Studies on the curative aspects of black cumin (Nigella Sativa) has seen an exponential growth in recent years. A single search of black cumin or Nigella Sativa at the database of the National Institutes of Health returns about 400 scientific publications, and more have been published every year on different aspects of black cumin and health, from diabetes, cancer, asthma, obesity, and so on. There is, however, still a great need of work to be done to uncover all the mysteries and healing capacity of black cumin which were miraculously heralded by the Prophet Muhammad, peace be upon him, 14 centuries ago: "There is healing in black cumin for all diseases except death" (Bukhari 7:71).
Nigella sativa, commonly known as black cumin or black seed, is native to the Mediterranean region, but has also been grown on the Arab peninsula, Africa, and western Asia. It belongs to the Ranunculaceae family and is one of the numerous plants from this family that has been shown to have great potential for therapeutic use. With more than 100 nutrients and compounds, black cumin is rich in unsaturated fatty acids and essential oils (about 0.4%), including but not limited to thymoquionone and carvacrol. The antioxidants in black cumin attributed to the compounds in the essential oil relieve oxidative stress by scavenging activity through free radicals. Other nutrients include proteins, carbohydrates, and many, many vitamins. The plant can grow up to 30 cm and have white flowers with black seeds no more than 3 mm in length.
Historically, black cumin has been used for two different purposes: as a seasoning and flavoring in foods, and as a medicine for the treatment of ailments. Ibn Sina (980-1037), also known as Avicenna, refers to black cumin as stimulating the body's energy and helping it recover from fatigue. Recent research shows that if it's taken over time, black cumin can greatly boost the immune system. Another report from the Prophet Muhammad, peace be upon him, similarly puts emphasis on consistent use of black cumin with the phrase, "hold onto the use of the seed."
Recent research highlights the benefits of black cumin in the induction of apoptosis (cell death) in cancer cell lines and in decreasing blood sugar levels, which can help limit complications from diabetes. Numerous medicinal properties of black seed extracts and oil have been shown to strengthen the immune system, radioprotectivity, antihistaminic, antihypertensive (reduces high blood pressure), analgesic (pain reliever), anti-inflammatory (reduction of swelling/inflammation), hypoglycemic (suffering from an abnormally low level of sugar in the blood), antibacterial, antifungal, antitumor and protective effects against oxidative stress, hepatotoxicity (toxicity to liver) and nephrotoxicity (damage to the kidneys). Black cumin seed extracts also inhibits NO production. Thymoquinone found in black seed improves liver antioxidant capacity while increasing expression of antioxidant genes. Black cumin reduces the risk of various other maladies such as respiratory disorders, skin disorders, and allergies.
Studies done decades ago suggested that the use of black cumin on regular basis enhances human immunity, especially in immune-compromised patients. In the 80s and 90s, different studies done on human volunteers show that black cumin acts as a natural immune enhancer. Use of black cumin for this purpose has been patented as well. These findings suggested that black cumin could play an important role in the treatment of cancer, AIDS, and other diseases associated with immuno-deficiency.
In 2010, Xuan and colleagues at University of Tubingen, Germany conducted a study on thymoquinone, a component of black cumin, to test its effect on dentritic cells, which take key role in the innate and adaptive immunity. By using mouse bone barrow derived dentritic cells as model, they showed that thymoquinone cooperate in the maturation, cytokine release and survival of dentritic cells.
Black cumin also has radioprotective effects. A study by Assayed in 2010 on rats aimed to investigate the radioprotective potential of black seed oil against exposure to radiation. Gamma irradiated rats fed black seed oil demonstrated that black seed oil is a promising natural radioprotective agent against the immunosuppressive and oxidative effects of ionizing radiation. Those findings suggest that black cumin might be used as protection against the adverse effects of radiation in the case of a nuclear leakage from nuclear plants, such as the one that happened in Japan following the massive earthquake in March 2011.
A study performed in Japan by Fararh and colleagues on the hypoglycemic effect of black cumin oil in streptozotocin-induced diabetic hamsters showed that treatment with black cumin oil has both a regulatory role in blood glucose levels and an immunopotentiating effect. In this study, black cumin oil decreased blood glucose from 391+/-3.0 to 179+/-3.1 mg/dl after the fourth week of treatment. Hepatic glucose production from gluconeogenic precursors (alanine, glycerol, and lactate) was also lower in the treated hamsters. In addition, they showed that black cumin has an immunopotentiating effect through inducing the phagocytic activity of macrophages and lymphocyte count in the blood. Approaches for the treatment of diabetes using black cumin are noteworthy, including patented ones (US Patent No 6042834).
Black seed oil has an anti-inflammatory effect and it could be useful in relieving the effects of arthritis. Thymoquinone, an active ingredient of black cumin, shows a remarkable anti-inflammatory potency. Research on thymoquinone also demonstrates that it increases T cells and natural killer cell-mediated immune responses.
Moreover, black cumin is known to show protection against cancer growth due to the induction of cellular death. A study on mice back in the 90s showed that fatty acids derived from black cumin could inhibit the various cancer cell lines, including Ehrlich ascites carcinoma and Dalton's lymphoma ascites. This study concluded that black seeds contain a potent anti-tumor agent, and this could be long chain fatty acids.
Another study also found that black cumin oil could inhibit eicosanoid generation; thus, black cumin demonstrates anti-oxidant activity. This inhibition of eicasanoid production, however, was higher compared to thymoquinone alone, suggesting the presence of other compounds within the oil that increases anti-inflammatory reactions.
A model based on experimental autoimmune encephalomyelitis (EAE) done by researchers at Gaziosmanpasa University in Turkey showed that black cumin may be protective against oxidative stress in the brain. Black cumin also regulates tissue NO levels, at least to some extent.
Bronchial asthma is associated with allergic reactions, and sometimes this could arise from the production of histamine from bodily tissues. Back in the 60s, it was shown that dimer dithymoquinone (nigellone) from black seed oil suppressed symptoms associated with bronchial asthma. In 1993, Chakravarty demostrated that nigellone inhibits histamine through the inhibition of protein kinase C, a protein known to induce the release of histamine. A clinical trial on 152 patients with the allergic disease done in 2003, in Germany, also demonstrated that black seed oil is an effective agent for the treatment of allergic diseases. These studies offered alternative treatments using black cumin to people who suffered from bronchial asthma and other allergic diseases.
Studies in Bangladesh showed that black cumin extracts exhibit anti-bacterial and anti-fungal properties as well. A study comparing the volatile oil of black cumin with five antibiotics (ampicillin, tetracycline, cotrimoxazole, gentamicin, and nalidixic acid) demonstrated that black cumin oil is effective against various strains of bacteria, including V. cholera, E. coli (a common infectious agent), and strains of Shigella.
It has been suggested that black cumin could support metabolism, improve digestion, and drive out worms and parasites from the intestines. It could also be used for soothing coughs, stimulation of menstrual periods, the promotion of lactation (the flow of breast milk), increasing sperm count and hair growth, and perhaps even more.
Modern technology and studies based on synthetic compounds for new therapeutics have diverted the attention of researchers to where they could seek cures that already exist in the natural world. Pharmaceutical drugs show a lot of benefits to human well-being, and have cured a number of diseases, but they also have unwanted side effects.
Black cumin could be a treasury for medicine. Research findings and historical practices shed light on the curative aspects of black cumin. However, the quantity, quality, and extent of studies on black cumin are not comparably high. This urges researchers to put more, and more intense efforts into understanding and discovering treatments for diseases that we are facing today by using black cumin – a natural cure that people have been using for 1400 years.