Is Nigella Sativa L. (Black Seed) a Phyto-Therapeutic Option in the Treatment of Asthma? A Case Study in Saudi Arabia

Background

Clinical research using herbal medicines requires specific considerations such as the method of production, which leads to chemical and pharmacological variability. Asthma is a leading chronic respiratory disease, remains sub-optimally controlled despite available conventional treatments. Nigella sativa L. (NS) is a herbal medicine traditionally used in asthma and for a multitude of other indications. It has claims associated with a diverse range of major and minor health problems [1] often associated with chronic inflammatory processes [2]. However, rigorous scientific evidence is often lacking.

Objectives

To develop an integrated research strategy incorporating preclinical and clinical research focusing on NS use in asthma by employing a chemically and pharmacologically well-characterised NS preparation in a well-designed clinical trial ([Fig. 1]).

Fig. 1 Research strategy.

Methods

Distinct NS preparations were chemically characterised for thymoquinone (main active compound) concentration by High Performance Liquid Chromatography. Human T-lymphocyte, monocyte and A549 epithelial cells were utilised to assess the anti-inflammation/immunomodulatory activity of NS preparations in the laboratory. The most potent and suitable NS preparation was clinically evaluated for efficacy in asthmatic patients as add-on oral treatment in a phase-II randomised double-blind placebo-controlled clinical trial (RDBPCT).

Results and Discussion

Ten different NS preparations were obtained, showing variability in the main active compound (thymoquinone) concentration and in-vitro anti-inflammatory/immunomodulatory activities. Clearly, lipophilic preparations with a higher thymoquinone content are of great therapeutic potential. In-vitro the suppression of IL-2, IL-6 and PGE2 in T-lymphocytes, of IL-6 and PGE2 in monocytes and enhancement of PGE2 release in A549 cells was correlated with the thymoquinone content. Two thymoquinone-rich oily preparations (a super critical fluid extract and an oil capsules product registered in Saudi Arabia) showed the best activity [3].

In the RDBPCT trial including 80 participants, the commercial product showed significant improvements in the Asthma Control Test as a primary outcome and on some secondary outcomes (inflammatory markers including blood eosinophilia and serum cytokines) without showing serious side effects [4]. Patients in the treatment group (30 assessed) had significant improvement in ACT score over placebo group (30 assessed) (ACT2 means 476 (SD 99) vs 401 (SD 146) p 0.024, respectively). NS also showed a non-statistical improvement effect for predicted FEV1 % (mean improvement in treatment group 4.4 % (SD 7) vs mean improvement in placebo group 1.3 % (SD 7.6) p = 0.148. At the end of treatment, ten patients had withdrawn from each group.

Conclusion

This project offers a case study on how to optimise clinical research using herbal medicines. Preclinical studies on the chemistry and in-vitro activity of the investigational NS product were the basis for the RDBPCT. The clinical trial showed potential therapeutic evidence for the complementary treatment of asthma with NS. This strategy is suggested for future clinical phytotherapeutic research.

• References

• 1 Dajani EZ et al.. Overview of the human investigations of Nigella sativa (black seeds): A complementary drug with historical and clinical significance. Gen Int Med Clin Innov 2018; 3 DOI: 10.15761/GIMCI.1000171.
• 2 Gholamnezhad Z et al.. Preclinical and clinical effects of Nigella sativa and its constituent, thymoquinone: A review. J Ethnopharmacol 2016; 190: 372-386 DOI: 10.1016/j.jep.2016.06.061.
• 3 Koshak AE et al.. Comparative immunomodulatory activity of Nigella sativa L. preparations on proinflammatory mediators: A focus on asthma. Front Pharmacol 2018; 9: 1705 DOI: 10.3389/fphar.2018.01075.
• 4 Koshak AE et al.. Nigella sativa supplementation improves asthma control and biomarkers: A randomized, double-blind, placebo-controlled trial. Phytother Res 2017; 31: 403-409 DOI: 10.1002/ptr.5761.

Publication History

Article published online:
13 June 2022