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-ß-D-glucopyranosyl-5ß-furostan-1ß,3ß,22α,26-tetraol-1-O-ß-D-glucopyranoside and (25S)-26-O-ß-D-glucopyranosyl-5ß-furostan-1ß,2ß,3ß,5ß,22α,26-hexaol and the known compounds (25S)-26-O-ß-D-glucopyranosyl-5ß-furostan-3ß,22α,26-triol-3-O-α-L-rhamnopyranosyl-(1 → 2)-O-ß-D-glucopyranosyl-(1 → 2)-O-ß-D-glucopyranoside and (25S)-26-O-ß-D-glucopyranosyl-5ß-furostan-3ß,22α,26-triol-3-O-ß-D-glucopyranosyl-(1 → 2)-O-ß-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.

Chemical composition and antimicrobial activity of wild garlic Allium ursinum of Bulgarian origin.

The chemical composition of fresh flowers from Allium ursinum (ramsons, bear's garlic, wild garlic) growing in Bulgaria has been studied. Thymidine (1), adenosine (2), astragalin (kaempferol-3-O-beta-D-glucopyranoside (3), kaempferol-3-O-beta-D-glucopyranosyl-7-O-beta-D-glucopyranoside (4), kaempferol-3-O-beta-D-neohesperoside (5), and kaempferol-3-O-beta-D-neohesperoside-7-O-beta-D-glucopyranoside (6) were isolated from the n-butanol extract and identified by different spectroscopic and spectrometric methods. Thymine (7), uridine (8), uracil (9) and 5-chloro-uridine (10) were detected in the same extract by GC-MS. This is the first report of the occurrence of 1, 2, 4, 7 - 10 in the flowers of A. ursinum. GC-MS of the volatile components of fresh flowers and leaves from the same plant revealed a high content of sulfur compounds, some of which are reported for the first time for A. ursinum. The antimicrobial activities of extracts from fresh flowers and leaves of A. ursinum have been tested; some extracts exhibited moderate antifungal properties.

Screening of some saponins and phenolic components of Tribulus terrestris and Smilax excelsa as MDR modulators.

BACKGROUND: Cytotoxic activity of saponins and phenolic compounds have been described in the literature, but no reports were found on their multidrug resistance (MDR)-modulating effects on human mdr1 gene-transfected mouse lymphoma cell line. MATERIALS AND METHODS: Methylprototribestin, structurally related compounds and a mixture of 3 acetylated isomers of methylprotodioscin were investigated for antiproliferative effect and modulation of drug accumulation. RESULTS: The growth inhibitory dose (ID50) of the compounds ranged from 12.64 to 20.62 mug/ml. Methylprototribestin was the most effective resistance modifier. However, methylprotodioscin, pseudoprotodioscin, prosapogenin A of dioscin, tribestin and 5-O-caffeoylshikimic acid showed moderate MDR reversal activity. In a checkerboard method, methyloprototribestin and the mixture of the 3 acetylated isomers enhanced the antiproliferative effects on MDR cells in combination with doxorubicin. CONCLUSION: Based on these results, methylprototribestin and the mixture of the 3 acetylated isomers can be recommended for further in vivo experiments in combination with anthracyclines in human MDR-cancer xenograft transplanted mice.

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-alpha-L-rhamnopyranosyl-(1 --> 2)-{alpha-L-rhamnopyranosyl-(1 --> 4)}-beta-D-glucopyranosyl]-26-O-[beta-D-glucopyranosyl]-22alpha-hydroxy-(25R)-furost-5-ene-3beta,26-diol (1), 3-O-[2-O-acetyl-alpha-L-rhamnopyranosyl-(1 --> 2)-{alpha-L-rhamnopyranosyl-(1 --> 4)}-beta-D-glucopyranosyl]-26-O-[beta-D-glucopyranosyl]-22alpha-hydroxy-(25R)-furost-5-ene-3beta,26-diol (2), 3-O-[3-O-acetyl-alpha-L-rhamnopyranosyl-(1 --> 2)-{alpha-L-rhamnopyranosyl-(1 --> 4)}-beta-D-glucopyranosyl]-26-O-[beta-D-glucopyranosyl]-22alpha-hydroxy-(25R)-furost-5-ene-3beta,26-diol (3), and three known saponins: protodioscin (4), pseudoprotodioscin (5) and dioscin (6) were isolated.

MDR-reversal activity of chalcones.

The ability of 11 chalcones with 3,4,5-trimethoxy substitution on ring A to inhibit the transport activity of P-glycoprotein was studied. Flow cytometry was applied in multidrug-resistant human mdr1 gene-transfected mouse lymphoma cells (L 5178 Y). The reversal of multidrug resistance (MDR) was investigated by measuring the accumulation of rhodamine-123 in cancer cells. Verapamil was applied as a positive control. The majority of the tested compounds were proved to be effective inhibitors of the outward transport of rhodamine-123. In the MTT test, chalcones 2, 3, 5 and 7 exhibited the strongest antiproliferative effects, with 50% inhibitory dose (ID50) =0.19, 0.19, 0.29 and 0.14 microg/mL, respectively. The least effective compounds were 1, 4, 8 and 11, with ID50 values in the range of 1.5-3.5 microg/mL. The antiproliferative effect was shown to be affected by the type of substitution at the p-position on ring B. Chalcone 7, with a p-chloro group on ring B, was the most effective in MDR reversal, causing a marked increase in drug accumulation from 0.4 to 40 microg/mL. In combination with epirubicin, compound 7 displayed synergistic properties while compound 3 exhibited an additive effect. The data presented here indicated that some calcone derivatives can be regarded as effective compounds for reversal of MDR.

Distribution of steroidal saponins in Tribulus terrestris from different geographical regions.

The steroidal saponins of Tribulus terrestris L. (Zygophyllaceae) are considered to be the factor responsible for biological activity of products derived from this plant. The activity depends on the concentration and the composition of active saponins, which in turn is influenced by the geographical origin of plant material. Samples of T. terrestris collected in Bulgaria, Greece, Serbia, Macedonia, Turkey, Georgia, Iran, Vietnam and India were analyzed by LC-ESI/MS/MS for the presence and the concentration of protodioscin (1), prototribestin (2), pseudoprotodioscin (3), dioscin (4), tribestin (5) and tribulosin (6). The flavonoid rutin (7) was also included in the comparison. The results revealed distinct differences in the content of these compounds depending on region of sample collection, plant part studied and stage of plant development. The samples from Bulgaria, Turkey, Greece, Serbia, Macedonia, Georgia and Iran exhibited similar chemical profile and only some quantitative difference in the content of 1-7 with protodioscin (1) and prototribestin (2) as main components. The Vietnamese and Indian samples exhibit totally different chemical profile. They lack 2 and 5, while tribulosin (6) is present in high amounts. Compounds different from 1 to 7 are dominating in these 3 samples. The presented results suggested the existence of one chemotype common to the East South European and West Asian regions. Most probably, the Vietnamese and Indian samples belong to other chemotypes which are still to be studied and characterized. No clear correlation between the burrs morphology and the chemical composition of the samples has been found.

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.

Complement inhibiting properties of dragon's blood from Croton draco.

The latex of Croton draco, its extracts and several latex components have been investigated for their influence on both classical (CP) and alternative (AP) activation pathways of the complement system using a hemolytic assay. The best inhibition was found for the classical pathway. The latex, ethyl acetate and ethyl ether extracts exhibited extremely high inhibition on the CP (94, 90 and 77%, respectively) at a concentration of 1 mg/ml. The flavonoid myricitrin, the alkaloid taspine and the cyclopeptides P1 and P2 showed high inhibition on CP (83, 91, 78 and 63%, respectively) at a concentration of 0.9 mM.

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 trihydroxy-derivatives 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.

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-beta-glucopyranosyl-22alpha-methoxy-(25R)-furost-5-ene-3beta,26-diol-3-O-alpha-rhamnopyranosyl-(1-->2)-beta-4-O-sulfo-glucopyranoside (methylprototribestin) and sodium salt of 26-O-beta-glucopyranosyl-22alpha-hydroxy-(25R)-furost-5-ene-3beta,26-diol-3-O-alpha-rhamnopyranosyl-(1-->2)-beta-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.