ACRIDONE ALKALOIDS AS INHIBITORS OF CATHEPSIN L AND V

Cathepsins represent a class of enzymes that has the primary function of randomly degrading proteins in the lysosomes, although are also involved in different pathologies. The aim of this paper was to evaluate the capacity of acridone alkaloids isolated from Swinglea glutinosa (Rutaceae) to inhibit cathepsin L in vitro . The IC50 values found were in the 0.8-57 µM range and the most promising compounds were alkaloids 1 and 2, with IC50 of 0.9 and 0.8 µM, respectively. Enzyme kinetics revealed that they are reversible competitive inhibitors with respect to the substrate Z-FR-MCA. This small series of acridone alkaloids showed low selectivity for both cathepsins, but represent promising lead candidates for the further development of competitive cathepsin L and V inhibitors

NEW DEGRADED QUINONE DITERPENOID FROM THE STEMS OF Byrsonima coccolobifolia Kunth. (Malpighiaceae)

A chemical investigation of two specimens of Byrsonima coccolobifolia collected in the southeast cerrado and from central Brazil was performed. A new degraded diterpenoid, byrsonimaquinone, was isolated from the stems along with known compounds. This is the first study on the roots of B. coccolobifolia, and several triterpenes, such as α-amyrin, β-amyrin, oleanolic acid, and glochidonol, along with a mixture of stigmasterol, β-sitosterol and campesterol, were identified. These compounds were identified by spectroscopic analysis techniques, including 1D and 2D NMR, GC-MS and high-resolution mass spectrometry

Syntheses of Enantiopure Aliphatic Secondary Alcohols and Acetates by Bioresolution with Lipase B from <em>Candida antarctica</em>

The lipase B from <em>Candida antarctica</em> (Novozym 435<sup>®</sup>, CALB) efficiently catalyzed the kinetic resolution of some aliphatic secondary alcohols: (±)-4-methylpentan-2-ol (<strong>1</strong>), (±)-5-methylhexan-2-ol (<strong>3</strong>), (±)-octan-2-ol (<strong>4</strong>), (±)-heptan-3-ol (<strong>5</strong>) and (±)-oct-1-en-3-ol (<strong>6</strong>). The lipase showed excellent enantioselectivities in the transesterifications of racemic aliphatic secondary alcohols producing the enantiopure alcohols (>99% <em>ee</em>) and acetates (>99% <em>ee</em>) with good yields. Kinetic resolution of <em>rac</em>-alcohols was successfully achieved with CALB lipase using simple conditions, vinyl acetate as acylating agent, and hexane as non-polar solvent

Acridone alkaloids as potent inhibitors of cathepsin V

Cathepsin V is a lysosomal cysteine peptidase highly expressed in thymus, testis and corneal epithelium. Eleven acridone alkaloids were isolated from Swinglea glutinosa (Bl.) Merr. (Rutaceae), with eight of them being identified as potent and reversible inhibitors of cathepsin V (IC(50) values ranging from 1.2 to 3.9 mu M). Detailed mechanistic characterization of the effects of these compounds on the cathepsin V-catalyzed reaction showed clear competitive inhibition with respect to substrate, with dissociation constants (K(i)) in the low micromolar range (2, K(i) = 1.2 mu M; 6, K(i) = 1.0 mu M; 7, K(i) = 0.2 mu M; and 11, K(i) = 1.7 mu M). Molecular modeling studies provided important insight into the structural basis for binding affinity and enzyme inhibition. Experimental and computational approaches, including biological evaluation, mode of action assessment and modeling studies were successfully employed in the discovery of a small series of acridone alkaloid derivatives as competitive inhibitors of catV. The most potent inhibitor (7) has a K(i) value of 200 nM. (C) 2011 Elsevier Ltd. All rights reserved.State of Sao Paulo Research Foundation (FAPESP, Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)National Council for Scientific and Technological Development (CNPq, Conselho Nacional de Pesquisa e Desenvolvimento), Brazi

Anacardic acid derivatives as inhibitors of glyceraldehyde-3-phosphate dehydrogenase from Trypanosoma cruzi

Chagas` disease, a parasitic infection caused by the flagellate protozoan Trypanosoma cruzi, is a major public health problem affecting millions of individuals in Latin America. On the basis of the essential role in the life cycle of T. cruzi, the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has been considered an attractive target for the development of novel antitrypanosomatid agents. In the present work, we describe the inhibitory effects of a small library of natural and synthetic anacardic acid derivatives against the target enzyme. The most potent inhibitors, 6-n-pentadecyl-(1) and 6-n-dodecylsalicilic acids (10e), have IC(50) values of 28 and 55 mu M, respectively. The inhibition was not reversed or prevented by the addition of Triton X-100, indicating that aggregate-based inhibition did not occur. In addition, detailed mechanistic characterization of the effects of these compounds on the T. cruzi GAPDH-catalyzed reaction showed clear noncompetitive inhibition with respect to both substrate and cofactor. (C) 2008 Elsevier Ltd. All rights reserved.FAPESPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPESConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNP