Isolation and identification of cytotoxic compounds from the rhizomes of Paris quadrifolia L.

BACKGROUND: Paris quadrifolia L. is a medicinal plant which contains steroidal saponins. The present study reports isolation and structural identification of six pennogenyl saponins obtained from P. quadrifolia rhizomes. The four spirostan saponins were obtained from P. quadrifolia for the first time. The cytotoxic effects of the sub-fractions and six compounds isolated from the plant extract were evaluated on tumour cells. MATERIALS AND METHODS: Ethanol extract from the rhizomes of P. quadrifolia were partinioned using column chromatography. The saponins were isolated from the obtained sub-fractions by isocratic RP HPLC and their structures were determined by means of 1D and 2D NMR spectroscopy and MALDI TOF MS. The cytotoxic effects of the sub-fractions and the isolated compounds were tested against human promyelocytic leukaemia cells (HL-60), human cervical adenocarcinoma cells (HeLa) and human breast cancer cells (MCF-7) using the [(3-(4,5-dimethylthiazol-2-yl)]-2,5-diphenyltetrazolium bromide (MTT) assay. RESULTS: Six pennogenyl saponins were isolated from P. quadrifolia rhizomes: pennogenin 3-O-ß-D-glucopyranoside (1), pennogenin 3-O-α-L-rhamnopyranosyl-(1→4)-ß-D-glucopyranoside (2), pennogenin 3-O-α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranoside (3), pennogenin 3-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)-ß-D-glucopyranoside (4), pennogenin 3-O-α-L-rhamnopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-ß-D-glucopyranoside (5), pennogenin 3-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-ß-D-glucopyranoside (6). Pennogenyl saponins 5 and 6 exhibited cytotoxic activity against HL-60, HeLa and MCF-7 tumour cells with IC50 values of 1.0 ± 0.04 µg/ml, 1.8 ± 0.072 µg/ml and 2.4 ± 0.096 µg/ml respectively, and 2.0 ± 0.08 µg/ml, 2.5 ± 0.125 µg/ml and 3.2 ± 0.128 µg/ml respectively. CONCLUSION: Compounds 1-4 were isolated from this species for the first time.

Structural determination of the O-antigenic polysaccharide from Salmonella Mara (O:39).

The O-antigenic polysaccharide of Salmonella Mara O:39 (formerly Q) was investigated by sugar and methylation analyses, absolute configuration assignment, mass spectrometry and NMR spectroscopy. The experiments revealed an O-polysaccharide chain composed of the following linear tetrasaccharide repeating units with the structure: -->2)-alpha-L-Quip3NAc-(1-->3)-alpha-D-Manp-(1-->3)-alpha-L-Fucp-(1-->3)-alpha-D-GalpNAc-(1--> where alpha-L-Quip3NAc is the residue of 3-acetamido-3,6-dideoxy-alpha-L-glucopyranose. This repeating unit is the first published structure of the O-polysaccharide from 27 serotypes of Salmonella bacteria belonging to serogroup O:39 in the Kauffmann-White classification system.

Chemical structure of the somatic antigen isolated from Salmonella Abortusequi (O4).

A neutral O-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide (LPS) of Salmonella Abortusequi O4 bacterium (previously serogroup B). As determined by compositional analyses and NMR spectroscopy, the O-polysaccharide consists of four or five residues in the repeating subunit. The assigned structures are: alpha-Abep -->2)-alpha-D-Manp-(1-->4)-alpha-L-Rhap-(1-->3)-alpha-D-Galp-(1--> and alpha-Abep alpha-D-Glcp -->2)-alpha-D-Manp-(1-->4)-alpha-L-Rhap-(1-->3)-alpha-D-Galp-(1-->. A distribution of the repeating units in O-chain was analysed by Western blotting with anti O12 serum and MS spectrometry of oligosaccharides obtained from partial hydrolysis of polysaccharide.

Identification of Ruta graveolens L. metabolites accumulated in the presence of abiotic elicitors.

The study aimed to elucidate the effects of benzothiadiazole (BTH) and saccharin on the biosynthesis of simple coumarins, linear furanocoumarins, dihydrofuranocoumarins, and furoquinolone alkaloids in shoots of R. graveolens cultivated in vitro. The biosynthesized metabolites were analyzed and identified by GC-MS and by comparison of Kovats indices. Eight coumarin metabolites were identified: bergapten, chalepin, isopimpinelin, pinnarin, psoralen, rutacultin, rutamarin, and xanthotoxin, and also four alkaloids: dictamnine, gamma-fagarine, skimmianine, and kokusaginine. Each of the tested BTH concentrations induced a significant production of furanocoumarins and furoquinolone alkaloids. The use of saccharin also increased the production of bergapten, isopimpinelin, pinnarin, psoralen, and xanthotoxin several times.