Dichloromethane

The bioactive extract, previously identified as the delipidated aqueous phase, was obtained as previously described [13 (link)]. Briefly, total biomass obtained from a 500 mL culture in BHI was submitted twice to fractionation with 200 mL n-hexane (Tedia, Fairfield, OH, USA). The hexane solution was then removed under vacuum, and the remaining aqueous residue was extracted twice (200 mL) using the following solvents in this order: dichloromethane, ethyl acetate, and butanol (Tedia, USA). The organic fractions were evaporated and tested for antibiofilm activities. The delipidated aqueous phase was filtered (Millipore 0.22 μm), tested, and named as the aqueous extract.

All solutions and samples were
prepared by using deionized water with a resistivity of 18.2 Ω
cm^–1 from a Millipore Milli-Q water purification
system (Millipore). Gluten from wheat was purchase from Sigma-Aldrich.
1,2-Dimethyl imidazole (98%), 1-fuloro pentane, methanol (99%), propanol
(99%), pentanol (99%), heptanol (98%), nonanol (98%), and dodecanol
(98%) were purchased from ACOS; dichloromethane (99%) was purchased
from Tedia (98% purity); acetonitrile (99%), ether (99%), fetal bovine
serum (FBS), Gluten from wheat, methanesulfonic acid (99), methane
sulfonic chloride (99%), thionyl chloride (98%), silver nitride (95%),
silver dihydrogen phosphate (99%), and silver bisulfate (99%) were
purchased from Sigma-Aldrich; antigliadin mouse IgG 2F (1 mg/mL) was
purchased from Antaimmu; antigliadin human IgA 3B7 (1 mg/mL) and a
gliadin solution (1 mg/mL) were purchased from Leadgene; HRP was present
in the MagicLink HRP antibody conjugation kit; 3,3′,5,5′-tetramethylbenzidine
(TMB) and hydrogen peroxide (H₂O₂) reagent were
purchased from TCI; and the Wheat/Gluten (Gliadin) ELISA kit was purchased
from Crystal Chem (AOAC no. 011804). DEMD and XTT reagents were purchased
from Thermo Fisher.
IL synthesis is given in the Supporting Information, and the product yield
is given in Table S1.

The compounds viz., catechin, epicatechin, gallocatechin, epigallocatechin, epigallocatechin gallate, epicatechin gallate, and procyanidin B2 were obtained from Sigma (St Louis, MO, USA). Cyanidin chloride and delphinidin chloride were purchased from Axxora Co. Ltd. (Lausanne, Switzerland). Benzyl mercaptan was obtained from Aladdin (Shanghai, China). HPLC grade methanol, acetonitrile, chloroform, dichloromethane, ethyl acetate, n-hexane, n-butanol, and acetic acid were procured from Tedia Co. Ltd. (Fairfield, OH, USA). The following materials and equipment were used for separation and chromatography: Sephadex LH-20 (GE Healthcare, Sweden); silica GF254 TLC sheet (5 × 20 cm; HeFei BoMei Biotechnology Co., Hefei, China); ordinary-phase silica gel column (silica gel H, 200–300 mesh; Anhui Liangchen Silicon Material Co. Ltd., Huoshan, China); and a Varian Prostar HPLC instrument, Model 325 (Varian, Mulgrave, Australia). ¹H-NMR and ¹³C-NMR spectra were obtained on an AVANCE AV 400 (400/100 MHz) spectrometer (Bruker, Fallanden, Switzerland). ¹³C-NMR spectra were recorded at 150 MHz in acetone-d6/D2O mixture using a Varian Mercury-600 spectrometer (USA).