Tanya Iossifova

Caffeic acid esters of phenylethanoid glycosides from Fraxinus ornus bark

Abstract A new phenylethanoid glucoside, 2-(3,4-dihydroxyphenyl)-ethyl- O -β- d -glucopyranosyl-(1→6)-3- O - trans -caffeoyl-β- d -glucopyranoside, named isolugrandoside, was isolated from Fraxinus ornus bark, together with the five known phenylethanoid glycosides 2-(4-hydroxyphenyl)-ethyl-(6- O -caffeoyl)-β- d -glucopyranoside, calceolarioside B, verbascoside, isoacteoside and lugrandoside. Isomerization of lugrandoside to isolugrandoside was not found under the employed conditions of isolation and purification.

Secoiridoid glucosides from Fraxinus ornus bark

Abstract Two novel secoiridoid glucosides, hydroxyframoside A and hydroxyframoside B, were isolated as a mixture from the ethanolic extract of Fraxinus ornus bark, together with the known secoiridoids hydroxyornoside, ligstroside, framoside and oleuropein, and the lignan l-hydroxypinoresinol glucoside. The structures of the new compounds were elucidated on the basis of spectral data.

Complement-mediated antiinflammatory action of extracts and pure secoiridoids isolated from Fraxinus species

Ethanol extracts from Fraxinus sp. were tested for in vitro and in vivo influence on complement activity. Total extracts from F. oxycarpa with a high anticomplement effect were tested in mice models of paw oedema. An inhibitory effect of about 48% in carrageenan‐induced oedema and inhibition of about 80% in cobra venom‐induced oedema was observed at a dose of 25 mg/kg. A correlation between the reduction of oedema volume and changes in the alternative pathway activity was established. A series of pure secoiridoid constituents was compared in vitro for anticomplement action as well as for their ability to prevent cobra venom‐induced complement activation in normal human serum. The substances selectively suppressed the classical pathway activity at 10−4 m. The results support data for the traditional use of Fraxinus stem bark in some inflammatory disorders.

A secoiridoid glucoside and a phenolic compound from Fraxinus ornus bark

Abstract A new secoiridoid glucoside named ornoside and a new tyrosol derivative named ornosol have been isolated from Fraxinus ornus bark, along with the k

Escuside, a new coumarin-secoiridoid from Fraxinus ornus bark

A new coumarin-secoiridoid, named escuside, was isolated from the bark of Fraxinus ornus and its structure determined by spectroscopic methods.

Epoxyconiferyl alcohol from Fraxinus oxycarpa bark

Abstract The new compound, epoxyconiferyl alcohol, has been isolated from the bark of Fraximus oxycarpa , along with the known hydroxycoumarins, esculin, fraxin, esculetin, isoscopoletin, fraxetin, and the secoiridoids, ligstroside and 10-hydroxyligstroside.

A secoiridoid dilactone fromFraxinus ornus bark

SummaryThe isolation and structure elucidation of the secoiridoid hydroxyornoside is described. The behaviour of secoiridoid dilactones on acid methanolysis is discussed.ZusammenfassungDie Isolierung und Strukturaufklärung des Secoiridoids Hydroxyornosid wird beschrieben. Das Verhalten von Secoiridoiddilactonen bezüglich saurer Methanolyse wird diskutiert.

Three 9,19-cyclotetracyclic triterpenes from Skimmia wallichii

Abstract Phytochemical studies on Skimmia wallichii resulted in the isolation of skimmiwallichin, skimmiwallin and a new cycloartanol type compound skimmiwallinin. The structure of skimmiwallinin is elucidated as 3β-methoxy-24-methyl-24-ethyl-9,19-cyclolanost-25(26)-ene on the basis of spectral studies. The structures of skimmiwallichin and another tetracyclic triterpene, now named skimmiwallin, were revised and established to be 3β-methoxy-24,24-diethyl-9,19-cyclolanost-25(26)-ene and 3β-methoxy-25-ethyl-9,19-cyclolanost-24(24 1 )-ene, respectively.

Chemical components of Fraxinus ornus bark — Structure and biological activity

Abstract This review describes the investigations carried out by the authors and co-workers on the chemical composition and biological activity of Fraxinus ornus . Its stem bark has been used in the traditional medicine for treatment of wounds, inflammation, arthritis and dysentery. Our results support the claims of the folk medicine by presenting scientific proofs for the antimicrobial, antiinflammatory, immuno-modulatory, skin-regenerating, antioxidant, photo-dynamic damage prevention and antiviral properties of the bark extract and its components. The ethanolic extract of the stem bark and its main constituent esculin were found practically non-toxic. They inhibited the classical and alternative pathways of complement activation. The extract and esculin displayed antiinflammatory activity in both zymosan- and carrageenan-induced paw edema in mice. The extract exhibited a pronounced antioxidative activity and caused intense wound epithelization. The antimicrobial and photodynamic damage prevention properties of the extract and its fractions were dependable on their hydroxycoumarin composition. The isolated secondary metabolites belong to the groups of hydroxycoumarins, secoiridoids, phenylethanoids and lignans. Most of the coumarins and secoiridoids possess the ability to affect the complement activity. A clear correlation between the structure and the biological activity (antimicrobial, antioxidative and photodynamic damage prevention) of the studied hydroxycoumarins was observed. Isolation of new biologically active compounds and finding of new biological properties of already known bioactive substances has been achieved.