Reactive oxygen species, including superoxide radicals (O
2
•-), hydrogen peroxide (H
2O
2) and hydroxyl radicals (OH
•) are generated as byproducts of normal metabolism [
1,
2]. Cumulative oxidative damage leads to numerous diseases and disorders [
3]. The enhanced production of free radicals and oxidative stress can also be induced by a variety of factors such as radiation or exposure to heavy metals and xenobiotics (e.g., carbon tetrachloride) [
4]. Carbon tetrachloride (CCl
4) intoxication in animals is an experimental model that mimics oxidative stress in many pathophysiological situations [
5]. CCl
4 intoxication in various studies has demonstrated that CCl
4 causes free radical generation in many tissues such as liver, kidney, heart, lung, brain and blood [
6]. The toxicity of CCl
4 probably depends on formation of the trichloromethyl radical (CCl
3
•), which in the presence of oxygen interacts with it to form the more toxic trichloromethyl peroxyl radical (CCl
3O
2
•) [
7]. Studies also showed that various herbal extracts could protect organs against CCl
4 induced oxidative stress by altering the levels of increased lipid peroxidation and enhancing the decreased activities of antioxidant enzymes, like superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) as well as enhanced the decreased level of the reduced glutathione (GSH) [
8]. In the modern medicine, plants occupy a significant berth as raw materials for some important drug preparations [
9].
Podophyllum hexandrum (PH) has been extensively exploited in traditional Ayurvedic system of medicine for treatment of a number of ailments like Condyloma acuminata, Taenia capitis, monocytoid leukemia, Hodgkins disease, non-Hodgkin's Lymphoma, cancer of brain, lung, bladder and venereal warts [
10]. PH is reported to contain a number of compounds with significant pharmacological properties, e.g. epipodophyllotoxin, podophyllotoxone, 4-methylpodophyllotoxin, aryltetrahydronaphthalene lignans, flavonoids such as quercetin, quercetin-3-glycoside, 4-demethylpodophyllotoxin glycoside, podophyllotoxinglycoside, kaempferol and kaempferol-3-glucoside [
11,
12]. In this particular study, protective role of aqueous extract of the
Podophyllum hexandrum was evaluated against free radical mediated damages under
in vitro and
in vivo situations.
In vitro assays were carried on superoxide radical scavenging activity and hydrogen peroxide radical scavenging activity. Here, kidney and lung toxicity was induced by administering a single dose of CCl
4 into experimental adult male albino rats and radical scavenging activity of the extract was evaluated by measuring the levels of GSH and extent of lipid peroxidation in kidney and lung tissue homogenates and activity of antioxidant enzymes via SOD, GP
X, GR and GST. In addition, study on the effect of a known antioxidant, vitamin E, was also included against CCl
4 induced kidney and lung oxidative stress. The major aim of the present study was to examine the protective mechanisms of aqueous extract of PH in kidney and lung tissues in carbon tetrachloride intoxicated rats.