Aikaterini Termentzi

Aristotle University of Thessaloniki, Saloníki, Central Macedonia, Greece

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Publications (11)27.48 Total impact

  • [Show abstract] [Hide abstract] ABSTRACT: In the framework of the detailed phytochemical analysis of the aerial parts of Sideritis syriaca, two novel acylflavones were isolated together with three acetylated flavone glycosides and acylated flavone glycosides. The novel acylflavones were identified as isoscutellarein 7-trans-p-coumarate and apigenin 7-,4′-bis(trans-p-coumarate). Their structures were elucidated by means of UV, 1D and 2D NMR, LC–DAD–MS and confirmed by HR-MS spectroscopy.
    No preview · Article · Dec 2010 · Food Chemistry
  • [Show abstract] [Hide abstract] ABSTRACT: The 8-, 9-, 10-, and 11-halo, hydroxy, and methoxy derivatives of the antimycobacterial 3,3-dimethyl-3H-benzofuro[3,2-f][1]benzopyran were synthesized by condensation of the diazonium salts of 2-chloroanilines (13-17) with 1,4-benzoquinone (18), reduction of the intermediate phenylbenzoquinones 19-22 to dihydroxybiphenyls, cyclisation to halo-2-hydroxydibenzofurans 24-27, and construction of the pyran ring by thermal rearrangement of the corresponding dimethylpropargyl ethers 35-38. Palladium catalyzed nucleophilic aromatic substitution permitted conversion of the halo to the corresponding hydroxy derivatives which were methylated to methoxy-3,3-dimethyl-3H-benzofuro[3,2-f][1]benzopyran. All compounds substituted on the A ring were found more potent than the reference compound 1 against Mycobacterium bovis BCG and the virulent strain Mycobacterium tuberculosis H37Rv. The effect of the most active derivatives on mycolate synthesis was explored in order to confirm the preliminary hypothesis of an effect on mycobacterial cell wall biosynthesis. The linear 9-methoxy-2,2-dimethyl-2H-benzofuro[2,3-g][1]benzopyran (46) exhibiting a good antimycobacterial activity and devoid of cytotoxicity appeared to be the most promising compound.
    No preview · Article · Oct 2010 · European Journal of Medicinal Chemistry
  • No preview · Chapter · Jan 2010
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    Aikaterini Termentzi · Maria Zervou · Eugene Kokkalou
    [Show abstract] [Hide abstract] ABSTRACT: In the framework of the detailed phytochemical analysis of Sorbus domestica fruits at several maturity stages and additively to the phenolic compounds elucidated by LC-DAD-MS (ESI+), ten more, novel phenolic compounds were isolated after preparative work and their structure elucidation was achieved with UV–vis, NMR (1H, 13C, COSY, HSQC, HMBC, NOESY, TOCSY, ROESY), LC-DAD-MS (ESI+) and HR-NanoESI-QqTOF-MS/MS. The novel compounds belong to the categories of hydroxybenzoic acid derivatives (Compounds 1, 2, 3), polyphenolic phenylpropanoid derivative (Compound 4), quercetin glycosides (Compounds 5, 6), flavanol glycoside (Compound 7), quercetin dimmer (Compound 8) and biphenyls (Compounds 9, 10). Their structures were established as: Vannilic acid 4-O-α-L-rhamnoside (1), protocatechuic acid anhydrite (2), trivanilloyl-(1,3,4-trihydroxybenzol) ester (3), 3-{4-(bis[4-hydroxy-3-(5-hydroxypentanoyloxy) phenyl) methoxy]-3,5-dihydroxy phenyl} propanoic acid (4), quercetin 3-O-β-D-glucopyranosyl(1′′′→2′′)-α-L-rhamnosyl(1′′′′→3′′′)-α-L-rhamnosyl(1′′′′′→3′′′′)-α-L-arabinofuranoside, quercetin 3-O-α-L-rhamnosyl(1′′′→3′′)-β-D-glucopyranoside (6), 5,7,3′,6′-tetrahydroxyflavanol 7-O-β-D-glucopyranoside (7), (7-O-4′′′, 4′O-7′′) quercetin dimmer (8), [2,2′-dihydroxy, 4-(propionic acid hexyl ester), 4′-(propionic acid heptyl ester)] biphenyl (9) and [2,6,2′,6′-tetrahydroxy, 4,4′-bis-(propionic acid hexyl ester)] biphenyl (10).
    Full-text · Article · Sep 2009 · Food Chemistry
  • [Show abstract] [Hide abstract] ABSTRACT: The flavonoid content of several methanolic extract fractions of Navel orange peel (flavedo and albedo of Citrus sinensis) cultivated in Crete (Greece) was first analysed phytochemically and then assessed for its antioxidant activity in vitro. The chemical structures of the constituents fractionated were originally determined by comparing their retention times and the obtained UV spectral data with the available bibliographic data and further verified by detailed LC-DAD-MS (ESI+) analysis. The main flavonoid groups found within the fractions examined were polymethoxylated flavones, O-glycosylated flavones, C-glycosylated flavones, O-glycosylated flavonols, O-glycosylated flavanones and phenolic acids along with their ester derivatives. In addition, the quantitative HPLC analysis confirmed that hesperidin is the major flavonoid glycoside found in the orange peel. Interestingly enough, its quantity at 48 mg/g of dry peel permits the commercial use of orange peel as a source for the production of hesperidin. The antioxidant activity of the orange peel methanolic extract fractions was evaluated by applying two complementary methodologies, DPPH(*) assay and the Co(II)/EDTA-induced luminol chemiluminescence approach. Overall, the results have shown that orange peel methanolic extracts possess moderate antioxidant activity as compared with the activity seen in tests where the corresponding aglycones, diosmetin and hesperetin were assessed in different ratios.
    No preview · Article · Mar 2009 · Biomedical Chromatography
  • M. Armata · C. Gabrieli · A. Termentzi · M. Zervou · E. Kokkalou
    [Show abstract] [Hide abstract] ABSTRACT: The aerial parts of Sideritis syriaca ssp. syriaca (Lamiaceae) were extracted, after defatting, with diethyl ether, ethyl acetate and n-butanol. The antioxidant activities of the extracts were evaluated through in vitro model systems, such as 1,1-diphenyl-2-picryl hydrazyl (DPPH) and Co(II) EDTA-induced luminol chemiluminescence. In both model systems the ethyl acetate extract was the most effective. Phytochemical analysis of ethyl acetate extract showed the presence of two new isomeric compounds (1 and 1′), identified as 1-rhamnosyl, 1-coumaroyl, dihydrocaffeoyl, protocatechuic tetraester of quinic acid, as well as chlorogenic acid (2), apigenin 7-O-glucoside (3), apigenin (4), 4′-O-methylisoscutellarein 7-O-[6′′′-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-d-glucopyranoside] (5), isoscutellarein 7-O-[6′′′-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-d-glucopyranoside] (6), 4′-O-methylisoscutellarein 7-O[β-d-allopyranosyl-(1 → 2)-β-d-glucopyranoside] (7) and 4′-O-methylisoscutellarein 7-O-[β-d-allopyranosyl-(1 → 2)-6′′-O-acetyl-β-d-glucopyranoside] (8). The above compounds were identified by spectroscopic methods.
    No preview · Article · Nov 2008 · Food Chemistry
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    A Termentzi · P Alexiou · V J Demopoulos · E Kokkalou
    [Show abstract] [Hide abstract] ABSTRACT: Aldose reductase (ALR2) is a rate-limiting enzyme in the polyol pathway associated with the conversion of glucose to sorbitol and whose activity is implicated in the development of the long-term diabetic complications. Upon previous years, several scientific efforts were focused towards the development of ALR2 inhibitors as effective secondary anti-diabetic drugs. To this regard and during our extensive phytochemical analysis of Sorbus domestica (fam. Rosaceae), twenty nine different extracts, fractions and residues of five different maturity stages of Sorbus domestica fruits were evaluated for their in vitro ALR2 inhibitory capacity. The data obtained thus far have indicated that the diethyl ether and ethyl acetate fractions possess high aldose reductase inhibitory activity. Furthermore, detailed phytochemical LC-DAD-MS (ESI+) analysis of such extracts has shown that this aldose reductase inhibitory activity could be attributed to the high content of flavonoids and hydroxycinnamoyl esters. These results suggest that Sorbus domestica fruit consumption may be a promising way for lowering the incidence of long-term complications of diabetes mellitus, especially at early stages, a possibility being discussed in this paper.
    Full-text · Article · Oct 2008 · Pharmazie
  • A Termentzi · M Zervou · E Kokkalou
    No preview · Article · Jul 2008 · Planta Medica
  • Aikaterini Termentzi · Eugene Kokkalou
    [Show abstract] [Hide abstract] ABSTRACT: In this study, various fractions isolated from the petals of Crocus sativus were assessed at first for their phenolic content both qualitatively and quantitatively and secondly for their antioxidant activity. The phytochemical analysis was carried out by LC-DAD-MS (ESI (+)) whereas the antioxidant potential was evaluated by applying two methodologies, the DPPH. radical scavenging activity test and the Co(II)-induced luminol chemiluminescence procedure. According to data obtained from these antioxidant tests, the diethyl ether, ethyl acetate and aqueous fractions demonstrated the strongest antioxidant capacity. Interestingly, the major constituents identified in these fractions correspond to kaempferol, quercetin, naringenin and some flavanone and flavanol derivatives glycosylated and esterified with phenylpropanoic acids. In addition, the presence of some nitrogen-containing substances, as well as other phenolics and phenylpropanoic derivatives was also traced. The identification and structural elucidation of all substances isolated in this study was achieved by both comparing available literature data and by proposed fragmentation mechanisms based on evaluating the LC-DAD-MS (ESI (+)) experimental data. The quantitative analysis data obtained thus far have shown that Crocus sativus petals are a rich source of flavonoids. Such a fact suggests that the good antioxidant capacity detected in the various fractions of Crocus sativus petals could be attributed to the presence of flavonoids, since it is already known that these molecules exert antioxidant capability. The latter, along with the use of Crocus sativus in food and pharmaceutical industry is discussed.
    No preview · Article · May 2008 · Planta Medica
  • Aikaterini Termentzi · Panagiotis Kefalas · Eugene Kokkalou
    [Show abstract] [Hide abstract] ABSTRACT: The aim of this study was the detailed qualitative and quantitative analysis of the phenolic content of several extracts and fractions of Sorbus domestica fruits. The analysis was realized by LC–DAD–MS (ESI+). Twenty-four different extracts and fractions of five different maturity stages of the fruit were analyzed for comparison reasons in order to determine the most beneficial for health type of consuming. Sixty-two different phenolics were identified. There were significant qualitative and quantitative differentiations in the phenolic content among the different types of the fruits. All categories were rich in benzoic, phenylpropanoic and cinnamoylquinic acids and derivatives. Unripe fruit categories were also rich in flavonoids, while well matured fruit categories had a low content of flavonoids. Fruit pulp, which was proved to be a strong antioxidant according to previous research work, contained very low amounts of both acids and flavonoids, but its phenolic content was highly qualitatively differentiated from the other categories.
    No preview · Article · Feb 2008 · Food Chemistry
  • Aikaterini Termentzi · Panagiotis Kefalas · Eugene Kokkalou
    [Show abstract] [Hide abstract] ABSTRACT: Thirty four different extracts, fractions and residues of five different maturity stages of the Greek Service tree fruits (Sorbus domestica, fam. Rosaceae) were evaluated for their antioxidant activities (DPPH and luminol-induced chemiluminescence methods) and in correlation with their total phenolic contents (Folin–Ciocalteau test).Dichloromethane, diethyl ether and ethyl acetate fractions possessed significant radical-scavenging activities which were greater than the activity of trolox. This seemed to be correlated with their total phenolic content. Unripe yellow fruits, together with the fruit pulp, were the strongest antioxidants, while the well-matured brown fruits were the weakest ones. Results showed that the fractions of diethyl ether, ethyl acetate and dichloromethane, can be used as antioxidants in food and medicinal preparations.
    No preview · Article · Dec 2006 · Food Chemistry