Frederico de M. Rodrigues

Headspace solid phase microextraction/gas chromatography-mass spectrometry combined to chemometric analysis for volatile organic compounds determination in canine hair: A new tool to detect dog contamination by visceral leishmaniasis

A new analytical methodology using HS-SPME/GC-MS was optimized in order to attain maximum sensitivity, using multivariate strategies. The proposed method was employed to evaluate the VOC profile exhaled from canine hair samples collected from 8 healthy dogs and from 16 dogs infected by Leishmania infantum. 274 VOCs were detected, which could be identified as aldehydes, ketones and hydrocarbons. After application of the Soft Independent Modeling of Class Analogy (SIMCA) and Principal Component Analysis (PCA) healthy and infected dogs, with similar VOCs profiles, could be separately grouped, based on compounds such as 2-hexanone, benzaldehyde, and 2,4-nonadienal. The proposed method is non-invasive, painless, readily accepted by dog owners and could be useful to identify several biomarkers with applications in the diagnosis of diseases.

Identification of biomarkers in the hair of dogs: new diagnostic possibilities in the study and control of visceral leishmaniasis

Visceral leishmaniasis (VL) is a zoonosis whose etiologic agent in the Americas is Leishmania infantum, and dogs are the main host. Research and innovation in diagnostic techniques are essential to improve the surveillance and control of VL in endemic areas. The present study investigates the profile of the volatile organic compounds (VOCs) emitted by healthy dogs and by dogs infected by L. infantum to detect variations in the VOCs that may be used as biomarkers in the diagnosis of VL. In total, 36 dogs were selected from an endemic area and divided into three groups: G1, not infected with L. infantum; G2, infected without clinical signs of VL; and G3, infected with clinical signs of VL. To analyze the profiles of the VOCs emitted by dogs from the three groups, solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) was used. Variations were observed between the profiles of the VOCs emitted in the three groups studied, and they also differentiated infected animals with or without clinical signs. Six VOCs were identified as potential biomarkers of infection, with significant variations between healthy dogs (G1) and infected dogs (G2 + G3). The detection of variations between groups G2 and G3 suggested that the profiles of some VOCs may be related to the type of immune response and the parasite load of the infected dogs. This study demonstrated the possibility of analysis of VOCs as biomarkers of VL in diagnostic, clinical, and epidemiological work.

Volatile Organic Compounds Obtained by in Vitro Callus Cultivation of Plectranthus ornatus Codd. (Lamiaceae)

Plectranthus spp (Lamiaceae) are plants of economic importance because they are sources of aromatic essential oils and are also cultivated and several species of this genus are used as folk medicines. This paper describes the effects of different concentrations of the 2,4-dichlorophenoxyacetic acid (2,4-D) and 1-naphthaleneacetic acid (NAA) on the induction of callus from nodal segments of Plectranthus ornatus Codd and in the production of volatile organic compounds (monoterpenes and sesquiterpenes). The 20 and 40 day calli were subjected to solid phase micro extraction (HS-SPME) and submitted to GCMS analysis. Variations in VOCs between the samples were observed and, a direct relationship was observed between of the major constituent detected (α-terpinyl acetate) and the monoterpenes α-thujene, α-pinene, β-pinene, camphene, sabinene and α-limonene that were present in the volatile fractions. Besides α-terpinyl acetate, isobornyl acetate and α-limonene were also major constituents. Variations were observed in VOCs in the analyzed periods. The best cultivation media for the production of VOCs was found to be MS0 (control). Moderate success was achieved by treatment with 2.68 µM and 5:37 µM NAA (Group 2). With 2,4-D (9.0 µM), only the presence of α-terpinyl acetate and isocumene were detected and, with 2.26 µM of 2,4-D was produced mainly α-terpinyl acetate, α-thujene and β-caryophyllene (16.2%). The VOC profiles present in P. ornatus were interpreted using PCA and HCA. The results permitted us to determine the best cultivation media for VOC production and, the PCA and HCA analysis allowed us to recognize four groups among the different treatments from the compounds identified in this set of treatments.

Immediate differentiation of unusual seed oils by easy ambient sonic-spray ionization mass spectrometry and chemometric analysis

Vegetable oils have gained continuous economic importance being increasingly used as renewable raw materials by the food, cosmetics and biofuel industries. As an alternative to the traditional sources of oils, unusual vegetable oils from Jatropha curcas, Bombacopsis glabra, Capparis flexuosa, Siparuna guianensis, Moringa oleifera, Hibiscus tiliaceus, Virola bicuhyba, Pouteria caimito and Syagrus coronata seeds are used. We describe herein the immediate as well as direct, fast and low cost characterization of such seed oils via triacylglycerol (TAG) and free fatty acid (FFA) profiles by easy ambient sonic-spray ionization mass spectrometry (EASI-MS) and chemometric analysis. The oils are shown to display indeed typical and unique chemical profiles of triacylglycerol (TAG) and free fatty acids (FFA) with contrasting carbon lengths, degree of unsaturation or with the presence of other chemical functions on the alkyl chain. V. bicuhyba and S. coronata seed oils were found to be constituted of relatively short chain TAG making them potential raw materials for obtaining biogasolines or biokeresones, which are used as aviation fuels. The TAG profiles of H. tiliaceus were very similar to those of soybean, P. caimito similar to those of andiroba oil, and C. flexuosa and S. guianensis similar to those of palm oil. FFA compositions from H. tiliaceus, P. caimito, C. flexuosa and S. guianensis are rich in oleic or linoleic acids, which are an important requirement of feedstock for biodiesel production. Some polyphenolic compounds determined by EASI-MS in some of these oils are also known to provide important nutritional and therapeutic benefits to human health. EASI-MS can therefore offer immediate characterization of such oils and help in quality monitoring and control of adulteration and to guide their application in food, cosmetics and the biofuel industries.

Attraction of phlebotomine sandflies to volatiles from skin odors of individuals residing in an endemic area of tegumentary leishmaniasis

Background Many studies have investigated what could attract insects of medical importance and a crucial role has lately been attributed to human skin odors. Most of these researches have been concerned with mosquitoes, e.g., vectors of dengue and malaria. Little is known about volatile organic compounds (VOCs) from human skin odors and their effects on leishmania vectors. Objective The present study aimed to identify the VOCs from human skin that can be attractive to female anthropophilic phlebotomine sandflies. Results Forty-two VOCs were identified from skin odors of 33 male volunteers, seven of which were tested in wind tunnel assays employing field-captured phlebotomine sandflies (75.4% identified as Lutzomyia intermedia). Hexane and (E)-oct-3-en-1-ol (octenol) were used as negative and positive controls, respectively. 2-Phenylacetaldehyde (hereafter called phenylacetaldehyde), 6-methylhept-5-en-2-one (also known as sulcatone), nonadecane and icosane were found to activate female phlebotomine sandflies, but only phenylacetaldehyde, 6-methylhepten-5-en-2-one and icosane elicited attraction responses. Conclusions These results suggest that phenylacetaldehyde, 6-methylhepten-5-en-2-one and icosane may be suitable candidates for attractiveness experimentation in the field which can be an important tool to develop strategies concerning human beings protection against phlebotomine sandflies bites and consequently against leishmaniasis.

Sources of Protein as Food Baits for Anastrepha obliqua (Diptera: Tephritidae): Tests in a Wind Tunnel and the Field

Abstract The West Indian fruit fly, Anastrepha obliqua Macquart (Diptera: Tephritidae), is an economically important fruit pest in the Americas. Food attractants are used as bait in traps for monitoring the population of flies in orchards, but their effectiveness differs with location, fruit fly variety, and the type of trap deployed. In this work, we tested the effectiveness of a hydrolyzed protein, BioAnastrepha®, and a yeast extract, Bionis YE MF®, under field conditions and in a laboratory bioassay and identified the main volatile compounds emitted from such mixtures. Hydrolyzed protein and yeast extract were attractive in a wind tunnel, but in the field, hydrolyzed protein was not attractive and only pure yeast extract and yeast extract with sugar were attractive for A. obliqua. Sugar alone was not attractive to the flies in either experiment. Yeast extract itself is a good attractant for A. obliqua. The addition of sugar, however, will stimulate feeding, which could be useful in insecticide-bait sprays.