Table 3. DPPH radical scavenging activity of grapefruit seed extract.

Samples	DPPH radical scavenging activity (%)	IC50 (μg/mL)
0.1251)	9.85±0.4004)c5)
0.25	37.50±1.13b	333.33±14.12a
0.5	70.83±2.47a
BHT2)		98.52±2.44b
BHA3)		92.01±4.88b
Vitamin C		58.24±3.28c

¹⁾Grapefruit seed extract: 0.125 ppm (0.125 mg/mL), 0.25 ppm (0.25 mg/mL), and 0.5 ppm (0.5 mg/mL).

²⁾BHT: Butylated hydroxytoluene.

³⁾BHA: Butylated hydroxyanisole.

⁴⁾All values are expressed as mean±SE of triplicate determinations.

⁵⁾Different superscript letters indicate significant differences at p<0.05 by Duncan's multiple range test.