In vitro Effects of Nigella sativa Seeds Extracts on Stimulated Peripheral Blood Mononuclear Cells

Abstract

Nigella sativa, commonly known as black cumin seed, belongs to the botanical family of Ranunculaceae. The active antioxidant components of Nigella sativa display a remarkable array of biochemical, immunological and pharmacological actions, including bronchodilatory, anti-inflammatory, antibacterial, hypoglycaemic, antitumoural and immunopotentiating effects. Effects of Nigella sativa seeds extracts were investigated in freshly isolated human peripheral blood mononuclear cells stimulated with the mitogens phytohaemagglutinin and concanavalin A in vitro. Tryptophan degradation and neopterin production were monitored in culture supernatants, both these immunobiochemical pathways are induced by pro-inflammatory cytokine interferon-γ. Compared to unstimulated cells, the mitogens enhanced degradation of tryptophan and production of neopterin. Nigella sativa seeds extracts significantly suppressed both pathways in a dose-dependent way. Suppression of tryptophan degradation and neopterin formation by Nigella sativa seeds extracts demonstrates an inhibitory influence on activated T-cells and macrophages. Data are in line with an anti-inflammatory activity of the extracts.

Keywords

• nigella sativa
• tryptophan
• kynurenine
• indoleamine (2,3)-dioxygenase
• neopterin