Supervisors info:
Κουρουνάκη Αγγελική, Καθηγήτρια Τμήμα Φαρμακευτικής ΕΚΠΑ (Επιβλέπουσα)
Κολοκούρης Αντώνιος, Καθηγητής Τμήμα Φαρμακευτικής ΕΚΠΑ,
Παπαναστασίου Ιωάννης, Επίκουρος Καθηγητής Τμήμα Φαρμακευτικής ΕΚΠΑ
Summary:
The metabolic syndrome and related cardiovascular disorders constitute a
global health problem. They depend on a wide variety of factors; interrelated conditions such as dyslipidemia, hypertension, inflammation and chronic oxidative stress contribute to the development of the metabolic syndrome, leading to cardiovascular diseases, such as atherosclerosis.
Atherosclerosis is a multifactorial disease and consequently its pharmacological treatment requires the co-administration of two or more drugs, each of which may
address a different molecular target. The strategy of treatment with multi-target drugs, i.e. the administration of a single pharmacomolecule, which is directed at several different targets, is a recently established approach for the treatment of multifactorial diseases.
The present research work aims at the design and development of multifunctional molecules with anti-inflammatory, antioxidant and anti-hyperlipidemic action. For this purpose, a series of molecules with 2-biphenyl-1,4-benzoxazine as a basic scaffold, were synthesized and studied for their in vitro/in vivo antioxidant, antiinflammatory and anti-dyslipidemic activity.
All derivatives were synthesized by modification of methods found in the literature through a 7-step procedure which led from satisfactory to very good yields. The
molecules were identified by elucidation of their 1H-NMR and 13C-NMR spectra as
well as their melting point.
In order to investigate antioxidant activity in vitro, first the ability of the new
derivatives to act as free radical scavengers via interaction with the free stable radical DPPH, was evaluated. In this test, compound 23 showed the best activity with IC50 = 102 μM, exceeding the activity of the corresponding reference compound. The rest of the derivatives showed appreciable antioxidant activity with the exception of compound 24, which did not show significant activity. In addition, the antioxidant activity of the compounds was further studied through in vitro protection against lipid peroxidation of mouse liver microsomal membranes. All derivatives, with the exception of compound 24, inhibited lipid peroxidation with IC50 values ranging from 57-380 µM. In vitro anti-inflammatory activity was evaluated by the ability to inhibit the enzyme lipoxygenase; all the new derivatives showed significant activity, while the optimal activity was expressed by compounds 22 and 25 with IC50 = 99μM for both.
The synthesized derivatives were studied for their antidyslipidemic and antioxidant activity in vivo, via acute onset of hyperlipidemia induced by tyloxapol administration in mice. All derivatives showed remarkable antihypercholesterolemic activity, reducing plasma total cholesterol levels by 17% to 55% and triglyceride levels by 31% to 94%. The maximum increase in plasma HDL-cholesterol levels was shown by compound 26 (54%) while all final compounds, except compound 22, significantly reduced LDL-cholesterol levels by 50% to 72%. The antiatherogenic index (HDL/LDL) was significantly increased by 2-7 fold in animals treated with the new compounds 22-26.
Total antioxidant capacity (TAC) of the plasma of mice was also evaluated. All derivatives, with the exception of compound 22, showed significant activity increasing TAC by 57% to 386%. At the same time, uric acid levels in plasma were also determined. In this case, all compounds, except compound 22, showed very high capacity in reducing (83-91%) uric acid levels of animals treated with tyloxapol and returned these levels back to normal.
The results of the in vitro and in vivo pharmacological evaluation of the new
derivatives confirm their multifunctional action, as they exhibited at least two of the
designed/desired activities, justifying potential interest for their further study in the
treatment of multifactional diseases such as atherosclerosis.
Keywords:
Structure-Activity Relationships (SAR), DPPH, lipid peroxidation, inflammation, hyperlipidemia
