Black Cumin Seed ( <i>Nigella sativa</i> ) Confers Anti‐Adipogenic Effects in 3T3‐L1 Cellular Model and Lipid‐Lowering Properties in Human Subjects

<i>Nigella sativa</i> (black cumin seed) has traditionally been valued for its medicinal properties. This study explored its potential in addressing obesity-related conditions by assessing its anti-adipogenic and lipid-lowering effects. Black cumin seed extract showed high phenolic (35.48 mg GAE/g DW) and flavonoid (39.51 mg QE/g DW) contents with excellent standard curve linearity (<i>R</i> ² > 0.99). FTIR confirmed thymoquinone-related functional groups, and GC-MS revealed 23 fatty acids, predominantly methyl eicosatrienoate (69.29%), methyl 11,14,17-eicosatrienoate (25.2%), and methyl linoleate (4.05%). These results indicate a rich phytochemical and fatty acid profile. In vitro, 3T3-L1 preadipocytes were treated with a methanolic black cumin seed extract (BSE). Oil red O staining revealed a significant reduction in lipid accumulation, while cell viability assays confirmed no cytotoxicity. Gene expression analysis demonstrated a marked downregulation of key adipogenic transcription factors, including C/EBPα, C/EBPβ, and PPARγ, following BSE treatment. A randomized controlled trial (RCT) further evaluated its effects in humans. Participants in the test group consumed 5 g of black cumin seed powder daily for 8 weeks, while the control group received no supplementation. Appetite levels were monitored using the Council on Nutrition Appetite Questionnaire (CNAQ), with reliability ensured through Cronbach's alpha validation. Serum lipid profiles, including triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and total cholesterol (TC), were assessed pre- and post-intervention. Results indicated that the black cumin seed group exhibited statistically significant reductions in TG, LDL-C, and TC levels, alongside an increase in HDL-C, while the control group showed no notable reductions. Our findings suggest that black cumin seed may offer potential anti-adipogenic and lipid-lowering benefits, contributing to obesity management.