Juglone

15-LOX (lipoxygenase), α-glucosidase, DPPH (2,2-diphenyl-1-picrylhydrazyl radical), bovine serum albumin (BSA), trichloroacetic acid (TCA), methylglyoxal (MGO) and D-glucose were purchased from Merck, (Dorset, UK), and Oxoid (Hampshire, UK), whereas NaN₃ was purchased from DaeJung (Siheung-si, Korea). Chemical for Gel analysis including Coomassie blue, Tris–HCl, sodium dodecyl sulphate, 2-mercaptoethanol, Glycerine, bromophenol blue were purchased from Sigma Aldrich, St. Louis, MO, USA. The standard compounds included aminoguanidine (≥98.5%, Sigma Aldrich, St. Louis, MO USA), eugenol (≥99%, Fluka, Riedstr, Germany), 2-phenylethylisothiocyanate (>99%, Sigma Aldrich, St. Louis, MO, USA), juglone (≥98.5%, Santa Cruz Biotechnology, Santa Cruz, CA, USA), quercetin (≥99%, Sigma Aldrich, St. Louis, MO, USA), quercitrin (≥85%, Sigma Aldrich, St. Louis, MO, USA), trans-caryophyllene (≥98.5%, Fluka, , Riedstr, Germany), α-humulene (>98%, Extrasynthese, Genay, France), caryophyllene-oxide (≥99%, Fluka Honeywell, Seelze, Germany) and apigenin (≥95.5% Sigma Aldrich, St. Louis, MO, USA) (structures are shown in the Supplementary Materials).

The bacteria isolated from dental plaques were identified as Staphylococcus epidermidis and Staphylococcus aureus (Specimen deposited in Pakistan culture bank), whereas the commercial strains used during investigation included Staphylococcus aureus (ATCC 33862), Chromobacterium violaceum (DSM 30191) and Pseudomonas aeruginosa (ATCC 15442). The bacterial growth media used included, Tryptic Soya Broth (TSB), nutrient agar (Hi Media, India) Luria-Bertani Broth (LB) (Oxoid). The standard compounds were purchased commercially, including juglone (Santa Cruz Biotechnology, Santa Cruz, CA, USA), eugenol (Fluka Honeywell, Seelze, Germany), quercetin (Sigma Aldrich, St. Louis, MO, USA), trans-caryophyllene (Fluka Honeywell, Seelze, Germany), ciprofloxacin (Sigma Aldrich, St. Louis, MO, USA) and azithromycin (Sigma Aldrich, St. Louis, MO, USA), quercitrin (Sigma Aldrich, Steinheim, Germany), 2-phenylisothiocyanate (Sigma Aldrich, Steinheim, Germany), α-humulene (Extrasynthese, Genay, France), caryophyllene-oxide (Fluka Honeywell, Seelze, Germany) and apigenin (Sigma Aldrich, Steinheim, Germany).