Efficacy of ethiopian medicinal plant extracts for lower limb care (lymphoedema) in in vitro models

  • Dereje Woldemichael

    Student thesis: Doctoral Thesis


    Lymphoedema is a pathological process that results from damage, infection, blockage, or genetic defects in the lymphatic system. The main causes of lower limb lymphoedema in Ethiopia are lymphatic filariasis (LF) and podoconiosis. The current care of lymphoedema in Ethiopia consists of foot hygiene, skin care, compression bandaging, exercise, and antibiotic therapy for ‘acute episodes’ (recurrent acute adenolymphangitis). A range of endemic plant extracts have also been used for the management of pain, wound infection, and inflammation in Ethiopia boosting the interest in medicinal plants and their compounds as an alternative medicine for the management of different diseases. Our systematic review revealed that there are many promising Ethiopian medicinal plant extracts and compounds for the management of wound infection and inflammation. Lawosinia inermis L, Achyranthes aspera L, and Azadirachta indica A. Juss were selected for the evaluation of the anti-inflammatory, wound healing, and anti-infective activities of the crude extracts in in vitro model. Aeromonas hydrophila/caviae, Acinetobacter lwoffii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Shewanella algae, Staphylococcus aureus, Streptococcus pyogenes, Streptococcus dysgalactiae, Staphylococcus haemolyticus, Streptococcus agalactiae, and Staphylococcus simulans were the most predominant bacteria identified which contributed to wound infection in patients with lower limb lymphoedema in the study area. Among the isolated bacteria, most of them were resistant to ampicillin, cefazoline, clindamycin, erythromycin, and tetracycline. Furthermore, this study showed that the methanol extracts of L. inermis L exhibited significant activity and demonstrated a bactericidal effect against most of the tested bacterial strains. However, A. Indica A. Juss and A. aspera L showed low to moderate activity against most tested strains at 400mg/ml. In in vitro model, all the methanol extracts have shown inhibitory activity towards COX-1, COX-2, and 15-LOX enzymes at 10mg/ml. However, L. inermis L was superior in dual inhibition of both LOX and COX enzymes. All the tested extracts showed the best free radical scavenging activity at 10 mg/ml, which is comparable to inhibitory activity to that of ascorbic acid. Moderate antioxidant activity was observed in stimulating the multiplication of human epidermal keratinocytes. Compound isolation, and characterization from the methanol extract of the leaves of L. inermis L was performed. L. inermis L has shown significant activity against bacteria isolated from the lymphoedema patients, in in vitro anti-inflammatory and wound healing activities. This has led to the isolation of three compounds, namely 2-hydroxy-1,4-naphthoquinone (lawsone), 2,3,4,6-tetrahydroxyacetophenone-2β-Dglucopyranoside (lalioside) and 1,2,3,4,5,6-hexahy-droxyhexane (D-mannitol). The new findings in this research work are the micro-organisms isolated and characterized from the wound lymphoedema patients, and the three major compounds that have been isolated from the leaves of methanol extracts of L. inermis which is growing in Ethiopia.
    Date of AwardMar 2022
    Original languageEnglish
    Awarding Institution
    • University of Brighton
    SupervisorGail Davey (Supervisor), Prof Eyasu Makonnen (Supervisor), Belete Adefris (Supervisor) & Abebaw Fekadu (Supervisor)

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