Oridonin's Antibacterial Effects on A. hydrophila

The effect of subinhibitory concentrations of oridonin on A. hydrophila AS 1.1801 was determined spectrophotometrically using microplate readers (Infinite F50, TECAN, Männedorf, Switzerland). Concisely, overnight cultures of A. hydrophila AS 1.1801 were inoculated into NB broth without or with oridonin at different concentrations (0, 3.125, 6.25, 12.5, 25, 50, 100, and 200 μg/mL) at 28 °C for 26 h (stationary phase) under the condition of shaking at 180 rpm. At each of the time points viz. 0, 2, 4, 6, 8, 10, 12, 24, and 26 h, 200 μL of the oridonin-treated or untreated inoculum was added to a 96-well plate and determined for optical density (OD) at 600 nm. The experiments were repeated three times.