Phytochemical and Biological Investigation of some Endemic Plants of Egypt with Development of a New HPTLC-β- Glucuronidase Inhibition Assay

St. Catherine region is located in Sinai Peninsula of Egypt, where two continents, Asia and Africa, are geographically connected. The area has a characteristic floristic diversity, within which a number of endemic plant species grow. So far, the biological and/or chemical analysis of many of these e...

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1. Verfasser: Mahran, Ehab
Beteiligte: Keusgen, Michael (Prof. Dr.) (BetreuerIn (Doktorarbeit))
Format: Dissertation
Sprache:Englisch
Veröffentlicht: Philipps-Universität Marburg 2019
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Zusammenfassung:St. Catherine region is located in Sinai Peninsula of Egypt, where two continents, Asia and Africa, are geographically connected. The area has a characteristic floristic diversity, within which a number of endemic plant species grow. So far, the biological and/or chemical analysis of many of these endemic species has not thoroughly reported. Accordingly, this study aimed at biological and chemical investigation of two plant species, P. boveana and A. pubescens, growing endemically in St. Catherine. The bacterial/ChE inhibition activities of P. boveana (leaf) and P. veris (flower) extracts were evaluated via HPTLC-EDA hyphenation. Identification of the active metabolites was based on the HPTLC-MS and NMR analysis. The active metabolites were identified as linoleic and linolenic acids (in P. veris) and unsubstituted flavone, 2'-methoxy-, 2'-hydroxy-, and 5,6,2',6'-tetramethoxyflavone (in P. boveana). In A. pubescens, the HPTLC-AChE inhibition activity screening of the 80% alcoholic extract of the plant led to determination of three active metabolites. Their characterization was based on the analysis of the collected mass and NMR data. Two of these metabolites were defined as newly isolated natural compounds; were elucidated to be 6-O-, 6'-O-di-trans-cinnamoylantirrhinoside and 5-O-, 6-O-difoliamenthoyl-antirrhinoside, while the previously known compound was determined as 6-O-foliamenthoyl-(6ꞌ-O-cinnamoyl)-antirrhinoside. In the third part of the study, a new HPTLC-β-glucuronidase inhibition assay was developed. The method was optimized and also verified using two botanical materials. The new hyphenation allowed, for the first time, the direct determination of the β-glucuronidase inhibitors present in complex mixtures. The fourth part of the study reported the HPLC-HRMS (/MS) analysis of the 80% alcoholic extract of P. boveana. A total of 25 metabolites have been tentatively identified as flavonoid compounds. The metabolites included, glycoconjugated flavonoids and flavonoid aglycones. Overall conclusion, the study supported the herbal-evidenced based medicine through establishment of important bioactivities to some plant species. It also confirmed the potential of chromatography/biological activity/chemical analysis hyphenation in evaluation of biological samples present in few amounts.
Umfang:129 Seiten
DOI:10.17192/z2019.0499