Assessment of black cumin (Nigella sativa L.) as a food ingredient and putative therapeutic agent.

The whole or ground seeds of the food ingredient Nigella sativa L., known in Western culture as "black cumin" or "black caraway", has a three-millennial history of use in Middle- and Far-Eastern cultures as a food ingredient. The seed and its extracts have also been increasingly reported as a successful therapeutic agent with efficacy often attributed to the presence of the powerful antioxidant, thymoquinone. However, quantitative analysis of the seed (especially the volatile fraction) yields widely variable results, which may be due to one or a combination of different crop origins or possible varietal differences, contamination/adulteration, method of extraction, stage of maturation of the extracted seed and other factors. Nonetheless, despite the reported wide variability in bioactive constituents, many publications cite quantifiable outcomes in in vitro and in vivo toxicity testing and in clinical trials. There are a few reports describing allergic reactions in humans when N. sativa extracts are applied to the skin. Notwithstanding the foregoing, N. sativa seeds, used as a food ingredient at historical levels of consumption and as traditionally practiced are safe and Generally Recognized As Safe.

Effect of roasting and microwave pre-treatments of Nigella sativa L. seeds on lipase activity and the quality of the oil.

The present research studied the thermal pre-treatment of non-soaked and soaked black seed (BS) by microwave radiation (1-3.5 min) in comparison with conventional roasting (2-8 min, 180 °C). As BS was treated for a longer time, a significant increase (p < 0.05) was observed in total chlorophylls, carotenoids and phenolic contents in the extracted oils. The oils obtained from the soaked seeds (to 8%) had significantly higher oil quality properties. The optimum extraction conditions were: irradiation time of 3.5 min and BS moisture content of 8%, which resulted in an extraction yield of 35.76%, 10643.730 caffeic acid equivalents/100 g, PV of 9.63 meq O2/kg and 18.88 h of Rancimat oxidative stability. The microwave pre-treatment was more effective than conventional roasting in reducing lipase activity. Based on the results obtained, it was advisable to treat BS with microwaves and soak them before extracting the oil in a cold press at room temperature.

Plant growth-promoting bacteria elevate the nutritional and functional properties of black cumin and flaxseed fixed oil.

BACKGROUND: In order to study the influence of plant growth-promoting bacteria (PGPB) belonging to Streptomyces sp., Paenibacillus sp., and Hymenobacter sp. on fixed oil content of flaxseed and black cumin, 2-year field experiments were conducted. PGPB was applied during seedtime of plants. The extraction of oil from seeds was performed using supercritical CO2 . RESULTS: The addition of PGPB significantly increases the content of C18:1 (from 16.06 ± 0.03% to 16.97 ± 0.03%) and C18:3 (from 42.97 ± 0.2% to 45.42 ± 0.5%) in flaxseed oil and C18:2 (from 52.68 ± 0.50% to 57.11 ± 0.40%) and C20:2 (from 4.34 ± 0.02% to 4.54 ± 0.03%) in black cumin seed oil. The contents of total polyphenols, flavonoids, and carotenoids, as well as antioxidant activity measured by ferric-reducing ability of plasma assay, were found to be greater in the oil from the seeds of plants treated with the PGPB, compared with the respective non-treated samples. CONCLUSION: The use of PGPB enhances plant nutritive properties; these represent a great source for obtaining valuable functional food ingredients. © 2017 Society of Chemical Industry.

Responses of Nigella sativa L. to Zinc Excess: Focus on Germination, Growth, Yield and Yield Components, Lipid and Terpene Metabolism, and Total Phenolics and Antioxidant Activities.

A comprehensive analysis of the responses of Nigella sativa L. to elevated zinc concentrations was assessed in pot experiments. Zn excess supply did not affect the germination but drastically reduced radicle elongation. A concentration-dependent reduction in all growth parameters, yield, and yield components was observed. With the increasing Zn concentrations, total lipid contents decreased and changes in fatty composition toward the production of saturated ones were underscored. Despite the reduction in the seeds essential oil yield, a redirection of the terpene metabolism toward the synthesis of oxygenated compounds has been evidenced. A significant increase in the total phenols and flavonoids contents concomitant with improved antioxidant activities has also been found. Collectively, these results highlight the possible use of N. sativa L. in phytoremediation applications, on the one hand, and that Zn excess could represent an excellent alternative to improve the nutritional attributes of this important species, on the other hand.

Evaluation of immunomodulatory effect of three herbal plants growing in Egypt.

A group of medicinal plant including Silene (Silene nocturna), Black seed (Nigella sativa) and Chamomile (Matricaria chamomilla) growing in Egypt were examined for their immunomodulatory effect in Balb/c mice. Treatment (intraperitoneal injection) with five doses of methanolic extract for each plant was found to enhance the total white blood cells count (up to 1.2 × 10(4) cells/mm(3)). Bone marrow cellularity also increased significantly (P < 0.01) after the administration of the extract of each of three test plants. Furthermore, spleen weight of the treated groups was significantly increased (P < 0.01). Two groups of mice were immunosuppressed with cyclophosphamide, the one which pretreated with the plants extracts significantly (P < 0.01) restored their resistance against lethal infection with the predominately granulocyte-dependant Candida albicans. These results confirm the immunomodulatory activity of Silene, Black seed, and Chamomile extracts and may have therapeutical implications in prophylactic treatment of opportunistic infections and as supportive treatment in oncogenic cases.

Biological activity of seed aqueous extract of Nigella sativa (L.) on germination and seedling growth of Vigna radiata (L.).

Seeds aqueous extract of Nigella sativa were evaluated for their effect on germination and seedling growth of Vigna radiata. Two different methods were used to prepare the seed aqueous extract. The aqueous extracts prepared were found to affect germination percentage and seedling growth of V. radiata. The germination percentage and seedling growth of V. radiata decreased as the concentration of the seeds aqueous extracts of N. sativa increased. Severe toxicity was observed at high concentrations and moderate toxicity at low concentrations in comparison with water control. Seeds aqueous extract significantly inhibited root length more than shoot. The aqueous dried powdered extract soaked for 4 days with or without boiling had inhibitory effect on germination and seedling growth of V. radiata, but method 2 (with boiling) was the most effective one specially on root length.

Evaluation of cytological effects of Zn2+ in relation to germination and root growth of Nigella sativa L. and Triticum aestivum L.

The effects of different treatments with zinc sulfate (Zn(2+)) on the cytology and growth of Nigella sativa and Triticum aestivum were investigated. Five concentrations of zinc sulfate ranging from 5 to 25mg/l were applied for 6, 12, 18, and 24h. The treatments reduced the germination percentages of N. sativa seeds and T. aestivum grains and inhibited the root growth of both plants. Concentrations higher than 25mg/l of Zn(2+) applied for 24h were toxic for both plants. The non-lethal concentrations of Zn(2+) showed an inhibitory effect on cell division in root tips of both plants and caused a decrease in their mitotic index values. The reduction in MI in root tips of T. aestivum was more evident than that of N. sativa. All treatments changed the frequency of mitotic phases as compared with the control values. The total percentage of abnormalities in N. saliva was more than that in T. aestivum. Zn(2+) treatments produced a number of mitotic abnormalities in dividing cells in root tips of both plants resulting from its action on the spindle apparatus such as C-metaphases, lagging chromosomes and multipolar anaphases and telophases. Also, Zn(2+) induced vacuolated nuclei and irregular prophases. The induction of chromosomal stickiness and chromosomal aberrations such as bridges and breaks indicates its action on the chromosome. These abnormalities (chromosome breaks and chromosomal bridges at ana-telophases) indicate true clastogenic potential of the ions tested.