Can Black Seed Help Fight Obesity?

Can Black Seed Help Fight Obesity?

New research combining laboratory experiments and a human trial shows that black cumin seeds not only downregulate the genes that drive fat cell formation, but also improve cholesterol levels, highlighting their potential as a natural approach to supporting healthier metabolic outcomes.

Study: Black cumin seeds (Nigella sativa) confer antiadipogenic effects in the 3T3-L1 cell model and lipid-lowering properties in humans. Photo credit: Dionisvera/Shutterstock.com

A study inFood Science and Nutritionis investigating the potential of Nigella sativa (black cumin seeds) to treat obesity-related diseases. In vitro and human test results underline the anti-adipogenic and lipid-lowering effects of black cumin extract.

What is Obesity?

Obesity is a chronic disease characterized by excessive accumulation of body fat, which is associated with metabolic disorders such as dyslipidemia and insulin resistance, as well as cardiovascular diseases (e.g., heart attack and stroke). Excess fatty tissue can lead to inflammation and hormonal imbalances, which can negatively impact blood sugar, blood pressure and cholesterol levels.

Adipogenesis is the process by which preadipocytes differentiate into mature adipocytes and plays a crucial role in the development of obesity and its associated complications. Previous studies have shown that transcription factors, including CCAAT/enhancer-binding proteins (C/EBPs) and peroxisome proliferator-activated gamma receptor (PPARγ), regulate adipogenesis and lipid accumulation.

Medicinal Values ​​of Black Cumin Seeds

Nigella sativa, also known as black cumin, belongs to the Ranunculaceae family and is traditionally used medicinally in North Africa, South Asia and the Mediterranean. Black cumin seeds and its oil contain many bioactive compounds including alkaloids, flavonoids and essential oils that contribute to its medicinal properties. Previous studies have identified thymoquinone (TQ) as the main active ingredient responsible for the therapeutic effects of black seed.

Studies in cell cultures and animal models have shown that black cumin has several beneficial properties, including antimicrobial, antioxidant, anti-inflammatory, antidiabetic, immunomodulatory, antihypertensive, antitumor, and antiobesity effects.

Cumin powder and oil showed significant improvement in lipid profiles by lowering low-density lipoprotein (LDL), cholesterol and triglycerides (TG) while increasing high-density lipoprotein cholesterol (HDL-C) levels. Regular consumption of 500 mg to 2 g daily has been associated with beneficial cholesterol modulation in previous studies.

Although previous research has shown that TQ inhibits adipogenesis through pathways such as AMPK and MAPKs, these studies have not yet fully elucidated the molecular mechanisms underlying its antiadipogenic effects.

Test cumin

The current study used the 3T3-L1 cell model to evaluate the antiadipogenic potential of black cumin extract (BSE). The seeds were washed in water, dried and ground into powder using a grinder. The methanolic extraction method with a rotary evaporator was used to obtain BSE.

Phytochemical analyzes of BSE were carried out following a standard protocol. Fourier transform infrared spectroscopy (FTIR) was used to identify the functional groups present in BSE, while gas chromatography (GC) and mass spectrometry (MS) techniques were used to analyze the fatty acid profile.

Cell viability was assessed using neutral red assay, lipid accumulation was assessed using Oil Red O staining, and adipogenic gene expression was assessed using real-time PCR.

In addition, a human randomized controlled trial was conducted to evaluate the lipid-lowering properties of black seed powder by measuring serum cholesterol levels. Participants in the intervention group consumed 5 g of black cumin powder daily for 8 weeks.

Effects of black cumin

Phytochemical analysis of BSE revealed a total phenolic content (TPC) of 35.475 mg GAE/g dry weight (DW) and a total flavonoid content (TFC) of 39.51 mg QE/g DW. FTIR spectra identified functional groups associated with TQ, including C=O stretching of the quinone, C-O stretching or C-H bending of the aromatic ring, and C=C aromatic stretching.

GC-MS analysis of black cumin oil revealed about 23 different fatty acids. The extract was dominated by methyl eicosatrienoate (69.29%), methyl 11,14,17-eicosatrienoate (25.2%) and methyl linoleate (4.05%).

The neutral red assay showed that BSE concentrations up to 250 μg/ml did not cause cytotoxicity in 3T3-L1 preadipocytes. Cell viability remained constant at all BSE concentrations tested, indicating the non-toxicity of the extract. In the current study, 80 μg/ml and 120 μg/ml BSE were selected for further experiments.

Compared to control cells, BSE-treated cells showed reduced lipid accumulation of 10.9% and 40.63% at concentrations of 80 μg/ml and 120 μg/ml, respectively. This finding suggests that BSE may hinder adipocyte differentiation in 3T3-L1 cells. Furthermore, BSE treatment at 80 μg/ml and 120 μg/ml decreased the activity of glycerol-3-phosphate dehydrogenase (GPDH), indicating a decrease in triglyceride levels. The current study highlights the role of black seed in adipogenesis by reducing glycerol production in 3T3-L1 cells.

Quantitative real-time PCR (qRT-PCR) analysis revealed that 3T3-L1 cells treated with BSE for 48 hours showed a significant reduction in mRNA levels of C/EBPα, C/EBPβ and PPARγ compared to the control group. This finding suggests that BSE inhibits adipogenesis by downregulating the expression of these important transcription factors.

The randomized study examined the impact of 8 weeks of black cumin supplementation on participants' appetite and lipid profile. This study included 42 eligible participants (male: 73%; female: 27%), including 22 in the treatment group and 20 in the control group. All participants were at least 18 years old and had a body mass index (BMI) of more than 25.0 kg/m2.

The intervention group showed a significant increase in Council on Nutrition Appetite Questionnaire (CNAQ) scores compared to the control group, suggesting that it does not have a negative effect on appetite but rather indicates a biological appetite-enhancing effect. Black cumin seed supplementation showed no signs of clinical toxicity or other adverse effects. In addition, the test group showed a significant reduction in total cholesterol, LDL-C and TG, as well as an increase in HDL-C.

The future for cumin

The current study highlighted the potential of black seed supplements to improve serum lipid profiles, which may help manage dyslipidemia and reduce cardiovascular risk. However, when interpreting the results, the absence of a placebo in the control group should be taken into account.

Long-term studies with larger samples are required in the future to validate the results. The underlying mechanisms of black cumin seeds' health benefits require further study.

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