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ABSTRACT: A phytochemical analysis of Aesculus pavia has led to the isolation of eight novel triterpenoid saponins, based on oleane type skeleton and named paviosides A-H (1a, 1b-4a, 4b). On the basis of chemical, and 2D NMR and mass spectrometry data, the structures of the new compounds were elucidated as 3-O-[β-D-xylopyranosyl (1 → 2)] [-β-d-glucopyranosyl (1 → 4)]-β-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (1a), 3-O-[β-D-xylopyranosyl (1 → 2)] [-β-D-glucopyranosyl (1 → 4)]-β-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (1b), 3-O-[β-D-xylopyranosyl (1 → 2)] [-β-D-galactopyranosyl (1 → 4)]-β-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (2a), 3-O-[β-D-xylopyranosyl (1 → 2)] [-β-D-galactopyranosyl (1 → 4)]-β-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (2b), 3-O-[β-D-xylopyranosyl (1 → 2)] [-β-D-xylopyranosyl (1 → 4)]-β-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (3a), 3-O-[β-D-xylopyranosyl (1 → 2)] [-β-D-xylopyranosyl (1 → 4)]-β-d-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (3b), 3-O-[β-D-xylopyranosyl (1 → 2)] [-β-D-xylopyranosyl (1 → 4)]-β-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl protoaescigenin (4a), and 3-O-[β-D-xylopyranosyl (1 → 2)] [-β-D-xylopyranosyl (1 → 4)]-β-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl protoaescigenin (4b). The compounds showed cytotoxic activity on J-774, murine monocyte/macrophage, and WEHI-164, murine fibrosarcoma, cell lines. Among them, paviosides E-H (3a, 3b and 4a, 4b) showed higher activity with values ranging from 2.1 to 3.6 μg/mL. Structure-activity relationship studies indicated the positive effect on the activity of xylose unit in the place of glucose, while a little detrimental effect is observed when glucose is substituted by galactose. The aglycone structure and the presence of a tigloyl or an angeloyl group at C-21 do not affect significantly the inhibitory activity on both tested cell lines.
Bioorganic & medicinal chemistry 03/2012; 20(10):3280-6. · 2.82 Impact Factor
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ABSTRACT: The effects of phytoestrogens have been studied in the hypothalamic-pituitary-gonadal axis and in various non-gonadal targets. Epidemiologic and experimental evidence indicates a protective effect of phytoestrogens also in colorectal cancer. The mechanism through which estrogenic molecules control colorectal cancer tumorigenesis could possibly involve estrogen receptor beta, the predominantly expressed estrogen receptor subtype in colon mucosa.To validate this hypothesis, we therefore used an engineered human colon cancer cell line induced to overexpress estrogen receptor beta, beside its native cell line, expressing very low levels of ERbeta and not expressing ERalpha; as a phytoestrogenic molecule, we used kaempferide triglycoside, a glycosylated flavonol from a Dianthus caryophyllus cultivar. The inhibitory properties of this molecule toward vegetal cell growth have been previously demonstrated: however, no data on its activity on animal cell or information about the mechanism of this activity are available. Kaempferide triglycoside proved to inhibit the proliferation of native and estrogen receptor beta overexpressing colon cancer cells through a mechanism not mediated by ligand binding dependent estrogen receptor activation. It affected HCT8 cell cycle progression by increasing the G(0)/G(1) cell fraction and in estrogen receptor beta overexpressing cells increased two antioxidant enzymes. Interestingly, the biological effects of this kaempferide triglycoside were strengthened by the presence of high levels of estrogen receptor beta.Pleiotropic molecular effects of phytoestrogens may explain their protective activity against colorectal cancer and may represent an interesting area for future investigation with potential clinical applications.
Phytotherapy Research 09/2010; 24(9):1302-8. · 2.09 Impact Factor
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ABSTRACT: Recently, the leafminer Cameraria ohridella Deschka & Dimic has caused heavy damage to the white-flowering horse chestnut in Europe. Among the Aesculus genus, A. pavia L. HBT genotype, characterised by red flowers, showed an atypical resistance towards this pest. Its leaves, shaken in water, originated a dense foam, indicating the presence of saponins, unlike the common horse chestnut tree. The aim was to isolate and identify these leaf saponins and test their possible defensive role against C. ohridella.
Spectroscopic analyses showed that A. pavia HBT genotype leaves contained a mixture of saponins, four of which were based on the same structure as commercial escin saponins, the typical saponin mixture produced by A. hippocastanum and accumulated only within bark and fruit tissues. The mixture showed a repellent effect on C. ohridella moth. The number of mines detected on the leaves of A. hippocastanum plants treated with A. pavia HBT saponins through watering and stem brushing was significantly lower than the control, and in many cases no mines were ever observed.
The results showed that the exogenous saponins were translocated from roots/stem to the leaf tissues, and their accumulation seemed to ensure an appreciable degree of protection against the leafminer.
Pest Management Science 03/2010; 66(7):767-72. · 2.25 Impact Factor
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ABSTRACT: A new prenylated coumarin, S-6-[2-(hydroxymethyl)butoxy]-7-hydroxy-4-methyl-2 H-chromen-2-one ( 1), named pavietin, has been isolated from the leaves of an Aesculus pavia genotype along with three known flavonol glycosides, quercetin 3- O-alpha-rhamnoside (quercitrin, 2), quercetin 3- O-alpha-arabinoside ( 3), and isorhamnetin 3- O-alpha-arabinoside (distichin, 4). The chemical structure of compound 1 was determined by chemical and spectroscopic methods, inclusive of UV, MS, and 1D and 2D NMR experiments. It showed appreciable antimicrobial properties against several pathogens, displaying a significant antifungal activity toward one of the main fungal parasites of Aesculus species, Guignardia aesculi. The same biological tests performed with a mixture of flavonoids 2- 4 resulted in weak or no activity. Compound 1 was undetectable in Aesculus hippocastanum, a closely related species lacking resistance to fungal pathogens. The possible role of 1 in plant resistance is discussed.
Journal of Natural Products 11/2007; 70(10):1668-71. · 3.13 Impact Factor
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ABSTRACT: Eighteen new hexyl esters of 2-naphthyloxyacetic acid (-NOA) were synthesized and their efficiency on sucker control of grapevine was investigated. Different solutions (0.5, 1, and 2%, w/w concentrations) of each compound were sprayed on suckers and the wilting effect after 4, 10, and 30days after treatment was evaluated. Esters derived from primary and secondary alcohols gave a rapid control of suckers, whereas tertiary alcohol derivatives showed milder activity. Moreover, all compounds proved to cause a long-lasting inhibition effect on the growth of new suckers even 1year after treatment, especially when applied at a 2% concentration.
Plant Growth Regulation 08/2004; 44(1):47-52. · 1.60 Impact Factor
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ABSTRACT: A new enzyme, S-adenosyl-l-methionine:flavonoid 4'-O-methyltransferase (EC 2.1.1.-) (F 4'-OMT), has been purified 1 399-fold from the tissues of carnation (Dianthus caryophyllus L). The enzyme, with a molecular mass of 43-45 kDa and a pI of 4.15, specifically methylates the hydroxy substituent in 4'-position of the flavones, flavanones and isoflavones in the presence of S-adenosyl-l-methionine. A high affinity for the flavone kaempferol was observed (Km = 1.7 micro m; Vmax = 95.2 micro mol.min-1.mg-1), while other 4'-hydroxylated flavonoids proved likewise to be suitable substrates. Enzyme activity had no apparent Mg++ requirement but was inhibited by SH-group reagents. The optimum pH value for F 4'-OMT activity was found to be around neutrality. Kinetic analysis of the enzyme bi-substrate reaction indicates a Ping-Pong mechanism and excludes the formation of a ternary complex. The F 4'-OMT activity was increased, in both in vitro and in vivo carnation tissues, by the inoculation with Fusarium oxysporum f. sp. dianthi. The enzyme did not display activity towards hydroxycinnamic acid derivatives, some of which are involved, as methylated monolignols, in lignin biosynthesis; the role of this enzyme could be therefore mainly defensive, rather than structural, although its precise function still needs to be ascertained.
European Journal of Biochemistry 09/2003; 270(16):3422-31. · 3.58 Impact Factor
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ABSTRACT: Eucalyptus gunnii Hook microcuttings, obtained in vitro through axillary bud stimulation, show different rooting responses on the same rooting medium depending on the physiological state induced by cytokinins used in the previous multiplication medium. 6-Furfurylamino purine and 6-(4-hydroxy-3-methylbut-2-enylamino)purine induced a physiological state characterized by high sensitivity of microcuttings to the rooting stimulus exerted by the auxin 3-indolebutyric acid, but N(6)-benzyladenine did not produce the same effect. The former physiological state was characterized by an increased accumulation of two endogenous flavonoids (identified as quercetin glycosides) which may be markers of a well defined physiological state. They could have some direct influence on the rooting processes of the explants cultivated in vitro.
Plant physiology 05/1990; 92(4):1148-53. · 6.53 Impact Factor
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ABSTRACT: One flavone-C-glycoside and two flavonol-O-glycosides were recognized and isolated as the main flavonoidal components in nine different carnation cultivars, and their chemical structures have been determined by spectroscopic methods, including UV detection, MS and NMR. The distribution of these three compounds in flowers, leaves, stems, young sprouts, and roots of each cultivar was evaluated by a simple HPLC-UV method: the graphic representation of their content in the different tissues allows to identify and characterize unambiguously each considered carnation cultivar. The presented method could be an easy, inexpensive and reliable tool for carnation cultivar discrimination.
Zeitschrift fur Naturforschung C 63(3-4):161-8. · 0.77 Impact Factor
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ABSTRACT: The phenol compositions of two cultivars of carnation (Dianthus caryophyllus) namely "Gloriana" and "Roland", which are partially and highly resistant, respectively, to Fusarium oxysporum f. sp. dianthi have been investigated with the aim of determining if endogenous phenols could have an anti-fungal effect against the pathogen. Analyses were performed on healthy and F. oxysporum-inoculated in vitro tissues, and on in vivo plants. Two benzoic acid derivatives, protocatechuic acid (3,4-dihydroxybenzoic acid) and vanillic acid (4-hydroxy-3-methoxybenzoic acid), were found within healthy and inoculated tissues of both cultivars, together with the flavonol glycoside peltatoside (3-[6-O-(alpha-L-arabinopyranosyl)-beta-D-glucopyranosyl] quercetin). These molecules proved to be only slightly inhibitory towards the pathogen. 2,6-Dimethoxybenzoic acid was detected in small amounts only in the inoculated cultivar "Gloriana", while the highly resistant cultivar "Roland" showed the presence of the flavone datiscetin (3,5,7,2'-tetrahydroxyflavone). The latter compound exhibited an appreciable fungitoxic activity towards F. oxysporum f. sp. dianthi.
Phytochemical Analysis 14(1):8-12. · 2.63 Impact Factor
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ABSTRACT: The efficacy of several antifungal compounds, chosen among salts, oils, plant extracts, and of the hyperparasitic fungus Ampelomyces quisqualis, were tested in seven glasshouse trials against powdery mildew on roses (Sphaerotheca pannosa var. rosae) in Sanremo (N. Italy). In the presence of a high disease incidence (55% of untreated leaves infected in six out of seven trials), all the antifungal compounds and the biocontrol agent A. quisqualis, applied individually, provided satisfactory control of powdery mildew. Most treatments were as efficient as the fungicide dodemorph, which, sprayed at weekly intervals, provided a 75% average efficacy throughout the trials. Among the test compounds, KH2PO2, at 0.5 and 1%, offered good and consistent disease control, NaHCO3, at 0.5%, showed a satisfactory level of activity, while at 1% it was phytotoxic. Wine vinegar, applied at 5 and 10%, gave good control, but acetic acid was phytotoxic. JMS Stylet oil, the canola oil, Synertrol and neem extract provided satisfactory disease control. Fatty acids formulated as potassium salts significantly and consistently reduced powdery mildew severity, but caused some phytotoxicity. Milsana, a concentrated extract from leaves of Reynoutria sachalinensis, only partially controlled powdery mildew. Several strategies based on the rotation of different antifungal compounds, with or without the application of dodemorph, provided very good, consistent disease control. The potential of some of the antifungal compounds and of the biocontrol fungus A. quisqualis against rose powdery mildew is discussed.
Crop Protection.
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ABSTRACT: Rooting trials were conducted with hardwood and softwood Chamaelaucium uncinatum Schauer cuttings; softwood cuttings showed good rootability, whilst hardwood cuttings did not root. A relationship between phenol composition of cuttings and rooting ability was demonstrated. Softwood cuttings are rich in flavonoids, while simple phenols prevailed in the hardwood tissues, and in particular a cinnamic acid derivative was present in high concentration. The effect of each identified phenol on adventive rhizogenesis was tested by the mung bean test: a promotive activity was evidenced for some flavonoids present in the softwood tissues (isoorientin, orientin and luteolin), while the cinnamic acid derivative, found exclusively in the hardwood tissues, was a strong rooting inhibitor.
Scientia Horticulturae.
