The flavonoid rutin presents several pharmacological effects, despite this, its application in the pharmaceutical industry can be significantly limited by its low bioavailability. The development of lipophilic derivatives by esterification of hydroxyl groups with fatty acid chains may be an effective strategy to change their physicochemical properties. This work aims to use high-speed countercurrent chromatography (HSCCC) to isolate rutin esters produced by esterification reactions catalyzed by the immobilized lipase from Candida antarctica (Novozyme 435®). The lipase-catalyzed synthesis of rutin esters (R3-R18:2) in 2-methyl-2-butanol exhibited conversions that ranged from 16 to 40% and highest conversion for short chain fatty acids (R4-R12). After initial partitioning tests of the reaction mixture in different solvent proportions followed by thin layer chromatography (TLC) analysis, the biphasic solvent systems consisting in HEMWat (hexane/ethyl acetate/methanol/water) in different proportions were chosen to separate rutin esters. These esters were separated for the first time to the reaction mixture via HSCCC. This technique proved to be more advantageous than the traditionally one since it allowed quick isolation and high purity (≥ 90%) of the products. It also permitted a substrate recovery for reuse in other enzymatic reactions. Furthermore, the results add valuable information, specially concerning the structures elucidation of different rutin esters not previously described.

The species Piper ottonoides Yuncker (Piperaceae), known as “joão-brandim”, is a shrub that occurs in the Brazilian Amazon rainforest. Its roots and leaves are used in traditional medicine as local anesthetic to treat toothache and sore throat. In this study, the structural characterization in mixture of isobutyl amides present in semi-purified fractions from fruits, leaves, stems and roots of P. ottonoides was achieved by employing gas chromatography-mass spectrometry (GC-MS) and a combination of nuclear magnetic resonance (NMR) techniques (1H, 1H-1H COSY, 1H-13C HSQC, 1H-13C HMBC, TOCSY and 1H-1H J-RES). The MS fragmentation patterns and the NMR chemical shifts, multiplicities, coupling constants and the signal correlations in the two-dimensional spectra were carefully analyzed also taking into account some key elements of differentiation among the compounds. The data set allowed identifying unequivocally the new amide N-isobutyl-7-(4’- methoxyphenyl)-2E,4E-heptadienamide, which we named ottonoidenamide as well as piperovatine and chingchengenamide A in all parts of the plant, the additional presence of pipercallosine and pipercallosidine in roots and of dihydropiperlonguminine in fruits and leaves. The presence of piperovatine and pipercallosine in P. ottonoides should be associated to its traditional use.

Two new alkaloids containing Nb-methyl-triptamine units linked to bis-quinoline moieties, N-8”-formyl-calycosidine and N-8”-methyl-N-1’-demethyl-iso-calycosidine, were isolated from the aerial part of Margaritopsis carrascoana, along with known calycosidine and hodgkinsine. The cytotoxicity of the isolated alkaloids has been evaluated against cancer cell lines. The first two compounds showed only weak activity against HL-60 cell line, while hodgkinsine was the most active compound against HCT-116, OVCAR-8, HL-60 and SF-295 cancer cell lines. The structures of the isolated compounds were established by spectroscopic and molecular mechanical methods.

Duas saponinas triterpênicas foram isoladas do extrato etanólico das raízes de Chiococca alba (L.) Hitch. (Rubiaceae). Suas estruturas foram elucidadas por RMN de ¹H e 13C 1D e 2D e por espectrometria de massas de alta resolução com ionização por eletronebulização como 3-O-β-D-glucopiranurosil-3-β-hidroxiolean-12,15-dien-28-oato de O-α-D-apiofuranosil (1→3)- [α-D-apiofuranosil (1→4)]-α-L-rhamnopiranosil (1→2)-α-L-arabinopiranosila (1) e 3-O-β-D-glucopiranurosil-3-β-hidroxiolean-12,15-dien-28-oato de 28-O-α-D-apiofuranosil (1→3)-α-L-rhamnopiranosil (1→2)-α-L-arabinopiranosila (2).

Two triterpene saponins were isolated from the ethanolic extract of the roots of Chiococca alba (L.) Hitch (Rubiaceae). Their structures were determined by ¹H and 13C 1D and 2D NMR and high resolution electrospray mass spectrometry as 3-O-β-D-glucopyranurosyl-3β-hydroxyolean-12,15-dien-28-oic acid 28-O-α-D-apiofuranosyl (1→3)-[α-D-apiofuranosyl (1→4)]-α-L-rhamnopyranosyl (1→2)-α-L-arabinopyranosyl ester (1) and 3-O-β-D-glucopyranurosyl-3β-hydroxyolean-12,15-dien-28-oic acid 28-O-α-D-apiofuranosyl (1→3)-α-L-rhamnopyranosyl (1→2)-α-L-arabinopyranosyl ester (2).

Neste trabalho é proposto o primeiro modelo por homologia para a nucleosídeo hidrolase de Leishmania donovani construído a partir das estruturas das nucleosídeo hidrolases de Crithidia fasciculata e de Leishmania major. Usando as informações de interação entre o inibidor p-aminofeniliminoribitol e a nucleosídeo hidrolase de Crithidia fasciculata foram planejados dois novos potenciais inibidores, os quais apresentam novas interações com alguns resíduos da bolsa hidrofóbica do sítio ativo do modelo. Simulações por dinâmica molecular dos protótipos ancorados nos sítios ativos do modelo e das enzimas usadas como moldes, mostraram que, diferente do p-aminofeniliminoribitol, eles permaneceram ancorados nos sítios ativos das três enzimas ao longo de toda a dinâmica, interagindo fortemente com os aminoácidos da bolsa hidrofóbica.

In this work we propose the first homology model for nucleoside hydrolase from Leishmania donovani, built based on the crystallographic structures of Crithidia fasciculata and Leishmania major nucleoside hydrolases. We used the interaction information from the crystallographic model of the enzyme of C. fasciculata in complex with the inhibitor p-aminophenyliminoribitol, to design two new potential inhibitors, which present new interactions with some residues of the hydrophobic pocket of the model active site. Molecular dynamics simulations of the prototypes inside the active sites of the model and the template enzymes showed that, differently from p-aminophenyliminoribitol, they remained tightly bound inside the active sites, interacting strongly with the amino acids from the hydrophobic pocket.