Black Cumin Seed Oil

Black seed oil is a substance that is extracted from the seeds of Nigella sativa, a plant that is native to Egypt, the sub-continent and Asia. Black seed and black seed oil have long been used as herbal medicine for skin conditions, such as eczema, psoriasis, acne and dry skin, allergies, colds and more serious health conditions, such as asthma, arthritis, cancer and diabetes. 

Nigella sativa seeds have shown schistosomicidal properties against Schistosoma mansoni (in vitro), through a strong biocidal effect against all stages of the parasite and an inhibitory effect on egg-laying of adult female worms [119, 120]. An ointment of N. sativa seed significantly contracted and inhibited the inflammatory reactions to cutaneous leishmaniasis produced experimentally in mice by a subcutaneous inoculation of Leishmania major at the abaxial base of the tail [121]. N. sativa extract at a dose of 1.25 g/kg prominently lowered Plasmodium yoelii infection in mice by 94%; however, the effect of chloroquine was only 86% as compared to the untreated group. In addition, methanolic extract of N. sativa revealed higher parasite clearance and restoration of altered biochemical indicators by P. yoelii infection than chloroquine [122]. Thus, considering N. sativa for future antiparasitic agents will have a very important input after conduction of further investigation of its curative, prophylactic and chemopreventive activity particularly in the era of emerging antimalarial drug resistance.

Studies suggest that this oil may offer many medicinal and cosmetic benefits, such as aiding weight loss, improving skin conditions, and even helping treat cancer and diabetes. The key to these benefits appears to be the main component of black seed oil, thymoquinone.

Steroidal glycosides of new and known structures have been isolated from N. sativa seeds which include 3-O-[β-D-xylopyranosyl-(1→2)-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl]-11-methoxy-16, 23-dihydroxy-28-methylolean-12-enoate, stigma-5,22-dien-3-β-D-glucopyranoside [24], and 3-O-[β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→4)-β-D-glucopy-ranosyl]-11-methoxy-16-hydroxy-17-acetoxy hederagenin [25]. Moreover, alkaloids of diverse types have been isolated from the seeds of black cumin, which include novel Dolabellane-type diterpene alkaloids: nigellamines A1, A2, B1, and B2 and nigellamines A3, A4, A5, and C [26, 27] possessing lipid metabolizing property, and indazole class of alkaloids: nigellidine, nigellicine [28, 29], and nigellidine-4-O-sulfite [30].

Black Seed Oil

Phytosterols are important part of human diet and are gaining greater interest due to their nutraceutical and medicinal benefits in lowering low density lipoprotein and total cholesterol level [21]. Phytosterols are also important as characteristic compounds for assessing the quality of vegetable oils and food labeling. The total sterols content of black cumin seed oil as estimated by different researchers was found to be between 18 and 42% of the unsaponified matter. The major sterols identified were β-sitosterol, campesterol, stigmasterol, and 5-avenasterol [19, 22]. Tocopherols exhibited attractive scavenging potentials of free radicals which are believed to terminate lipids peroxidation [23]. The total tocopherol contents of black seed oil reported in varied quantities from diverse sources ranged from 9.15 to 27.92 mg/100 g. Among the foremost tocopherols recognized in black cumin seeds, α- and γ-tocopherol and β-tocotrienol are well recognized [19].

The acute oral toxicity of active constituents of black cumin seed, TQ, lethal dose 50 (LD50) value has been reported to be 2.4 g per kg of body weight of Swiss albino mice, whereas the instant behavioral alteration at two and three g per kg of body weight of the composite was hypoactivity and trouble in breathing, while late toxicities comprising a substantial lessening in the virtual organ weight and glutathione distribution of the hepatic, renal, and cardiovascular system have been reported [149]. Daily administration of aqueous extract (AqE) of N. sativa to mice for six weeks led to death of one mouse after 2 weeks of treatment with 6.4 g/kg of AqE. On the other hand, 2 and 3 mice experienced death at 3rd and 5th weeks while they received 21 g/kg and 60 g/kg of the extract, respectively. Otherwise, no other deaths were recorded for the application of other doses used [150]. In addition, the subchronic toxicity study in mice treated with 30, 60, and 90 mg/kg/day of TQ for 90 days resulted in no mortality or signs of toxicity but substantial decrement of fasting plasma glucose and also showed no change in toxicological significance in body organs and histological investigation [149]. The toxicity of the fixed oil of black cumin in mice and rats was also examined and the LD50 values were found to be 28.8 ml/kg and 2.06 ml/kg when given by oral and intraperitoneal routes, respectively. Chronic toxicity was also studied in rats treated daily with an oral dose of 2 ml/kg for 12 weeks' black cumin oil, while alterations in vital liver enzyme levels and histopathological modifications (heart, liver, kidneys, and pancreas) were not detected [151]. The minor and/or negligible toxicological effects and wider therapeutic margin of N. sativa and its active constituents, thymoquinone, as evident by various scientific studies support its safe use for the long-term traditional food and medicinal purposes.