Rilka Taskova

Iridoid glucosides from three Veronica species

Abstract A new iridoid glucoside, 6′-O-menthiafoloylmussaenosidic acid, was isolated from the methanolic extract of Veronica bellidioides along with 11 known iridoid glucosides and the aromatic glucosides, picein and 4-O-glucopyranosylzingeron. The structure of the new iridoid was elucidated on the basis of its spectral data. Geniposidic acid and 4-O-glucopyranosylzingeron were found for the first time in the genus Veronica and verminoside in V. bellidioides. Nine known iridoids of which the major ones were mussaenoside and aucubin were found in V. alpina, and nine known iridoids with amphicoside as the major one were found V. kellererii.

Iridoid glucosides from Plantago cornuti, Plantago major and Veronica cymbalaria

Abstract The new iridoid glucoside from the rare Δ8,9 type, 10-acetoxymajoroside, was isolated from Plantago cornuti and P. major along with known iridoids. The main constituents in V. cymbalaria were the known catalpol, amphicoside and verproside together with alpinoside, aucubin, 6-O-veratroylcatalpol and verminoside. The iridoid alpinoside with a 8,9-double bond was found for the first time in genus Veronica.

Iridoid glucosides of the genus Veronica s.l. and their systematic significance

Abstract. 16 iridoid glucosides and 3 aromatic compounds were isolated from Bulgarian natural populations of Veronica L. and Pseudolysimachion Opiz species. The distribution of 11 compounds in 34 species (96 samples) was shown. Seven Veronica and Pseudolysimachion species were screened for iridoids for the first time and a phenylethanoid glycoside, calceolarioside C, was found for the first time in the genus Veronica. The systematic significance of iridoid glucosides at subspecies, species, sectional, and generic levels is discussed. A correlation between the chemical characters (iridoids and flavonoids) and the chromosome base numbers of the perennial Veronica species was established. Origin of the annual species from the perennials through two evolutionary lines was supposed.

Iridoid patterns of genus Plantago L. and their systematic significance

The distribution of 14 iridoid glucosides in 14 Plantago L. species (44 samples corresponding to 18 taxa) was shown. P. tenuiflora and P. gentianoides were studied for iridoids for the first time. The iridoid patterns showed a good correlation with morphological and other chemical features of the representatives of genus Plantago. The studied species are grouped together according to the iridoid patterns: species containing mainly aucubin (P. major, P. cornuti, P. gentianoides); species containing aucubin and aucubin derivatives (P. subulata, P. media); species containing aucubin and catalpol (P. lanceolata, P. altissima, P. argentea, P. lagopus, P. atrata); species containing aucubin and plantarenaloside (P. afra, P. scabra).

Bioactive Phenolics from Carthamus lanatus L.

Abstract Two flavonoid aglycons, eight flavonoid glycosides, chlorogenic acid and syringin were isolated from aerial parts of Carthamus lanatus. Isorhamnetin 3-O-β-ᴅ-glucoside and chlorogenic acid were found for the first time in the genus Carthamus and respectively, quercimeritrin, astragalin, kaempferol 3-O-β-ᴅ-sophoroside and syringin in the species. The ethyl acetate fraction of the methanol extract exhibited a higher antioxidant activity than the butanol fraction measured by the α,α-diphenyl-β-picrazylhydrazyl (DPPH) free radical scavenging assay. Cytotoxicity and antioxidant activities of the main constituent, luteolin 7-O-β-D-glucoside, were evaluated.

Antimicrobial activity and cytotoxicity of Carthamus lanatus.

Total dichloromethane, methanol and water extracts, their fractions as well as volatiles of Carthamus lanatus aerial parts were phytochemically screened and evaluated for antibacterial, antifungal and cytotoxic activity. The H(2)O/MeOH fraction of the CH(2)Cl(2) extract exhibited noticeable antibacterial activity. The same fraction and the volatiles showed significant cytotoxic activity.

GC/MS analysis of some bioactive constituents from Carthamus lanatus L.

Abstract Sterols, triterpenes, volatiles, polar and other constituents in aerial parts of Carthamus lanatus were analyzed by gas chromatography-mass spectrometry. Over 90 compounds were identified most of them new for the species. Sitosterol and stigmasterol were the most abundant of 10 sterols identified in the sterol fraction. Taraxasterol, α- and β-amyrine prevailed in the triterpene fraction. Volatiles, sterols and a fraction of the dichloromethane extract showed strong cytotoxicity (Artemia salina assay).

Antiinflammatory and analgesic effects of Carthamus lanatus aerial parts

Fractions of methanol, dichloromethane, water extracts and volatiles of Carthamus lanatus aerial parts given by oral route at a dose of 2 mg/kg showed significant antiinflammatory activities in rats. On the contrary, only the water fraction of MeOH extract possesses a significant analgesic activity.

Terpenoids from Achillea clypeolata

Abstract A new sesquiterpene alcohol named clypeotriol and characterised as eudesm-4(15)-en-3 α ,7 α , 11-triol was isolated from Achillea clypeolata collected in south-western Bulgaria. Populations of the same taxon growing in the eastern regions of Bulgaria afforded only sesquiterpene lactones two of which were the novel guaianolides 3 α ,4 α -epoxyrupicolin-A and 3 α ,4 α -epoxyrupicolin-B. The structures of the new compounds were elucidated on the basis of spectral data.

Oxygenated Bisabolane Fucosides from Carthamus lanatus L.

The aerial parts of Carthamus lanatus (Asteraceae) afforded four new oxygenated bisabolane fucosides, 10-hydroperoxy-bisabola-2,11-diene 7-O-β-ᴅ-fucopyranoside, 11-hydroperoxy- bisabola-2,9-diene 7-O-β-ᴅ-fucopyranoside, 10-hydroxy-bisabola-2,11-diene 7-O-β-ᴅ-fucopyranoside and 11-hydroxy-bisabola-2,9-diene 7-O-β-ᴅ-fucopyranoside together with the known compounds α-bisabolol β-ᴅ-fucopyranoside, asperuloside, sitosterol 3-O-β-ᴅ-glucoside and stigmasterol 3-O-β-ᴅ-glucoside. Asperuloside appears to be the second representative of the iridoid monoterpene group found in the plant family Asteraceae, which until recently was considered to lack iridoids. The main constituent α-bisabolol fucoside exhibited noticeable antibacterial and cytotoxic activities.