Table 4.

Nitric oxide radical scavenging activity of ursolic acid and thujone.

Concentration (µg/mL)	Nitric oxide radical scavenging activity (% of inhibition)∗
	Ursolic acid	Thujone	Ascorbic acid	BHA
20	|21.70 ± 0.25a	14.25 ± 0.88a	28.80 ± 1.21a	30.26 ± 0.66a
40	32.86 ± 0.32b	29.61 ± 0.66b	54.53 ± 0.91b	41.23 ± 1.54b
60	40.16 ± 0.34c	39.55 ± 2.16c	65.79 ± 0.96c	53.58 ± 0.67c
80	59.49 ± 0.18d	51.24 ± 0.51d	79.39 ± 1.22d	65.35 ± 1.54d
100	70.50 ± 0.39e	74.12 ± 0.66e	94.15 ± 1.13e	87.28 ± 0.38e

^∗The values are mean of triplicates with (±) standard deviation (mean ± S.D; n = 3). Different superscript letters (a–e) in column within treatments indicates significant differences (at p < 0.05) when subject to Tukey's multiple comparison test.