The Effect of the Alcoholic Essence of <i>Laurus nobilis L.</i> on Pro-inflammatoiry Cytokine Gene Expression in Synoviocytes and Macrophage/Monocyte

Abstract

Osteoarthritis (OA) is a chronic degenerative joint disease with an inflammatory component. It is associated with progressive histological alterations and disabling symptoms. Today, drugs such as glucocorticoids (GCs) and nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly employed for the treatment of osteoarthritis but have serious and life-threatening side effects. The current study aims to evaluate the effects of alcoholic essences of <i>Laurus nobilis L.</i> (AELN) on pro-inflammatory cytokines such as cyclooxygenase-2 (COX-2, isoform), inducible nitric oxide synthase (iNOS), interleukin-1β (IL-1β), interleukin-18 (IL-18), tumor necrosis factor-alpha (TNF-α), and nitric oxide (NO), as well as prostaglandin E2 (PGE2) on inflammatory cells, similar osteoarthritis in synoviocytes, and monocytes/ macrophages, and to compare it with dexamethasone (DEX) and ibuprofen (IBP). After collecting the leaves of the <i>Laurus nobilis L.</i> (LN) and after drying, the essences were collected by the Center for Genetic and Biological Resources of Iran. Synovial cells were isolated from the synovial membrane of the radiocarpal joint cartilage of an 8-month-old Holstein cow. THP-1 cells were prepared from the Pasteur Institute of Iran. Cells were cultivated and exposed to lipopolysaccharide (LPS) stimulation without, or in the presence of, DEX, IBP, or alcoholic essences of <i>Laurus nobilis L.</i> (AELN) The gene expressions of IL-1β, TNF-α, IL-18, COX-2, and iNOS were evaluated by real-time PCR. Concentrations of NO and PGE2 were measured by ELISA methods. Treatment of the studied cell with alcoholic essences of Laurus nobilis L, before stimulation with lipopolysaccharide, reduces the expression of proinflammatory cytokine genes such as cyclooxygenase-2, nitric oxide synthase, interleukin-6, interleukin-1 beta, interleukin-18, tumor necrosis factor-alpha, and It also reduces the production of nitric oxide and prostaglandin E2 by almost 50%. This reduction is significant compared to the 90% reduction due to treatment with dexamethasone and ibuprofen. Significant reduction in the expression of pro-inflammatory cytokines by alcoholic essences of Laurus nobilis L can be considered as a new drug in the treatment of osteoarthritis and requires further studies in laboratory animals and clinical studies.