Figure 2.

Spin trapping study of superoxide scavenging by mastic gum. (A) ESR spectrum of EMPO (60 mM) with xanthine (50 μM) and xanthine oxidase (20 mU/ml); (B) ESR spectrum of (A) plus 10 μg/ml mastic gum; (C) ESR spectrum of (A) plus 20 μg/ml mastic gum; (D) ESR spectrum of (A) plus 200 μg/ml mastic gum; (E) ESR spectrum of (A) plus 50 U/ml Cu, Zn-SOD. Computer simulation of ESR spectra (hyperfine coupling constants a^N = 13.3 G, a^H_β = 10.8 G, a^H_γ = 1.1 G) [41] and inhibition by SOD (E) confirmed detection of EMPO/*OOH radical adduct. ESR settings were as described in Materials and Methods.