LPS-induced oxidative inflammation and hyperlipidemia in male rats: The protective role of Origanum majorana extract 1

The antimicrobicidal activity of the phenolic compounds in the methanolic extract of Origanum majorana was recommended. The present study aimed to investigate the protective effect of Origanum majorana against LPS-induced toxicity in rats. Forty-eight male Sprague-Dawley rats were randomly divided into four equal groups, with 12 rats each group. Group C was used as control, while group E was treated with plant extract orally for 10 days (0.5 mg/kg/day). Group I was given LPS at a single i.p. dose (10 mg/kg BW) and group E + I was treated with plant extract (0.5 mg/kg/day) for 10 days, followed by a single i.p. dose of LPS (10 mg/kg BW). The WBC count and the number of macrophages in addition to the nitric oxide level in the peritoneal fluid were determined. Also, the lipids profile and the levels of urea and creatinine were detected. In addition, the MDA, glutathione and total proteins, as well as AST and ALT activities, were measured in all groups. The results indicated that the LPS injection caused significant decrease in the WBC count, hepatic glutathione and the total proteins, as well as serum HDL-c. On the other hand, LPS injection showed significant increase in the number of peritoneal macrophages, the levels of nitric oxide and MDA. Moreover, the total lipids, total cholesterol, triglycerides, urea, and creatinine concentrations, as well as AST and ALT activities, were significantly elevated. The pretreatment with Origanum majorana extract prior to LPS antagonized and alleviated its toxic effects in the treated animals. The results indicated that the treatment with Origanum majorana extract alone did not affect the tested parameters, except the number of peritoneal macrophages, which were significantly decreased.