<i>Rosmarinus officinalis</i> Ethanolic Extracts Rescues BV‐2 Cells via Modulating Inflammation and Redox Balance: Comparative Study With Carnosol and Carnosic Acid

Neuroinflammation generally refers to an inflammatory response within the central nervous system caused by various pathological insults, including infection, trauma, ischemia, and toxins. As the brain's sentinel immune cell, microglia are tasked as the first responders to infection or tissue injury and initiating an inflammatory response. The perennial shrub plant Rosmarinus officinalis L. was reported to possess anti-inflammatory, anticancer, anti-nociceptive, antidiabetic, neuroprotective, and antioxidative properties. The present study aimed to investigate the effects of Rosmarinus officinalis ethanolic extracts on the lipopolysaccharide (LPS)-induced neuroinflammation model of BV-2 cells in comparison to carnosol and carnosic acid, phenolic diterpenes of the plant. Ultrasound-assisted extraction was used to have ethanolic extract of the plant. LPS was used to induce inflammation in BV-2 cells. Tumor necrosis alpha (TNF-α), interleukin 1 beta (IL-1β) secretion, reactive oxygen species (ROS) production, GSH/GSSG ratio, protein carbonyl level, and caspase-3 activity were evaluated. Inflammation induced by LPS was reduced by the ethanolic extract. Both carnosol and carnosic acid decreased the TNF-α and IL-1β levels as well. The ethanolic extract reduced ROS production and protein carbonylation, and increased GSH/GSSG ratio more effectively compared to the effects of carnosol and carnosic acid. Results depicted that caspase-3 activity was reduced by the ethanolic extract and this effect was more pronounced compared to carnosol and carnosic acid. The present study indicates the ethanolic extract of Rosmarinus officinalis rescues BV-2 cells from apoptosis via alleviating inflammation and oxidative stress.