Thesis (Ph.D.) - Cairo University - Faculty of Pharmacy - Department of Pharmacognosy

Centaurea genus is one of the largest genera of family Asteraceae consisting of 500-600 species. It is centered in the Mediterranean region and western Asia. Around 17 species of Centaurea are growing in Egypt. Reviewing the available literature on these species, there were no previous reports regarding C. pumilio. Few studies were found on C. eryngioides, C. alexandrina, C. calcitrapa, C. glomerata, C. scoparia, C. pallescens and C. lippii. A comparative chemical and biological study of the selected Centaurea species were carried out. Preliminary phytochemical screening was performed. The genetic diversity and genetic relationships between the 8 Centaurea species were investigated. Essential oil of selected Centaurea species was obtained by two different techniques, conventional hydrodistillation (HD) and microwave assisted extraction (MAE). Potential essential oil inhibitors of gyrase B enzyme and N-myristoyltransferase via an in silico molecular docking were screened to study the antibacterial activity. Gas chromatography-mass spectrometry analysis (GC-MS) of the essential oils obtained by both techniques was carried out. PCA (Principal component analysis) and AHC (Agglomerative hierarchical cluster) were used for categorization of essential oil samples. The in vitro antimicrobial activity for all essential oils was investigated against Staphylococcus aureus, Escherichia coli and Aspergillus niger. The biological activity of these Centaurea species was evaluated using sensitive and multidrug-resistant cancer cell lines

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