Amaya Castro, PhD

Amaya Castro, PhD

León, Castilla y León, España
538 seguidores Más de 500 contactos

Actividad

Unirse para ver toda la actividad

Experiencia

Educación

  • Universitat de Barcelona

    -

  • -

Publicaciones

  • Podophyllotoxin and essential oil profile of Juniperus and related species

    Industrial Crops and Products

    Podophyllotoxin is currently in high demand as the lead chemical precursor for the anti-cancer drugs etoposide and teniposide. We conducted a two-phase study: (i) screening of Juniperus and other related species and identified Juniperus virginiana as the species with the highest podophyllotoxin concentration and (ii) established the limits of variations of podophyllotoxin and essential oil content and composition in J. virginiana in the United States. In the second phase of the study, J…

    Podophyllotoxin is currently in high demand as the lead chemical precursor for the anti-cancer drugs etoposide and teniposide. We conducted a two-phase study: (i) screening of Juniperus and other related species and identified Juniperus virginiana as the species with the highest podophyllotoxin concentration and (ii) established the limits of variations of podophyllotoxin and essential oil content and composition in J. virginiana in the United States. In the second phase of the study, J. virginiana trees at 49 locations in Mississippi, Alabama, Tennessee, and North Dakota were sampled and analyzed for both podophyllotoxin and essential oil. Both the essential oil and podophyllotoxin had similar concentration ranges as percent of dry J. virginiana leaves. Hence the following qualitative grouping with respect to concentration of natural products in the leaves was assigned: very high (>0.3%), high (0.2–0.3%), medium (0.1–0.2%), and low (<0.1%). Based on the above qualitative grouping, the J. virginiana accession were divided into 10 different groups (chemotypes). The J. virginiana accessions also differed in essential oil composition, with wide variation of individual constituents. Based on the essential oil composition, the J. virginiana accessions were divided into different groups (chemotypes). The essential oil of two of the J. virginiana chemotypes showed differential antioxidant activity. J. virginiana leaves, a by-product from the timber industry could be used as a sustainable source for both podophyllotoxin and essential oil. The availability of various chemotypes offers an opportunity for the development of cultivars for commercial production of podophyllotoxin and essential oil with specific compositional profile to meet the market requirements.

    Otros autores
    Ver publicación
  • neo-Clerodane diterpenoids from Ajuga bracteosa

    Journal of Natural Products

    Different neo-clerodane diterpenoids were isolated
    from a dichloromethane extract of Ajuga bracteosa depending
    on the isolation procedure used, owing to the labile
    nature of these tetrahydrofurofuran derivatives. Under “hydroxyl-
    free” purification conditions, both clerodin- and dihydroclerodin-
    type diterpenes were obtained [four new compounds,
    ajubractins A-D, along with clerodin, 3-epi-caryoptin, ajugapitin, 14,15-dihydroclerodin, 3-epi-14,15-dihydrocaryoptin, ivain II, and…

    Different neo-clerodane diterpenoids were isolated
    from a dichloromethane extract of Ajuga bracteosa depending
    on the isolation procedure used, owing to the labile
    nature of these tetrahydrofurofuran derivatives. Under “hydroxyl-
    free” purification conditions, both clerodin- and dihydroclerodin-
    type diterpenes were obtained [four new compounds,
    ajubractins A-D, along with clerodin, 3-epi-caryoptin, ajugapitin, 14,15-dihydroclerodin, 3-epi-14,15-dihydrocaryoptin, ivain II, and 14,15-dihydroajugapitin. When methanol-water mixtures were used for a C18 reversed-phase prepurification procedure and for semipreparative HPLC, the new ajubractin E was also isolated. Epimeric (15R and 15S) mixtures were obtained instead of 14-hydro-15-hydroxyclerodin derivatives [15-hydroxyajubractin C, 14-hydro-15-hydroxyajugachin A,and 14-hydro-15-hydroxyajugapitin], along with 15-epi-lupulin B. The structures of the new compounds were elucidated by NMR and MS data analysis and by comparison with values previously reported. Antifeedant activity against Spodoptera littoralis larvae was evaluated for the compounds obtained.

    Otros autores
    • Josep Coll
    • Mohammad Arfan
    Ver publicación
  • LC-MS-SPE-NMR for the isolation and characterization of neo-clerodane diterpenoids from Teucrium luteum subsp. flavovirens

    Journal of Natural Products 73 (5), pp. 962-965

    neo-Clerodane diterpenes of plant origin are molecules difficult to monitor due to their nonspecific UV/vis absorption. The present work describes for the first time the application of the LC-MS-SPE-NMR technique for the isolation and characterization of three new neo-clerodane diterpenes, 3β-hydroxyteucroxylepin and teuluteumin A and teuluteumin B, from Teucrium luteum subsp. flavovirens, harvested from two different locations.

    Ver publicación
  • Phytotoxic activity of flavonoids from Dicranostyles ampla

    Natural Product Communications 5 (8), pp. 1233-1237

    Crude extracts from over 16 species of plants from the family Convolvulaceae were evaluated for phytotoxic activity against Agrostis stolonifera (bentgrass) and Lactuca sativa (lettuce) at 1000 μg/mL. Ethanol extracts of Dicranostyles ampla Ducke were among the most active of those species tested. Systematic bioassay-guided fractionation of the ethanol extract of the aerial parts from this species was performed to identify specifically the phytotoxic compounds. Two phytotoxic flavonoids…

    Crude extracts from over 16 species of plants from the family Convolvulaceae were evaluated for phytotoxic activity against Agrostis stolonifera (bentgrass) and Lactuca sativa (lettuce) at 1000 μg/mL. Ethanol extracts of Dicranostyles ampla Ducke were among the most active of those species tested. Systematic bioassay-guided fractionation of the ethanol extract of the aerial parts from this species was performed to identify specifically the phytotoxic compounds. Two phytotoxic flavonoids, dihydromyricetin (1) and myricetin-3-O-α-rhamnoside or myricetrin (2), were found to be responsible for much of the activity of the extract as a whole in the A. stolonifera and L. sativa bioassay. In a Lemna paucicostata bioassay, 1 and 2 had no activity at 100 μM.

    Ver publicación
  • neo-Clerodane diterpenoids from Verbenaceae: Structural elucidation and biological activity

    Natural Product Communications 3 (6), pp. 1021-1031

    This reviews focuses on the occurrence and structural elucidation of neo-clerodane type diterpenes from Verbenaceae and the semisynthetic compounds of closely related structure obtained. Biological activities of crude extracts and isolated diterpenes will be briefly discussed.

    Ver publicación
  • Phytoecdysteroids from Ajuga macrosperma var. breviflora roots

    Journal of Natural Products 71 (7), pp. 1294-1296

    Three new phytoecdysteroids, ajugacetalsterones C (1) and D (3) and breviflorasterone (2), were isolated from the roots of Ajuga macrosperma var. breviflora along with five known compounds, namely, 20-hydroxyecdysone, cyasterone, makisterone A, 20-hydroxyecdysone 3-acetate, and 20-hydroxyecdysone 2-acetate. The structures of 1-3 were elucidated on the basis of extensive 1D and 2D NMR spectroscopic studies. The new compounds possess acetal oxygen bridges between C-26 and C-20/C-22, or C-26/C-23,…

    Three new phytoecdysteroids, ajugacetalsterones C (1) and D (3) and breviflorasterone (2), were isolated from the roots of Ajuga macrosperma var. breviflora along with five known compounds, namely, 20-hydroxyecdysone, cyasterone, makisterone A, 20-hydroxyecdysone 3-acetate, and 20-hydroxyecdysone 2-acetate. The structures of 1-3 were elucidated on the basis of extensive 1D and 2D NMR spectroscopic studies. The new compounds possess acetal oxygen bridges between C-26 and C-20/C-22, or C-26/C-23, or a lactone bridge between C-26 and C-23.

    Ver publicación

Más actividad de Amaya

Ver el perfil completo de Amaya

  • Descubrir a quién conocéis en común
  • Conseguir una presentación
  • Contactar con Amaya directamente
Unirse para ver el perfil completo

Perfiles similares

Añade nuevas aptitudes con estos cursos