Antioxidant and Anti-Inflammatory Properties of Nigella sativa Oil in Human Pre-Adipocytes

Abstract

The oil obtained from the seeds of <i>Nigella sativa</i> L. (<i>N. sativa</i>), also known as black cumin, is frequently used in the Mediterranean area for its anti-inflammatory, anti-oxidant, and anti-cancer activities. The aim of the present study was to evaluate the antioxidant and anti-inflammatory properties of the oil extracted from seeds of a <i>N. sativa</i> cultivar produced in the Marche region of Italy, and to determine if the thymoquinone content, antioxidant properties, and biological activity would decay during storage. Cytotoxicity and anti-inflammatory properties of <i>N. sativa</i> oil were tested in an in vitro model of low-grade inflammation in Simpson⁻Golabi⁻Behmel syndrome human pre-adipocytes. The fresh extracted oil (FEO) contained 33% more thymoquinone than stored extracted oil (SEO), demonstrating that storage affects its overall quality. In addition, the thymoquinone content in the <i>N. sativa</i> oil from the Marche region cultivar was higher compared with other <i>N. sativa</i> oils produced in the Middle East and in other Mediterranean regions. Pro-inflammatory cytokines (e.g., Interleukin (IL)-1alpha, IL-1beta, IL-6) were differently modulated by fresh and stored extracts from <i>N. sativa</i> oils: FEO, containing more thymoquinone reduced IL-6 levels significantly, while SEO inhibited IL-1beta and had a higher antioxidant activity. Total antioxidant activity, reported as µM of Trolox, was 11.273 ± 0.935 and 6.103 ± 0.446 for SEO and FEO (<i>p</i> = 1.255 × 10^-7), respectively, while mean values of 9.895 ± 0.817 (SEO) and 4.727 ± 0.324 (FEO) were obtained with the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay (<i>p</i> = 2.891 × 10^-14). In conclusion, the oil capacity to counteract proinflammatory cytokine production does not strictly depend on the thymoquinone content, but also on other antioxidant components of the oil.