This study aimed to isolate, purify and characterize secondary metabolites present in Amburana acreana leaves, native to the state of Rondônia, using classical chromatographic methods and 1D, 2D nuclear magnetic resonance spectroscopy. From the hydroethanolic leaves extract of A. acreana, p-hydroxybenzoic acid, vanillic acid, coumarin, campesterol 3-β-D-glucoside and amburoside B, all known compounds, were identified. To the best of our knowledge, this is the first report of isolation and chemical characterization of secondary metabolites in A. acreana. In addition, in vitro assays indicated that amburoside B does not have inhibitory potential on the growth of gram-negative bacteria. The presence of these compounds suggests that, thus far, amburosides (A and B) could be chemotaxonomic markers of the genus Amburana. isolate Rondônia 1D D spectroscopy A phydroxybenzoic p hydroxybenzoic acid coumarin 3βDglucoside βDglucoside 3 β glucoside identified knowledge addition gramnegative gram negative bacteria far

Malaria, a parasitic infection caused by Plasmodium falciparum, is a serious global public health problem. The enzyme enoyl-acyl carrier protein (ACP) reductase present in a limiting step in the biosynthesis of fatty acids type II was used to search for novel molecules with potential inhibitor by virtual screening techniques. A flavonoid library obtained in ChEMBL database (n = 4,008) was filtered through physico-chemical similarity using the Euclidean distance as a criterion. The selected molecules were subjected to molecular docking using the scoring function GridScore in the DOCK 6.5 software. The top 30 ranked molecules by molecular docking were submitted to the AuPosSOM 2.1 software with the aim of clustering molecules by means of intermolecular interactions in order to understand the patterns of these interactions with enoyl-ACP reductase from Plasmodium falciparum (PfENR). We observed the importance of flavonoid moiety to hydrophobic interactions with the active site of enzyme, this confirmed the choice to study this metabolite class as PfENR inhibitors. Moreover, it was possible to recognize which intermolecular interactions contribute to the molecular recognition process.

<p>Phytochemical investigation of the MeOH extract of Schinopsis brasiliensis Engl. stems led to the isolation of the new biflavanone (2R*,3R*,2''R*,3''R*)-7-hydroxy-4'-methoxy-flavanone- (3→3'')-3''',7''-dihydroxy-4'''-methoxy-flavanone and 4,2',4'-trihydroxychalcone-(3→O→4'')- 2''',4'''-dihydroxychalcone, whereas methyl gallate, gallic acid, (6R,9R)-megastigma-4-en-3-one- 9-O-β-glucopyranoside, quercetin-3-O-β-D-xylopyranoside and tricetin-3'-O-β-D-glucopyranoside were isolated from the MeOH extract of leaves. Their chemical structures were elucidated using spectroscopic methods and comparison with the literature data. Both biflavonoids showed weak inhibition activities of acetyl and butyrylcholinesterase enzymes when compared with eserine.</p>

This work describes the phytochemical study of stems of Mimosa invisa (Mimosaceae) and the evaluation of the antioxidant potential of isolated compounds. Cromatografic techniques were employed to isolate salicifoliol, pinoresinol, quercetin, quercetin-3-O-rhamnopyranosyl, quercetin-3-O-arabinofuranosyl lupeol, β-amyrin, sitosterol, p-hydroxy coumaric acid, 4-hydroxy-3-methoxy benzaldehyde (vanillin), 4-hydroxy-3,5-dimethoxy benzaldehyde, 4-hydroxy-3-methoxy benzoic acid and 4',6,7- trimethoxy flavonol. The latter had been previously described but the spectrometric data shown indicated the structure required review. The antioxidant activity of the compounds was evaluated by the DPPH test and capability of NBT reduction by superoxide radicals. Quercetin glycosides showed lower antioxidant potential than quercetin and, salicifoliol was found to be more active than pinoresinol.

This work describes the phytochemical study of stem bark and leaves of Cenostigma macrophyllum Tul. (Leguminosae). Through usual chromatographic techniques were isolated bergenin as the primary compound of the stem bark of and from the leaves gallic acid, methyl gallate, ellagic acid, quercetin, quercetin-3-O-β-D-glucopyranoside, quercetin-3-O-(6"-O-galloyl)-β-D-glucopyranoside (tellimoside), quercetin-3-O-(6"-O-E-p-coumaroyl)-β-D-glucopyranoside (helichrysroside), agathisflavone and vitexin were obtained. The isolates were identified by spectroscopic data analysis, and bergenin showed dose-related antinociception when assessed in acetic acid-induced writhing in mice.

In the literature there are a considerable number of chemical and biochemical tests for evaluation of in vitro antioxidant activities of pure compounds or fractions and organic extracts. These tests are important tools for screening of synthetic and natural bioactive compound as well as they can be employed in food chemistry. This work is a critical review of the main methods employed for in vitro antioxidant determination.