Named Bioactive Compounds · Compound
Thymoquinone
Moderate Evidencequinone
Hermetica Superfood Encyclopedia
Thymoquinone is the primary bioactive quinone compound found in Nigella sativa (black seed) that demonstrates anti-inflammatory and nephroprotective effects. It works primarily by inhibiting the NF-κB signaling pathway and reducing inflammatory cytokines like IL-8 and IgE.
Thymoquinone (TQ; 2-isopropyl-5-methyl-1,4-benzoquinone) is a monoterpenoid quinone and the primary bioactive compound in Nigella sativa L. (black cumin) seeds, constituting 30-48% of the essential oil. It is isolated via steam distillation or supercritical CO2 extraction and standardized in supplements to 2-5% in black cumin seed oil formulations like BCO-5.
A phase I randomized, double-blind, placebo-controlled trial (n=70) tested BCO-5 standardized to 5% TQ at 200 mg/day for 90 days, finding no serious adverse effects and improvements in sleep/stress (PMID: 36518481). A comprehensive review of 76 trials (31 RCTs) confirmed efficacy of black seed/oil in asthma, chronic kidney disease, type 2 diabetes, and NAFLD, with TQ identified as the key constituent (PMID: 30087794).
Clinically studied doses include 200 mg/day BCO-5 (5% TQ, providing ~10 mg TQ) for 90 days, and 2.5 mL/day black seed oil (providing 1-10 mg TQ) for 12 weeks. Higher doses of 1-10 mL/day oil have been used in trials for asthma and diabetes. Consult a healthcare provider before starting any new supplement.
Thymoquinone (TQ) is a pure bioactive compound (2-isopropyl-5-methylbenzo-1,4-quinone), not a whole food, and therefore has no conventional macronutrient or micronutrient profile. Molecular weight: 164.20 g/mol. Chemical formula: C10H12O2. It is the primary bioactive constituent of Nigella sativa (black seed) volatile oil, typically constituting 30–48% of the total essential oil fraction. In black seed oil preparations, TQ concentration typically ranges from 0.4–2.5 mg/mL depending on extraction method and cultivar. As an isolated compound, it contains no fiber, protein, conventional vitamins, or dietary minerals. Bioactive properties are attributed to its quinone structure, which confers potent antioxidant activity via free radical scavenging (DPPH IC50 approximately 0.7–1.2 mg/mL in vitro). TQ also exhibits thymol and carvacrol-related terpenoid chemistry. Bioavailability notes: TQ is highly lipophilic (log P ≈ 2.5), resulting in poor aqueous solubility (~1 mg/mL in water) and limited oral bioavailability in native form. Peak plasma concentration (Cmax) in animal models reached approximately 4.5 µg/mL following 10 mg/kg oral dosing. Nanoencapsulation and lipid-based delivery systems (nanoemulsions, solid lipid nanoparticles) have demonstrated 2–5 fold improvements in bioavailability. First-pass hepatic metabolism is significant, with rapid conjugation and oxidative metabolism. Half-life estimated at 1–2 hours in rodent models; human pharmacokinetic data remains limited. Protein binding is approximately 99%, primarily to albumin, which may influence distribution and activity.
Thymoquinone exerts its effects primarily through inhibition of the nuclear factor kappa B (NF-κB) signaling pathway, a key regulator of inflammatory responses. This quinone compound suppresses the production of pro-inflammatory cytokines including interleukin-8 (IL-8) and immunoglobulin E (IgE). The compound also appears to modulate oxidative stress pathways and may influence renal function markers through anti-inflammatory mechanisms.
Clinical evidence for thymoquinone comes primarily from studies using black seed oil containing this compound. A randomized controlled trial in 70 chronic kidney disease patients demonstrated significant reductions in urea, creatinine, and proteinuria levels with black seed oil supplementation. The anti-inflammatory effects are supported mainly by mechanistic studies showing NF-κB pathway inhibition and cytokine reduction. Current clinical evidence is limited, with most benefits extrapolated from black seed oil studies rather than isolated thymoquinone trials.
Thymoquinone safety data is primarily derived from black seed oil studies, with generally good tolerability reported in clinical trials. Potential side effects may include gastrointestinal upset, though specific adverse effects of isolated thymoquinone are not well-documented. The compound may interact with medications metabolized through cytochrome P450 enzymes, though specific drug interactions require further research. Pregnant and breastfeeding women should avoid supplementation due to insufficient safety data for isolated thymoquinone.
