Animal model and study protocol
The experiment was carried out with 48 male Wistar rats
(5
±
0.5 months and body weight 150
±
20 g). They were
housed in a temperature controlled room (25
±
5 C) with
12-h light–dark cycles for at least 1 week. After the stabilization
period of one week, the rats were randomly divided into
eight groups, containing six animals each. Onion extracts and
flavonoids (catechin and quercetin) were administered by gavage
for 30 days. Flavonoids under certain reaction conditions, can
display prooxidant activity, thus, we selected optimal dosages
for the flavonoid treatments as reported in previous studies
[8]. Group I: Control, receiving no treatment/supplementation.
Group II: Onion extract treated group (1 mL/100 g bw/day) for
30 days. Group III: Quercetin-only group, quercetin was dissolved
in 0.5% DMSO and rats were treated per day via gavage
(20 mg/kg bw) for 30 days. Group IV: Catechin-only group, catechin
was dissolved in 0.5% DMSO and rats were treated per day
via gavage (20 mg/kg bw) for 30 days. Group V (negative control):
Rats were injected intra peritonealy HgCl2 5 mg/kg body
weight in 0.9% NaCl [9]. Group VI: Onion extract plus HgCl2
treated group, onion extract (1 mL/100 g bw/day) was given via
gavage 10 days before HgCl2 injection and onion extract continued
for next 30 days. Group VII: Quercetin plus HgCl2 treated
group, quercetin dissolved in 0.5% DMSO (20 mg/kg bw per
day) was given via gavage 10 days before HgCl2 injection and
quercetin continued up to next 30 days. Group VIII: Catechin
plus HgCl2treated group, catechin dissolved in 0.5% DMSO
(20 mg/kg bw•
d) was given via gavage 10 days before HgCl2
injection and catechin continued up to 30 days.
2.4. Collection of blood, isolation of red blood cells