Nutrient agar broth

The de Man, Rogosa and Sharpe (MRS) agar/broth, glycerol (Analytical grade), nutrient agar/broth, Vogel’s agar/broth, ethyl acetate (HPLC grade), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2-oxopropanoic acid (pyruvic acid), 2-hydroxypropane-1,2,3-tricarboxylic acid (citric acid), 2-hydroxybutanedioic acid (malic acid), 2-hydroxypropanoic acid (malonic acid), propanedioic acid (lactic acid), butanedioic acid (succinic acid), β-carotene, sodium benzoate, potassium sorbate and sodium acetate were mainly purchased from Sigma-Aldrich, St. Louis, MO, USA. Maize grains (FMC Variety C-7065) were collected from a grain market in Faisalabad, Pakistan.

PrestoBlue® was purchased from Life Technologies (Johannesburg, South Africa). The University of Cape Town (South Africa) donated the spontaneously immortalized human keratinocyte (HaCat) cell line. Strains of S. aureus (ATCC 6538 and ATCC 25293) and P. aeruginosa (ATCC 9027) were obtained from Anatech Analytical Technology (Johannesburg, South Africa). Cell culture reagents, including Dulbecco’s Modified Eagle Medium (DMEM), trypsin-EDTA (0.25%), fetal bovine serum (FBS), phosphate buffer saline (PBS), and antimicrobials, such as penicillin, streptomycin and amphotericin B, were supplied by ThermoFisher Scientific (Johannesburg, South Africa). Sterile cell culture flasks and multi-well plates were purchased from Lasec South Africa (Pty) Ltd. (Midrand, South Africa). Sodium nitroprusside, Nutrient Agar/Broth, Tryptic Soy Agar/Broth, vancomycin (purity ≥90%), ciprofloxacin (purity ≥98%), actinomycin D (purity ≥95%), ascorbic acid (purity >98%), Griess-Ilosvay’s nitrite reagent, HPLC-grade methanol, galangin (purity ≥99%) and all other chemicals and reagents were acquired from Sigma Chemicals Co. (St. Louis, MO, United States ). The LEGENDPlex™ Growth Factor Panel Flow cytometry Kit was supplied by Biocom Biotech (Pty) Ltd. (Centurion, South Africa).

Chemicals, culture media and HPLC grade organic solvents used in this study [ethyl acetate, chloroform, methanol, dimethyl sulfoxide (DMSO), Ethanol], crystal violet, de Man, Rogosa & Sharpe (MRS) agar/broth and nutrient agar/broth were mainly purchased from Sigma-Aldrich, USA. Moreover, Silica gel (70–230 mesh size) and thin-layer chromatography (TLC) Silica gel 60 F₂₅₄, aluminium sheet (20 x 20 cm²) were purchased from Merck, Darmstadt, Germany.