In order to produce bioactive derivatives of carvacrol and thymol, nine derivatives of each compound were prepared through modifications the phenolic hydroxyl group. The structures of compounds were confirmed by spectral data from MS, IR and NMR. Carvacrol, thymol and derivatives were submitted to the evaluation of the inhibition of the enzyme acetylcholinesterase, using a colorimetric method in which the inhibition of the enzyme is measured by coloration, and larvicidal activity against Aedes aegypti. Derivatives carvacryl acetate-1b and thymyl hexanoate-2b showed the best results for the inhibition of the acetylcholinesterase enzyme, and for the larvicidal activity the derivatives 1a, 1b, 1c, 3h, 2a, 2b, 2c and 4h showed positive results, emphasizing compound thymyl 4-methoxybenzoate-4h which showed LC50 values of 23.60 ppm, considered a very good result.

Analysis of essential oil from fresh leaves of Capraria biflora allowed identification of fourteen essential oil constituents among which thirteen are sesquiterpene compounds, and α-humulene (43.0%) the major constituent. The essential oil was tested for larvicidal activity against Aedes aegypti showing good activity, with LC50 73.39 µg/mL (2.27 g/mL). Chromatographic studies of extracts from roots and stems allowed the isolation of five compounds: naphthoquinone biflorin, sesquiterpene caprariolide B, the steroid β-sitosterol, the carbohydrate D-mannitol and iridoid myopochlorin first reported in the species C. biflora. The structures of compounds were characterized by spectroscopic data, IR, MS, NMR13C, NMR¹H, NOE, HSQC and HMBC.

Um novo diterpeno, (5S*,8S*,9R*,10S*)-11β,12β-epoxi-9α-hidróxi-19(4→3) abeo-abieta-3,13-dieno-19,18-olideo, e as substâncias conhecidas estemodina, D-manitol, ácido betulínico, uma mistura de 3β-O-β-D-glicopiranosil-β-sitosterol e 3β-O-β-D-glicopiranosilestigmasterol, e 5,7,4'-triidróxi-3,8,3'-trimetoxiflavona, foram isolados das folhas e talos de Stemodia maritima. A elucidação estrutural de todas as substâncias baseou-se na interpretação de dados espectrais, principalmente RMN (1D e 2D) e espectrometria de massa (EM), envolvendo comparação com valores descritos na literatura.

A new diterpene, (5S*,8S*,9R*,10S*)-11β,12β-epoxy-9α-hydroxy-19(4→3) abeo-abieta-3,13-diene-19,18-olide, together with the known compounds stemodin, D-mannitol, betulinic acid, a mixture of 3β-O-β-D-glucopyranosyl-β-sitosterol and 3β-O-β-D-glucopyranosylstigmasterol and 5,7,4'-trihydroxy-3,8,3'-trimethoxyflavone were isolated from the leaves and stems of Stemodia maritima. Structural elucidation of all compounds was based on interpretation of spectral data, mainly NMR (1D and 2D) and MS, including comparison with values described in the literature.

A composição química dos óleos essenciais das partes aéreas de Pectis apodocephala e Pectis oligocephala foi analisada por CG-EM. Os óleos essenciais destas espécies foram predominantemente constituídos por monoterpenos. Geranial (42, 9-44, 5%), neral (32, 2-34, 2%) e alfa-pineno (10, 7-11, 4%) foram os constituintes majoritários no óleo de P. apodocephala, enquanto p-cimeno (50, 3-70, 9%) e timol (24, 4-44, 7%), foram os compostos prevalentes no óleo de P. oligocephala. Ambos os óleos foram testados contra o nematóide Meloidogyne incognita e larvas do mosquito Aedes aegypti no terceiro estágio. Os resultados obtidos mostraram que os óleos exibem significante atividade e podem, portanto, ser considerados como potenciais agentes nematicida e larvicida naturais.

The chemical composition of the essential oils from aerial parts of Pectis apodocephala and Pectis oligocephala were analyzed by GC-MS. The essential oils of these species were predominantly constituted by monoterpenes. Geranial (42.9-44.5%), neral (32.2-34.2%) and alpha-pinene (10.7-11.4%) were the main constituents in the oil of P. apodocephala, while p-cymene (50.3-70.9%) and thymol (24.4-44.7%), were the prevalent compounds in the oil of P. oligocephala. The essential oils were tested against the root knot nematode Meloidogyne incognita and Aedes aegypti larvae survival. The results obtained show that both essential oils exhibited significant activity and could be considered as potent natural namaticidal and larvicidal agents.

Os óleos essenciais das folhas de Cordia leucomalloides e Cordia curassavica foram obtidos por hidrodestilação e suas composições químicas determinadas por uma combinação de CG-EM e CG-DIC. Como resultado, vinte e três componentes foram identificados em ambos os óleos, representando 98,6 e 91,2% da composição volátil. O óleo essencial de C. leucomalloides foi caracterizado por uma alta percentagem de sesquiterpenos (90,6%), sendo delta-cadineno (17,4%), (E)-cariofileno (15,7%), biciclogermacreno (12,5%) e germacreno D (11,2%) os majoritários. Por outro lado, o óleo de C. curassavica mostrou proporções similares de monoterpenos (47,3%) e sesquitepenos (43,9%), entre os quais alfa-pineno (20,5%), beta-pineno (13,1%), (E)-cariofileno (12,4%) e biciclogermacreno (13,8%) foram os compostos predominantes. O potencial larvicida dos dois óleos foi avaliado contra larvas no terceiro estágio do mosquito Aedes aegypti. Os resultados mostraram que ambos os óleos apresentaram atividade biológica significativa, particularmente o óleo essencial de C. leucomalloides, o qual foi capaz de matar 98,7% das larvas numa concentração de 100 ppm.

The essential oils obtained from the leaves of Cordia leucomalloides and Cordia curassavica were obtained by hydrodistillation and their chemical compositions determined by a combination of GC-MS and GC-FID. Twenty-three components were tentatively identified in both oils representing 98.6 and 91.2% of the volatile content. The oil of C. leucomalloides was characterized by a large percentage of sesquiterpenes (90.6%), being delta-cadinene (17.4%), (E)-caryophyllene (15.7%), bicyclogermacrene (12.5%) and germacrene D (11.2%) the major ones. On the other hand, the oil of C. curassavica showed similar proportions of monoterpenes (47.3%) and sesquiterpenes (43.9%) among which <FONT FACE=Symbol>a-</FONT>pinene (20.5%), beta-pinene (13.1%), (E)-caryophyllene (12.4%) and bicyclogermacrene (13.8%) were the predominant compounds. The larvicidal potential of the two oils were evaluated against the third-instar of Aedes aegypti larvae. The results showed that both oils exhibited significant activity, particularly the oil of C. leucomalloides which was able to kill 98.7% of the larvae in the concentration of 100 ppm.