Aluminium chloride hexahydrate

Cadmium oxide (99.5%, powder), 2-ethylhexanoic acid (2-EHA, 99%), 1-octadecene (ODE, technical grade, 90%), oleylamine (OLA, technical grade, 70%), hexadecylamine (technical grade, 90%), trioctylamine (98%), trioctylphisphine (TOP, technical grade, 97%), selenium powder (powder, 100 mesh, 99.5%), zinc oxide (puriss, 99–100%), thiourea (TU, ACS Reagent,>99%), triethylene glycol dimethyl ether (TEGDME, 99%), hexadecylamine (technical grade, 90%), palmitic acid (BioXtra, ≥99%) zinc acetate dihydrate (ACS reagent, ≥99.0%), magnesium acetate tetrahydrate (ACS reagent, ≥98%), aluminium chloride hexahydrate (99%), gallium nitrate hydrate (99.9%), lithium chloride (anhydrous, ACS reagent, ≥99%), tetramethylammonium chloride (TMACl, reagent grade, ≥98%), potassium hydroxide (reagent grade, 90%), dimethyl sulfoxide (DMSO, anhydrous, ≥99.9%), and monoethanolamine (MEA, ACS reagent, ≥99.0%) were purchased from Sigma-Aldrich. n-Hexadecylphosphonic acid (97%) was from PlasmaChem GmbH. Methyl acetate (extra pure, 99%) was from Acros. Hexane, n-octane, toluene, acetone, methanol, ethanol, n-butanol, and isopropyl alcohol of spectroscopy grade were purchased from the local supplier Ekos-1. All reagents were used as received, without purification.

Ultrapure water and ethanol absolute pro analysis were used for the preparation of all solutions and leaves extracts. Trolox ((±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid), 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) diammonium salt, sodium carbonate decahydrate, sodium nitrite, sodium hydroxide and gallic acid were obtained from Fluka (Buchs, Switzerland). Folin-Ciocalteu reagent, (+)-catechin hydrate, sodium acetate trihydrate, aluminium chloride hexahydrate, and potassium persulfate were obtained from Sigma-Aldrich (St. Louis, MO, USA). The total phenolic content (TPC) determination involved the preparation of 3:10 (v/v) in water of Folin-Ciocalteu reagent, 24.3% (w/v) of Na₂CO₃·10 H₂O and a stock solution of 100 mg∙L⁻¹ of gallic acid. The total flavonoid content (TFC) determination involved the preparation of 6 g∙L⁻¹ NaNO_2, 0.8 M NaOH, and 22 g∙L⁻¹ AlCl₃ · 6 H₂0 solutions as well as a stock solution of 250 mg∙L⁻¹ of (+)-catechin prepared daily. For the total antioxidant capacity (TAC) determination, an ABTS^●+ radical solution was prepared daily with equal volumes of 14 mM of ABTS stock solution and 7 mM of potassium persulfate and kept for 12–16 h before being used at dark conditions and a stock solution of 1.0 mM of Trolox.

Most of the chemicals used for extraction and characterization were analytical grade and purchased from Sigma-Aldrich (Castle Hill, NSW, Australia). The standards for antioxidant assays included gallic acid, quercetin, catechin and L-ascorbic acid, which were purchased from Sigma-Aldrich (St. Louis, MO, USA). For antioxidant assays, Folin and Ciocalteu’s phenol, aluminium chloride hexahydrate, vanillin, 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric (III) chloride anhydrous, 2,4,6-tripyridyl-s-triazine (TPTZ), potassium persulfate and 2,2′-azino-bis(3-ethylbenz-thiazoline-6-sulphonate) (ABTS) were purchased from Sigma-Aldrich (St. Louis, MO, USA) and sodium carbonate anhydrous (chem-supply; Gillman, SA, Australia), sodium acetate hydrated (Ajax Finechem, Scoreby, VIC, Australia) and sulfuric acid 98% were purchased from RCI Labscan Limited, (Bangkok, Thailand). The HPLC grade methanol was purchased from Fisher Chemical Company (San Jose, CA, USA). The mobile phases for LC-ESI-QTOF/MS and HPLC were mainly comprised of 50% acetic acid solution (Sigma-Aldrich, St. Louis, MO, USA) and acetonitrile (LiChrosolv, Darmstadt, Germany). The reference standards including protocatechuic acid, catechin, 4-hydroxybenzoic acid, chlorogenic acid, quercetin 3-O-glucoside, kaempferol 3-O-glucoside and quercetin were purchased from Sigma-Aldrich (St. Louis, MO, USA).