The use of traditional, plant-based oils as potential antioxidant treatments for sickle cell anaemia

Abstract

Sickle cell anaemia (SCA) is a genetically inherited red blood cell disorder, affecting populations worldwide. SCA patients suffer from vaso-occlusive crises, whereby erythrocytes sickle and adhere to blood vessel endothelium, culminating in painful symptoms. Tiger nut (Cyperus esculentus) oil and black seed (Nigella sativa) oil are plant-based products that could potentially reduce SCA crises, through their antioxidant properties. As part of this thesis, a questionnaire was constructed to be completed anonymously by SCA participants at the University of Nigeria. The questionnaire focused on the attitudes of the participants towards the use of natural and prescribed SCA treatments. The investigative focus of this research was on the potential in vitro reversal, and increased antioxidant capacity, of sickle cell erythrocytes following treatment with these oils. The anti-sickling efficacy of the oils was deduced through morphological observations, as well as investigating the in vitro effect on sickle haemoglobin (HbS) polymerisation and osmotic fragility. Also, reactive oxygen species (ROS) and antioxidant presence were monitored using a fluorometric intracellular ROS assay and spectrophotometric TEAC antioxidant assay. Corroboration of the antioxidant strength of the oils was undertaken using a DPPH radical scavenging protocol, along with a Folin-Ciocalteau phenol assay. Additionally, an initial study into the anti-adhesive capability of the oil treatments was completed, focusing on CD36-FITC and CD239-FITC antibodies as adhesion markers, with the use of flow cytometric analysis. The questionnaire revealed that most participants were consuming natural treatments, alongside prescribed drugs, as part of their sickle cell routine. In vitro results found that the oil treatments resulted in an increase in the antioxidant presence of sickle cell samples, as well as a morphological decrease of sickle cells, including following sodium metabisulphite induction of HbS polymerisation. Promising results were also identified regarding a reduction of adhesion markers in treated SCA reticulocyte samples. In vivo testing would be the next point of focus for these novel, natural supplements; therefore, a clinical trial for the oral consumption of tiger nut oil and black seed oil by SCA participants was designed and feedback from an ethical committee was reviewed. Overall, the outlook is promising for the global use of tiger nut oil and black seed oil as dietary antioxidant supplements to aid the management of SCA.

Date of Award	Apr 2020
Original language	English
Awarding Institution	Coventry University
Supervisor	Yvonne Elliott (Supervisor), Ellen Hatch (Supervisor) & Afthab Hussain (Supervisor)