Andrés F Olea

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Herein, we explore the potential use of two micelle-forming block copolymers, i.e., Pluronic F-127 and poly(ethylene oxide)-b-poly(caprolactone), for application of fungicide agents. The polymer effect on the in vitro fungicide activity of a series of geranyl orcinol derivatives against Botrytis cinerea has been assessed. The results show that, for all test(More)
The properties of the microheterogeneous systems formed by mixtures of cetyltrimethylammonium bromide (CTAB) and an alternating copolymer of maleic acid and styrene, MAS, and their anionic monoesters, MAS-n with n=2, 4, 6, 8, were investigated. The fluorescence of pyrene was used to sense the polarity of the polymer/CTAB aggregates. Measurements of the(More)
Sesquiterpene lactones have attracted much attention in drug research because they present a series of biological activities such as anticancer, antifungal, anti-inflammatory, antimicrobial and antioxidant. Leptocarpin (LTC) is a sesquiterpene lactone isolated from a native Chilean plant, Leptocarpha rivularis, which has been widely used in traditional(More)
Natural geranyl compounds are known to exhibit important biological activities. In this work a series of geranylphenols were synthesized to evaluate their effect on the mycelial growth of Botrytis cinerea. Geranyl derivatives were synthesized by direct geranylation reactions between the corresponding phenol derivatives and geraniol, using BF3.OEt2 as(More)
The quenching of the benzophenone triplet by lysozyme and its constituent amino acids in aqueous solutions have been studied. Native lysozyme quenches the benzophenone triplet with a high rate constant, 4 x 10(9) M-1 s-1. The quenching process takes place with production of significant amounts of free ketyl radicals, phi ketyl = 0.56, but with a very low(More)
The inhibitory effects on the mycelial growth of plant pathogen Botritys cinerea have been evaluated for a series of geranylphenols substituted with one, two and three methoxy groups in the aromatic ring. The results show that the antifungal activity depends on the structure of the geranylphenols, increasing from 40% to 90% by increasing the number of(More)
An improved synthesis route for obtaining known brassinosteroid analogues, i.e., methyl 2α,3α-dihydroxy-6-oxo-5α-cholan-24-oate (11), methyl 3α-hydroxy-6-oxo-7-oxa-5α-cholan-24-oate (15) and methyl 3α-hydroxy-6-oxa-7-oxo-5α-cholan-24-oate (16), from hyodeoxycholic acid (4) maintaining the native side chain is described. In the alternative procedure, the(More)
The solubilization of p-nitrophenol into the hydrophobic microdomains provided by polyelectrolytes carrying alkyl side chains of different length has been investigated in aqueous solutions of pH 5.0 and 8.0. Under these pH conditions p-nitrophenol is predominantly present in its neutral and ionic forms, respectively. Potassium salts of poly(maleic(More)
The formation of reverse micelles by nonionic alcohol ethoxylates surfactants in two "dry" non polar solvents, heptane and dibutoxymethane (DBM), has been studied. These surfactants are formed by a linear hydrocarbon chain consisting of i carbons, and a poly(ethylene oxide) chain with j ethoxylate units (EO) ending with a hydroxyl group, CiEOj. The study is(More)
Molecular aggregation in a mixture of Triton X-100/n-hexanol/cyclohexane at a molar ratio of 1/16/74 is studied upon addition of small amounts of water. The composition of organic components has been chosen at a ratio n-hexanol/cyclohexane where a well-formed hydrogen bond network has been described. The ratio Triton X-100/n-hexanol has been chosen to(More)