The isolation and characterisation of bioactive metabolites from ficus carica and their effects on acrolein-induced oxidative stress and NQO1 expression in neuronal differentiated SH-SY5Y cell line

  • Hanan Khojah

Student thesis: Doctoral Thesis

Abstract

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder. Evidence has shown that a key feature of AD is increased brain oxidative stress. This oxidative damage causes the formation of reactive oxygen species (ROS), leading to the expression of endogenous anti-oxidant proteins such as NAD(P)H dehydrogenase (quinone 1) (NQO1) and to the production of Aβ peptides and thereafter to neuronal death. The current drug treatments available for the treatment of AD cause various severe side effects. Therefore, herbal therapies should be considered as alternative/complementary medicines to existing therapeutic approaches due to its traditional used and its richness of anti-oxidant constituents (Wightman, 2017). The fig (Ficus carica L., or F. carica) is a classic fruit tree associated with the beginning of horticulture in the Mediterranean region. Middle Eastern countries in particular have been an important centre of fig growth for centuries (Khedr et al., 2016). Few studies have focused on F. carica in the treatment of AD; however, this edible fruit has been shown to be effective in managing the disease (Ango et al., 2016; Bhangale and Acharya, 2016; Essa et al., 2015). In this study, metabolite profiling was performed on the exocarp, endocarp, and mesocarp of F. carica’s fruit via high throughput screening (HTS) (namely metabolomics). The secondary metabolites of these parts were extracted using TLC and Flash® chromatography. The secondary metabolites were then screened and their putative biomarkers targeted through a multivariate analysis conducted using SIMCA-P, including dereplication, HCA, PCA, OPLS-DA, and S-plot analysis. No higher molecular ion peaks (m/z) were detected. Moreover, the isolation and structural identification of phytosterols (namely γ-Sitosterol, lupeol acetate) and unsaturated fatty acid (Oleioyl-β-D-arabinoside) from the mesocarp, and polyphenols (namely P-hydroxybenzoic acid and vanillic acid) and triterpene (namely lawsaritol) from the endocarp of F. carica were carried out. As well as the isolation and structural elucidation of β-amyrin acetate and campesterol from the fruit’s exocarp. The structures of these compounds were verified using various spectroscopic methods, including HRESIMS, GC-MS, and NMR spectroscopy. The cell viability test, cytotoxic activities as well as the qualitative western blotting test with the anti-oxidant NQO1 anti-body of the isolated compounds were evaluated, and exhibited activity that mitigated the oxidative stress of acrolein-related AD in in-vitro differentiated SH-SY5Y neuro-cell line. These findings introduced the potential of using phytosterol as a therapeutic intervention in AD in addition to other protective agents. This is the first study to implement metabolomics on the chemical composition and biological potential of F. carica parts.
Date of Award20 Jul 2018
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SupervisorRuangelie Edrada-Ebel (Supervisor) & David Watson (Supervisor)

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