Phytochemical studies on natural products and their biological activities against Trypanosoma

  • Naif Dakhil K Alenzi

Student thesis: Doctoral Thesis

Abstract

The therapeutic properties of plants have been recognised since the earliest human communities. One plant considered to have biological effects is Holy Basil (Ocimum sanctum L.), with pre-clinical screening uncovering many compounds with effects against bacteria, anaphylaxis, histamines, and diabetes as well as with wound healing and radio-protective effects, including eugenol, euginal, ursolic acid, carvacrol, linalool, limatrol, and caryophyllene. The phytochemistry of this plant is studied in the first section of this thesis.Propolis is also receiving ample attention in the context of initiatives to discover novel drugs, thanks to its biological and pharmacological qualities. A resinous substance, propolis is produced by honeybees from different plant materials. Different biological effects have been allocated to propolis extracts by earlier studies and their phytoconstituents have been extensively characterised, especially flavonoids, polyphenols, phenolic aldehydes, sesquiterpene quinines, coumarins, amino acids, steroids and inorganic compounds.The present study employed high-resolution LC-MS, HPLC-ELSD and NMR profiling to analyse the chemical composition of Holy Basil (Ocimum sanctum L.) and a range of types of propolis from various geographical areas. Subsequently, suitable methods of extraction, fractionation and identification were be employed to isolate and identify compounds. Furthermore, one-dimensional and two-dimensional NMR as well as LCMS will be applied to elucidate the structures of the isolated compounds.A range of compounds were isolated from Holy Basil extracts and different types of propolis by employing various phytochemical methods, including VLC, CC, SEC, preparative TLC.All crudes extracts, fractions as well as 12 isolated compounds then were subjected for biological testing against Trypanosoma, T. brucei S427 WT, and their cytotoxicity against mammalian cells was also determined. The Holy Basil MeOH extract yielded three pure compounds which were testesd against Trypanosoma, T. brucei S427 WT for the first time and scored relatively moderate to weak activity. While the ethanolic extracts of different types of propolis yielded nine pure compounds.Three of themwere isolated for the first time from Philippine propolis and yelided against Trypanosoma, T. brucei S427 WT relatively moderate acitivity. The other pure compoundes were isolated from Saudi, red Nigerian and red Brazilian, two pures per each sample, gave as well relatively moderate acitivity. Red Nigerian and red Brazilian showed a high degree of similarity in pures obtained from them.
Date of Award1 Jun 2018
LanguageEnglish
Awarding Institution
  • University Of Strathclyde
SupervisorDavid Watson (Supervisor) & (Supervisor)

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