Marta Ponzi

LD50 and Repellent Effects of Essential Oils from Argentinian Wild Plant Species on Varroa destructor

Abstract The repellent and acaricidal effects of some essential oils from the most typical wild plant species of northern Patagonia, Argentina, on Varroa destructor Anderson & Trueman were evaluated using a complete exposure test. Honey bees, Apis mellifera L., and mites (five specimens of each per dish) were introduced in petri dishes having different oil concentrations (from 0.1 to 25 μl per cage). Survival of bees and mites was registered after 24, 48, and 72 h. An attraction/repellence test was performed using a wax tube impregnated with essential oil and another tube containing wax only. The lowest LD50 values for mites were registered for Acantholippia seriphioides (A. Gray) Mold. (1.27 μl per cage) and Schinus molle L. (2.65 μl per cage) after 24 h, and for Wedelia glauca (Ortega) O. Hoffm. ex Hicken (0.59 μl per cage) and A. seriphioides (1.09 μl per cage) after 72 h of treatment. The oil with the highest selectivity ratio (A. mellifera LD50/V. destructor LD50) was the one extracted from S. molle (>16). Oils of Lippia junelliana (Mold.) Troncoso, Minthostachys mollis (HBK) Grieseb., and Lippia turbinata Grieseb. mixed with wax had repellent properties. None of the oils tested had attractive effects on Varroa mites.

ACIDITY OF H3PW12O40/SiO2 AND CATALYTIC ACTIVITY OF a -PINENE

The isomerization reaction in liquid phase of a -pinene in camphene catalyzed by tungstophosphoric acid supported on silica is studied. The catalyst is characterized with FT-IR and XRD to establish if the tungstophosphoric acid maintains the Keggin structure after being supported. The catalyst acidity exposed to different thermal treatments was determined by using FT-IR and TPD techniques of ammonia adsorbed. Two types of sites are distinguished, weak acid sites and strong acid sites. The weak acid sites concentration increases with the thermal treatment and can be responsible for the selectivity decrease in camphene by formation of products of higher molecular weight, while the strong acid sites concentration remains almost constant affecting in a lesser degree the obtention of monocyclic compounds

COMPOSICION DEL ACEITE ESENCIAL Y ACTIVIDAD ANTIMICROBIANA DE EUPATORIUM PATENS

El estudio del aceite esencial de Eupatorium patens por cromatografia gaseosa, espectrometria de masas e indices de retencion, determino que los principales componentes son: (E)-cariofileno (14,15%), g-muuroleno (13,47%), a-pineno (11,11%). El analisis de las propiedades antimirobianas resulto positivo frente a Bacillus subtillis

Essential Oil of Hyptis mutabilis (Rich.) Briq. Grown in San Luis, Argentina

Abstract The essential oil from Hyptis mutabilis (Rich.) Briq., obtained by hydrodistillation of the aerial part of the plants over two consecutive years, and collected at diferent vegetative stages, flowering and flowering-fructification, did not differ in regard to the composition of analyzed sesquiterpenes but showed variation in the relative concentration of one of its constituents. The oil yield decreased from 0.5% during flowering to 0.3% during flowering-fructification (fresh weight basis). It was analyzed by GC and GC/MS. Twenty-four compounds were identified, which represented 93–5% of the oil in the flowering stage and 92.5% of it in the flowering-fructification one. The oil was found to contain β-caryophyllene (14.3–12.0%), germacrene D (14.7–15.3%), curzerene (11.5–12.7%) and bicyclogermacrene (12.1–14.2%) as major compounds.

Composition of the Essential Oil from Flowers and Leaves of Heterotheca latifolia Buckley (Compositae)

Abstract Oils obtained by hydrodistillation, separately from flowers and leaves of Heterotheca latifolia Buck. (Compositae), which is a weed in west central Argentina, were analyzed by GC and GC/MS. Twenty-eight compounds were identified in the flower oil representing 88.9%; and 90.7% of the leaf oil was represented by 15 compounds. Although the composition of both oils was similar, the quantity of individual components differed between them. The major components of both oils were borneol (19.0-39.9%) and camphor (12.0–24.3%). The monoterpene hydrocarbon content of the flower oil (47–3%) was much higher than in leaf oil (7.4%), while the oxygenated compounds were much higher in leaf oil (71.5%)

Antimicrobial Activity of the Essential Oil of Heterotheca latifolia Buckley (Compositae)

The essential oil of Heterotheca latifolia Buckley (Compositae) was screened for its antimicrobial activity against Staphylococcus aureus, Escherichia coli, Bacillus subtillis, Candida albicans and Aspergillus niger. Solid phase tests were carried out using petri dishes and applying the agar dilution method for bacteria and the agar diffusion method with paper disks for fungi. H. latifolia oil was found to possess antimicrobial activity against Bacillus subtillis and Escherichia coli.

Dimerization of α-pinene, Using Phosphotungstic Acid Supported on SiO 2 as Catalyst

Fil: Merino, Nora Andrea. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico San Luis. Instituto de Investigaciones En Tecnologia Quimica; Argentina

Zirconia-Supported Copper and KNO 3 Catalysts for Diesel Soot Combustion. Deactivation by Hydrotreatment and SO 2

Fil: Mosconi, Sandra Mariela. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico San Luis. Instituto de Investigaciones en Tecnologia Quimica; Argentina