Phytopharmacy research in the context of Saudi Arabian healthcare : the example of Nigella sativa L. efficacy on asthma inflammation and outcomes

• Main Author: Koshak, Abdulrahman Emad
• Published: University College London (University of London) 2017
• Subjects: 615.1
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.747113

BACKGROUND: Clinical research using herbal medicines requires specific considerations such as production method, which leads to chemical and pharmacological variability. Asthma is a leading chronic respiratory disease, remains sub-optimally controlled despite conventional costly treatments. Nigella sativa L. (NS) is a traditional herbal treatment for asthma, but lacking well-established scientific evidence. 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. 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 in-vitro anti-inflammation/immunomodulatory activity of NS preparations. The most potent and suitable NS preparation was clinically evaluated for efficacy as add-on treatment for asthmatics in a phase-II randomised double-blind placebo-controlled clinical trial (RDBPCT). Asthma Control Test (ACT) was the primary outcome. Pulmonary function, blood eosinophils and serum inflammatory markers were secondary outcomes. RESULTS AND DISCUSSION: Ten different NS preparations were obtained, showing variability in thymoquinone concentration and in-vitro anti-inflammatory/immunomodulatory activities. Two thymoquinone-rich oily preparations (a super critical fluid extract and a commercial product registered in Saudi Arabia) showed the best in-vitro activity via inhibiting inflammatory cytokines in human cellular models. In the RDBPCT including 80 asthmatics, the commercial product capsules showed significant improvements in ACT, eosinophilia and some serum cytokines without serious side effects. CONCLUSION: This project addressed important requirements to optimise clinical research using herbal medicines particularly for NS in asthma. Preclinical research on the chemistry and activity of the investigational NS product were the basis for the clinical trial. The RDBPCT revealed a higher level of evidence for the add-on NS treatment in asthma within the Saudi healthcare. This strategy is suggested for future clinical phytotherapeutic research.