Antoaneta Ivanova

Two New Sulfated Furostanol Saponins from Tribulus terrestris

The known furostanol saponins methylprotodioscin and protodioscin and two new sulfated saponins, sodium salt of 26-O-β-glucopyranosyl-22α-methoxy-(25R)-furost-5-ene-3β,26-diol- 3-O-α-rhamnopyranosyl-(1→2)-β-4-O-sulfo-glucopyranoside (methylprototribestin) and sodium salt of 26-O-β-glucopyranosyl-22α-hydroxy-(25R)-furost-5-ene-3β,26-diol-3-O-α-rhamnopyranosyl-( 1→2)-β-4-O-sulfo-glucopyranoside (prototribestin) have been isolated from the aerial parts of Tribulus terrestris L. growing in Bulgaria. The structures of the new compounds were elucidated on the basis of 1D and 2D (DQF-COSY, TOCSY, HSQC-TOCSY, HSQC, HMBC, ROESY) NMR data, ESI mass spectra and chemical transformation.

Alkaloids and Coumarins from Ruta graveolens

Summary. The aerial parts of Ruta graveolens cultivated in Bulgaria afforded four new 2-alkyl-4-(1H)-quinolone alkaloids together with thirteen known components. The new alkaloids were obtained as a mixture of homologues. The structures of all compounds were determined by spectroscopic methods.Zusammenfassung. Aus den oberirdischen Teilen von in Bulgarien gezogener Ruta graveolens konnten neben dreizehn bereits bekannten Substanzen vier neue 2-Alkyl-4(1H)-chinolonalkaloide als Gemisch homologer Verbindungen isoliert werden. Die Strukturen der neuen Komponenten wurden mit spektroskopischen Methoden aufgeklärt.

New furostanol saponins from Smilax aspera L. and their in vitro cytotoxicity

The occurrence of the two new cis-fused A/B rings furostanol saponins (25S)-26-O-β-D-glucopyranosyl-5β-furostan-1β,3β,22α,26-tetraol-1-O-β-D-glucopyranoside and (25S)-26-O-β-D-glucopyranosyl-5β-furostan-1β,2β,3β,5β,22α,26-hexaol and the known compounds (25S)-26-O-β-D-glucopyranosyl-5β-furostan-3β,22α,26-triol-3-O-α-L-rhamnopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranoside and (25S)-26-O-β-D-glucopyranosyl-5β-furostan-3β,22α,26-triol-3-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranoside, trans-resveratrol, (+) catechin and (-) epicatechin in the rhizomes of Smilax aspera is reported. All saponins have been isolated as their 22-OMe derivatives, which were further subjected to extensive spectroscopic analysis. The isolated furostanol saponins were evaluated for cytotoxic activity against human normal amniotic and human lung carcinoma cell lines using neutral red and MTT assays. In vitro experiments showed significant cytotoxicity in a dose dependent manner with IC(50) values in the range of 32.98-94.53 µM.

Steroidal saponins from Smilax excelsa rhizomes

From the n-butanol soluble fraction of the methanol extract of the rhizomes of Smilax excelsa, three new furostanol saponins 3-O-[4-O-acetyl-α-L-rhamnopyranosyl-(1 → 2)-{α-L-rhamnopyranosyl-(1 → 4)}-β-D-glucopyranosyl]-26-O-[β-D-glucopyranosyl]-22α-hydroxy-(25R)-furost-5-ene-3β,26-diol (1), 3-O-[2-O-acetyl-α-L-rhamnopyranosyl-(1 → 2)-{α-L-rhamnopyranosyl-(1 → 4)}-β-D-glucopyranosyl]-26-O-[β-D-glucopyranosyl]-22α-hydroxy-(25R)-furost-5-ene-3β,26-diol (2), 3-O-[3-O-acetyl-α-L-rhamnopyranosyl-(1 → 2)-{α-L-rhamnopyranosyl-(1 → 4)}-β-D-glucopyranosyl]-26-O-[β-D-glucopyranosyl]-22α-hydroxy-(25R)-furost-5-ene-3β,26-diol (3), and three known saponins: protodioscin (4), pseudoprotodioscin (5) and dioscin (6) were isolated.

Alkaloids derived from genus Veratrum and Peganum of Mongolian origin as multidrug resistance inhibitors of cancer cells

Alkaloids comprise one of the largest groups of plant secondary metabolites including vinca alkaloids. The ability of six alkaloids from Veratrum lobelianum, one from Veratrum nigrum and three from Peganum nigellastrum to modify transport activity of MDR1 was studied. Flow-cytometry in a multidrug-resistant human MDR1-gene-transfected mouse lymphoma cells (L5178Y) was applied. The inhibition of multidrug resistance was investigated by measuring the accumulation of rhodamine-123 in cancer cells. Veralosinine and veranigrine were the most effective resistance modifiers. In a checkerboard method veralosinine and veranigrine enhanced the antiproliferative effects of doxorubicin on MDR cells in combination. The structure-activity relationships were discussed.

Volatile Components of Some Rutaceae Species

The volatile components of the aerial parts of Ruta graveolens and Haplophyllum suaveolens, as well as of leaves of Zanthoxylum limoncello, Z. panamense and Z. setulosum have been studied by GC/MS analysis.

GC-mS analysis and anti-microbial activity of acidic fractions obtained from Paeonia peregrina and Paeonia tenuifolia roots.

Fourteen aromatic and 24 aliphatic acids were determined by GC-MS analysis of acidic fractions obtained from Paeonia peregrina and Paeonia tenuifolia roots. Benzoic acid and its monohydroxy-, dihydroxy- and trihydroxyderivatives are the main acid components of both Paeonia species. Some fractions could serve as a source of benzoic, 4-hydroxybenzoic, vanillic and gallic acids, as well as of ethyl gallate. The fractions inhibited the growth of Staphylococcus aureus, Escherichia coli and Candida albicans.

Bioactive chemical constituents from Smilax excelsa

Plants from the genus Smilax are used to treat syphilis, acute bacillary dysentery, acute and chronic nephritis, eczema, dermatitis, cystitis, and mercury and silver poisoning [1, 2]. Several species from this genus have demonstrated antimutagenic [3], antioxidant [4], anti-inflammatory, and anti-nociceptive activities [5]. A survey of the literature showed that several Smilax species contain phenylpropanoid glycosides [3], anthocyanins [6], flavanoid glucosides [2], and steroidal saponins [7, 8]. We investigated the constituents of the rhizomes of Smilax excelsa, a climbing shrub growing in Bulgaria. In this paper we report the isolation and structural identification of trans-resveratrol (1) [9], naringenin (2) [10], 5-O-caffeoylshikimic acid (3) [11], 1-O-trans-feruloylglycerol (4) [12], 1-O-trans-p-coumaroylglycerol (5) [12], and 1,2-O-di-trans-feruloylglycerol (6) [12]. The antimicrobial and cytotoxic activities of the methanol, chloroform, n-butanol, and water-methanol extracts were tested.

Intraspecific Variability of Biologically Active Compounds of Different Populations of Tribulus Terrestris in Thracian Floristic Region

ABSTRACT Tribulus terrestris, commonly known as Puncture vine, is a member of the Zygophyllaceae family. The steroidal saponins are considered to be the factor responsible for the biological activity of the products derived from this plant. The content of the main steroidal saponins protodioscin, prototribestin, dioscin and the flavonoid glucoside rutin in T. terrestris populations from 19 localities in the Thracian floristic region were analyzed using an HPLC method. Seven localities from Haskovo Plain and Pazardzhik-Plovdiv Plain showed the highest content of Pd, which varied from 12.79 to 22.39 mg/g and Pt -from 7.29 to 21.70 mg/g with a total of 47000 kg dry mass exploitation reserve. Cluster analysis was performed to reveal the possible similarities among the investigated habitats. The economically important populations can be successfully used in our country and international markets for the preparation Tribestan and some food supplements containing extracts from T. terrestris.

HPLC METHOD FOR SCREENING OF STEROIDAL SAPONINS AND RUTIN AS BIOLOGICALLY ACTIVE COMPOUNDS IN TRIBULUS TERRESTRIS L.

ABSTRACT An improvement method for extraction of steroidal saponins and rutin of Tribulus terrestris L. (Zygophyllaceae) was evaluated. It is shown that the ultrasound extraction is faster, easier, solvent-saving, more reliable and effective method than the conventional heat reflux extraction method. Under optimized conditions, the main biologically active compounds protodioscin, prototribestin, dioscin and rutin were extracted from Tribulus terrestris with different origin and analyzed by revesed phase HPLC with UV detector.