Isolation and Identification of Flavonoids Found in <i>Zostera marina</i> Collected in Norwegian Coastal Waters

Abstract

In extracts of the seagrass Zostera marina, collected in coastal waters of West-Norway, fourteen different flavones and high amounts of rosmarinic acid were identified. Five of the flavones were found to be sulphated, among these were luteolin 7,3'-disulphate and chrysoeriol 7-sulphate structures previously not published with complete NMR assignments. Luteolin 7-O-β-(6''-malonyl) glucoside, and two other malonylated flavone compounds occurring in trace amounts, were identified for the first time in Z. marina. The sulphated flavones were fairly stable in slightly acidified (0.1% trifluoroacetic acid) extracts stored for months, however, under more acidic conditions (0.5% trifluoroacetic acid in the extracts) they were susceptible to undergo hydrolyses. When the solvents of purified fractions were removed by rotary evaporation, the sulphated flavones quickly decomposed to their corresponding aglycones due to the increased acid concentrations.

Sulphated Flavonoids: Biosynthesis, Structures, and Biological Activities

“…Thus, this uptake usually requires active transporters in roots, phloem, tonoplast and plastid to ensure the S uptake and distribution. The transporters have been shown to play a key role to maintain the homeostasis of S and derived compounds [ 16 , 17 , 18 ].…”

“…Enerstvedt et al (2016) investigated the stability of sulphated flavonoids from Zostera marina extract, showing that the compounds presented good stability in solutions containing 0.1 to 1.0% formic acid and in 0.1% trifluoroacetic acid (TFA). However, in the extract containing 0.5% TFA, the sulphated flavones suffered acid hydrolysis decomposing to their corresponding aglycones [ 17 ].…”

Chemical Analysis of Selected Seaweeds and Seagrass from the Adriatic Coast of Montenegro

“…According to published data of Enerstvedt et al . : ‘UV absorption spectra of luteolin 7‐sulfate and luteolin are relative similar, whilst the significant hypsochromic shift in the UV max of luteolin 7,3′‐disulfate, is strongly indicating the presence of a sulfate group in the 3′‐ or 4′‐position on the B‐ring. Introducing a sulfate group to the flavonoid A‐ring does not influence the UV absorption significantly, but sulfation in the 3′‐ or 4′‐position on the B‐ring will cause a large hypsochromic shift in band I.…”

“…There is an increasing evidence that flavonoid sulfates increase the physiological survival of seagrasses in marine environment . Sulfated flavonoids are reported to be involved in plant growth regulation, and their presence in marine plants represents an ecological adaptation to the saline environment …”

Characterization of Polyphenolic Content in the Aquatic Plants Ruppia cirrhosa and Ruppia maritima —A Source of Nutritional Natural Products

“…On the other hand, marine angiosperms, such as seagrasses, are known for their content of secondary metabolites [ 2 , 3 ]; however, these are very little exploited to find commercially valuable natural products. A few seagrass species, especially of the genus Zostera , Halophila , Posidonia , Thalassia and Syringodium , have been investigated for their content of phenolics and flavonoids [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ].…”