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

The use of innovative methods as potential techniques for improving the efficiency of extraction of bioactive phytochemicals from certain economically important medicinal plants has been explored. This has been achieved through conducting ultrasonically assisted extraction, microwave assisted extraction and accelerated solvent extraction in comparison to conventional extraction methods (maceration, heat reflux and soxhlet). Altering extraction parameters, including: extraction time, temperature, ultrasonic frequency, microwave power and static cycles of extraction have been studied. Silymarin contents from Silybum marianum seeds and chlorogenic acid contents from Cynara scolymus leaves have been determined. High Performance Liquid Chromatography has been used for quantitative determination of extracted bioactive compounds. From the obtained results, extraction mechanisms accounting for the observed yields were proposed and rationalised in more general terms for the extraction of bioactive principles from natural products. Conventional hydrodistillation for extraction of essential oil of Foeniculum vulgare fruits has been compared to microwave assisted extraction method. GC/MS was used for evaluation of essential oils obtained. Certain biological activities, including: hepatoprotection, hepatotoxicity and antioxidant activities of the prepared extracts were evaluated. It can be concluded that, innovative extraction techniques showed improvement in the extraction efficiency of medicinal and aromatic plants under study, which will encourage further research in this field for better pharmaceutical industrial applications

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