Isolation and biological activity of active ingredients of natural products (Doctoral thesis)

Αναστασοπούλου, Σταυρούλα


This thesis focuses on the study of the chemical composition and biological activity of five native taxa Sideritis: two taxa S. raeseri Boiss & Heldr ssp. raeseri were collected in Syrrako of Ioannina and in Kellari of Melissourgi, two taxa S. scardica Griseb were collected in Vourino in Rhodian of Kozani and in Krystallopigi of Florina, one taxon S. perfoliata L. ssp perfoliata was collected in Koryfi of Trikala. A comparative approach between Sideritis taxa and a commercial Ceylon green Tea (C. sinensis), known for its use in a wide range of research and its many biological activities) has been performed.In particular, extractions were performed with three solvents of different polarity (methanol, water, hexane). Dry extracts:•were tested for their percent yield of solid extraction for each plant species,•were tested for their content in total flavonoids and total phenolics as well as for their antioxidant activity with the DPPH test and were compared with the antioxidant activity of the standard compounds Quercetin, Vitamin C and Troxol,•were qualitatively and quantitatively determinated with standard compounds (eight phenolic acids, nine flavonoids, phenylethanoid glycoside verbascoside, two monoterpenoids and two triterpenoids) using ultra high pressure liquid chromatography coupled to high resolution and precision mass spectrometry and UHPLC / LTQ- Orbitrap XL,•were tested for their biological activity.The results were found to be similar among Sideritis taxa, while there were differences between them and C. Sinensis. In particular, Sideritis taxa exhibited the highest content in total flavonoids in highly polar solvents (methanol, water). In contrast to C. sinensis the highest content of total flavonoids was found in the solvent hexane. Finally, we compared the results (IC50) of the extracts with those of the standard compounds and all the methanolic and aqueous extracts were characterized by moderate antioxidant activity, except of the C. sinensis methanol extract, which had a strong antioxidant effect, and all hexane extracts were characterized by a weak antioxidant activity. We obtained similar quantitative and qualitative results for the Sideritis taxa while different ones for C. Sinensis. Finally, the biological activity was tested in vitro against four cell lines and was compared to cis-Diamminadichloroplatinum (cis-platin). Cell lines were: HeLa, A549, LS174 and the MRC5 series. Τhe results were compared to cis-DDP, which showed the highest cytotoxic activity. Interestingly, the S. perfoliata L. ssp.perfoliata extract exhibited the highest activity against the three cancer cell lines among all the extracts, including that of C. Sinensis, with a selective activity for the normal cell line. Finally, the results for the activity of the methanolic and aqueous extracts of the other two Sideritis taxon in the HeLa cell cancer cell line were also of interest.
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
Subject classification: Φυτά
Keywords: Χημική σύσταση φυτών,Βιολογική δράση φυτών,Chemical composition plants,Biological activity plants
URI: http://olympias.lib.uoi.gr/jspui/handle/123456789/29025
Appears in Collections:Διδακτορικές Διατριβές

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