Flavonoid glucuronides with anti-leukaemic activity from Polygonum amphibium L.

INTRODUCTION: The chemical and pharmaceutical studies carried out on species from Polygonum L. genus showed biological activity both of the extracts and the components isolated from them. These results were the impulse to examine Polygonum amphibium L. OBJECTIVE: The aim of this study was the isolation of active components from methanol extract and the determination of their cytotoxic effect on human leukaemic cell lines. METHODOLOGY: Three flavonoid components from butanol soluble fractions of methanol extract by CC and PC preparative chromatography were isolated. Their structures were established on the basis of 1H, 13C and correlation (DEPT, H-H, COSY, HMQC, HMBC) NMR, UV and FAB-MS spectroscopic techniques. The evaluation of the anti-leukaemic activities of 1 and 2 against Jurkat and HL60 cell lines was carried out in vitro using annexin V fluorescence assay. RESULTS: Two new flavonoid glucuronides, quercetin-3-O-beta-glucuronide (1) and quercetin-3-O-alpha-rhamnosyl-(1 --> 2)-beta-glucuronide (2), and kaempferol-3-O-alpha-rhamnosyl-(1 --> 2)-beta-glucuronide (3), were isolated from Polygonum amphibium L. It was demonstrated that the glucuronides of quercetin are able to induce apoptosis in the tested human leukaemic cells. These compounds penetrate through cytoplasm to the cellular nucleus of the cultured cells, and give intensive apoptotic responses in the stimulated leukaemic cells. The number of apoptotic cells increased with the concentration (1 nm to 10 microm) of 1 or 2 and periods of exposure (1-3 days). CONCLUSION: Compounds 1 and 2 may be considered good candidates for leukaemia chemotherapeutic agents.

Phenolic compounds in two Solidago L. species from in vitro culture.

The regenerated S. virgaurea and S. graminifolia, obtained previously by micropropagation from shoot tips and the callus tissue of S. virgaurea, were analysed for phenolic compounds. Preliminary used 2D-TLC methods (fingerprinting) showed the presence of phenolic glucoside--leiocarposide (S. virgaurea only), C-glycosyflavones--schaftoside and isoschaftoside (S. graminifolia), flavonoids and caffeoylquinic acids, similar to the ones reported earlier for naturally growing plants with the exception of the callus tissue. The latter contained predominantly caffeoylquinic acids, which were isolated and identified by NMR as 5-O-caffeoylquinic and 3,5-di-O-caffeoylquinic acids. The content of leiocarposide (HPLC) and flavonoids (colorimetry) in S. virgaurea was determined.

The flavonoids, quercetin and isorhamnetin 3-O-acylglucosides diminish neutrophil oxidative metabolism and lipid peroxidation.

Two natural flavonoids, quercetin and isorhamnetin 3-O-acylglucosides, were examined for their inhibitory influence on the in vitro production and release of reactive oxygen species in polymorphonuclear neutrophils (PMNs). The generation of superoxide radical, hydrogen peroxide and hypochlorous acid were measured by, respectively, cytochrome c reduction, dichlorofluorescin oxidation and taurine chlorination. Membrane lipid oxidation was studied by the thiobarbituric acid method in mouse spleen microsomes. The addition of flavonoids at the concentration range 1-100 microM inhibited PMNs oxidative metabolism and lipid peroxidation in a dose-dependent manner. The results suggest that these flavonoids suppress the oxidative burst of PMNs and protect membranes against lipid peroxidation.

Naphthoquinone glucosides of Drosera gigantea from in vitro cultures.

From the shoots of Drosera gigantea propagated under in vitro culture, the rare naphthoquinone glucosides droserone (3,5-dihydroxy-2-methyl-1,4-naphthoquinone) and hydroxydroserone (3,5,8-trihydroxy-2-methyl-1,4-napthoquinone) 5-O-beta-glucosides, together with the free naphthoquinones droserone, hydroxydroserone and plumbagin were isolated. The structures of the glucosides and hydroxydroserone were studied by 2D NMR techniques. The glucosides appear to be responsible for the brown-red (maroon) colour of this plant. Of the other naphthoquinones typical for the family Droseraceae only hydroplumbagin glucoside could be detected, whereas the presence of 7-methyljuglone and rossoliside (= 7-methylhydrojuglone glucoside) was excluded.

Microvascular protective activity of flavonoid glucuronides fraction from Tulipa gesneriana.

A mixture of flavonoid glucuronides, consisting of 7-O-glucuronides of kaempferol and quercetin 3-O-rutinosides, 3-O-gentiobiosides and 3-O-glucosides, was isolated from the perianths of Tulipa gesneriana L. var. 'Paradae'. It showed protective activity against the increased (both chloroform and histamine) skin vascular permeability in rabbits. The protective effect, measured as the reduction in leakage of Evans blue, was 59.8% after peritoneal treatment at a dose of 25 mg/kg, while that of troxerutin was 45.5%.

Phenylpropanoid esters from Lamium album flowers.

Two phenylpropanoid glycosides, a new one, lamalboside (2R-galactosylacteoside) and the known acteoside, the flavonol p-coumaroylglucoside, tiliroside, 5-caffeoylquinic acid (chlorogenic acid), along with rutoside and quercetin and kaempferol 3-O-glucosides were isolated from the flowers of Lamium album. Esters of glycosides were obtained as mixtures of trans/cis isomers. The presence of flavonoid p-coumaroylglucosides links Lamium to other members of the subfamily Lamioideae.

Studies on antioxidative activity of some C-glycosylflavones.

Ten flavonoid C-glycosyl derivatives: orientin (1), isoorientin (2), vitexin (3), isovitexin (4), isovitexin 7,2"-di-O-glucoside (5), isovitexin 7-O-galactoside-2"-O-glucoside (6), two different 6,8-di-C-hexosylapigenins (7, 8), and two different 6-C-hexosyl-8-C-pentosylapigenins (9, 10) have been either produced from flavonoid fractions from Adonis vernalis L. (1, 2) and Crataegus species (3, 4), or isolated from Stellaria media (L.) Vill. (5-10) to study their antioxidative properties. These were found only for two compounds: orientin (1) and isoorientin (2).

[Effect of flavonoid fractions of Solidago virgaurea L on diuresis and levels of electrolytes]. / Wplyw frakcji flawonoidowych gatunków rodzaju Solidago L. na diureze i stezenie elektrolitów.

The flavonoid fractions of Solidago virgaurea L.S. gigantea Ait., S. canadensis var. canadensis and S. canadensis var. "scabra" flowers were administrated p.o. to rats and showed diuretic activity. Increase in overnight diuresis reached 57-88%. Decrease of overnight excretion of potassium and sodium also occurred after administration of form examined fractions. The flavonoids from S. virgaurea and S. canadensis var. canadensis caused increased excretion of calcium with urine.

Kaempferol glycosides from Hosta ventricosa.

Leaves of Hosta ventricosa yielded eight kaempferol glycosides, of which six: the 3-(2G-glucosylrutinoside)-7-glucoside, 3-sophoroside-7-glucoside, 3-rutinoside-7-glucoside, 3-(2G-glucosylrutinoside), 3-sophoroside, 3-rutinoside were fully characterized and two: the 3-xylosylrutinoside-7-glucoside and 3-xylosylrutinoside were tentatively identified. Investigations included 1H-1H COSY and 1H-1H 2D J NMR analysis.

[Nitrogenous triterpene derivatives. 10. Hemisuccinates of some oleanolic acid derivatives and their antiulcer effect]. / Stickstoffhaltige Triterpenderivate. 10. Mitteilung: Hemisuccinate einiger Oleanolsäurederivate und deren Antiulkuswirkung.

The synthesis of hemisuccinates of some derivatives of oleanolic acid is reported, their inhibitory response to experimentally induced gastric ulcers in rats is examined. The hemisuccinates 13a (sodium salt of 13), 14 and 17 are more effective inhibitors than carbenoxolon-sodium.

[Nitrogenous triterpene derivatives. 9. 3-Acetyloleanol acid-28-amides and their antiulcer effect]. / Stickstoffhaltige Triterpenderivate. 9. Mitteilung: 3-Acetyloleanolsäure-28-amide und ihre antiulceröse Wirkung.

The authors report on the synthesis of 3-acetyloleanol acid-28-amids 10, 12-16, 19, 20, 22 and 24. The amids 16 (30%) and 24 (37%) were of most favourable inhibiting effect on the formation of gastric ulcera following pylorus ligature. The ulcer formation caused by p. o. administration of indometacin (Metindol) was in the main reduced by the amids 15 (60%), 16 (34%), and 24 (46%). With both the methods the effect of carbenoxolon sodium amounts to 40 or 50%. In ulcera induced by indometacin, the 11- and 3-oxooleanol acid derivates 12 and 18 revealed stimulating characteristics.