The fungal Hemileia vastatrix is the causal agent of coffee leaf rust, one of the worst and devastating disease in coffee cultures worldwide. As a result of our research on natural products for the development of novel agrochemicals, we found that the hexane extract from leaves of the Brazilian medicinal plant Garcinia gardneriana, at 500 μg mL-1, inhibited in 98% the germination of H. vastatrix urediniospores. This extract showed no phytotoxicity when tested for seed germination and seedling growth inhibitory activity using sensible plant species. Also, the hexane extract from leaves was tested for anti-acetylcholinesterase activity, which constitutes a mechanism of action of major commercial insecticides used in agriculture, and showed low activity even at concentrations about two times higher than the half maximal inhibitory concentration (IC50) found in the antifungal assays. Gas chromatography-mass spectrometry (GC-MS) analysis showed that the hexane extract is constituted mainly by the pentacyclic triterpene lupeol, together with a series of sesquiterpenes as minor components. This is the first report on the investigation of antifungal, phytotoxic and acetylcholinesterase activities of extracts from leaves of G. gardneriana. These findings indicate that G. gardneriana may constitute a promising source of natural products for controlling the coffee leaf rust fungus.

A previous study for the identification of acetylcholinesterase (AChE) inhibitors demonstrated that the hybrid between tyrosol, the 1,2,3-triazole nucleus, and the coumarin group, namely 7-({1-[2-(4-hydroxyphenyl)ethyl]-1H-1,2,3-triazol-4-yl}methoxy)-4-methyl-2H-chromen-2-one (10), has a high enzyme inhibitory activity. Here, we synthesized analogues of 10 via triazole with pharmacophoric groups represented by tyrosine, phenylalanine, tryptophan, and glycine in addition to evaluating the impact of coumarin-linked amino acids on AChE inhibition. We obtained eight triazoles, six of which are undescribed. In general, the presence of carboxylic acid decreased the inhibitory activity, while aromatic amino acids increased enzymatic inhibition compared to glycine. The derivative containing tyrosine, structurally most similar to 10, presented the lowest inhibition percentage, indicating that phenolic hydroxyl is not the preponderant factor for inhibition. Molecular docking was not enough to explain in vitro experiments. On the other hand, MlogP (logP calculated by the Moriguchi method) was related positively to enzymatic inhibition. To increase the hydrophobicity of the molecules, we tested the esterified triazole derivatives comparatively with the enzyme. The compound ethyl 2-(4-(((4-methyl-2-oxo-2H-chromen-7-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl)acetate (6) presented an increment of inhibitory activity of 46.97 ± 1.75% at 100 μmol L-1. We also associated the best activity with the lowest van der Waals volume and molar mass values.

Benzophenones display several biological activities, including antioxidant, anticancer, and photoprotective. Furthermore, antioxidants can minimize both ultraviolet absorption and tumor development. In the present investigation, a series of twenty-six 1,2,3-triazole-benzophenone derivatives were synthesized and had their antioxidant, anticancer, and photoprotective effects evaluated. For the compounds synthesis, 4,4’-dihydroxybenzophenone (1a) and 2,4-dihydroxybenzophenone (1b) were propargylated, affording the alkynes bis(4-(prop-2-yn-1-yloxy))benzophenone (2a) and (2-hydroxy-4-(prop-2-yn-1-yloxy))benzophenone (2b), respectively. The copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction between the compounds 2a/2b and several benzyl azides gave the 1,2,3-triazole-benzophenone derivatives with yields ranging from 35 to 95%. The 1,2,3-triazole-benzophenone derivatives at the concentration of 0.2 μg mL-1 (a no-cytotoxic concentration) exhibited a solar protection factor (SPF) comparable to positive control benzophonen-3 (BP-3). Concerning their antioxidant and cytotoxic effects, the derivatives from 1b showed high in vitro antioxidant effects as well as cytotoxicity against A549 (lung carcinoma), MCF-7 (breast carcinoma), and HT-144 (metastatic melanoma) cell lines, without significant cytotoxicity to a non-cancerous cell line. Derivatives 19, 20, and 24 induced cell death and cell cycle arrest at G1/S in HT-144 melanoma cells.

Carpotroche brasiliensis is a tree native to Brazil, belonging to the family Flacurtiaceae, whose seeds contain a group of cyclopentenyl fatty acids: gorlic (12%), chaulmugric (27%), and hydnocarpic (48.7%). These compounds are considered the main therapeutic agents in the treatment of leprosy. In the present study, a series of novel triazole compounds were obtained by conjugation between hydnocarpic acid and functionalized azides via copper(I)-catalyzed azide-alkyne cycloaddition reaction (CuAAC). Hydnocarpic acid and its derivatives were tested against estrogen-positive breast carcinoma (MCF-7), hepatocellular carcinoma (HepG2), and non-small cell lung cancer (A549) cell lines. The (R)-(1-(pyridin-2-ylmethyl)-1H-1,2,3-triazol-4-yl)methyl-11-(cyclopent-2-en-1-yl)undecanoate (8) displayed promising antiproliferative activity against A549 cells. We demonstrated that this compound selectively inhibited the viability of A549 cell cultures. Furthermore, compound 8 inhibited the clonogenic capacity of A549 cells, and this effect was associated to its ability to inhibit cell cycle progression at G1 phase. These findings indicate that 8 is a promising antitumor agent on A549 cells and support further studies to evaluate the molecular mechanisms underlying its antiproliferative activity. In addition, hydnocarpic acid should be considered as a promising chemical prototype to obtain novel antineoplastic agents.

The benzophenones are synthetic and natural compounds presenting a variety of activities, including photoprotective, cytotoxic and antiviral. It is herein described the preparation of a series of twenty-seven benzophenone derivatives bearing 1,2,3-triazole functionalities and the evaluation of their photoprotective, cytotoxic and antiviral on Zika Virus (ZIKV) activities. The compounds were prepared in three steps, namely reduction of benzophenone, alkylation of diphenylmethanol and CuAAC reactions. The in vitro evaluation of the photoprotective activity revealed that the most active derivative 4-((benzhydryloxy)methyl)-1-(4-nitrobenzyl)-1H-1,2,3-triazole (4k) displayed UVB sun protection factor equal to 6,9±0,53, which make this compound a possible candidate to be used in formulations for photoprotective applications. In terms of cytotoxicity, the compounds were evaluated against MDA-MB-231 and B16F10 cell lines. It was observed that the compounds were more active against MDA-MB-231 cells and three of them were capable of reducing cell viability by approximately 55% at 100 µmol L-1. In the antiviral screening against ZIKV, compound 4-(3-benzhydryloxy)propyl)-1-(3-methylbenzyl)-1H-1,2,3-triazole (5j) was the most effective in mantaining Vero cell viability.

The present investigation describes the synthesis of a series of novel triazole derivatives from 4,4'-dihydroxybenzophenone along with their elastase inhibitory activity. The 1,2,3-triazoles were obtained via the copper(I)-catalyzed azide-alkyne cycloaddition reaction (CuAAC), also known as click reaction, between bis(4-(prop-2-yn-1-yloxy))benzophenone and several benzyl azides. It was found that five derivatives exhibited significant inhibitory effects, presenting half maximal inhibitory concentration (IC50) values in the range of 16.6 to 72.1 µM. The most active compound, namely bis(4-(1-(4-iodobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)benzophenone (IC50 = 16.6 ± 1.9 µM), was found to bind to elastase with the inhibition constant (Ki) of 11.12 µM, thereby illustrating competitive inhibitory behavior. Further, docking investigations provided insights on the possible binding mode of the most active compound with the elastase.

This study investigates the mechanisms of interaction between benzophenone derivatives and cruzain and Llacys1 (the protein expressed by cysteine protease gene isoform 1 of L. amazonensis) by homology modelling, docking and molecular dynamics simulation. The results predict that the same binding site in cruzain and Llacys1 is involved in complexes with benzophenone derivatives that cause non-competitive inhibition of the enzymes. The Gln residue is conserved among the enzymes, and is shown to be a key residue in the allosteric site of these cysteine proteases and in the interaction with benzophenone derivatives. The binding free energies highlight that the main energetic term contributing to the cruzain- and Llacys1-benzophenone compound interactions is the van der Waals term. Experimental results showed that benzophenone derivatives are promising potential inhibitors of cysteine proteases. Moreover, we found that two benzophenone derivatives are the most effective inhibitors of cruzain and L. amazonensis cysteine protease.

AbstractArrabidaea brachypoda Bureau, Bignoniaceae, known as "cipó-una", is widely used in traditional medicine in Southeastern and Northeastern Brazil for kidney stones and painful joints. This study was aimed at evaluating the anti-inflammatory proprieties of the oleanane-type triterpenoid 3β-estearioxy-olean-12-ene isolated from the roots of A. brachypoda. Carrageenan-induced paw oedema, formalin test and hot plate test were used to investigate the antiinflammatory activity of 3β-estearioxy-olean-12-ene in animals. We observed that 3β-estearioxy-olean-12-ene at doses of 5, 10 and 15 mg/kg p.o. demonstrated anti-inflammatory effects, by reduced (p < 0.05) paw oedema induced by carrageenan and by decreased (p < 0.05) licking time caused by a subplantar injection of formalin. In conclusion, 3β-estearioxy-olean-12-ene, a triterpene isolated from the roots of A. brachypoda, demonstrate anti-inflammatory effect in different tests. Thus, it may be useful in the treatment of inflammatory disorders, which supports previous claims of its traditional use.

The present study aimed to investigate the presence of compounds with antitumor activity in the plant Caesalpinia pluviosa var. peltophoroides. From bioactivity guided studies it was possible to isolate a new biflavonoid, named caesalpinioflavone, whose chemical structure was determined by spectroscopic (1H and 13C nucler magnetic ressonace, homonuclear correlation spectroscopy and heteronuclear multiple-bond correlation spectroscopy) and spectrometric (high resolution electrospray ionization mass) methods. According to in vitro assays, caesalpinioflavone was effective in reducing the cell viability of tumor cell lines A549, MCF7, Hst578T and HTC. This effect was consequent of cell cycle arrest in G1/S transition (A549 and MCF7) and cytotoxic activity (Hs578T and HTC). Taken together, these data indicate that caesalpinioflavone has a promising antitumor activity.

O estudo do tautomerismo ceto-enólico e da estereoquímica de uma benzofenona natural com propriedades inibitórias sobre HIV, denominada (1R,5R,7R,8S)-(+)-3-(10-(3,4 -diidroxifenil)-10-hidroximetileno)-8-metil-1,5,7-tris(3-metil-2-butenil)-8-(4-metil-3-pentenil) -biciclo[3.3.1]nonano-2,4,9-triona (a), a qual foi isolada das sementes de Garcinia brasiliensis, é apresentado. A estrutura cristalina de (a), também conhecida como gutiferona A, foi determinada por difração de raios X e suas geometrias intra e intermolecular discutidas e comparadas com duas benzofenonas naturais análogas: clusianona and epiclusianona. Em (a), o átomo de hidrogênio hidroxílico proveniente do sistema ceto-enólico 2,4,10-triona está ligado ao átomo de oxigênio conectado ao grupo 10-(3,4-diidroxifenil)metileno, contrariamente ao verificado nas outras duas benzofenonas naturais similares, onde o átomo de hidrogênio equivalente está ligado em diferentes átomos de oxigênio pertencentes ao sistema anelar biciclo[3.3.1]nonano. Tal comportamento pode ser explicado pela presença do grupo OH6 no anel aromático que origina uma via ressonante deslocalizada adicional ao longo do sistema 3,4-diidroxifenil-C10-OH2. Em adição, a estereoquímica em torno do átomo C7 de (a) é comparada com as estruturas conhecidas da clusianona e da epiclusianona e a influência da configuração neste átomo de carbono quiral sobre as características estruturais encontradas no sistema ceto-enólico é proposta.

The keto-enol tautomerism and stereochemistry study of a HIV-inhibitory natural benzophenone, (1R,5R,7R,8S)-(+)-3-(10-(3,4-dihydroxyphenyl)-10-hydroxymethylene)-8-methyl -1,5,7-tris(3-methyl-2-butenyl)-8-(4-methyl-3-pentenyl)-bicyclo[3.3.1]nonane-2,4,9-trione (a), isolated from Garcinia brasiliensis seeds is presented. The crystal structure of (a), which is also know as guttiferona A, was determined by X-ray diffraction and its intra and inter-molecular geometries discussed and compared with two analogue natural benzophenones: clusianone and epiclusianone. In (a), the hydroxyl H atom from enolizable 2,4,10-trione moiety is linked in the oxygen atom bonded to 10-(3,4-dihydroxyphenyl)methylene group, in opposition to the related natural benzophenones, where this analogue H-atom is placed in different O-atoms from bicyclo[3.3.1]nonane ring system. Such behaviour can be explained by the presence of aromatic OH6 group in (a) that origins a further delocalized resonance path along of 3,4-dihydroxyphenyl-C10-OH2 group. In addition, the (a) stereochemistry around C7 atom is compared with known structures of clusianone and epiclusianone and the influence from configuration in this chiral C-atom to structural features found in the enolizable system is proposed.

Este trabalho relata o isolamento e a identificação de uma nova xantona, 1,4,8-triidroxixantona (1,4,8-triidroxi-9H-xanten-9-ona), isolada das raízes de Vismia latifolia (Guttiferae). Quatro outras xantonas conhecidas também foram isoladas: 1,5-diidroxi-8-metoxixantona, 1,7-diidroxixantona, 1,6-diidroxi-7-metoxixantona e 1,3,5,6-tetraidroxixantona, sendo as duas últimas inéditas no gênero Vismia. As estruturas foram estabelecidas através das técnicas de espectroscópicas de UV, IV, EM e RMN (1D e 2D).

A new xanthone,1,4,8-trihydroxyxanthone (1,4,8-trihydroxy-9H-xanthen-9-one), was isolated from the roots of Vismia latifolia (Guttiferae). Four other known xanthones were isolated: 1,5-dihydroxy-8-methoxyxanthone, 1,7-dihydroxyxanthone, 1,6-dihydroxy-7-methoxyxanthone and 1,3,5,6-tetrahydroxyxanthone. The last two compounds were isolated for the first time from a Vismia species. The structures were established by UV, IR, MS, 1D and 2D NMR spectroscopic techniques.