Gallic acid

L-Proline (>85%), ninhydrin, choline chloride, and (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox) were purchased from Acros Organics (Geel, Germany). Lactic acid was acquired from Panreac (Barcelona, Spain), and gallic acid, Folin–Ciocalteu (F-C) reagent, and sodium carbonate from VWR (Leuven, Belgium). Sodium hydroxide (NaOH), ascorbic acid, potassium iodide, and acetic acid were supplied by Merck (Darmstadt, Germany). Trichloroacetic acid (TCA), 2-thiobarbituric acid (TBA), hydrogen peroxide (H₂O₂), L-Proline (≥99%), indole-3-acetic acid, toluene, Bradford reagent, glucose, shikimic acid, periodic acid, cinnamic acid, Bovine Serum Albumin (BSA), luteolin, protocatechuic acid, and epigallocatechin gallate, HPLC-MS-grade water, HPLC-MS grade acetonitrile, and formic acid were purchased from Sigma–Aldrich (Steinheim, Germany). Quercetin and rosmarinic acid were acquired from Extrasynthese (Genay, France). Catechin, caffeic, and ρ-coumaric acids were supplied by AASC Ltd. (Southhampton, UK). Phenol, glycine, sulfuric acid, 6-benzyladenine were acquired from Fluka (Buchs, Switzerland), and L-phenylalanine was obtained from Fisher Scientific (Leicestershire, UK).

Lignified biomass of S. ramosissima cultivated in an open greenhouse by seawater irrigation by Riasearch, Portugal (40.73835,-8.66183) in October 2019 was used. The biomass used for Soxhlet extraction was rinsed to remove impurities, dried at room temperature, shredded by an agricultural straw shredder (AM55, Agerskov, Denmark) to <2 cm, and washed using a bath of water at room temperature to remove salts. Biomass used for DSCE was washed with water, dried at room temperature, and ground using a knife mill. Biomass was stored dry and dark at room temperature. Dry matter (DM) content was determined by drying the biomass at 105 °C.
The analytical grade chemicals used for the isolation of polyphenols and analysis were ethyl acetate (EtOAc), n-butanol (n-BuOH), ethanol (EtOH), methanol, sulfuric acid, hydrochloric acid (HCl), sodium carbonate, hexane, gallic acid, Folin–Ciocalteu reagent (VWR, Søborg, Denmark), and ultrapure water produced from the Synergy Water Purification System (Merck KgaA, Darmstadt, Germany). Chemicals of LC-MS grade for calibration of the UPLC-TQMS were acetonitrile (VWR, Leuven, Belgium); methanol (Chem-Lab, Zedelgem, Belgium); and formic acid, ammonium formate (Merck KgaA, Darmstadt, Germany). The standard compounds used for the calibration of the UPLC-TQMS were purchased from Sigma-Aldrich (Merck KgaA, Darmstadt, Germany).

All reagents and standards that were used in chemical assays were American Chemical Society (ACS) grade. Folin–Ciocalteu phenol reagent, DPPH (2,2-Diphenyl-1-picrylhydrazyl), gallic acid (3,4,5-Trihydroxybenzoic acid), trolox (6-Hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), sodium carbonate monohydrate, ACS grade solvents hexane, methanol, and hydrochloric acid, as well as HPLC grade acetic acid and acetonitrile, were purchased from VWR International (Radnor, PA, USA), while ethanol (95% v/v) was supplied by Louisiana State University Stores (Baton Rouge, LA, USA).

Magnesium nitrate hexahydrate (Mg(NO₃)₂·6H₂O), aluminum nitrate nonahydrate
(Al(NO₃)₃·9H₂O), ammonium solution
(23%), gallic acid (GA), sodium chloride (NaCl), sodium acetate (C₂H₃NaO₂), 2,2-diphenyl-1-picrylhydrazyl
(DPPH), ethanol (99%), copper chloride dihydrate (CuCl₂·2H₂O), neocuproine (Nc), and acetic acid (99%) were
purchased from VWR in analytical grade. The reduced form of nicotinamide
adenine dinucleotide (NADH) and the oxidized form of nicotinamide
adenine dinucleotide (NAD) were obtained from Sigma-Aldrich and were
analytical grade. Ultrapure water was produced with an Adrona B30
purification system.