Anti-inflammatory activity and chemical composition of dichloromethane extract from Piper nigrum and P. longum on permanent focal cerebral ischemia injury in rats

White pepper (Piper nigrum L.) and long pepper (Piper longum L.) belong to family Piperaceae and are commonly used as household spices and traditional medicine worldwide, specifically in China and Southeast Asia. In Traditional Chinese Hui Medicine, these herbs are widely used for treatment of stroke. Our present study investigated effects of these herbs on inflammation in rat model with cerebral ischemia. After subjecting the rats to permanent middle cerebral artery occlusion (pMCAO) for 6 h, at doses of 100 and 200 mg/kg, dichloromethane fraction from white pepper and long pepper, respectively, was intragastrically administered once a day for seven consecutive days. Cerebral cortical and hippocampal tissues were collected after seven days. Superoxide dismutase, malonaldehyde, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and IL-6 were measured by spectrophotometer. Phytochemical profile of dichloromethane fraction was determined through HPLC. Dichloromethane fraction exhibited anti-inflammatory activity by suppressing expression or production of IL-1β, IL-6, and TNF-α. By contrast, dichloromethane fraction showed activity against pMCAO injury by reducing oxygen-free radicals through increased superoxide dismutase activity and decreased malonaldehyde level. HPLC analysis revealed piperine as major component of dichloromethane fraction. These results show that dichloromethane fraction provides protection against cerebral ischemia. The possible mechanism is related to anti-inflammatory activity and reduction in oxygen-free radicals.