Paolo Curir

Kaempferide triglycoside: a possible factor of resistance of carnation (Dianthus caryophyllus) to Fusarium oxysporum f. sp. dianthi.

A kaempferide triglycoside has been found as a constitutive component in an uninfected carnation (Dianthus caryophyllus) of the cultivar Novada. The chemical structure has been determined mainly by the use of spectroscopic methods, including 2D NMR experiments. It showed a strong activity in restricting fungal parasite development, which could contribute to the known ability of carnation cv. Novada to resist to Fusarium oxysporum f. sp. dianthi infection.

3-Hydroxyacetophenone in carnations is a phytoanticipin active against Fusarium oxysporum f. sp. dianthi

Among other constitutive phenols, 3-hydroxyacetophenone has been detected in an uninfected carnation cultivar totally resistant to Fusarium oxysporum f. sp. dianthi, a fungus known to cause the main disease affecting this plant species. In both in vivo and in vitro experiments, the isolated compound proved very active in restricting parasite development. Thus, 3-hydroxyacetophenone, as a preformed and constitutive component of the uninfected cultivar, can be considered as a carnation phytoanticipin.

Influence of endogenous phenols on rootability of Chamaelaucium uncinatum Schauer stem cuttings

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.

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 β, the predominantly expressed estrogen receptor subtype in colon mucosa.

The Possible Role of Phenolics in Incompatibility Expression in Eucalyptus gunnii Micrografts

As a result of incompatibility, Eucalyptus gunnii showed in the graft area of in vitro micrografts a typical accumulation of gallic, ellagic, gentisic and p-coumaric acid: (+)-catechin also increased in concentration. In compatible grafts, a lower concentration of phenolics accumulated. The possible role of both specific types of phenolic accumulation and the higher activities of soluble peroxidases and polyphenol oxidase in incompatible grafts as opposed to compatible ones is discussed.

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-[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.

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.

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

The plant antifungal isoflavone genistein is metabolized by Armillaria mellea Vahl to give non-fungitoxic products

Abstract Armillaria mellea, the causal agent of root rot, is a fungal pathogen which proved able to convert the leguminous plant antifungal compound 4′,5,7-trihydroxyisoflavone (genistein) into intermediate metabolites. After suitable periods of incubation, the metabolites were extracted and concentrated from liquid culture media, containing both the isoflavone and the fungus. After purification by column chromatography, the molecular structure of the metabolites was determined by means of mass spectrometry and nuclear magnetic resonance analyses. Five different compounds were identified: 1,3,5-trihydroxybenzene, 4-hydroxyphenylacetic acid, 2,5-dihydroxyphenylacetic acid (homogentisic acid), its lactone 5-hydroxy-2(3H)-benzofuranone, and 1,4-benzoquinone. In vitro experiments showed that while the starting compound, i.e. genistein, has some activity in inhibiting the growth of the fungal pathogen, the degradation products are devoid of any appreciable fungitoxic activity. Moreover, results show that the isoflavone metabolites can be, at least partially, utilized by A. mellea as a carbon source.

Filiferol, a chalconoid analogue from Washingtonia filifera possibly involved in the defence against the Red Palm Weevil Rhynchophorus ferrugineus Olivier

A chalconoid analogue, 1,3,5-benzentriol 2-[(2S,3R)-3-(3,4-dihydroxylphenyl)-2,3-dihydroxylpropyl], named filiferol (1), has been isolated and purified for the first time from the leaf basal tissues of the palm species Washingtonia filifera. The chemical structure of the isolated compound has been elucidated unambiguously by spectroscopic and chemical methods. Filiferol has been based on a flavonol structure with the reduction of the common flavonoid keto group to give an unprecedented methylene carbon on the three carbon chain. An analogous compound with S stereochemistry at C3 has been obtained as synthetic intermediate for developing an enantioselective synthesis of (2R,3S)-(+)-catechin. Even though 1 proved to be deprived of antifungal properties, it displays a very effective larvicidal activity against Red Palm Weevil, Rhynchophorus ferrugineus, an important pest affecting cultivated and ornamental palms. 1 has been isolated from leaf tissues of W. filifera, a species resistant to this pest, but this molecule seems instead undetectable in tissues of other palm species susceptible to the parasite. The presence of 1 could therefore account for W. filifera natural resistance to the attacks of the Red Palm Weevil (R. ferrugineus).