Anti-neuroinflammatory effects of tannic acid against lipopolysaccharide-induced BV2 microglial cells via inhibition of NF-κB activation

Microglia mediated neuroinflammation is known to cause various neurodegenerative and neurological ailments. Tannic acid is a natural polyphenol which has been reported to possess antioxidant, anti-inflammatory, anticarcinogenic, antimutagenic, antitumor, and antimicrobial activities. As there are no reports till date on the anti-neuroinflammatory effects of tannic acid, this study was conducted to analyze the possible mechanism and pathway involved in the prevention of neuroinflammation by tannic acid in BV2 microglial cells. BV2 microglial cells were pretreated with tannic acid (10, 25, and 50 mu M/mL) and induced with lipopolysaccharide (LPS; 1 mu M/mL) to assess the production of reactive oxygen species (ROS), nitric oxide (NO), prostaglandin E2 (PGE2), pro-inflammatory cytokines (IL-6, IL-1 beta, and TNF-alpha), and nuclear factor-kappa B (NF-kappa B) protein expressions through western blotting. The results showed that LPS significantly activated the BV2 cells via toll-like receptor 4 to induce elevated productions of ROS, NO, PGE2, IL-6, and IL-1 beta. However, tannic acid was able to reverse all the neuroinflammatory effects of LPS-induced BV2 cells in a dose-dependent manner. Collectively, the anti-inflammatory effects of tannic acid on LPS-induced BV2 microglial cells are attributed to the inhibition of ROS formation and the suppression of NF-kappa B pathway activation. Tannic acid could be a potential therapeutic agent for the treatment of neurological related disorders.