*2.1. Chemicals and Reagents*

2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ) was from Sigma/Aldrich (St. Louis, MO, USA). Gallic acid was from Energy Chemical (Shanghai, China). Dimethyl sulfoxide (DMSO) was from Beyotime (Shanghai, China), Folin–Ciocalteu reagent was from Macklin (Shanghai, China), 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (trolox) was from Fluka Chemika AG (Buchs, Switzerland). Hydrochloric acid, iron (III) chloride hexahydrate and Iron (II) sulfate heptahydrate were from Sinopharm Chemical Reagent (Shanghai, China), acetic acid and sodium acetate were from Molbase (Shanghai, China). Potassium persulphate and ethanol were obtained from Titanchem (Shanghai, China). Sodium carbonate and methanol were purchased from J&K (Beijing, China). Luria Bertani (LB) broth, agar bacteriological, and Mueller–Hinton (MH) broth were purchased from Oxiod (Basingstoke, England). Antibiotics, including ampicillin, cefazolin, ciprofloxacin, clindamycin, erythromycin, gentamicin, oxacillin, penicillin, streptomycin, sulfisoxazole, and tetracycline were purchased from Meilune (Dalian, China). All chemicals used in the experiment were of analytical grade.
