Rats were pretreated with beta-amyrin (5 and 10 mg/kg, p. o.), two hours before the induction of periodontal inflammation.

The L1 larvae of wild-type N2 nematodes were pretreated with EtOH (0.1%, solvent control) or β‐amyrin (5 μM) for 72 h at 20 °C and incubated under dark conditions as described in the antioxidant activity assays. The adult nematodes were then washed with S-basal medium 3 times. The cell-permeable dye (i.e., non-fluorescent 2′,7′-dichlorodihydrofluoroscein diacetate H2DCFDA) interacts with intracellular esterases and H2O2 to form detectable fluorescent 2′7′-dichlorofluorescein (DCF) this was used to measure the ROS level in this assay. Fifty randomly selected worms from each treatment were transferred into wells of a black 96-well plate and labeled by 100-μM H2DCFDA in 200 μl of M9 for 2.5 h at 20 °C under dark conditions. The fluorescence levels were measured by a fluorescence plate reader FlexStationTM III (Molecular Devices, CA, US) at excitation (485 nm) and emission (520 nm) wavelengths at room temperature.