Olive leaf extract (OLE) reduces mast cell-mediated allergic inflammation

Area of Science:

• Immunology
• Pharmacology
• Natural Products

Background:

• Mast cell-mediated reactions are central to allergic diseases like asthma and dermatitis.
• Existing antihistaminic drugs face challenges with side effects and resistance, necessitating novel therapeutic strategies.
• Olive leaf extract (OLE) is a natural product with known antioxidant and anti-tumoral properties.

Purpose of the Study:

• To investigate the anti-allergic effects of OLE on human mast cells.
• To elucidate the mechanisms underlying OLE's action in mast cell-mediated inflammation.

Main Methods:

• Human mast cells (HMC-1.2) were activated using phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI).
• OLE's effects on histamine and β-Hexosaminidase release were measured.
• Gene and protein expression of pro-inflammatory cytokines (TNF-α, IL-8, IL-6) were analyzed.
• ROS production, mitochondrial mass, membrane potential, and NF-kB activation were assessed.

Main Results:

• OLE significantly reduced histamine and β-Hexosaminidase release from activated mast cells by modulating calcium signaling.
• OLE suppressed the PMACI-induced gene expression and secretion of TNF-α, IL-6, and IL-8.
• These anti-inflammatory effects were linked to reduced reactive oxygen species (ROS) and altered mitochondrial function.
• OLE's inhibitory action was confirmed to be dependent on the modulation of nuclear factor-kappa B (NF-kB) activation.

Conclusions:

• OLE effectively inhibits mast cell degranulation and the release of pro-inflammatory cytokines.
• OLE acts by modulating calcium signaling, ROS production, mitochondrial function, and NF-kB activation.
• OLE presents a promising therapeutic candidate for managing mast cell-associated allergic disorders.