Herb of the Month – Nigella sativa

🌿 This month’s Herb of the Month is Nigella sativa
Family: Ranunculaceae

🌿 Description:

Commonly known as Black Cumin, Nigella sativa is a flowering annual that reaches anywhere from 20-90 centimetres in height. Its flowers are delicate and fragrant, their hues varying from white through to yellow, pink and pale blue/purple. The leaves are finely divided, and the plant features large, black, seed-filled fruits from which the medicinal seeds are harvested.

Nigella sativa is native to the eastern Mediterranean region, north-eastern Africa and south-western Asia and has been naturalised in many areas throughout the globe. It is widely cultivated for both medicinal and culinary purposes; the essential oil rich seeds and oil pressed from them having a caraway-like flavour profile, with lemony and peppery notes that is sought after in many cuisines.

🌿 History and traditional use:

Descriptive tablets of botanical preparations discovered in Egypt and the region that was ancient Mesopotamia offer evidence for Nigella sativa being used both medicinally and spiritually from as far back as 1324BCE. In particular, the seeds were traditionally prepared in combination with products of the hive – honey, propolis, royal jelly and bee bread – to formulate both internal and external medicines. It appears that the seeds were also used in burial offerings and in sacred ceremony (1, 2).

In Dioscoredes’ De Materia Medica a plant medicine referred to as ‘melanthion’ is believed to have been Nigella sativa. It features in various prescriptions, usually in combination with vinegar, bread and other foods. Dioscoredes applied it to toothaches and skin conditions specifically (1).

Avicenna recommended use of Nigella sativa seeds for recovery from exhaustion and dispiritedness and the enhancement of energy in “The Canon of Medicine” (3). In the traditional healing systems of India, the Arabic and Islamic regions, Iran and Sudan, Nigella sativa is frequently referenced as a primary medicine for the respiratory, gastrointestinal and nervous systems (1, 2, 4).

🌿 Actions and indications:

Primarily, Nigella sativa has been shown to possess a particularly significant combination of antioxidant, antiinflammatory and immunomodulatory actions that have clear and multifaceted indications for complex modern autoimmune conditions.

Additionally, there is a large body of strong preclinical data that supports a myriad of traditional actions of Nigella sativa, including:

  • Antidiabetic
  • Anticancer
  • Analgesic
  • Antimicrobial
  • Bronchodilatory
  • Gastroprotective
  • Hepatoprotective
  • Reno-protective
  • Spasmolytic (4, 5)

🌿 Science and clinical trials:

It is generally considered that the volatile thymoquinone component of the essential oil is the most significant active constituent in Nigella sativa (5). Animal studies have shown that isolated thymoquinone significantly reduces a spectrum of proinflammatory mediators and provides antioxidant protection (6) two key medicinal actions of the herb. Nigella sativa is also rich in alkaloids (nigellicines and nigelledine), saponins (alpha-hederin), flavonoids, proteins and fatty acids (7). New novel lipids have been isolated from Nigella sativa, including a new dienoate and two monoesters (3).

Hashimoto’s thyroiditis
Clinical trials have shown that Nigella sativa holds promise for Hashimoto’s thyroiditis. In one 2016 study, 40 patients diagnosed with Hashimoto’s were split into equal groups and administered either two grams of ground seeds or placebo daily for an eight-week trial period. At trial conclusion, the study group experienced significant reductions in body weight, body mass index (BMI) and waist to hip ratios when compared to placebo. Researchers concluded that Nigella influenced thyroid function, which could be measured in serum decreases in TSH and anti-thyroid peroxidases and serum increases in triidothyronine (T3) when compared to baseline (8).

Similar results have been seen in animal trials, where Nigella sativa has influenced thyroid and reproductive hormones in healthy rats (9) and have also demonstrated positively influential activity on serum insulin and glucose concentrations in diabetic animals (2), leading to investigations for its application in metabolic disorders.

Metabolic disorders
In an experimental randomised controlled trial of 99 patients with diabetes, two treatment groups received orally administered black seed oil (and 1.5mL and 3mL respectively) and one received placebo. After 20 days of treatment, the study groups showed clinically significant reduction of glycated hemoglobin A1c and random blood sugar levels (10). In patients with type-2 diabetes, Nigella sativa has been trialled as an adjunct treatment to pharmaceutical oral hypoglycaemics, resulting in significant reduction of fasting plasma glucose and glycated hemoglobin (HbA1c) without notable body weight changes (11). Rat models have also shown significant reduction in fasting plasma glucose and intensification of insulin levels in diabetic animals taking the seed oil as compared to a control group, and these animals showed substantial improvements in lipid profiles and levels of both hepatic and pancreatic enzymes (12). It appears that the influence of the herb on lipid profiles is somewhat dose dependent, with lower doses increasing high-density lipoprotein cholesterol (HDL-c) levels and higher doses additionally decreasing serum levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-c) and increasing plasma HDL-c (13).

Male infertility
A randomised, double-blind, placebo-controlled trial on 68 infertile men administered 2.5mL of black seed oil to the study group and a placebo to the control. After 2 months of treatment, sperm motility and semen volume were significantly raised in the study group compared with placebo (14). Animal studies support these findings, where ethanolic extracts of Nigella sativa have been found to significantly increase viable and motile sperm cells, enhance sperm reservation, result in weight gain in the reproductive organics, improve testosterone density, increase sperm motility and positively impact other fertility metrics in rats in addition to positively affecting oxidative phosphorylation enzymes (15).

Antiparasitic activity
Both internal and topical preparations of Nigella sativa have been shown to have antiparasitic activity against:

  • Schistosoma mansoni 
  • Leishmania major 
  • Plasmodium yoelii (16-20)

It is likely that the antiparasitic effect of Nigella sativa is broad spectrum, warranting investigation into its use amid rising concerns related to parasitic drug resistance.

Antihypertensive
In a nonrandomised controlled trial, 57 patients were administered 2g of Nigella sativa daily for one year. At the end of the trial period, clinically significant reductions were seen in systolic, diastolic, and mean arterial BP, heart rate, TC, LDL-c, the fractions of TC/HDL-c, and LDL-c/HDL-c (21). However, trials specific to elderly patients have not shown results as promising (22).

In animal models, reduction in BP resulting from Nigella sativa administration were linked to reductions in cardiac lipid peroxidation products and an inhibitory action on angiotensin converting enzyme. Reductions in oxidative stress via calcium channel blockades and increased urine output activity may also be linked to reduction in blood pressure (23).

🌿 Prescribing considerations:

Nigella sativa is considered to have minor and/or negligible toxic effects and a wide safety margin.

It is advised to avoid prescription in pregnancy and lactation purely to a lack of studies, and with caution in combination with pharmaceutical medications as its potential interactions are not yet understood.

🌿 References:

  1. Engels G and Brinckmann J 2017, Herbalgram – Nigella, The Journal of the American Botanical Council, 114, pp. 8-16.
  2. Sultana S, A Hmakhtar N, Iqbal A, Nazar H and Rehman RU 2015, Nigella sativa : Monograph, Journal of Pharmacognosy and Phytochemistry, 4:4, pp. 103-106.
  3. Yimer EM, Tuem KB, Karim A, Ur-Rehman N, Anwar F 2019, Nigella sativa L. (Black Cumin): A Promising Natural Remedy for Wide Range of Illnesses. Evidence Based Complementary Alternative Medicine. May 2019.
  4. Datta AK, Saha A, Bhattacharya A, Mandal A, Paul R and Sengupta S 2012, Black Cumin (Nigella sativa L.) – a review, Journal of Plant Development Sciences, 4:1, pp. 1-43.
  5. Ahmad A, Husain A, Mujeeb M, Khan SA, Najmi AK, Siddique NA, Damanhouri ZA and Anwar F 2013, A review on therapeutic potential of Nigella sativa: A miracle herb, Asian Pacific Journal of Tropical Biomedicine, 3:5, pp. 337-352.
  6. Umar S, Zargan J, Umar K, Ahmad S, Kativar CK and Khan HA 2012, Modulation of the oxidative stress and inflammatory cytokine response by thymoquinone in the collagen induced arthritis in Wistar rats, Chemico-biological Interactions, 197:1, pp. 40-46.
  7. Tavakkoli A, Mahdian V, Razavi BM, Hosseinzadeh H 2017, Review on Clinical Trials of Black Seed (Nigella sativa) and Its Active Constituent, Thymoquinone. Journal of Pharmacopuncture. 2017 Sep;20(3):179-193.
  8. Farhangi MA, Dehghan P, Tajmiri S and Mesgari M 2016, The effects of Nigella sativa on thyroid function, serum Vascular Endothelial Growth Factor (VEGF) – 1, Nesfatin-1 and anthropometric features in patients with Hashimoto’s thyroiditis: a randomized controlled trial, BMC Complementary and Alternative Medicine, 16:471, pp. 1-9.
  9. Jasim WK, Hassan MS and Keam GG 2016, Study the effect of Nigella sativa on thyroid function and reproductive hormone of female rat, Journal of Contemporary Medical Science, 2:6, pp. 67-69.
  10. Rachman PNR, Akrom, Darmawan E 2017, The efficacy of black cumin seed (Nigella sativa) oil and hypoglycemic drug combination to reduce HbA1c level in patients with metabolic syndrome risk. Proceedings of the International Pharmacy Conference; 2017; Indonesia.
  11. Bamosa A,  Kaatabi H, Badar A 2015, Nigella sativa: A potential natural protective agent against cardiac dysfunction in patients with type 2 diabetes mellitus. Journal of Family and Community Medicine, 22(2):88–95.
  12. Abdelrazek HMA, Kilany OE, Muhammad MAA, Tag HM, Abdelazim AM 2018, Black seed and thymoquinone improved insulin secretion, hepatic glycogen storage, and oxidative stress in streptozotocin-induced diabetic male wistar rats. Oxidative Medicine and Cellular Longevity, 2018:10.
  13. Kaatabi H, Bamosa AO, Lebda FM, Al ELq AH, Al-Sultan 2012, Favorable impact of Nigella sativa seeds on lipid profile in type 2 diabetic patients. Journal of Family and Community Medicine. 2012;19(3):155–160.
  14. Kolahdooz M, Nasri S, Modarres SZ, Kianbakht S, Huseini HF 2014, Effects of Nigella sativa L. seed oil on abnormal semen quality in infertile men: A randomized, double-blind, placebo-controlled clinical trial. Phytomedicine. 2014;21(6):901–905.
  15. Parandin R, Yousofvand N, Ghorbani R 2012, The enhancing effects of alcoholic extract of Nigella sativa seed on fertility potential, plasma gonadotropins and testosterone in male rats. Iranian Journal of Reproductive Medicine, 10(4):355–362.
  16. Assi MA, Noor MHM, Bachek NF 2016, The various effects of Nigella sativa on multiple body systems in human and animals. Pertanika Journal of Scholarly Research Reviews, 2(3):1–19. 
  17. Abd El-Hack ME, Alagawany M, Farag MR, Tiwari R, Karthik K, Dhama K, 2016, Nutritional, healthical and therapeutic efficacy of black cumin (Nigella sativa) in animals, poultry and humans. International Journal of Pharmacology, 12(3):232–248.
  18. Bafghi AF, Vahidi AR, Anvari MH, Barzegar K, Ghafourzadeh M 2011, The in vivo antileishmanial activity of alcoholic extract from Nigella sativa seeds. African Journal of Microbiology Research, 5(12):1504–1510.
  19. Okeola VO, Adaramoye OA, Nneji CM,Falade CO,  Farombi EO,  Ademowo OG 2011, Antimalarial and antioxidant activities of methanolic extract of Nigella sativa seeds (black cumin) in mice infected with Plasmodium yoelli nigeriensis. Parasitology Research, 108(6):1507–1512.
  20. Okeola VO, Adaramoye OA, Nneji CM, Falade CO, Farombi EO, Ademowo OG 2011, Antimalarial and antioxidant activities of methanolic extract of Nigella sativa seeds (black cumin) in mice infected with Plasmodium yoelli nigeriensis. Parasitology Research, 108(6):1507–1512.
  21. Badar A, Kaatabi H, Bamosa A 2017, Effect of Nigella sativa supplementation over a one-year period on lipid levels, blood pressure and heart rate in type-2 diabetic patients receiving oral hypoglycemic agents: Nonrandomized clinical trial. Annals of Saudi Medicine, 37(1):56–63.
  22. Rizka A, Setiati S, Lydia A, Dewiasty E 2017, Effect of Nigella sativa seed extract for hypertension in elderly: a double-blind, randomized controlled trial. Acta Medica Indonesiana, 49(4):307–313.
  23. Leong XF, Rais Mustafa M, Jaarin K. 2013, Nigella sativa and its protective role in oxidative stress and hypertension. Evidence-Based Complementary and Alternative Medicine, 2013:9.