Luzia Koike

Acidic biomarkers from Albacora oils, Campos Basin, Brazil

Abstract Acidic biomarkers of 8 different oil samples from Albacora oil field, Campos Basin, Brazil, were analyzed in order to obtain additional information about biodegradation and thermal evolution. For this purpose, we selected oils (lacustrine saline origin) showing different biodegradation levels and at different distances from the fault that acted as migration pathway in the area. Previous analyses using hydrocarbon biomarkers suggested a mix of oil charges, characterizing two distinct oil cycles interrupted by meteoric water circulation in these reservoirs. Analyses of the naphthenic acid biomarkers revealed a parallelism between the hydrocarbon and the acidic biomarkers. Notwithstanding, there is evidence that the carboxylic acid biomarkers, more resistent to biodegradation, can provide information on past reservoir history when most important neutral biomarkers have been biodegraded. The limitations to the use of these biomarkers are their “de novo” synthesis in the biodegradation process and the complexity of the sample manipulation prior to the analysis.

Naphthenic acids from crude oils of Campos Basin

Abstract Previous work based on chemical evidence and information from the hydrocarbon fractions of Marlim and Albacora, giant oil fields of Campos Basin (offshore Brazil), in connection with other geochemical parameters, led to conclusions on the oil accumulation, migration and biodegradation. The acidic components, as carboxylic acids of Marlim and Albacora were never investigated before and this work revealed a significant correlation between both fractions (neutral and acidic) therefore opening new horizons for the use of these naphthenic acids as additional geochemical parameters to enrich and enlarge previous geological conclusions on Marlim and Albacora. A naphthenic acid of 16 carbon atoms was detected and based on its mass spectrum and that of its corresponding deuterated hydrocarbon an 8-carboxy-9-ethyl-drimane structure was proposed.

3-Alkyl and 3-carboxyalkyl steranes in marine evaporitic oils of the Potiguar Basin, Brazil

Abstract The geochemical characterization of marine evaporitic oils from the Fazenda Belem oil field, Potiguar Basin, Brazil showed good correlation between both acidic and neutral fractions, and led to the identification of several biomarkers including the homologous series of 3-alkyl- and 3-carboxyalkyl-5α(H) steranes and also the new series of 3-alkyl- and 3-carboxyalkyl-5β(H) steranes. These compounds were identified using GC/MS and their structures were confirmed by coinjection with synthetic standards. A minor series of 4-carboxyalkyl steranes was also detected. The analysis of the acidic biomarkers allowed a more accurate evaluation of maturation, biodegradation and migration of the studied oils.

Callus culture of Aspidosperma ramiflorum Muell. Arg.: growth and alkaloid production

Callus culture of Aspidosperma ramiflorum was established in Murashige and Skoog medium. Callus were supplemented with 1 mg.L 2,4-dichlorophenoxyacetic acid, 1.5 mg.L benzylaminopurine, 30 g L sucrose and 10 g L agar. Cultures accumulated the same major alkaloids, ramiflorine A and ramiflorine B, present in the stem bark of the parent plant. The alkaloid contents of 10-methoxy-geissoschizol, ramiflorine A and ramiflorine B, of bark and callus cultures were quantitatively compared by HPLC.

Indole alkaloids from Aspidosperma pruinosum

Abstract Two new indole alkaloids, 10-methoxy-yohimbine and 10-methoxy-4-methylgeissoschizol, and the known compounds yohimbine, β-yohimbine, compactinervine, 10-methoxy-geissoschizol, 10-methoxy-dihydrocorynantheol, normacusine B and 3,4,5,6-tetradehydrositsirikine were isolated from the bark of Aspidosperma pruinosum . A 13 C NMR analysis of some corynanthein types and model compounds was carried out to confirm the structure of the new compounds.

Stereochemical aspects and 13C NMR spectroscopy of the berbamine class of bisbenzylisoquinoline alkaloids

Abstract An analysis of the 13 C NMR spectra of bisbenzylisoquinoline alkaloids of the berbamine type shows the dependence of spectroscopic properties on preferred conformation.

Preliminary studies on the antibacterial activity of crude extracts and alkaloids from species of Aspidosperma

Screening tests of hydroethanolic crude extracts of six species of Aspidosperma (Apocynaceae) against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa were performed. Aspidosperma ramiflorum Muell. Arg. showed good activity against Bacillus subtilis with MIC and MBC of 15.7 and 125 μg/mL, moderate activity against Staphylococcus aureus with MIC and MBC of 250 and 500 μg/mL, and weak activity against Escherichia coli with MIC and MBC of 1000 μg/mL. Aspidosperma pyricolum Muell. Arg. (MIC/MBC 125/250 μg/mL) and Aspidosperma olivaceum Muell. Arg. (MIC/MBC 250/ > 1000 μg/mL) displayed moderate antibacterial activity against Bacillus subtilis. Separation of the crude extract of Aspidosperma ramiflorum was performed according to the usual acid–base process, which produces alkaloid mixtures and closely related metabolites. The basic fraction was active against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli, with MICs of 31.2, 62.5, and 250 μg/mL, respectively. The basic fractions were more active than the acid fractions, probably because they contained some active alkaloids and/or closely related metabolites absent from the other fractions, or they contained a higher concentration of these active compounds.

Experimentação em química de compostos organometálicos: preparação do cloreto de dicarbonilciclopentadienilferro(II)

In this work, we describe a new method for obtaining [Fe(CO)2[(h5-C5H5)Cl] employing simple techniques and low-cost reagents. It is worth mentioning that this method is faster than others reported in the literature. It was applied in laboratory classes for undergraduate students, exploring different concepts in organometallic chemistry and discussing the steps involved in the synthetic route.

Use of Associated Chromatographic Techniques in Bio-Monitored Isolation of Bioactive Monoterpenoid Indole Alkaloids from Aspidosperma ramiflorum

The genus Aspidosperma (Apocynaceae) have been commonly used in folk medicine as potential antimalarial agents; in the treatment of leishmaniasis; uterus and ovary inflammations; as a contraceptive; in diabetes; stomach disorders; against cancer; fever and rheumatism (Oliveira et al, 2009). It commonly grows in tropical America, extracted from trees ranging 2 to 60 m in height. It is found in a variety of habitats from the dry fields of south-central Brazil, Paraguay, and Argentina to the inundated river margins of the Amazon basin (Tanaka, 2006). The main constituents of the Aspidosperma genus are indole alkaloids, a class of substances with a wide range of pharmacological activities such as cholinesterase inhibitors, analgesic, anti-inflammatory, bactericidal, oestrogenic, stimulant and depressant of the central nervous system (CNS) (Zocoler et al, 2005).

Uma síntese alternativa para o (±)-1,2,3,4-tetraidro-{9H-pirido-[3,4-b]}-indol

The 1,2,3,4-tetrahydro-9H-pyrido-[3,4-b]-indole, a compound with tranquillizing properties, was prepared in 16% overall yield from the 3-indole-acetaldehyde and tryptamine by applying the classical Pictet-Spengler condensation. Physical and spectroscopic data for such compound are presented.