Black cumin seed has not been shown to treat cancer in humans.
Black cumin seed is used for cooking and in medicine in India, Arabia, and Europe. Laboratory studies have shown that some components have antioxidant and anti-inflammatory effects. Therefore, there is some speculation that black cumin seed may be useful in the treatment of cancer and protect against the side effects of radiation therapy, but these have not been proven in humans. Early phase studies suggest that black cumin seed may help to control high blood pressure, asthma, diabetes, and rheumatoid arthritis.
To treat cancer
Animal studies have shown that black cumin seed can stop the growth of tumor cells and reduce the incidence of tumors. However, the effects in humans are unclear.
To protect the body from the adverse effect of radiation therapy
Animal studies have shown that black cumin seed oil, when injected, may protect against tissue damage caused by radiation. However, the effects in humans are unknown.
To decrease hypertension
In one study in humans, daily use of black cumin seed extract for 2 months may have help to lower blood pressure in patients with mild hypertension.
To decrease symptoms of asthma
An early phase study suggests black cumin seed may help to prevent the asthmatic symptoms. More research is warranted.
To treatment rheumatoid arthritis
One study shows black cumin seed oil when taken orally, can help reduce symptoms of rheumatoid arthritis
Do Not Take If
You are taking cytochrome P450 substrate drugs: Nigella sativa may increase the risk of side effects of these drugs.
High doses of Nigella sativa caused liver and kidney damage in rats.
Topical use of Nigella sativa caused allergic reactions.
Nigella sativa is a flowering plant found throughout India, Arabia, and Europe. The seeds, commonly known as black seeds or black cumin, are used in cooking and in traditional medicine for inflammation, infection, and cancer.
Constituents from N. sativa demonstrated immunomodulatory (1)(2)(11), antioxidant (15), antiparasitic (13) and hepatoprotective effects (14) in vitro and in animal studies. N. sativa seed may be useful in the treatment of asthma (21), hypertension (5)(10)(22), rheumatoid arthritis (26), dyspepsia (27), and diabetes (28) in humans. Thymoquinone, a major constituent of N. sativa, exhibited antiepileptic effects in children with refractory seizures (23). N. sativa may also relieve symptoms of allergic reactions (12), but allergic contact dermatitis was reported with topical use (19).
Evidence also suggests that N. sativa has anticancer properties. Thymoquinone and other constituents of the seeds reduced the growth and size of tumors in rats (4)(5)(6)(7)(8)(9). Thymoquinone also enhanced the anticancer effects of doxorubicin in certain cancer cell lines (25). N. sativa oil, when injected, demonstrated a protective effect against tissue damage caused by radiation in rats (15). Human studies are lacking.
Adverse effects are rare, but high doses of N. sativa oil caused liver and kidney damage in rats (7).
Mechanism of Action
Thymoquinone, one of the chief constituents of Nigella sativa oil has antioxidant effects and restored the levels of lactate dehydrogenase, glutathione, and SOD in animal models (6)(7)(9). This may also explain N. sativa’s hepatoprotective effects (3)(4). Studies have also shown that N. sativa oil has anti-inflammatory properties by inhibiting cyclooxygenase and lipoxygenase (18). An in vitro study demonstrated that nigellone, a constituent of the crude extract of N. sativa seeds, inhibited histamine release from rat peritoneal mast cells (10) and may reduce allergy symptoms in humans (12). N. sativa decreased hypertension in rats possibly due to its diuretic effects (5). It was also shown to decrease uterine smooth muscle contractions (14).
The antioxidant effect is thought to protect tissues from radiation injury (15). However, it is not clear if this would also make radiation therapy less effective. Thymoquinone administered to mice reduced the incidence of stomach tumors (7). Possible mechanisms include inhibition of DNA synthesis (7), and promotion of apoptosis by inhibiting cell growth in G1 phase (8).
The methanol extract of N. sativa exhibits in vitro estrogenic activity after naringinase treatment (30).
In animals, the fixed oil of N. sativa orally administered to rats for up to 12 weeks did not produce any significant changes in hepatic enzymes and did not cause mortality (16). However, high doses may cause liver damage (29).
Topical use of pure oil of N. sativa caused allergic contact dermatitis in 2 people with maculopapular eczema (19).
Cytochrome P450 substrates:Nigella sativa inhibits CYP2D6 and CYP3A4 and can affect the intracellular concentration of drugs metabolized by these enzymes (24).
Herb Lab Interactions
In animal studies, Nigella sativa oil decreased serum glucose, triglyceride, cholesterol levels and leukocyte and platelet counts, but there was an increase in hematocrit and hemoglobin levels (16)(20).