Thiago Guilherme Schwanz

Chemical composition and antioxidant activity of the essential oil of Tabernaemontana catharinensis A. DC. leaves

The essential oils obtained by hydrodistillation from the leaves of Tabernaemontana catharinensis had their composition analysed by GC–MS. A total of 18 substances were identified, consisting of a complex mixture of sesquiterpenes (83.52%), monoterpenes (5.46%) and triterpenes (4.56%). The main components in the oil were β-caryophyllene (56.87%), α-cadinol (12.52%), 8S,13-cedran-diol (5.41%), α-terpineol (3.99%), β-eudesmol (2.54%), caryophyllene oxide (2.51%) and ethyl iso-allocholate (2.03%) along with β-cubebene, γ-cadinene, cubenol, 1,8-cineol, o-cymene, curcumenol, spathulenol, friedeline and β-sitosterol as minor constituents. An antioxidant property was tested with the oil obtained by means of 1,1-diphenyl-2-picrylhydrazyl assay; the oil presented interesting radical scavenging activity. To the best of our knowledge, this is the first study of the composition and antioxidant activity of essential oil from the T. catharinensis collected from Brazil.

Isolation and chromatographic analysis of bioactive triterpenoids from the bark extract of Cariniana domestica (Mart) Miers

The Lecythidaceae family is composed of 25 genera and 400 species that occur in the form of trees with a pantropical distribution. The genera Cariniana belongs to the family Lecythidaceae, and there are few reports considering these species. In this work, fractionation of the dichloromethane fraction obtained from the aqueous extract of the stem bark of Cariniana domestica (Mart) Miers, popularly known as Jequitibá-roxo, led to the isolation of two mixtures of triterpenoids: lupeol and β-amyrin and β-sitosterol and stigmasterol. The structures of the isolated compounds were elucidated by spectroscopic (NMR) and chromatographic (GC-MS) techniques as well as literature data comparisons. β-Sitosterol, stigmasterol, lupeol and β-amyrin were quantified in dichloromethane fraction by high-performance liquid chromatography (HPLC/DAD). The dichloromethane fraction was also investigated for antioxidant and antifungal activities. The isolated compounds and their biological activities are reported for the first time for the species C. domestica.

Determinação de bifenilos policlorados em milho através de extração em fase sólida seguida de cromatografia a gás acoplada à espectrometria de massas

This paper describes an analytical method for analyzing polychlorinated biphenyls in corn samples using solid phase extraction (SPE) followed by determination by GC-MS. All calibration curves proved linear (r> 0.99). Recoveries ranged between 74.1 and 110.6% with relative standard deviation lower than 20% for all compounds. The limits of quantitation for the method were between 0.025 and 0.1 ng g-1. Of the 51 samples analyzed, PCB 180 showed the highest frequency, being detected in more than 39%, followed by PCB 138, detected in more than 33% of samples.

Determinação de bifenilos policlorados em soro de cordão umbilical através de extração por hidrólise ácida seguida de cromatografia a gás acoplada a um microdetector de captura de elétrons

The present work describes the determination of polychlorinated biphenyls in 123 umbilical cord serum samples by liquid-liquid extraction method with acid hydrolyze step and analysis by GC-mECD. The analytical method was evaluated with following figures of merit for all PCBs: linearity (>0.997); precision (<12.55%); recoveries (73-119%); limit of detection (0.1 ng mL-1); limit of quantification (0.25-0.5 ng mL-1). The results showed high contamination in the analyzed samples. PCB more frequent was 138 (66.7%), followed by 180 (55.3%) and 52 (51.3%).

Scutia buxifolia Reissek essential oil: in vitro antioxidant and antimicrobial activities

The volatile oil from the stem bark of Scutia buxifolia (Rhamnaceae) has been obtained by hydrodistillation and analyzed by GC-MS. Twenty-one components were identified representing 99.93 % of the total oil composition, spathulenol (35.87%), β-cubebene (17.26%), germacrene D (6.43%), linalool (5.19%), carvacrol (4.05%) were the main components of S. buxifolia essential oil. Antioxidant and antimicrobial properties of the essential oil were evaluated by free radical scavenging (DPPH) assay and micro broth dilution method, respectively. S. buxifolia essential oil presented interesting radical scavenging activity (IC50 = 15.03 ± 0.11 µg/mL). The antibacterial assay showed that S. buxifolia stem bark essential oil was moderately active against the Staphylococcus aureus and Micrococcus sp. (MIC = 500 µg/mL) and Escherichia coli (250 µg/mL). To the best of our knowledge, this is the first study on the composition, antioxidant and antimicrobial activities of essential oil from the S. buxifolia collected from Brazil.

Composition and antioxidant capacity of the essential oil of leaves of Vitex megapotamica (Sprengel) Moldenke

This study is designed to examine the chemical composition and antioxidant activity of the essential oil of Vitex megapotamica. Gas chromatography–mass spectrometry analysis resulted in the detection of 27 components, representing 92.36% of the total oil composition. The main components in the oil were butylated hydroxytoluene (BHT) (34.17%), phytol (12.66%), α-caryophyllene (11.84%), δ-elemene (10.65%), β-caryophyllene (7.82%), γ-elemene (4.24%) and germacrene D (2.82%). The antioxidant activity of the oil was evaluated in terms of their free-radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl. The oil showed percentage inhibition of 35.62% and 75.25% at concentrations of 76 and 101.6 mg mL−1, respectively. BHT (36.30%) was also determined by HPLC-DAD in the hexane fraction from the leaves. To the best of our knowledge, this is the first study of the composition and antioxidant activity of the essential oil of the species V. megapotamica.

Chemical Composition, Antioxidant and Antimicrobial Activities of the Essential Oil of Scutia buxifolia Reissek Leaves

The chemical composition, antioxidant and antibacterial activities of essential oil isolated by hydrodistillation from the leaves parts of Scutia buxifolia were evaluated. The chemical composition was analyzed by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Twenty-five substances were identified, consisting of a complex mixture of sesquiterpenes (73.69%) and monoterpenes (18.74%). The main components in the oil were spathulenol (27.09%), β-cubebene (11.26%), germacrene D (9.81%), carvacrol (7.01%), globulol (5.36%), α-copaene (4.17%), γ-eudesmol (3.59%), thymol (3.27%), 1,8-cineol (3.08%), p-cymene (2.56%), α-eudesmol (2.34%), β-elemene (2.04%), butylated hydroxytoluene (2.00%) along with eugenol acetate, n-hexanol, α-pinene, α-humulene, eugenol, humulene epoxide, phytol as minor constituents. The antioxidant property of the oil was assessed by free radical scavenging (DPPH) assay. S. buxifolia essential oil presented interesting radical scavenging activity (IC50=13.62 ± 0.17 μg/mL). The antibacterial properties of the oils also was tested by broth microdilution method and was effective only against S. aureus and E. coli (MIC=500 and 750 μg/mL, respectively). To the best of our knowledge, this is the first study of the composition, antioxidant and antimicrobial activities of essential oil from the S. buxifolia collected from Brazil.