Marcelo Guerra Santos

Prof. Dr. Marcelo Guerra Santos


Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2014 in Journal of Nanobiotechnology
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Caio FernandesCaio Fernandes
Caio Fernandes
FAFernanda B de Almeida
Fernanda B de Almeida
ASAmanda N Silveira
Amanda N Silveira
LSLilia Serodio
Lilia Serodio
CMCicero B Mello
Cicero B Mello
DFDeborah Quintanilha Falcão
Deborah Quintanilha Falcão
Plants have been recognized as a good source of insecticidal agents, since they are able to produce their own defensives to insect attack. Moreover, there is a growing concern worldwide to develop pesticides with low impact to environment and non-target organisms. Hexane-soluble fraction from ethanolic crude extract from fruits of Manilkara subsericea and its triterpenes were considered active against a cotton pest (Dysdercus peruvianus). Several natural products with insecticidal activity have poor water solubility, including triterpenes, and nanotechnology has emerged as a good alternative to solve this main problem. On this context, the aim of the present study was to develop an insecticidal nanoemulsion containing apolar fraction from fruits of Manilkara subsericea.

17 November 2017 in Molecules
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GBGisele Botas
Gisele Botas
Rodrigo Alves Soares CruzRodrigo Alves Soares Cruz
Rodrigo Alves Soares Cruz
FAFernanda B. De Almeida
Fernanda B. De Almeida
Jonatas DuarteJonatas Duarte
Jonatas Duarte
RARaquel S. Araújo
Raquel S. Araújo
Caio FernandesCaio Fernandes
Caio Fernandes
Baccharis reticularia DC. is a plant species from the Asteraceae family that is endemic to Brazil. Despite the great importance of Baccharis genus, no study has been carried out regarding either the phytochemical composition of B. reticularia or the evaluation of its larvicidal potential. Considering the intrinsic immiscibility of essential oils, this study shows larvicidal nanoemulsions containing the B. reticularia phytochemically characterized essential oil and its main constituent against Aedes aegypti. The major compound found was d-limonene (25.7%). The essential oil inhibited the acetylcholinesterase, one of the main targets of insecticides. The required hydrophile-lipophile balance of both nanoemulsions was 15.0. The mean droplet sizes were around 90.0 nm, and no major alterations were observed after 24 h of preparation for both formulations. After 48 h of treatment, the estimated LC50 values were 118.94 μg mL−1 and 81.19 μg mL−1 for B. reticularia essential oil and d-limonene nanoemulsions, respectively. Morphological alterations evidenced by scanning electron micrography were observed on the larvae treated with the d-limonene nanoemulsion. This paper demonstrated a simple and ecofriendly method for obtaining B. reticularia essential oil and d-limonene aqueous nanoemulsions by a non-heating and solvent-free method, as promising alternatives for Aedes aegypti control.

15 December 2018 in Environmental Entomology
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MSMarcelo Guerra Santos
Marcelo Guerra Santos
PHPaul Hanson
Paul Hanson
VMValéria Cid Maia
Valéria Cid Maia
KMKlaus Mehltreter
Klaus Mehltreter
Fern–insect interactions have not received the same attention as angiosperm–insect interactions have. It has even been stated that ferns may have very few interactions with animals because of their lack of flowers, fruits, and seeds. Consequently, for many decades fern–insect interactions have been overlooked and underestimated, especially for highly developed interactions such as those with gall-formers. The present work aims to review the galls of ferns and lycophytes worldwide, to provide an updated checklist including unpublished data and to estimate the global gall diversity of ferns and lycophytes. We recorded 93 host species, belonging to 41 genera. Galls were found in 20 fern families and one lycophyte family (Selaginellaceae). Most galls occur within the more derived ferns of the order Polypodiales, especially the fern families Polypodiaceae (21 host species), Dryopteridaceae (14 host species) and Athyriaceae (11 host species). Thirty-eight of the 133 gall morphotypes were induced by mites and 95 by insects of six orders (Coleoptera, Diptera, Hymenoptera, Lepidoptera, Thysanoptera, and Hemiptera). Among the insects, Cecidomyiidae (Diptera) caused most of the galls (35 morphotypes). So far, most galls have been reported from the Neotropical region (40 spp.) and Oriental region (28 spp.).

11 October 2016 in Molecules
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EOEduardo De Oliveira
Eduardo De Oliveira
Rodrigo Alves Soares CruzRodrigo Alves Soares Cruz
Rodrigo Alves Soares Cruz
NANayanna De Mello Amorim
Nayanna De Mello Amorim
MSMarcelo Guerra Santos
Marcelo Guerra Santos
LJLuiz Junior
Luiz Junior
AFAndre Fuly
Andre Fuly
Snake venoms are composed of a complex mixture of active proteins that induce toxic effects, such as edema, hemorrhage, and death. Lachesis muta has the highest lethality indices in Brazil. In most cases, antivenom fails to neutralize local effects, leading to disabilities in victims. Thus, alternative treatments are under investigation, and plant extracts are promising candidates. The objective of this work was to investigate the ability of crude extracts, fractions, or isolated products of Erythroxylum ovalifolium and Erythroxylum subsessile to neutralize some toxic effects of L. muta venom. All samples were mixed with L. muta venom, then in vivo (hemorrhage and edema) and in vitro (proteolysis, coagulation, and hemolysis) assays were performed. Overall, crude extracts or fractions of Erythroxylum spp. inhibited (20%–100%) toxic effects of the venom, but products achieved an inhibition of 4%–30%. However, when venom was injected into mice before the plant extracts, hemorrhage and edema were not inhibited by the samples. On the other hand, an inhibition of 5%–40% was obtained when extracts or products were given before venom injection. These results indicate that the extracts or products of Erythroxylum spp. could be a promising source of molecules able to treat local toxic effects of envenomation by L. muta venom, aiding in the development of new strategies for antivenom treatment.

1 March 2011 in Revista Brasileira de Entomologia
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VMValéria Cid Maia
Valéria Cid Maia
MSMarcelo Guerra Santos
Marcelo Guerra Santos
A new genus and species of gall midge (Diptera, Cecidomyiidae) associated with Microgramma vacciniifolia (Langsd. & Fisch.) Copel. (Polypodiaceae) from Brazil. A new gall midge genus Primadiplosis Maia, gen. nov. and a new species, P. microgrammae Maia,sp. nov., that induces galls on stems of the fern Microgramma vacciniifolia (Langsd. & Fisch.) Copel. are described from Brazil (larva, pupa, male, female, and gall). Novo gênero e espécie de Cecidomyiidae (Diptera) associados a Microgramma vacciniifolia (Langsd. & Fisch.) Copel. (Polypodiaceae) do Brasil. Um novo gênero de Cecidomyiidae, Primadiplosis Maia, gen.nov.,e uma nova espécie, P. microgrammae Maia, sp. nov., que induz galhas no caule da samambaia Microgramma vacciniifolia (Langsd. & Fisch.) Copel. (Polypodiaceae) são descritos do Brasil (larva, pupa, macho, fêmea e galha)

21 April 2022 in Pharmaceutics
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BMBetina Magalhães
Betina Magalhães
Francisco Paiva MachadoFrancisco Paiva Machado
Francisco Paiva Machado
PSPaola S. Sanches
Paola S. Sanches
BLBárbara Lima
Bárbara Lima
DFDeborah Quintanilha Falcão
Deborah Quintanilha Falcão
RFRobson Faria
Robson Faria
P2X7R is a purinergic receptor with broad expression throughout the body, especially in immune system cells. P2X7R activation causes inflammatory mediators to release, including interleukin-1β (IL-1β), the processing and release of which are critically dependent on this ion channel activation. P2X7R’s therapeutic potential augments the discovery of new antagonistic compounds. Thus, we investigated whether the Eugenia sulcata essential oil could block P2X7R activity. The essential oil (ESO) dose-dependently inhibited ATP-promoted PI uptake and IL-1β release with an IC50 of 113.3 ± 3.7 ng/mL and 274 ± 91 ng/mL, respectively, and the essential oil nanoemulsion (ESON) improved the ESO inhibitory effect with an IC50 of 81.4 ± 7.2 ng/mL and 62 ± 2 ng/mL, respectively. ESO and ESON reversed the carrageenan-activated peritonitis in mice, and ESON exhibited an efficacy higher than ESO. The majority substance from essential oil, β-caryophyllene, impaired the ATP-evoked PI uptake and IL-1β release with an IC50 value of 26 ± 0.007 ng/mL and 97 ± 0.012 ng/mL, respectively. Additionally, β-caryophyllene reduced carrageenan-induced peritonitis, and the molecular modeling and computational simulation predicted the intermolecular interactions in the P2X7R situs. In silico, results indicated β-caryophyllene as a potent allosteric P2X7R antagonist, although this substance may present toxic effects for humans. These data confirm the nanoemulsion of essential oil from E. sulcata as a promisor biotechnology strategy for impaired P2X7R functions and the inflammatory response.