Thymoquinone, the marker compound in black seed oil
Nigella sativa, the black cumin or black seed, owes much of its studied activity to thymoquinone, the main component of its volatile oil. Thymoquinone is what most standardised black seed oils are measured against. It is light and heat sensitive, which is why storage and processing affect potency, and its oral bioavailability is relatively low, prompting interest in oil and nanoparticle formulations.
What the metabolic and anti-inflammatory data support
In animal studies and a growing set of small human trials, thymoquinone shows broad anti-inflammatory and antioxidant activity and has been linked to modest improvements in markers such as blood pressure, fasting glucose and lipid levels. The signals are interesting but the human trials are generally small, short and varied in preparation, so the effects should be read as preliminary rather than established.
Black seed is not a treatment for diabetes, hypertension or any condition, and thymoquinone may interact with medications including those for blood sugar and blood pressure. This is general educational information, not medical advice; consult a qualified clinician before use.