Browsing by Autor "Daniel Lorenzo"

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Asaricin, the Main Component ofOcotea opiferaMart. Essential Oil
(Taylor & Francis, 2001) Daniel Lorenzo; Ingrid Loayza; Lilibeth Leigue; Caren D. Frizzo; Eduardo Dellacassa; Patrick Moyna
Abstract Investigation of the volatile fraction from the stem bark of Ocotea opifera Mart. led to the isolation and characterization of asaricin, a phenolic derivative with antifungal and insecticidal activity, as the main component, which is described for the first time for the genus Ocotea. The structure has been established by a study of its mono-and bidimensional NMR spectra and mass spectrometry.
Composition and chiral characterization of the essential oil ofBuddleja tucumanensis from Bolivia
(Wiley, 2005) Daniel Lorenzo; Ingrid Loayza; Eduardo Dellacassa
Analysis by GC and GC-MS of the essential oil obtained from aerial parts of Buddleja tucumanensis revealed 28 components (81% of the total composition). The major constituents were found to be α-thujene, β-pinene, α-pinene, p-cymene, α-trans–bergamotene and β-caryophyllene; the enantiomeric distribution of α-pinene, sabinene, β-pinene, limonene and terpinen-4-ol was studied by multidimensional HRGC-HRGC. The enantiomeric excess found for each monoterpene allowed better characterization of this species. Copyright © 2005 John Wiley & Sons, Ltd.
Composition of the essential oil of Erechtites hieracifolia from Bolivia
(Wiley, 2001) Daniel Lorenzo; Gloria Saavedra; Ingrid Loayza; Eduardo Dellacassa
Abstract Analysis by GC and GC–MS of the essential oil obtained from aerial parts of Erechtites hieracifolia revealed 22 components (93% of the total composition). The major constituents were found to be α‐pinene, myrcene, (E) ‐β‐ocimene, (E) ‐caryophyllene and germacrene D; the enantiomeric distribution of α‐pinene, sabinene, β‐pinene, limonene and linalool was studied by multidimensional HRGC–HRGC. The major component was α‐pinene (48%) with an enantiomeric purity of 100% for (1 R )‐(+)‐α‐pinene. Copyright © 2001 John Wiley & Sons, Ltd.
Composition of the essential oil of Tagetes maxima Kuntze from Bolivia
(Wiley, 2002) Daniel Lorenzo; Ingrid Loayza; Eduardo Dellacassa
Abstract The essential oil of leaves and stems of Tagetes maxima Kuntze growing wild in Bolivia was analysed by HRGC and HRGC–MS (quadrupole). Twenty‐four components (93% of the total composition) were identified and the enantiomeric distribution of α‐pinene, sabinene, β‐pinene and limonene was studied by multidimensional HRGC–HRGC. The major components were found to be ( Z )‐tagetone (19%), ( Z )‐tagetenone (14%), ( Z )‐β‐ocimene (13%), ( E )‐tagetenone (18%), dihydrotagetone (8%) and piperitenone (6%). Copyright © 2002 John Wiley & Sons, Ltd.
Composition of the Essential Oil ofPolylepis besseriHieron. ssp.besserifrom Bolivia
(Taylor & Francis, 2002) Daniel Lorenzo; Eduardo Dellacassa; Ingrid Loayza; W. de Groot
Abstract The essential oil of aerial parts of Polylepis besseri Hieron. ssp. besseri was analyzed by GC and GC/MS; 43 components (90% of the total composition) were identified. The study showed that the main components were the diterpenes abietadiene (40.3%) and abietatriene (6.1%).
Composition of the essential oil ofPorophyllum ruderale (Jacq.) Cass. from Bolivia
(Wiley, 1999) Ingrid Loayza; W. de Groot; Daniel Lorenzo; Eduardo Dellacassa; Luigi Mondello; Giovanni Dugo
The essential oil of aerial parts of Porophyllum ruderale (Jacq.) Cass. was analysed by HRGC, HRGC–MS (quadrupole) and 26 components (93% of the total composition) were identified. The enantiomeric distribution of β-pinene, sabinene, 4-terpineol and α-terpineol was studied by multidimensional HRGC–HRGC. The major component was sabinene (64%) with an enantiomeric purity of 97% for (+)-sabinene. Copyright © 1999 John Wiley & Sons, Ltd.
Composition of the essential oils from leaves of two Hedyosmum spp. from Bolivia
(Wiley, 2002) Daniel Lorenzo; Ingrid Loayza; Eduardo Dellacassa
Abstract Essential oils obtained by hydrodistillation from aerial parts of Hedyosmum angustifolium (Ruiz & Pavón) Solms‐Laubach and H. scabrum (Ruiz & Pavón) Solms‐Laubach from Bolivia were analysed by GC–FID and GC–MS. Monoterpene hydrocarbons, especially α‐ and β‐pinene, and oxygen containing monoterpenes, mainly 1,8‐cineole and linalool, were the major constituents found in the oils of H. angustifolium . The oil of H. scabrum was mainly made up of monoterpenes, in particular δ‐3‐carene, the sesquiterpene hydrocarbons α‐gurjunene and germacrene D, and 3′, 4′‐dimethoxypropiophenone. For both oils, the enantiomeric distribution of α‐pinene, sabinene, β‐pinene, limonene, linalool, terpinen‐4‐ol and α‐terpineol was studied by multidimensional HRGC–HRGC. The main difference between the oils corresponded to the reverse enantiomeric distribution found for linalool, indicating a clear index of different metabolic response in each species. Copyright © 2002 John Wiley & Sons, Ltd.
Searching for Natural Bioactive Compounds in Four Baccharis species from Bolivia
(SAGE Publishing, 2008) Marcelo Dávila; Ingrid Loayza; Daniel Lorenzo; Eduardo Dellacassa
The volatile oil composition of four Baccharis species ( Baccharis papilosa, B. polycephala, B. buxifolia, and B. convawyi) growing wild in Bolivia were studied by GC and GC/MS. The antimicrobial activity of the oils was determined by the agar diffusion and bioautography methods. Solvent extracts, polar and non-polar, of the same species were also tested for antimicrobial and antioxidant activities. Extracts from B. polycephala, B. papilosa and B. convawyi presented significant antioxidant activity, determined using the DPPH radical scavenging method, showing EC 50 values of 4.74, 7.17 and 7.97 μg/mL, respectively. Screening for antimicrobial activity was conducted using the agar diffusion test. The most active extracts (% inhibition ≥ 50) were further examined by the dilution method. All the plant extracts studied showed higher antimicrobial activity against S. aureus (Gram-positive) than against E. coli and P. fluorescens (Gram-negative).