Paviosides A-H, eight new oleane type saponins from Aesculus pavia with cytotoxic activity.

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-[ß-D-xylopyranosyl (1 → 2)] [-ß-d-glucopyranosyl (1 → 4)]-ß-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (1a), 3-O-[ß-D-xylopyranosyl (1 → 2)] [-ß-D-glucopyranosyl (1 → 4)]-ß-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (1b), 3-O-[ß-D-xylopyranosyl (1 → 2)] [-ß-D-galactopyranosyl (1 → 4)]-ß-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (2a), 3-O-[ß-D-xylopyranosyl (1 → 2)] [-ß-D-galactopyranosyl (1 → 4)]-ß-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (2b), 3-O-[ß-D-xylopyranosyl (1 → 2)] [-ß-D-xylopyranosyl (1 → 4)]-ß-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (3a), 3-O-[ß-D-xylopyranosyl (1 → 2)] [-ß-D-xylopyranosyl (1 → 4)]-ß-d-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (3b), 3-O-[ß-D-xylopyranosyl (1 → 2)] [-ß-D-xylopyranosyl (1 → 4)]-ß-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl protoaescigenin (4a), and 3-O-[ß-D-xylopyranosyl (1 → 2)] [-ß-D-xylopyranosyl (1 → 4)]-ß-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.

Inhibition of in vitro growth and arrest in the G0/G1 phase of HCT8 line human colon cancer cells by kaempferide triglycoside from Dianthus caryophyllus.

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.

Quantification of major flavonoids in carnation tissues (Dianthus caryophyllus) as a tool for cultivar discrimination.

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.

Clinical evaluation of zirconium dental implants placed in esthetic areas: a case series study.

PURPOSE: The purpose of this study was to evaluate the esthetic result of monophasic zirconium dental implants, placed in the highly esthetic areas of the jaws. MATERIAL AND METHODS: In this case series the results of 12 monophasic zirconium dental implants placed in highly esthetic areas of 8 patients (6 male and 2 female). For each implant the Pink Esthetic Score (PES) and the White Esthetic Score (WES) were evaluated. All implants were inserted in fresh postextraction sites. RESULTS: The esthetic parameters PES/ WES has given a total average value of 15.5 ± 1.5. Analyzing the two indices individually, the PES has given a value equal to 7.5 ± 1 and the WES has given a value equal to 8 ± 1.13. Both values obtained indicate the achievement of an absolutely satisfactory esthetic result. CONCLUSION: Within the limits of this study, the zirconium dental implants seems to give excellent results with regard to the esthetic result and for the maintenance of peri-implant soft tissues.

Evaluation of the success criteria for zirconia dental implants: a four-year clinical and radiological study.

Objectives. The aim was to evaluate survival and success rates, soft tissue health, and radiographic marginal bone loss (MBL) of zirconia implants placed in the esthetic and posterior areas of the jaws and in association with multiple or single implant restorations after at least 6 months of definitive restoration. Material and Methods. 35 one-piece zirconium implants were utilized for single or partially edentulous ridges rehabilitation. All implants received immediate temporary restorations and six months after surgery were definitively restored. Every 6 months after implant placement, a clinical-radiographic evaluation was performed. For each radiograph, the measurements of MBL were calculated. Results. The results showed that the mean MBL at 48-month followup was 1.631 mm. The mean MBL during the first year of loading was not more significant for implants placed in the first molar regions than for those positioned in other areas. Moreover, no differences in marginal bone level changes were revealed for multiple and single implants, whereas MBL in the first year was observed to be slightly greater for implants placed in the maxilla than for those placed in the mandible. Conclusion. Zirconia showed a good marginal bone preservation that could be correlated with one-piece morphology and characteristics of zirconia implants.

Aesculus pavia foliar saponins: defensive role against the leafminer Cameraria ohridella.

BACKGROUND: 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. RESULTS: 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. CONCLUSION: 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.

Pavietin, a coumarin from Aesculus pavia with antifungal activity.

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.

Fungitoxic phenols from carnation (Dianthus caryophyllus) effective against Fusarium oxysporum f. sp. dianthi.

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.

Purification and properties of a new S-adenosyl-L-methionine:flavonoid 4'-O-methyltransferase from carnation (Dianthus caryophyllus L.).

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.