Lippia gracilis, popularly known in Brazil as 'alecrim-de-tabuleiro', is used for many purposes, especially antimicrobial and antiseptic activities. The leaves of three L. gracilis genotypes, including LGRA-106, LGRA-109 and LGRA-110 were collected from the Active Germplasm Bank located in the "Campus Rural da UFS" research farm at the São Cristóvão country, Sergipe State, Brazil. The essential oils were obtained from leaves of L. gracilis plants by hydrodistillation. Chemical analysis of the essential oils was performed by gas chromatography-mass spectrometry (GC-MS). The susceptibility of Trichophyton rubrum strains, MYA3108 and TruMDR2, to the two L. gracilis genotypes (LGRA-106 and LGRA-109) essential oils was determined by the serial microdilution method. Leishmanicidal activity of essential oil from LGRA-106 and LGRA-110 was assayed by tetrazolium-dye (MTT) colorimetric method. The oxygenated monoterpene thymol was the main component of the essential oil from genotype LGRA-106, while Carvacrol was more abundant in LGRA-109 and LGRA-110. The concentrations of LGRA-106 and LGRA-109 essential oils that completely eliminate the fungi were determined and these concentrations were similar to those observed for fluconazole, a common antifungal drug. Among the genotype tested, LGRA-106 essential oil exhibited the best fungicidal activity at 46.87μgmL(-1). Regarding to leishmanicidal activity, the IC50, for LGRA-106 and LGRA-110, was 86.32 and 77.26μgmL(-1), respectively. The results showed that L. gracilis essential oil, rich in thymol and thymol itself presented best antidermatophytic activity, while the best leishmanicidal activity was obtained with essential oil from genotype rich in Carvacrol and Carvacrol itself.

Leishamaniasis is a disease that aff ects more than 2 million people worldwide, whose causative agent is Leishmania spp. The current therapy for leishmaniasis is far from satisfactory. All available drugs, including pentavalent antimony, require parenteral administration and are potentially toxic. Moreover, an increase in clinical resistance to these drugs has been reported. In this scenario, plant essential oils used traditionally in folk medicine are emerging as alternative sources for chemotherapeutic compounds. In this study, in vitro leishmanicidal eff ects of a thymol-and a carvacrol-rich essential oil from leaves of Lippia sidoides Cham. were investigated. The essential oils were extracted and their constituents were characterized by gas chromatography coupled to mass spectrometry (GC/MS). Both essential oils showed signifi cant activity against promastigote forms of Leishmania chagasi. However, we found that carvacrol-rich essential oil was more eff ective, with IC 50 /72 h of 54.8 μg/mL compared to 74.1 μg/mL for thymol-rich oil. Carvacrol also showed lower IC 50 than thymol. Our data suggest that L. sidoides essential oils are indeed promising sources of leishmanicidal compounds.

Several constituents of essential oils have been shown to be active against pathogens such as bacteria, fungi, and protozoa. This study demonstrated the in vitro action of ten compounds present in essential oils against Leishmania amazonensis promastigotes. With the exception of p-cymene, all evaluated compounds presented leishmanicidal activity, exhibiting IC50 between 25.4 and 568.1 μg mL−1. Compounds with the best leishmanicidal activity presented a phenolic moiety (IC50 between 25.4 and 82.9 μg mL−1). Alicyclic alcohols ((−)-menthol and isoborneol) and ketones ((−)-carvone) promoted similar activity against the parasite (IC50 between 190.2 and 198.9 μg mL−1). Most of the compounds showed low cytotoxicity in L929 fibroblasts. Analysis of the structure-activity relationship of these compounds showed the importance of the phenolic structure for the biological action against the promastigote forms of the parasite.

Fatty acids, especially those from phospholipids (PLFA), are essential membrane components that are present in relatively constant proportions in biological membranes under natural conditions. However, under harmful growth conditions, such as diseases, environmental changes, and chemical exposure, the fatty acid proportions might vary. If such changes could be identified and revealed to be specific for adverse situations, they could be used as biomarkers. Such biomarkers could facilitate the identification of virulence and resistance mechanisms to particular chemotherapeutic agents. Therefore, specific biomarkers could lead to better therapeutic decisions that would, in turn, enhance treatment effectiveness. The objective of this study was to compare the fatty acid profiles of trivalent antimony and nitric oxide (NO)-resistant and -sensitive Leishmania chagasi and Leishmania amazonensis isolates. Fatty acid methyl esters (FAMEs) were obtained from total lipids (MIDI), ester-linked lipids (ELFA), and ester-linked phospholipids (PLFA). FAMEs were analyzed by chromatography and mass spectrometry. Species- or resistance-associated differences in FAME profiles were assessed by nonmetric multidimensional scaling, multiresponse permutation procedures, and indicator species analyses. The isolate groups had different MIDI-FAME profiles. However, neither the ELFA nor PLFA profiles differed between the sensitive and resistant isolates. Levels of the fatty acid 18:1 Δ9c were increased in sensitive isolates (p < 0,001), whereas the fatty acid 20:4 Δ5,8,11,14 showed the opposite trend (p < 0.01). We conclude that these two fatty acids are potential biomarkers for NO and antimony resistance in L. chagasi and L. amazonensis and that they could be helpful in therapeutic diagnoses.

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In order to find new alternatives for vector control and personal protection, we evaluated the larvicidal and repellent activity of essentials oils from plants found in the Northeast of Brazil against Aedes aegypti Linnaeus mosquitoes. The plants tested include Xylopia laevigata, Xylopia frutescens, and Lippia pedunculosa and their major compounds, piperitenone oxide, and (R)-limonene. The essential oil of L. pedunculosa and its major volatile compounds were shown to be toxic for Ae. aegypti larvae with a LC lower than 60 ppm. The essential oil of plants from the Xylopia genus, on the other hand, showed no activity against Ae. aegypti, proving to be toxic to mosquito larvae only when concentrations were higher than 1000 ppm. All plants tested provided some degree of protection against mosquitoes landing, but only the essential oil of L. pedunculosa and the volatile compound piperitenone oxide suppressed 100% of mosquitoes landing on human skin, in concentrations lower than 1%. Among the plants studied, the essential oil of L. pedunculosa and its volatiles compounds have shown the potential for the development of safe alternative for mosquito larvae control and protection against Ae. aegypti mosquito bites.

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Key words: Leishmania major -anti-silencing factor 1 -histone chaperone Leishmania spp is a member of the Trypanosomatidae family and a parasitic protozoa and digenetic eukaryote of medical and veterinary relevance. Leishmania undergoes several changes to adapt to and survive in different hostile environments, namely the insect vector digestive tract and the vertebrate host's macrophagic phagolysosomes. For that a tight and agile control of gene expression is required.Differently from most of the eukaryotes, these parasites have polycistronic transcription and control of gene expression occurs primarily at the posttranscriptional level (reviewed by Clayton 2002, Martinez-Calvillo et al. 2010. Likewise other eukaryotes, in these parasites the chromatin structure modulates the access of proteins to the DNA, which ultimately regulates different aspects of gene expression, DNA processing, replication and double-stranded DNA repair (Navarro et al. 1999, Elias et al. 2001, Gontijo et al. 2003, McNairn & Gilbert 2003.Anti-silencing factor 1 (ASF1) is a histone chaperone that together with chromatin assembly factor (CAF)-1 adds histones H3 and H4 onto newly replicated DNA (Tyler et al. 2001). This suggests a role for ASF1 in chro- matin assembly regulation (Loyola & Almouzni 2004, Zhang et al. 2005. ASF1 can be involved either in gene activation or transcriptional repression; it depends on the factors it interacts with (Sutton et al. 2001, Schwabish & Struhl 2006, Adkins et al. 2007, Takahata et al. 2009, Varv et al. 2010. In different eukaryotes deletion of ASF1 alters response to DNA damage and DNA replication blocking agents (Le et al. 1997, Tyler et al. 1999) and leads to gross chromosomal rearrangements (Prado et al. 2004) and even to cell death (Sanematsu et al. 2006).The increased susceptibility of chromatin-assembly factor mutants to DNA-damaging agents may be an effect of the direct role of these factors in modulating chromatin structure (Mello et al. 2002). In addition, an association between ASF1 and genomic stability has been provided by the identification of a dynamic interaction between ASF1 and the Rad53 DNA damage checkpoint protein. Also, activation of ASF1 may be an important cellular response to DNA damage and replication stress (Emili et al. 2001, Hu et al. 2001. When DNA damage occurs, ASF1 is recruited to the lesion site where it may disrupt the H3/H4 tetramer. This results in nucleosome eviction and allows access of the repair machinery to unencumbered DNA (Canfield et al. 2009).In Leishmania species ASF1 roles have not been investigated, although orthologous genes have been annotated in the sequenced genomes (tritrypdb.org). In another trypanosomatid, Trypanosoma brucei, the participation of ASF1 in the machinery that regulates spindle assembly and S-phase progression has been described (Li et al. 2007). Therefore, given that ASF1 is associated with gene expression in other eukaryotes and that chromatin modifications are relevant for controlling ASF1 from L. major • Ricardo Scher et al. 37...