9 documents found, page 1 of 1
A novel alkaloid isolated from Crotalaria paulina and identified by NMR and DFT...
Oliveira, Ramon Prata; Demuner, Antonio Jacinto; Alvarenga, Elson Santiago; Barbosa, Luiz Claudio Almeida; Silva, Thiago de MeloPyrrolizidine alkaloids (PAs) are secondary metabolites found in Crotalaria genus and are known to have several biological activities. A novel macrocycle bislactone alkaloid, coined ethylcrotaline, was isolated and purified from the aerial parts of Crotalaria paulina. The novel macrocycle was identified with the aid of high resolution mass spectrometry and advanced nuclear magnetic resonance techniques. The rel...
Selection of an essential oil from Corymbia and Eucalyptus plants against Ascia...
Ribeiro, Arthur Vieira; Farias, Elizeu de Sá; Santos, Abraão Almeida; Filomeno, Claudinei Andrade; Santos, Izailda Barbosa dosDue to an increase in environmental and health issues and with the excessive use of synthetic pesticides, many studies are investigating plant essential oils (EOs) for pest control. These compounds are considered safe control agents since they have low toxicity to non-target organisms. Thus, this study aimed to select potential EOs from the Myrtaceae family and their constituents for the control of Ascia monust...
Conformerism, enantiomorphism and double catemer motifs in para-substituted nos...
Teixeira, Róbson Ricardo; Barbosa, Luiz Claudio Almeida; Antolinez, Isabel Valero; Corrêa, Rodrigo de Souza; Martins, Felipe TerraWe have here elucidated the crystal structures of five nostoclide analogues. A common feature in all compounds is a substituent at the para-position of the benzylidene group. Compounds with either bromine (3) or hydroxyl (4) as para-substituent crystallizes with Z’ = 2 as result of conformerism. It was also observed that Z' > 1 in the compound with a para-dimethylamino substituent (1). However, its four crystal...
Corymbia spp. and Eucalyptus spp. essential oils have insecticidal activity aga...
Filomeno, Claudinei Andrade; Barbosa, Luiz Claudio Almeida; Teixeira, Robson Ricardo; Pinheiro, Antônio Lelis; Farias, Elizeu de SáPlutella xylostella (L.) is the main brassica pest worldwide and is difficult to control even with commercial insecticides. In this study, assessments were made of the contact toxicity of essential oils (EOs) from ten Myrtaceae species. For this, the leaves of four Corymbia species (C. citriodora, C. intermedia, C. maculata, and C. ptychocarpa) and six Eucalyptus species (E. andrewsii, E. crebra, E. punctata, E...
Experimental and theoretical studies on the characterization of monocrotaline b...
Oliveira, Ramon Prata; Demuner, Antonio Jacinto; Alvarenga, Elson Santiago; Parma, Monica Cropo; Barbosa, Luiz Claudio AlmeidaThe use of plants in folk medicine has a long and ancient history in the treatment of various diseases. Currently, a large proportion of commercial drugs are based on natural products or are synthetic compounds inspired on such natural substances. Therefore, in this communication to aid that research, structural and spectroscopic analysis of the natural pyrrolizidine alkaloid called monocrotaline was carried ou...
Organocatalysis in the three-component Povarov reaction and investigation by ma...
Simões, Juliana Baptista; Fátima, Ângelo de; Sabino, Adão Aparecido; Aquino, Francisco José Tôrres de; Silva, Daniel Leite daA diastereoselective three-component cascade reaction, catalyzed by p-sulfonic acid calix[4]arene, provides a unique method to access diverse julolidine derivatives in high yields. Additionally, the reaction was also monitored by mass spectrometry and the mechanistic pathway uncovered.
Stink bug predator kills prey with salivary non-proteinaceous compounds
Martínez, Luis Carlos; Fialho, Maria do Carmo Queiroz; Barbosa, Luiz Claudio Almeida; Oliveira, Leandro Licursi; Zanuncio, José ColaPodisus nigrispinus Dallas (Hemiptera: Pentatomidae) is a predator insect with potential applications in biological control because both nymphs and adults have been shown to prey on other insect pests by injection of toxic salivary gland contents. This study identified non-proteinaceous compounds with insecticidal activity from the saliva of P. nigrispinus in Anticarsia gemmatalis. In particular, the ether extr...
Seasonal variation in the chemical composition and antimicrobial activity of vo...
Demuner, Antonio Jacinto; Barbosa, Luiz Claudio Almeida; Magalhaes, Cassia Gonçalves; Silva, Cleber Jose Da; Maltha, Celia Regina AlvaresThis study investigates the seasonal variation of three species of Leptospermum (Myrtaceae) grown in Brazil. The chemical composition of the volatile oils of L. flavescens and L. petersonii did not show any significant seasonal variation in the major components, while for Leptospermum madidum subsp. sativum the levels of major constituents of the volatile oils varied with the harvest season. Major fluctuations ...
Chemical variability and biological activities of Eucalyptus spp. essential oils
Barbosa, Luiz Claudio Almeida; Filomeno, Claudinei Andrade; Teixeira, Robson RicardoMany plant species produce mixtures of odorous and volatile compounds known as essential oils (EOs). These mixtures play important roles in Nature and have been utilized by mankind for different purposes, such as pharmaceuticals, agrochemicals, aromatherapy, and food flavorants. There are more than 3000 EOs reported in the literature, with approximately 300 in commercial use, including the EOs from Eucalyptus s...