The Experts below are selected from a list of 2412 Experts worldwide ranked by ideXlab platform

Ernesto Fattorusso - One of the best experts on this subject based on the ideXlab platform.

  • the flavonoids of leek Allium porrum
    Phytochemistry, 2001
    Co-Authors: Ernesto Fattorusso, Virginia Lanzotti, Orazio Taglialatelascafati, Carla Cicala
    Abstract:

    A phytochemical investigation of the extracts obtained from bulbs of leek. Allium porrum L. has led to the isolation of five flavonoid glycosides based on the kaempferol aglycone. Two of them are new compounds and have been identified as kaempferol 3-O-[2-O-(trans-3-methoxy-4-hydroxycinnamoyl)-beta-D-galactopyranosyl]-(1-->4)-O-beta-D-glucopyranoside, and kaempferol 3-O-[2-O-(trans-3-methoxy-4-hydroxycinnamoyl)-beta-D-glucopyranosyl]-(1-->6)-O-beta-D-glucopyranoside, on the basis of spectroscopic methods, including 2D NMR. The isolated compounds have been evaluated for their human platelet anti-aggregation activity.

  • Cytotoxic saponins from bulbs of Allium porrum L.
    Journal of agricultural and food chemistry, 2000
    Co-Authors: Ernesto Fattorusso, Orazio Taglialatela-scafati, Virginia Lanzotti, M. Di Rosa, Angela Ianaro
    Abstract:

    An extensive phytochemical analysis of the saponin content has been undertaken on leek, Allium porrum L., sown and collected at different seasons. As a result of this investigation, eight saponins (1-8) have been isolated, four of them (5-8) being novel compounds. Compounds 5 and 6, possessing the same tetrasaccharide moiety of compounds 1 and 3, display very unusual spirostane aglycones, 12-ketoporrigenin and 2,12-diketoporrigenin (named porrigenin C), respectively, recently isolated for the first time as free sapogenin in the same plant. Compounds 7 and 8 are rare cholestane bidesmosides possessing a di- and trisaccharide residues linked to a polyhydroxycholesterol aglycone, respectively. The structures of the isolated compounds have been determined by nondegradative spectroscopic analysis, mainly based on NMR. All the eight saponins isolated from leek were tested for their cytotoxic activity against two different cell lines in vitro, and compounds 1, 2, and 6 resulted particularly active.

  • Spirostanol saponins of Allium porrum L.
    Phytochemistry, 1999
    Co-Authors: Alfonso Carotenuto, Ernesto Fattorusso, Virginia Lanzotti, Silvana Magno
    Abstract:

    Abstract An investigation of the extracts from bulbs of Allium porrum L. has led to the isolation of four spirostanol saponins. Two of them are new compounds and have been identified as: (25R)-5a-spirostan-3 β ,6 β -diol 3- O -{ O - β - d -glucopyranosyl- (1→2)- O - [ β - d xylopyranosyl- (1→3)]- O - β - d -glucopyranosyl- (1→4)- β - d -galactopyranoside} (3) and (25 R )-5a-spirostan-3 β ,6 β -diol 3- O -{ O - β - d g l u c o p y r a n o s y l - ( 1 → 3 ) - O - β - d - g l u c o p y r a n o s y l - ( 1 → 2 ) - O - [ β - d - x y l o p y r a n o s y l - ( 1 → 3 ) ] - O - β - d - g l u c o p y r a n o s y l - ( 1 → 4 ) - β - d - g a l a c t o p y r a noside} (4). The isolated compounds were evaluated for their antifungal activity.

  • Sapogenins of Allium porrum L.
    Journal of Agricultural and Food Chemistry, 1998
    Co-Authors: Ernesto Fattorusso, And Silvana Magno, Virginia Lanzotti, Orazio Taglialatela-scafati
    Abstract:

    A chemical study of the sapogenin content has been conducted on leek, Allium porrum L., sown and collected at different times. As a result of this investigation, a variability in the sapogenin composition depending on the climate was observed. In addition, a novel sapogenin named porrigenin C (1a) and its 25S epimer (1b) have been isolated, together with the previously described sapogenins 2−5 and the known compounds agigenin, diosgenin, β-chlorogenin, and 24-ethylcholesta-(6-acyl)-3-O-β-d-glucoside. The chemical structure of the novel compound was elucidated by a detailed spectroscopic analysis based mainly on 1D and 2D NMR techniques. Porrigenin C showed a considerable antiproliferative activity on four tumor cell lines in vitro. Keywords: Allium porrum L.; Liliaceae; spirostanol sapogenin; NMR; antiproliferative activity

  • porric acids a c new antifungal dibenzofurans from the bulbs of Allium porrum l
    European Journal of Organic Chemistry, 1998
    Co-Authors: Alfonso Carotenuto, Ernesto Fattorusso, Virginia Lanzotti, Silvana Magno
    Abstract:

    Three new dibenzofurans, porric acids A (1), B (2) and C (3), have been isolated from the bulbs of Allium porrum L. Their structures have been elucidated by a detailed spectroscopic analysis, including 2D HMBC and ROESY correlation experiments. When tested against Fusarium culmorum, porric acids A−C (1−3) were found to exhibit antifungal activity.

Eric Thibout - One of the best experts on this subject based on the ideXlab platform.

  • consequences for a specialist insect and its parasitoid of the response of Allium porrum to conspecific herbivore attack
    Physiological Entomology, 2006
    Co-Authors: Sebastien Dugravot, Eric Thibout
    Abstract:

    Recent studies on the leek Allium porrum L. demonstrate that a sharp increase in the release of volatile and nonvolatile sulphur compounds occurs in response to attack by the specialist phytophage, the leek moth Acrolepiopsis assectella (Zeller). The consequences of that response on the developmental capacity and behaviour of the leek moth and on the host-searching behaviour of the parasitoid hymenoptera Diadromus pulchellus Wesmael have been studied. No immediate adverse effect on larval development is seen, but the duration of male development is significantly longer. In addition, an almost 20% decrease is observed in the number of oocytes produced by adult females that developed on attack-damaged leek plants. Leek moths do not avoid damaged plants system- atically. On attacked plants, larvae tend to consume more and females to lay more eggs, although the latter tendency disappears after intensive attack. Concerning host-searching by D. pulchellus, the data indicate that females make use of the induced leek response. Parasitoids are attracted more strongly to attacked plants than to undamaged plants and mechanically damaged plants. The results of this study in a tritrophic system involving a biannual plant suggest a complex defence system combining direct and indirect mechanisms. Sulphur compounds may act by reducing second-generation pests, thereby preventing the specialist insect population from exploding at the expense of the leek.

  • increased sulfur precursors and volatiles production by the leek Allium porrum in response to specialist insect attack
    Journal of Chemical Ecology, 2005
    Co-Authors: Sebastien Dugravot, Nicole Mandon, Nathalie Mondy, Eric Thibout
    Abstract:

    To defend themselves against herbivory, plants use a variety of direct and indirect strategies involving induced increases in secondary substances. Species of the Allium genus (Alliaceae), such as the leek Allium porrum (L.), produce nonprotein sulfur amino acids derived from cysteine, i.e., alk(en)yl-cysteine sulfoxides that are precursors of volatile thiosulfinates and disulfides. These defend most species including the specialist leek moth, Acrolepiopsis assectella. We determined by measuring the increase in the sulfur precursor propyl-cysteine sulfoxide (PCSO) if production of this precursor is induced in response to moth attack and mechanical wounding. The concentration of PCSO was determined by HPLC in 2- or 6-mo-old leeks after attacks of various intensity either by the specialist leek moth or by a generalist moth, Agrotis ipsilon. Injury-induced release of sulfur volatiles was measured by GC/MS after the attacks. Results showed an increase in the production of sulfur compounds in both the precursor and volatile form, occurring only in association with intensive attacks by leek moths. The increase in sulfur precursors also led to an increase in the release of sulfur volatiles. This induced response may provide an effective defense strategy against the plant’s main natural enemy, both directly and indirectly by attracting entomophagous insects.

Virginia Lanzotti - One of the best experts on this subject based on the ideXlab platform.

  • the flavonoids of leek Allium porrum
    Phytochemistry, 2001
    Co-Authors: Ernesto Fattorusso, Virginia Lanzotti, Orazio Taglialatelascafati, Carla Cicala
    Abstract:

    A phytochemical investigation of the extracts obtained from bulbs of leek. Allium porrum L. has led to the isolation of five flavonoid glycosides based on the kaempferol aglycone. Two of them are new compounds and have been identified as kaempferol 3-O-[2-O-(trans-3-methoxy-4-hydroxycinnamoyl)-beta-D-galactopyranosyl]-(1-->4)-O-beta-D-glucopyranoside, and kaempferol 3-O-[2-O-(trans-3-methoxy-4-hydroxycinnamoyl)-beta-D-glucopyranosyl]-(1-->6)-O-beta-D-glucopyranoside, on the basis of spectroscopic methods, including 2D NMR. The isolated compounds have been evaluated for their human platelet anti-aggregation activity.

  • Cytotoxic saponins from bulbs of Allium porrum L.
    Journal of agricultural and food chemistry, 2000
    Co-Authors: Ernesto Fattorusso, Orazio Taglialatela-scafati, Virginia Lanzotti, M. Di Rosa, Angela Ianaro
    Abstract:

    An extensive phytochemical analysis of the saponin content has been undertaken on leek, Allium porrum L., sown and collected at different seasons. As a result of this investigation, eight saponins (1-8) have been isolated, four of them (5-8) being novel compounds. Compounds 5 and 6, possessing the same tetrasaccharide moiety of compounds 1 and 3, display very unusual spirostane aglycones, 12-ketoporrigenin and 2,12-diketoporrigenin (named porrigenin C), respectively, recently isolated for the first time as free sapogenin in the same plant. Compounds 7 and 8 are rare cholestane bidesmosides possessing a di- and trisaccharide residues linked to a polyhydroxycholesterol aglycone, respectively. The structures of the isolated compounds have been determined by nondegradative spectroscopic analysis, mainly based on NMR. All the eight saponins isolated from leek were tested for their cytotoxic activity against two different cell lines in vitro, and compounds 1, 2, and 6 resulted particularly active.

  • Spirostanol saponins of Allium porrum L.
    Phytochemistry, 1999
    Co-Authors: Alfonso Carotenuto, Ernesto Fattorusso, Virginia Lanzotti, Silvana Magno
    Abstract:

    Abstract An investigation of the extracts from bulbs of Allium porrum L. has led to the isolation of four spirostanol saponins. Two of them are new compounds and have been identified as: (25R)-5a-spirostan-3 β ,6 β -diol 3- O -{ O - β - d -glucopyranosyl- (1→2)- O - [ β - d xylopyranosyl- (1→3)]- O - β - d -glucopyranosyl- (1→4)- β - d -galactopyranoside} (3) and (25 R )-5a-spirostan-3 β ,6 β -diol 3- O -{ O - β - d g l u c o p y r a n o s y l - ( 1 → 3 ) - O - β - d - g l u c o p y r a n o s y l - ( 1 → 2 ) - O - [ β - d - x y l o p y r a n o s y l - ( 1 → 3 ) ] - O - β - d - g l u c o p y r a n o s y l - ( 1 → 4 ) - β - d - g a l a c t o p y r a noside} (4). The isolated compounds were evaluated for their antifungal activity.

  • Sapogenins of Allium porrum L.
    Journal of Agricultural and Food Chemistry, 1998
    Co-Authors: Ernesto Fattorusso, And Silvana Magno, Virginia Lanzotti, Orazio Taglialatela-scafati
    Abstract:

    A chemical study of the sapogenin content has been conducted on leek, Allium porrum L., sown and collected at different times. As a result of this investigation, a variability in the sapogenin composition depending on the climate was observed. In addition, a novel sapogenin named porrigenin C (1a) and its 25S epimer (1b) have been isolated, together with the previously described sapogenins 2−5 and the known compounds agigenin, diosgenin, β-chlorogenin, and 24-ethylcholesta-(6-acyl)-3-O-β-d-glucoside. The chemical structure of the novel compound was elucidated by a detailed spectroscopic analysis based mainly on 1D and 2D NMR techniques. Porrigenin C showed a considerable antiproliferative activity on four tumor cell lines in vitro. Keywords: Allium porrum L.; Liliaceae; spirostanol sapogenin; NMR; antiproliferative activity

  • porric acids a c new antifungal dibenzofurans from the bulbs of Allium porrum l
    European Journal of Organic Chemistry, 1998
    Co-Authors: Alfonso Carotenuto, Ernesto Fattorusso, Virginia Lanzotti, Silvana Magno
    Abstract:

    Three new dibenzofurans, porric acids A (1), B (2) and C (3), have been isolated from the bulbs of Allium porrum L. Their structures have been elucidated by a detailed spectroscopic analysis, including 2D HMBC and ROESY correlation experiments. When tested against Fusarium culmorum, porric acids A−C (1−3) were found to exhibit antifungal activity.

Sebastien Dugravot - One of the best experts on this subject based on the ideXlab platform.

  • consequences for a specialist insect and its parasitoid of the response of Allium porrum to conspecific herbivore attack
    Physiological Entomology, 2006
    Co-Authors: Sebastien Dugravot, Eric Thibout
    Abstract:

    Recent studies on the leek Allium porrum L. demonstrate that a sharp increase in the release of volatile and nonvolatile sulphur compounds occurs in response to attack by the specialist phytophage, the leek moth Acrolepiopsis assectella (Zeller). The consequences of that response on the developmental capacity and behaviour of the leek moth and on the host-searching behaviour of the parasitoid hymenoptera Diadromus pulchellus Wesmael have been studied. No immediate adverse effect on larval development is seen, but the duration of male development is significantly longer. In addition, an almost 20% decrease is observed in the number of oocytes produced by adult females that developed on attack-damaged leek plants. Leek moths do not avoid damaged plants system- atically. On attacked plants, larvae tend to consume more and females to lay more eggs, although the latter tendency disappears after intensive attack. Concerning host-searching by D. pulchellus, the data indicate that females make use of the induced leek response. Parasitoids are attracted more strongly to attacked plants than to undamaged plants and mechanically damaged plants. The results of this study in a tritrophic system involving a biannual plant suggest a complex defence system combining direct and indirect mechanisms. Sulphur compounds may act by reducing second-generation pests, thereby preventing the specialist insect population from exploding at the expense of the leek.

  • increased sulfur precursors and volatiles production by the leek Allium porrum in response to specialist insect attack
    Journal of Chemical Ecology, 2005
    Co-Authors: Sebastien Dugravot, Nicole Mandon, Nathalie Mondy, Eric Thibout
    Abstract:

    To defend themselves against herbivory, plants use a variety of direct and indirect strategies involving induced increases in secondary substances. Species of the Allium genus (Alliaceae), such as the leek Allium porrum (L.), produce nonprotein sulfur amino acids derived from cysteine, i.e., alk(en)yl-cysteine sulfoxides that are precursors of volatile thiosulfinates and disulfides. These defend most species including the specialist leek moth, Acrolepiopsis assectella. We determined by measuring the increase in the sulfur precursor propyl-cysteine sulfoxide (PCSO) if production of this precursor is induced in response to moth attack and mechanical wounding. The concentration of PCSO was determined by HPLC in 2- or 6-mo-old leeks after attacks of various intensity either by the specialist leek moth or by a generalist moth, Agrotis ipsilon. Injury-induced release of sulfur volatiles was measured by GC/MS after the attacks. Results showed an increase in the production of sulfur compounds in both the precursor and volatile form, occurring only in association with intensive attacks by leek moths. The increase in sulfur precursors also led to an increase in the release of sulfur volatiles. This induced response may provide an effective defense strategy against the plant’s main natural enemy, both directly and indirectly by attracting entomophagous insects.

Orazio Taglialatela-scafati - One of the best experts on this subject based on the ideXlab platform.

  • Cytotoxic saponins from bulbs of Allium porrum L.
    Journal of agricultural and food chemistry, 2000
    Co-Authors: Ernesto Fattorusso, Orazio Taglialatela-scafati, Virginia Lanzotti, M. Di Rosa, Angela Ianaro
    Abstract:

    An extensive phytochemical analysis of the saponin content has been undertaken on leek, Allium porrum L., sown and collected at different seasons. As a result of this investigation, eight saponins (1-8) have been isolated, four of them (5-8) being novel compounds. Compounds 5 and 6, possessing the same tetrasaccharide moiety of compounds 1 and 3, display very unusual spirostane aglycones, 12-ketoporrigenin and 2,12-diketoporrigenin (named porrigenin C), respectively, recently isolated for the first time as free sapogenin in the same plant. Compounds 7 and 8 are rare cholestane bidesmosides possessing a di- and trisaccharide residues linked to a polyhydroxycholesterol aglycone, respectively. The structures of the isolated compounds have been determined by nondegradative spectroscopic analysis, mainly based on NMR. All the eight saponins isolated from leek were tested for their cytotoxic activity against two different cell lines in vitro, and compounds 1, 2, and 6 resulted particularly active.

  • Sapogenins of Allium porrum L.
    Journal of Agricultural and Food Chemistry, 1998
    Co-Authors: Ernesto Fattorusso, And Silvana Magno, Virginia Lanzotti, Orazio Taglialatela-scafati
    Abstract:

    A chemical study of the sapogenin content has been conducted on leek, Allium porrum L., sown and collected at different times. As a result of this investigation, a variability in the sapogenin composition depending on the climate was observed. In addition, a novel sapogenin named porrigenin C (1a) and its 25S epimer (1b) have been isolated, together with the previously described sapogenins 2−5 and the known compounds agigenin, diosgenin, β-chlorogenin, and 24-ethylcholesta-(6-acyl)-3-O-β-d-glucoside. The chemical structure of the novel compound was elucidated by a detailed spectroscopic analysis based mainly on 1D and 2D NMR techniques. Porrigenin C showed a considerable antiproliferative activity on four tumor cell lines in vitro. Keywords: Allium porrum L.; Liliaceae; spirostanol sapogenin; NMR; antiproliferative activity