyl chains on the glycerol moiety was obtained by NMR analysis of hexane and AcOEt extracts, with results consistent with those expected for the genera studied. Fatty acid composition of TGs in the two Dunaliella strains was diferent, with polyunsaturated acyl chains almost absent in the storage lipids produced by D. salina. Except in C. calcitrans, the polar nature of soluble compounds was inferred through the relative extraction yield using methanol as the extraction solvent. Glycerol was the major component of this fraction for the Dunaliella strains. In T. lutea 1,4/2,5-cyclohexanetetrol (CHT) and dimethylsulfoniopropionate (DMSP) preponderated. CHT was also the major polyol present in the Chaetoceros strains in which DMSP was not detected, but prominent signals of 2,3-dihydroxypropane-1-sulfonate (DHSP) were observed in the 1H NMR spectra of methanolic extracts. The presence of DHSP confrms the production of this metabolite by diatoms. In addition, several other minor compounds (digalactosyldiacyglycerols (DGDGs), sulphoquinovosyldiacylglycerols (SQDGs), amino acids, car- bohydrates, scyllo-inositol, mannitol, lactic acid and homarine) were also identifed in the methanolic extracts. The antibacterial and antibioflm activities of the extracts were tested. The AcOEt extract from C. gracilis showed a moderate antibioflm activity. https://doi.org/10.1016/j.phytochem.2019.05.001 Received 9 January 2019; Received in revised form 11 April 2019; Accepted 6 May 2019 ∗ Corresponding author. Área de Química Orgánica, Universidad de Almería. Carretera de Sacramento s/n, 04120 Almería, Spain. ∗∗ Corresponding author. Área de Química Orgánica, Universidad de Almería. Carretera de Sacramento s/n, 04120 Almería, Spain. E-mail addresses: mjigle@ual.es (M.J. Iglesias), fortiz@ual.es (F.L. Ortiz). Phytochemistry 164 (2019) 192–205 0031-9422/ © 2019 Elsevier Ltd. All rights reserved. T