Μελέτη των βιολογικών επιδράσεων συστατικών διατροφικών προϊόντων (Doctoral thesis)

Σίμος, Ιωάννης


Flavonoids are a group of chemical molecules found in plants, characterized by the presence of several phenolic units. Flavonoids posses strong antioxidant and anticancer properties. These molecules can act as scavengers of reactive oxygen species (ROS) and as inhibitors of various active enzymes. Thus, the aim of this study was to examine the in vitro cytotoxic properties of flavanols (catechin epicatechin, EGCG)-a group of flavonoids- and their activity as in vivo inhibitors of oxidative stress caused by ozone administration on healthy Wistar rats. Methodology: For the in vitro studies, Trypan Blue exclusion assay and MTT assay were used for cell viability and cell proliferation, respectively, of LMS, MCF-7 and MRC-5 cells. Flow cytometry was used for the determination of apoptosis/necrosis on LMS cells. For the in vivo studies, female Wistar rats aged 3-6 months were used. Oxidative stress was induced by intra-peritoneal administration of 6.1μg/kg body weight of ozone. Flavanols mixture (20mg/kg body weight) was also administrated intra-peritoneally before and after ozone-induced oxidative stress. The Blue CrO5 assay was used for estimation of Total Antioxidant Capacity (TAC) and Liquid Chromatography-Mass Spectra (LC-MS) for the determination of malonaldehyde levels in urine. SOD and GPx enzyme activity were determined by commercial available kits. Hematological indices, indicators of nutrition and metabolism, levels of TNF-a, plasma levels of zinc and copper were also measured. Results: In vitro incubation of various flanavols with tumor cell lines presented an inhibition of cell proliferation. These molecules acted through apoptosis on cancer cells lines. Among the flavanols tested EGCG exerted the highest cytotoxic activity while epicatechin and catechin showed similar but weaker activity. According to the in vivo findings the ozone doses used in this study and the chosen route of administration caused a significant increase in oxidative stress in adult Wistar rats, as shown by significantly increased levels of MDA in urine and a significant decrease in plasma TAC. The results show that flavanols may act as modulators of TAC and maintain the activity of endogenous antioxidant defense enzymes. Conclusion: Flavanols are chemical molecules that have strong biological activity with strong health benefits. Their role and their use as therapeutic agents to treat or prevent diseases or pathogenic situations is promising but requires further research
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων Σχολή Ιατρικής Τμήμα Ιατρικής Τομέας Λειτουργικός - Κλινικοεργαστηριακός Εργαστήριο Πειραματικής Φυσιολογίας
Subject classification: Οξειδωτικό στρες
Αντιοξειδωτικά
Keywords: Αντιοξειδωτικά,Οξειδωτικό στρες,Φλαβονοειδή,Κατεχίνες,Ολική αντιοξειδωτική ικανότητα,Αντιοξειδωτικά ένζυμα
URI: http://olympias.lib.uoi.gr/jspui/handle/123456789/631
Link: http://thesis.ekt.gr/thesisBookReader/id/22145#page/1/mode/2up
Appears in Collections:Διδακτορικές Διατριβές

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