12 documents found, page 1 of 2
Computation and structural elucidation of compounds formed via epoxide alcoholysis
Alvarenga, Elson S.; Teixeira, Milena G.; Lopes, Dayane T.; Demuner, Antonio J.Isobenzofuranones are known for their wide range of biological activities such as fungicide, insecticide, and anticancer. The search for novel bioactive compounds was performed by reaction of epoxide 2 with methanol, ethanol, propan‐1‐ol, propan‐2‐ol, and butan‐1‐ol. The mechanism for the stereoselective and stereospecific epoxide opening with methanol was reasoned by calculating the transition states for the t...
Hederagenin amide derivatives as potential antiproliferative agents
Barbosa, Luiz C. A.; Demuner, Antonio J.; Rodríguez-Hernández, Diego; Martins, João Paulo Ataide; Csuk, René; Fischer (nee Heller), LucieIn this study, a series of C-28 amides derivatives of hederagenin with or without the presence of an acetyl group at positions 3 and 23 in ring A, were synthetized aiming to develop potent cytotoxic agents. Their structures were confirmed by MS, IR, 1H NMR and 13C NMR spectroscopic analyses and their cytotoxic activities were screened in SRB assays using a panel of six human cancer cell lines. The majority of t...
Chemical composition and antibacterial activities from the essential oils of my...
Silva, Cleber J.; Barbosa, Luiz C. A.; Demuner, Antonio J.; Montanari, Ricardo M.; Pinheiro, Antônio L.; Dias, Iara; Andrade, Nélio J.The essential oils of seven Myrtaceae species were investigated for its chemical composition and antibacterial activity. The volatile oils were characterized by a high content of monoterpenoids of which 1,8-cineole (88.0, 65.0 and 77.0% for Melaleuca hypericifolia, Callistemon viminalis and Callistemon citrinus respectively), terpinen-4-ol (47.0 and 49.8% for Melaleuca thymifolia and Callistemon polandii respec...
Highly potent anti-leishmanial derivatives of hederagenin, a triperpenoid from ...
Rodríguez-Hernández, Diego; Barbosa, Luiz C.A.; Demuner, Antonio J.; Almeida, Raquel M.de; Fujiwara, Ricardo T.; Ferreira, Sebastião R.Leishmaniasis is a neglected tropical disease (NTDs), endemic in 88 countries that affect more than 12 million people. Current drugs are limited due to their toxicity, development of biological resistance, length of treatment and high cost. Thus, the search for new effective and less toxic treatments is an urgent need. In this study, we report the synthesis of 3 new amide derivatives of hederagenin (22–24) with...
Chemical composition and histochemistry of Sphagneticola trilobata essential oil
Silva, Cleber José da; Barbosa, Luiz C. A.; Demuner, Antonio J.; Montanari, Ricardo M.; Francino, Dayana; Meira, Renata M. S. A.; Souza, Ana Olívia deAnatomical and histochemical investigations of Sphagneticola trilobata (L.) Pruski, Asteraceae, secretory structures in leaves and stems and the seasonal variation of essential oils were carried out. Histochemical techniques enabled the specific location of the essential oil accumulation in the internal (canals) and external structures (trichomes). Histochemical analysis showed that the secretory trichomes prod...
Novel hederagenin–triazolyl derivatives as potential anti-cancer agents
Rodríguez-Hernández, Diego; Demuner, Antonio J.; Barbosa, Luiz C.A.; Heller, Lucie; Csuk, RenéA series of novel aryl-1H-1,2,3-triazol-4-yl methylester and amide derivatives of the natural product hederagenin was synthesized aiming to develop new antitumor agents, using Huisgen 1,3-dipolar cycloaddition reactions, with yields between 35% and 95%. The structures of all derivatives (2–31) were confirmed by MS, IR, ^1H NMR and ^13C NMR spectroscopic data. The cytotoxic activities of all compounds were scree...
Leishmanicidal and cytotoxic activity of hederagenin-bistriazolyl derivatives
Rodríguez-Hernández, Diego; Barbosa, Luiz C.A.; Demuner, Antonio J.; Nain-Perez, Amalyn; Ferreira, Sebastião R.; Fujiwara, Ricardo T.Aiming to obtain new potent leishmanicidal and cytotoxic compounds from natural sources, the triterpene hederagenin was converted into several new 1,2,3-triazolyl derivatives tethered at C-23 and C-28. For this work hederagenin was isolated from fruits of Sapindus saponaria and reacted with propargyl bromide to afford as a major product bis-propargylic derivative 1 in 74%. Submitting this compound to Huisgen 1,...
Chemical composition and antibacterial activity of essential oils from verbenac...
Montanari, Ricardo M.; Barbosa, Luiz C. A.; Demuner, Antonio J.; Silva, Cleber J.; Carvalho, Larissa S.; Andrade, Nélio J.Volatile oils from the leaves of Verbenaceae species Aloysia virgata, Lantana camara, Lantana trifolia, Lantana montevidensis, Lippia brasiliensis and Lippia sericea were investigated for its chemical composition and antibacterial activity. The volatile oils were characterized by a high content of sesquiterpenes of which (E)-caryophyllene (10-35%), germacrene-D (5-46%) and bicyclogermacrene (7-17%) were the maj...
Chemical characterization by GC-MS and phytotoxic potential of non-polar and po...
Oliveros-Bastidas, Alberto de J.; Demuner, Antonio J.; Barbosa, Luiz Claudio de AlmeidaDipteryx odorata (Aubl.) Willd. is a tall arboreal species native to Central and Northern South America. This paper describes the chemical characterization and phytotoxic potential of polar and non-polar extracts from D. odorata seeds. Structural determinations were accomplished by chemical derivatization and analyzed by GC/MS. The chemical composition of the non-polar fraction (hexane and dichloromethane) pres...
Coffee leaf volatiles and egg laying by the coffee leaf miner Leucoptera coffeella
Magalhães, Sérgio Tinôco V.; Guedes, Raul Narciso C.; Lima, Eraldo R.; Demuner, Antonio J.Recent reports of coffee genotypes resistant to one of its key pests in the Neotropical region, the leaf miner Leucoptera coffeella (Lepidoptera: Lyonetiidae), sparked studies trying to recognize the underlying causes of resistance. An association between increased egg laying by the leaf miner and increased caffeine levels in coffee leaves was recently recognized. However, since caffeine is not volatile, its ef...