Detection of flavonoids in microalgae from different evolutionary lineages

Abstract

Flavonoids are important secondary plant metabolites believed to be present mainly in land plants. As phenolics were detected previously in microalgae using photometric assays, we wanted to investigate the nature of these phenolics and verify whether flavonoids are present. Therefore, in this study, we used state-of-the-art ultra-high performance liquid chromatography-two-dimensional mass spectrometry (UHPLC-MS/MS) technology to investigate whether microalgae also contain flavonoids. For this, representative microalgal biomass samples from divergent evolutionary lineages (Cyanobacteria, Rhodophyta, Chlorophyta, Haptophyta, Ochrophyta) were screened for a set of carefully selected precursors, intermediates, and end products of the flavonoid biosynthesis pathways. Our data unequivocally showed that microalgae contain a wide range of flavonoids and thus must possess the enzyme pool required for their biosynthesis. Further, some of the microalgae displayed an intricate flavonoid pattern that is compatible with the established basic flavonoid pathway as observed in higher plants. This implies that the flavonoid biosynthesis pathway arose much earlier in evolution compared to what is generally accepted.

Antioxidant Activity of Marine Algal Polyphenolic Compounds: A Mechanistic Approach

“…82 The biosynthesis of flavonoids proceeds through the phenylpropanoid metabolic pathway, whereas the amino acid phenylalanine acts as the precursor in producing 4-coumaroyl-CoA that combines with malonyl-CoA yielding chalcones. 81,83 The stereospecific cyclization of chalcones results in the formation of the general ring structure of flavonoids. 84 Flavonoids are well known for their superoxide and hydroxyl radical scavenging activities both in hydrophilic and lipophilic systems.…”

“…80 Flavonoids are found to be present mainly in land plants, but recent investigations indicate the presence of flavonoids in marine flora. 81 Several flavonol glycosides, including quercetin derivatives, have been identified in the fresh water microalga Hematococcus pluvialis. 81 Flavonol glycosides are compounds where a sugar molecule is bound with the flavonoid group through a glycosidic bond.…”

“…81 Several flavonol glycosides, including quercetin derivatives, have been identified in the fresh water microalga Hematococcus pluvialis. 81 Flavonol glycosides are compounds where a sugar molecule is bound with the flavonoid group through a glycosidic bond. In addition, isoflavones have also been identified from several marine and fresh water algae and cyanobacteria.…”

Chlorella and Spirulina Microalgae as Sources of Functional Foods, Nutraceuticals, and Food Supplements; an Overview

“…The phenolic compounds biosynthesized by Chlorella and Spirulina microalgae were compared [42]. They found that Chlorella microalgae have more content of phoroglucinol, which is used by the pharmaceutical industry -gastrointestinal disorders [43] and also apigenin, which induces autophagy in leukemia cells (Table 2) [44].…”

On plant defense signaling networks and early land plant evolution

“…In streptophyte algae, several homologs, but few orthologs of the genes required for flavonoid biosynthesis were detected [121]. That being said, Goiris et al [154] reported the presence of flavonoids in algae from various lineages, including chlorophytes. A 1969 study by Markham and Porter [155] reported on the presence of flavonoids in the charophyceae Nitella , highlighting the need to further investigate streptophyte algae with regard to the presence of these metabolites.…”