Amphidinolide P from the Brazilian octocoral Stragulum bicolor

Abstract Dinoflagellates are an important source of unique bioactive secondary metabolites. Symbiotic species, commonly named zooxanthellae, transfer most of their photosynthetically fixed carbon to their host. The mutualistic relationship provides the organic metabolites used for energy production but there are very few reports of the role of the dinoflagellates in the production of secondary metabolites in the symbiotic association. Corals and other related cnidarians are the most well-known animals containing symbiotic dinoflagellates. In the present paper we describe the isolation of amphidinolide P (1) from the octocoral Stragulum bicolor and its prey, the nudibranch Marionia limceana, collected off the coasts of Fortaleza (Ceará, Brazil). The coral extracts also contained 3-O-methyl derivative (2) of amphidinolide P, together with minor compounds still under investigation. Amphidinolides have been so far reported only in laboratory cultures of Amphidinium sp., thus compounds 1 and 2 represents the first identification of these polyketides in invertebrates. The finding proves the possibility to isolate amphidinolides from a natural symbiosis, enabling further biological and biotechnological studies.

In vitro and in vivo antiproliferative activity of Calotropis procera stem extracts

The cytotoxic potential of stem organic extracts from Calotropis procera (Asclepiadaceae) was firstly evaluated against cancer cell lines by MTT assay. Subsequently, samples considered cytotoxic were tested for antimitotic activity on sea urchin egg development and for in vivo antiproliferative activity in mice bearing Sarcoma 180 tumor. Among the five extracts (hexane, dichloromethane, ethyl acetate, acetone and methanol), ethyl acetate and acetone extracts displayed higher cytotoxic potential against tumor cells, with IC50 ranging from 0.8 to 4.4 μg/mL, while methanolic extract was weakly cytotoxic. Cytotoxic extracts also exhibited cell division inhibition capacity by antimitotic assay, revealing IC50 values lower than 5 μg/mL. In the in vivo antitumor assessments, ethyl acetate- and acetone-treated animals showed tumor growth inhibition ratios of 64.3 and 53.1 percent, respectively, with reversible toxic effects on liver and kidneys. Further studies are in progress in order to identify C. procera cytotoxic compound(s) and to understand the mechanism of action responsible for this tumor-decreasing potential.

O potencial citotóxico de extratos orgânicos do caule de Calotropis procera (Asclepiadaceae) foi primeiramente avaliado frente a linhagens de células tumorais através do ensaio de MTT. Aquelas amostras consideradas citotóxicas foram sub-sequentemente testadas para atividade antimitótica sobre o desenvolvimento de ovos de ouriço-do-mar e para atividade antiproliferativa in vivo em camundongos transplantados com tumor Sarcoma 180. Dentre os cinco extratos estudados (hexano, diclorometano, acetato de etila, acetona e metanol), os extratos acetato de etila e acetona mostraram maior potencial citotóxico contra células tumorais, com CI50 variando de 0,8 to 4,4 μg/mL, enquanto o extrato metanólico revelou ser fracamente citotóxico. s extratos citotóxicos também exibiram capacidade de inibição da divisão celular com valores de CI50 menores que 5 μg/mL. Nas avaliações antitumorais in vivo, os animais tratados com os extratos acetato de etila e acetona mostraram taxas de inibição do crescimento tumoral de 64,3 e 53,1 por cento, respectivamente, com efeitos tóxicos reversíveis sobre o fígado e os rins.

O oleo essencial de Lippia gracilis Schauer, Verbenaceae, em ratos diabeticos / The essential oil from Lippia gracilis Schauer, Verbenaceae, in diabetic rats

O óleo essencial das folhas de Lippia gracilis Schauer, Verbenaceae, foi examinado por CG e CG-MS. Quinze constituintes foram identificados, onde o carvacrol, p-cimeno e o γ-terpineno foram as substâncias majoritárias. No estudo in vitro, a solução a 5 por cento do óleo de L. gracilis Schauer apresentou atividade antibacteriana para Staphylococcus aureus isolado de úlcera infectada de paciente diabético. O estudo avaliou a atividade antibacteriana da solução a 5 por cento do óleo de L. gracilis Schauer em modelo experimental em diabetes utilizando ratos albinos Wistar machos com membro pélvico infectado com cepa de Staphylococcus aureus. No experimento foram utilizados 28 ratos Wistar distribuídos em quatro grupos (G1-branco, G2-controle negativo, G3-controle positivo, G4-teste) de sete ratos. Quando comparado o grupo G4 com G3, observou-se que a solução a 5 por cento promoveu uma redução nas CFU/mL após 24h da administração do inóculo (S.aureus sem L. gracilis Schauer 10(8) ± 313 versus S.aureus com L. gracilis Schauer 13,28 ± 4,03). Os resultados foram expressos através do cálculo da média±EPM) e análise de variança (ANOVA). A diferença entre a concentração inibitória mínima no estudo in vitro foi determinada pelo teste Turkey (p<0.05). O teste Newman-Keuls com nível de significância (p<0.05) foi utilizado para o cálculo dos resultados obtidos no experimento in vivo. A solução a 5 por cento do óleo essencial de Lippia gracilis Schauer apresentou boa atividade antibacteriana tanto no estudo in vivo como no in vitro.

The essential oil from Lippia gracilis Schauer (Verbenaceae) leaves was examined by GC and GC-MS. Fifteen constituents were identified. Carvacrol, p-cymene and γ-terpinene were found to be the major components. In the in vitro study, 5 percent solution of the Lippia gracilis Schauer oil presented antibacterial activity against Staphylococcus aureus isolated from diabetic patients with infected ulcers. The study evaluated the antibacterial activity of the 5 percent solution of the Lippia gracilis Schauer oil on the experimental model of diabetic adult male albino Wistar rats with leaft pelvic limb infected by Staphylococcus aureus strain. In this experiment, 28 diabetic Wistar rats were used, randomly distributed in four different groups of seven rats, (G1-white; G2-negative control; G3-positive control and G4-test). When comparing group G4 with G3, it was observed that the 5 percent solution presented a reduced CFU/mL level showing the antibacterial effect of the oil 24 hours after the administration of the inoculum (S .aureus without Lippia gracilis Schauer 108 ±313 versus S.aureus with Lippia gracilis Schauer 13.28±4.03). The results were expressed as mean±S.E.M. One-way analysis of the variance (ANOVA) was used. The differences between the minimum inhibitory concentration in vitro test were determined by the Tukey test (p<0.05). The Newman-Keuls test with level of significance (p<0.05) was used to measure the results in vivo. The findings have shown that 5 percent solution of the Lippia gracilis Schauer oil presented antibacterial activity in vitro and in vivo.

Nematicidal and larvicidal activities of the essential oils from aerial parts of Pectis oligocephala and Pectis apodocephala Baker

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 percent), neral (32.2-34.2 percent) and alpha-pinene (10.7-11.4 percent) were the main constituents in the oil of P. apodocephala, while p-cymene (50.3-70.9 percent) and thymol (24.4-44.7 percent), 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.

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 por cento), neral (32, 2-34, 2 por cento) e alfa-pineno (10, 7-11, 4 por cento) foram os constituintes majoritários no óleo de P. apodocephala, enquanto p-cimeno (50, 3-70, 9 por cento) e timol (24, 4-44, 7 por cento), 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.

Estudo fitoquimico de Auxemma glazioviana Taub

Phytochemical investigation of heartwood of Auxemma glazioviana (Boraginaceae) has led to the isolation of three benzoquinones, one hydroquinone identified as: oncocalyxone A (1), oncocalyxone C (2), glazioviana A (3), glaziovianol (4) besides allantoin (5) á-bisabolol (6) and á-cadinol (7). Their structures were determined based on spectral analysis, including 2D NMR experiments. Essential oil obtained from heartwood by hydrodistillation was analyzed by GC/MS. The major constituents were identified as á-bisabolol and á-cadinol. The oil was active against larvae of dengue (Aedes aegypti ) with DL50 2.98 ppm.