<i>Nigella sativa</i>: A Dietary Supplement as an Immune-Modulator on the Basis of Bioactive Components.

Abstract

Nutrients can be considered as functional foods, which exert physiological benefits on immune system. The seeds of <i>Nigella sativa</i>, which have many active constituents, are mainly used for medicine, food spice, and nutritional supplements in Egypt. Much attention has been paid to <i>N. sativa</i> seeds for their anticancer, antibacterial, anti-inflammatory, and immune properties. However, their active constituents and mechanisms underlying functions from <i>N. sativa</i> seeds is unclear. Thus, the bioactive constituents with immune regulation in <i>N. sativa</i> seeds were systematically studied. A new compound (3-methoxythymol-6-<i>O</i>-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside <b>1</b>) and 11 known compounds (<b>2-12</b>) were separated from the <i>N. sativa</i> seeds by chromatographic methods. Their structures were then elucidated by spectroscopic analysis of MS, UV, IR, ¹H-, and ¹³C-NMR. Furthermore, immunomodulatory effects of those compounds in RAW 264.7 cells were evaluated by phagocytosis, nitric oxide (NO) and cytokine release, related mRNA transcription, and key proteins expression <i>in vitro</i>. Monosaccharide derivatives, Ethyl-α-D-furaarabinose (<b>5</b>), and Ethyl-β-D-fructofuranoside (<b>8</b>) were shown to played bidirectional regulatory roles in immunity and anti-inflammation through the regulation of nuclear factor-κB (NF-κB) signaling pathways. The results showed the active compounds and mechanisms of immune regulation in <i>N. sativa</i>, thus indicating that <i>N. sativa</i> seeds could be used as dietary supplements in immunomodulation.