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Um novo triterpeno (22β-hidroxilupeol) foi isolado do extrato em metanol do caule de Moldenhawera nutans (Leguminosae) além de diterpenos derivados do ácido labdenóico de ocorrência comum nesta espécie. A partir do ácido labd-8(17)-en-15-óico foram preparados derivados com atividade in vitro discreta frente à Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Salmonella cholerasuis e Vibrio parahaemolyticus.A new triterpene derivative (22β-hydroxylupeol) was isolated from the MeOH extract of stems of Moldenhawera nutans (Leguminosae) together with labdenoic acid derivatives of common occurrence in this species. From the labd-8(17)-en-15-oic acid were prepared simple derivatives, which exhibited in vitro weak activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Salmonella cholerasuis, and Vibrio parahaemolyticus. Keywords: Moldenhawera nutans, Leguminosae, antibacterial labdene derivatives, 22β-hydroxylupeol IntroductionGenus Moldenhawera Schrard. (Leguminosae: Caesalpinoideae), endemic to Northeast Brazil, is represented by approximately ten species. 1 Previous phytochemical study of M. nutans resulted in the isolation of four known labdene diterpenes besides a new bisditerpene named moldenin. 2 The present work describes the results of the fractionation of the hexane phase obtained from the MeOH extract of M. nutans. Besides the known diterpenes previously isolated, it was also obtained the 3-oxo-labd-8(17)-en-15-oic acid (1) as a methyl derivative (1a), and three triterpenes, lupeol, betulin, and the new lupane derivative (2). The labd-8(17)-en-15-oic acid (3) was the predominant compound in this extract. From this compound, derivatives (4-8) were prepared and some of them were submitted to in vitro antibacterial assays. Results and DiscussionThe structural elucidation of 1a (Figure 1) insignificant effect observed at C-19 in the NMR spectra of 2a together with the coupling constants observed in the 1 H NMR suggested that the hydroxyl group is in equatorial position. The 1 HNMR nOe difference spectra of this compound permitted to corroborate the proposition. When the H-22 was irradiated it was possible to assign increments in Hα-21 (25%), H-29 (3%) and, H-19 (10%). These findings are indicative that all the affected protons were in the same plane. The fragmentation pattern observed in the MS of 2 was also indicative of a hydroxyl group in C-22 of the cyclopentyl ring, especially by mass fragments of 2 at m/z 374 and 2a at m/z 458 ( Figure 2). Since labd-8(17)-en-15-oic acid (3) showed antibacterial activity ( Table 2), some of its simple chemical derivatives were prepared and also evaluated. Derivative 3 was refluxed with MeOH/HCl to obtain the isomeric methyl esters 4a and 5. Next, 4a was submitted to allylic oxidation by t-butyl chromate 6 and furnished 6a. It was also prepared the epoxy derivatives 7a and 8a from 4a by reaction with MCPBA. The derivatives 7a and 8a are new and they were characterized by spectrometric analyses data. Compounds 1a, 2, 4a, and 6a-8a w...

Key indicatorsSingle-crystal X-ray study T = 297 K Mean (C-C) = 0.006 Å R factor = 0.057 wR factor = 0.204 Data-to-parameter ratio = 7.7For details of how these key indicators were automatically derived from the article, see

Key indicatorsSingle-crystal X-ray study T = 297 K Mean (C-C) = 0.004 Å Disorder in main residue R factor = 0.076 wR factor = 0.204 Data-to-parameter ratio = 12.9For details of how these key indicators were automatically derived from the article, see

Recebido em 30/6/10; aceito em 14/9/10; publicado na web em 27/10/10This study represents an integrated approach towards understanding the electronic and structural aspects of 2-benzylamino-1,4-naphthalenedione, a representative 2-amino-napfthoquinone. To this end, theoretical calculations performed at the B3PW91/6-31+G(d) level of density functional theory, electrochemical and X-ray structural investigation were employed. Two intramolecular H-bonds and other two intermolecular H-bonds were observed, including non-classical interactions. Cyclic voltammogram (CV) and differential pulse voltammetry (DPV) show two pairs of peaks, being each one a monoelectronic process.

The methanolic extract from stem bark of Bauhinia monandra, a medicinal plant employed in folk medicine, yielded by column chromatography lup-20(29)-en-3β,24-diol (1) and methyl galloate (2) along with β-sitosterol (3). These known phytoconstituents are being reported for the first time from this plant and their structures were established by NMR and MS spectral studies and by comparison with their literature data. Furthermore, lup-20(29)-en-3β,24-diol (1), a minor constituent, was isolated from this genus for the first time.