The aim of this work was to study the larvicidal activity of Lippia sidoides essential oil against Aedes aegypti larvae. The essential oil and its hydrolate (saturated solution of essential oil in water) were obtained by vapor extraction and their chemical composition determined by GL-chromatography coupled to mass spectroscopy. Bioassays were run with the essential oil, pure and diluted hydrolate and with their main constituents thymol and carvacrol. The results obtained showed that L. sidoides essential oil and its hydrolate have larvicidal action against the mosquito A. aegypti, causing an almost instantaneous mortality. Thymol, an alkylated phenol derivative and one of the major components of L. sidoides essential oil, was identified as the active principle responsible for the larvicidal action, causing 100% larval mortality at the lowest tested concentration of 0.017% (w/v). These results suggest that the essential oil of L. sidoides is promising as larvicide against A. aegypti and could be useful in the search of newer, more selective, and biodegradable larvicidal natural compounds to be used in official combat programs and at home.

Uma nova isoflavona denominada harpalicina e quercetina foram isoladas das folhas e 3-hidroxi-4-isopentenil-8,9-metilenodioxipterocarpano e ácido betulínico das raizes de Harpalyce brasiliana. As estruturas foram elucidadas usando métodos espectrométricos, inclusive RMN bidimensional (2D) da nova isoflavona.

A new isoflavone named harpalycine and quercetin were isolated from the leaves and 3-hydroxy-4-isopentenyl-8,9-methyle-nedioxypterocarpan and betulinic acid from the roots of Harpalyce brasiliana. The structures were elucidated using spectroscopic methods, including 2D NMR techniques of the new isoflavone.

Os isoflavonóides 6,7-dimetoxi-3’,4’-metilenodioxi-, 4’-hidroxi-3’,6,7-trimetoxi-, 3,4,6,7-tetrametoxi-, 7-hidroxi-6-metoxi-3,4-metilenodioxi-, 2’,6,7-trimetoxi-3’,4’-metilenodioxi-, 2’,3’,4’,7,7-pentametoxi- e 2’,4’,5,6,7-pentametoxiisoflavona, os triterpenóides lupeol e betulina e o ácido 4-metoxibenzóico foram isolados dos extratos acetônicos do alburno e do cerne de Pterodon polygalaeflorus. As estruturas destes produtos naturais foram caracterizadas por métodos espectrométricos, principalmente experiências de RMN 1D e 2D de hidrogênio e carbono-13, que foram também utilizados para a atribuição inequívoca dos deslocamentos químicos dos átomos de hidrogênio e carbono-13 dos isoflavonóides.

The isoflavonoids 6,7-dimethoxy-3’,4’-methylenodioxy-, 4’-hydroxy-3’,6,7-trimethoxy-, 3,4,6,7-tetramethoxy-, 7-hydroxy-6-methoxy-3,4-methylenodioxy-, 2’,6,7-trimethoxy-3’,4’-methylenedioxy-, 2’,3’,4’,6,7-pentamethoxy- and 2’,4’,5,6,7-pentamethoxyisoflavone, together with the triterpenoids lupeol and betulin and 4-methoxybenzoic acid, were isolated from acetone extracts of the sapwood and heartwood of Pterodon polygalaeflorus. The structures of these natural products have been characterized by spectrometric methods, mainly extensive 1D and 2D NMR experiments, which were also used for complete assignments of the chemical shifts of the hydrogen and carbon-13 atoms of isoflavonoids.

Os neoflavonóides 7-hidroxi-5-metil-4-(4’-metoxifenil)-3,4-diidrocumarina (1), 5-hidroxi-7-metil-4-(4’-metoxifenil)-3,4-diidrocumarina (2), 5-metil-7-O-cumaroil-4-(4’-metoxifenil)-3,4-diidrocumarina (3), 5-hidroxi-4-(4’-metoxifenil)-a-pirano-(6",5":7,8)-3,4- diidrocumarina (7) e 7-pentadecil-4-(4’-metoxifenil)-3,4-diidrocumarina (8) foram sintetizados por condensação, catalisada pelo tricloreto de alumínio, entre o cloreto do ácido 4-metoxicinâmico com orcinol, 5,7-dihidroxicumarina e cardanol hidrogenado. Os produtos das reações foram caracterizados com base nos dados espectrais de RMN ¹H e 13C, usando-se principalmente a técnica de espectroscopia nOe diferencial.

The neoflavonoids 7-hydroxy-5-methyl-4-(4’-methoxyphenyl)-3,4-dihydrocumarin (1), 5-hydroxy-7-methyl-4-(4’-methoxyphenyl)-3,4-dihydrocoumarin (2), 5-methyl-7-O-coumaroyl-4-(4’-methoxyphenyl)-3,4-dihydrocoumarin (3), 5-hydroxy-4-(4’-methoxyphenyl)-a-pirano-(6",5":7,8)-3,4-dihydrocoumarin (7), and 7-pentadecyl-4-(4’-methoxyphenyl)-3,4- dihydrocoumarin (8) were synthesized via the AlCl3-catalyzed condensation of 4-methoxycinnamic acid chloride with orcinol, 5,7-dihydroxycoumarin and hydrogenated cardanol. The compounds were characterized on the basis of their ¹H- and 13C-NMR spectroscopic properties, including nOe difference spectroscopy.