Piperine relieves neuropathic pain induced by paclitaxel in mice.

Piperine is an amide alkaloid isolated from the black pepper plant. This study examined the pain‑relieving activity of piperine against paclitaxel (PTX)‑induced neuropathy. Male mice were divided into 6 groups: Sham‑operated group (remained intact), PTX group (PTX‑treated mice receiving normal saline), PTX+ piperine 10, 25, and 50 mg/kg groups (PTX‑treated mice receiving piperine) and positive control group (PTX‑treated mice receiving imipramine 10 mg/kg). Neuropathic pain was induced by PTX 2 mg/kg/day on days 1, 3, 5 and 7. On day 7, behavioral tests were conducted and serum levels of interleukin‑6 (IL‑6), tumor necrosis factor‑alpha (TNF‑α), malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) were assayed. PTX produced significant thermal hyperalgesia compared to the sham group. Piperine at all doses alleviated neuropathic pain, and significantly decreased IL‑6, TNF‑α, and MDA, but induced CAT and SOD activities compared to the control group. Piperine could confer beneficial effects against neuropathic pain, at least partially, via reduction of inflammatory and oxidative stress markers.