Aluminum nitrate

Instruments including UV-1801 UV-Vis Spectrophotometer (Beijing Ruili Analytical Instrument Co., Ltd.); SB5200DTD Ultrasonic Cleaner (Ningbo Xinzhi Biotechnology Co., Ltd.); CP214 Electronic Balance (Ohaus Instrument Co., Ltd.); and Ultrapure Water Meter (South Korea) Human Company) were used in this study. Diosgenin (batch number: 111539–202102, purity: 98.7%), D-anhydroglucose reference substance (batch number 110833–201908, mass fraction: 99.8%) were all purchased from China Food and Drug Administration Research Institute. Rutin (batch number: B20771, purity: ≥98%), gallic acid (batch number: B20851, purity: ≥98%) were purchased from Shanghai Yuanye Biotechnology Co., Ltd. Folin phenol reagent, and amino acid mixed reference substances were purchased from Sigma reagent company (Sigma-Aldrich). Methanol, ethanol, anhydrous glucose, dimethyl sulfoxide, anthrone, sulfuric acid, sodium nitrite, aluminum nitrate, sodium hydroxide, n-butanol, vanillin, and glacial acetic acid were all analytical grades and purchased from Shanghai Sinopharm Chemical Reagent Co., Ltd.

Isoorientin (luteolin-6-C-glucoside, IsoO), orientin (luteolin-8-C-glucoside, Or), rutin (Quercetin-3-o-rhamnosylglucoside, Rut), isoquercitrin (Quercetin-3-o-glucoside, IsoQ), kaempferol-3-0-rutinoside (Km3rut), quercetin (Qu), and apigenin (Ap) were purchased from the National Institute for the Control of Pharmaceutical and Biological Products, Beijing, China. Astragalin (kaempferol-3-0- glucoside, Ast) and kaempferol (Km) were obtained from Yuanye Biological Technology Co., Ltd. (Shanghai, China). Analytical grade anhydrous diethyl ether, ethyl acetate, petroleum ether, methanol, ethanol, aluminum nitrate, sodium hydroxide, sodium nitrite, formic acid, concentrated sulfuric acid, iron (III) chloride hexahydrate, glucose, and β-sitosterol (analytical grade) were purchased from Sinopharm Chemical Reagent Co., Ltd. Shanghai, China. HPLC-grade acetonitrile and methanol were purchased from Tedia Company, Inc. USA.
Individual flavonoids were dissolved in different amounts of acetone (HPLC grade) to generate a set of standard stock solutions: 2.0, 0.8, 3.0, 2.8, 3.1, 3.5, 0.8, 1.3, and 1.8 mg/mL, and each solution was progressively diluted into eight different concentration gradients. All solutions were stored at 4°C prior to UPLC analysis.

Cotton flowers came from the CAAS Cotton Research Institute, Wang Jiang city planting base, Anhui Province. Cotton flowers were divided into two parts by different pretreatment methods: one was treated with liquid nitrogen (LNT) and ground into powder. The other treatment was dried for 3 h at 60 °C before being ground into powder (DT). All powder was stored in a −80 °C freezer before the further experiment. Anhydrous ethanol, 70% ethanol, DPPH (Synonyms:2,2-Diphenyl-1-picrylhydrazyl), Aluminum nitrate, Sodium hydroxide, Hydrogen peroxide, Trichloroacetic acid, Ferrous sulfate, Phosphoric acid buffer, and Salicylic acid, were all from Sinopharm Group.

Standard reagent sodium hypochlorite (NaClO, 50 mL 0.10 M) was purchased from Beijing Putian Genesis Biotechnology Co., Ltd. (Beijing, China) Tetrachloroauricacid hydrate (HAuCl₄·4H₂O), ascorbic acid (AA), sodium borohydride (NaBH₄), silver nitrate (AgNO₃), hexadecyltrimethylammoniumbromide (CTAB), ferric chloride hexahydrate, calcium chloride, magnesium sulfate, copper sulphate, aluminum nitrate, zinc nitrate, cobalt chloride, hydrochloric acid, nitric acid were purchased from Sinopharm Chemical Reagent Co. Ltd. (Shanghai, China).
All reagents were analytical grade and without further purification. Ultrapure water was prepared with a Milli-Q water purification system (Millipore, Bedford, MA, USA).