Supervisors info:
Κουρουνάκη Αγγελική, Αναπληρώτρια καθηγήτρια, Φαρμακευτική σχολή, ΕΚΠΑ
Σκαλτσά Ελένη, Καθηγήτρια, Φαρμακευτική σχολή, ΕΚΠΑ
Ράλλης Μιχαήλ, Επίκουρος καθηγητής, Φαρμακευτική σχολή, ΕΚΠΑ
Summary:
The present diploma thesis was carried out in order to evaluate the antioxidant and anti-inflammatory effect of the essential oil, various extracts, as well as fractions, of the plant Achillea umbellata Sm. of the Asteraceae family. Evaluation was performed through both in vitro and in vivo experiments. The stages of this experimental study are three as described below:
In the first experimental stage, the essential oil of the plant (ES) and the aqueous extract (W), which remained as a residue after the distillation, were obtained. In addition, the plant was extracted with methanol and water in a ratio of 5:1 (MW) and cyclohexane, methanol and ether in ratios 1:1:1 (CME). From the latter, through a series of fractions, three flavonoids were finally isolated: a) 5,7,3-trihydroxy-3,6,4-trimethoxy-flavone (centaureidin), b) 5,7-dihydroxy- 6,4-trimethoxy-flavone (santin); and c) 5-hydroxy, 3,6,7,8-tetramethoxyflavone.
In the second experimental step, in vitro assays were performed on the fractions and extracts obtained. Initially, their antioxidant activity was investigated using the DPPH reagent. According to this assay, the MW extract was particularly active with an IC50 of 20 μg/ml as well as the fractions ACH-G, ACH-H, I'C, I'DB, I'DC, I'DD, HI and HJ with an IC50 of 21, 17, 18, 10, 8, 7, 17 and 10 μg/ml, respectively. Their total phenolic content was then determined by the Folin-Ciocalteu method. This revealed that the richest phenolic content was exhibited by the MW extract (0.116 GAE) and the fractions ACH-H (0.126 GAE), I'C (0.144 GAE), HI (0.214 GAE) and HJ (0.241 GAE).
In the third and last experimental stage, three different in vivo experiments were conducted to study the antioxidant, antihyperlipidemic and anti-inflammatory effects of extracts and fractions that showed good antioxidant activity in the in vitro assays. Initially, the anti-inflammatory activity of W and MW extracts and ACH-D, ACH-F and ACH-H fractions was investigated, following carrageenin-induced paw edema in mice. It is noteworthy that in this assay all the extracts/fractions, that were chosen to be evaluated, showed from good to very good activity. The antihyperlipidemic and antioxidant activity of MW, ACH-F and ACH-H was then studied after inducing acute hyperlipidemia and oxidative stress with tyloxapol. The MW extract and the ACH-F fraction showed good antioxidant activity, while the ACH-F fraction showed the best reduction of cholesterol and triglyceride levels in plasma. Finally, the protective/therapeutic action of an aqueous gel with the MW extract was studied in an in vivo experiment where skin inflammation was induced by UV irradiation. From this experiment, the extract showed an interesting effect on treated mice that appeared to have increased skin hydration and elasticity, reduced transepidermal water loss (TEWL), as well as reduced epidermis thickness.
These results all together verify the interesting biological activity of several Achillea umbellata extracts.
