Ursolic acid, an important bioactive compound, was isolated from ethanol extract of aerial parts of Sambucus australis. In order to develop bioactive ursolic acid derivatives, two semi-synthetic compounds were obtained through modification at C-3. The antibacterial activity of the ursolic acid and its derivatives was investigated. The microdilution method was used for determination of the minimal inhibitory concentration (MIC), against twelve bacterial strains. The influence of ursolic acid and its derivatives on the susceptibility of some bacterial pathogens to the aminoglycosides antibiotics neomycin, amikacin, kanamycin and gentamicin was evaluated. The most representative synergistic effect was observed by 3β-formyloxy-urs-12-en-28-oic acid at the concentration of 64 μg/mL in combination with kanamycin against Escherichia coli (27), a multidrugresistant clinical isolate from sputum, with reduction of MIC value from 128 μg/mL to OPEN ACCESSMolecules 2014, 19 1318 8 μg/mL. Ursolic acid and its derivatives were examined for their radical scavenger activity using the DPPH assay, and showed significant activity.

Resumo -A bioatividade de ácidos húmicos (AH) isolados de lodo da estação de tratamento de esgoto (AHL) e de vermicomposto (AHV) foi avaliada pela ação dessas substâncias sobre o transporte de prótons através da membrana plasmática de células de raízes de café e milho e sua relação com o desenvolvimento dessas espécies. Houve estímulo da área superficial radicular em ambas as espécies cultivadas com ambos AH, mostrando uma concentração ótima em torno de 40 mg L -1 . Nessa condição, os tratamentos com AHL e AHV estimularam a H + -ATPase de membrana plasmática em plântulas de café e milho. Os AHL foram mais efetivos na promoção desses efeitos do que os AHV. A modificação do perfil cromatográfico dos AH em solução antes e após o cultivo das plântulas revelou que a interação planta-AH promoveu uma redistribuição das massas moleculares dessas substâncias, sugerindo uma dinâmica de mobilização de subunidades funcionais dos AH por exsudatos das raízes. A análise estrutural dos AH detectou a presença de grupamentos de auxina. A análise comparativa da ação desses dois AH sobre as espécies representantes de plantas monocotiledôneas (milho) e dicotiledôneas (café) apontam para a ativação da H + -ATPase de plasmalema como possível marcador metabólico de bioatividade dos ácidos húmicos.Termos para indexação: Zea mays, Coffea arabica, lodo residual, ácidos orgânicos, vermicomposto. Humic acids bioactivity: effects on root development and on the plasma membrane proton pumpAbstract -The bioactivity of humic acids (HA) isolated from sludge of the station of sewer treatment (HAL) and from vermicompost (HAV) was evaluated through the action of those substances on primary transport of protons of the plasma membrane of coffee and corn root cells and its relationship with the development of those species. A stimulation in the superficial area of roots was observed for both species cultivated with both humic acids, exhibiting an optimum concentration, about 40 mg L -1 of HA. In this condition the treatment with HAL and HAV stimulated the plasma membrane H + -ATPase of corn and coffee roots. HAL were more effective to promote those effects than HAV. The modification of the chromatographic profile of the HA in solution before and after the cultivation of the seedlings revealed that the interaction plant-HA promoted a rearrangement of the average molecular weight of those substances suggesting a dynamic mobilization of bioactive subunits of the HA by plant exudates. The structural analysis of the HA has detected the presence of auxin groups. A comparative analysis of the action of those HA on the monocotyledonous (corn) and dicotyledonous (coffee) plants indicates to the activation of plasmallema H + -ATPase as a possible metabolic marker for bioactivity of humic acids.

Recebido em 5/4/02; aceito em 6/2/03 FLAVONOIDS GLYCOSIDES FROM LEAVES AND FLOWERS OF Bauhinia forficata (LEGUMINOSAE). From the leaves of Bauhinia forficata kaempferol and four flavonoid glycosides, 3,

Dos frutos dePterodon polygalaeflorus (Leguminosae) foram isolados o novo diterpeno 6α-hidroxivouacapano e os conhecidos diterpenóides 6α,7β,14β,19-tetraidroxivouacapano, 6α,7β-diidroxivouacapan-17β-oato de metila e o flavonóide taxifolina. As estruturas foram determinadas com base em análise espectroscópica, inclusive RMN bidimensional, transformação química do novo diterpeno e comparação com dados da literatura.From fruits of Pterodon polygalaeflorus (Leguminosae) the new diterpene 6a-hydroxyvouacapane, the known diterpenoids vouacapane-6α,7β,14β,19-tetraol and methyl 6α,7β-dihydroxyvouacapan-17β-oate and the flavonoid taxifolin were isolated. Structural determinations were accomplished by spectroscopic analysis, including two-dimensional NMR, chemical transformation of the new diterpene and comparison with literature data.

No abstract

A convenient synthesis of the new enamine derivatives 2-(4-morpholinyl)-3-(3-methyl-2-butenyl)-1,4-naphthalenedione, 2-(1-piperidinyl)-3-(3-methyl-2-butenyl)-1,4-naphtalenedione and 2-(1-pyrrolidinyl)-3-(3-methyl-2-butenyl)-1,4-naphthalenedione was carried out from natural 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthalenedione (lapachol) and morpholine, piperidine and pyrrolidine. The structures of the products were established mainly by NMR analysis, including 2D experiments. Biological activities of these products were evaluated against Artemia salina, Aedes aegypti and cytotoxicity using A549 human breast cells.

Summary. The carbon shifts of the Iboga-type alkaloids catharanthine, voacanginc, coronaridine, ibogaine, dihydrocatharanthine and epiibogamine were recorded and correlated with the conformation of the natural bases. A 13C-NMR. analysis of heyneaninc determined its C(19) configuration and a similar study of cpihcyneanine proved its structure.In connection with problems of structure determination and synthesis of indole alkaloids of the Iboga type it became of importance to apply 13C-NMR. spectroscopy thereto. As a consequence the following study of a select group of such natural products was undertaken and isoquinuclidine (l), its N-methyl derivative (2), some monosubstituted bicyclo[2.2.2joctanes (3) and two bicyclo[2.2.2]octenes (4) used as models. The carbon shifts of the first two models are depicted on formulas 1 4 ) and 2 and those of bicycles 3 5 ) and 46) listed in Table 1. The total of the y-effects on C(l) and C(3) is 7.7 ppm greater for the hydroxy group of 3c than the methyl group of 3b, relative to 3a. The comparable magnitude of the y-effect of the two groups as a result of fixed gauche, non-bonded interactions [3] [4] and thc shielding of ycarbons by hydroxy groups truns anti-periplanar to them within rigid six-membered rings [j] suggest that the excess shielding by the hydroxy group of 3c is an acyclic equivalent of the lattcr phcnomenon. This result indicates that caution must be cxerciscd in the assessment of shielding contributions to y carbon atoms from oxygen in all staggered, acyclic conformations.The introduction of a double bond into the strained bicyclo[2.2.2]octane skeleton leads to stronger deshielding of the allylic carbons and a decrease of the cndocyclic homoallyl effect relative to the shift differences of cyclohexenes and cyclohexanes [2] [6] (cf. also the 6b + 5a change).

Lichens are a form of symbiont between a fungus and an alga or cyanobacterium, which contains a wide variety of organic compounds with certain secondary metabolite classes typical of these organisms. The Ramalina genus has approximately 246 species distributed around the World, of which in this review approximately 118 species with published chemical or biological activity studies of extracts or isolated compounds were cited. From the 153 mentioned compounds, only 27 passed were tested for biological activity, being usnic acid the most studied compound and the one showing the best results in almost all in vitro tests performed, although other compounds also presented excellent results as antimicrobial, antitumor and anti-inflammatory agents, among others. Extracts of several species also presented significant results in performed biological tests, demonstrating the potential that these organisms have, in particular, the gender Ramalina, to produce bioactive molecules that can be used as a model for the production of pharmaceuticals.