Leishmanicidal Activity of (+)-Phyllanthidine and the Phytochemical Profile of Margaritaria nobilis (Phyllanthaceae).

The effects of the Securinega alkaloid (+)-phyllanthidine on Leishmania (L.) amazonensis and the first chemical investigation of Margaritaria nobilis L.f. (Phyllanthaceae) are described. Treating the parasites with this alkaloid caused a dose-dependent reduction in promastigote growth of 67.68% (IC50 82.37 µg/mL or 353 µM) and in amastigote growth of 83.96% (IC50 49.11 µg/mL or 210 µM), together with ultrastructural alterations in the promastigotes. No cytotoxic effect was detected in mammalian cells (CC50 1727.48 µg/mL or CC50 5268 µM). Classical chromatographic techniques and spectral methods led to the isolation and identification of betulinic acid, kaempferol, corilagin, gallic acid and its methyl ester, besides (+)-phyllanthidine from M. nobilis leaves and stems. Margaritaria nobilis is another source of the small group of Securinega alkaloids, together with other Phyllanthaceae (Euphorbiaceae s.l.) species. The low toxicity to macrophages and the effects against promastigotes and amastigotes are suggestive that (+)-phyllanthidine could be a promising antileishmanial agent for treating cutaneous leishmaniasis.

Flavonoids from leaves of Derris urucu: assessment of potential effects on seed germination and development of weeds.

In some previous studies, we described the isolation of nine compounds from leaves of Derris urucu, a species found widely in the Amazon rainforest, identified as five stilbenes and four dihydroflavonols. In this work, three of these dihydroflavonols [urucuol A (1), urucuol B (2) and isotirumalin (3)] were evaluated to identify their potential as allelochemicals, and we are also reporting the isolation and structural determination of a new flavonoid [5,3'-dihydroxy-4'-methoxy-(7,6:5″,6″)-2″,2″-dimethylpyranoflavanone (4)]. We investigated the effects of the dihydroflavonols 1-3 on seed germination and radicle and hypocotyl growth of the weed Mimosa pudica, using solutions at 150 mg.L-1. Urucuol B, alone, was the substance with the greatest potential to inhibit seed germination (26%), while isotirumalin showed greater ability to reduce the development of the hypocotyl (25%), but none of the three substances showed the potential to inhibit radicle. When combined in pairs, the substances showed synergism for the development of root and hypocotyl and effects on seed germination that could be attributed to antagonism. When tested separately, the trend has become more intense effects on seed germination, while for the substances tested in pairs, the intensity of the effect was greater on development of weed.

Volatiles, a glutarimide alkaloid and antimicrobial effects of Croton pullei (Euphorbiaceae).

Chemical investigation of Croton pullei (Euphorbiaceae) collected in the Brazilian Amazon region was revisited. The chemical composition of the essential oils of leaves and stems was analyzed by GC/MS. It was found that both the oils comprise mainly terpenes, among which linalool was the major one (24.90 and 39.72%, respectively). Phytochemical investigation of the stem methanol extract led to the isolation of a new natural product from the glutarimide alkaloid group named N-[2,6-dioxo-1-(2-phenylethyl)-3-piperidinyl]-acetamide, confirming that C. pullei is a rich source of this class of alkaloids. The hexane and methanol extracts of the stems of C. pullei showed moderate antibacterial and antifungal activity and the highest inhibition was observed when the methanol extract was tested against Staphylococcus aureus CCMB 262 and CCMB 263.

Flavonoids and other compounds from Ouratea ferruginea (Ochnaceae) as anticancer and chemopreventive agents.

The chemical study of the extracts from leaves and stems of Ouratea ferruginea allowed the identification of a new isoflavone, 5-hydroxy-7,3'4'5'-tetramethoxyisoflavone, and twenty two known compounds, including friedelin, 3ß-friedelinol, lupeone, a mixture of sitosterol, stigmasterol and campesterol, sitosteryl- and stigmasteryl-3-O-b-D-glucopyranosides, 5,4'-dihydroxy-7,5',3'-trimethoxyisoflavone, 5,4'-dihydroxy-7,3'-di-methoxyisoflavone (7,3'-di-O-methylorobol), 5,7,4'-trihydroxy-3',5'-dimethoxyisoflavone (piscigenin), 2R,3R-epicatechin, syringic acid, 2,6-dimethoxybenzoquinone, 2,6-dimethoxyhydroquinone, syringic and ferulic aldehyde, a mixture of vanillic acid, 1-hydroxy-2-methoxy-4-(1E-3-hydroxy-1-propenyl)-benzene and 3,5-dimethoxy-4-hydroxy-dihydrocinamaldehyde, besides amenthoflavone and 7-O-methylamenthoflavone (sequoiaflavone) which are considered as chemotaxonomic markers of Ouratea. The structures were identified by IR, (1)H- and (13)C-NMR and GC-MS, HPLC-MS, besides comparison with literature data. The inhibitory effects of 5,4'-dihydroxy-7,5',3'-trimethoxyisoflavone, 7,3'-di-O-methylorobol, piscigenin and 7-O-methylamenthoflavone on cytochrome P450-dependent 7-ethoxycoumarin O-deethylase (ECOD) and glutathione S-transferase (GST) were evaluated in vitro. The 5,4'-dihydroxy-7,5',3'-trimethoxy-isoflavone was the best inhibitor, inhibiting almost 75% of GST activity. Sequoiaflavone was the most potent inhibitor, inhibiting ECOD assay in 75%. These activities allow us to consider both these flavonoids as potential anticancer and chemopreventive agents.

Identification of (-)(E)-N-[2(S)-Hydroxy-2-(4-hydroxyphenyl) ethyl]ferulamide, a natural product isolated from Croton pullei: theoretical and experimental analysis.

Ferulic acid (FA) and its derivatives (FADs) are known for a variety of biological activities, such as photo-protective agent, antioxidant, antiatherogenic and antiplasmodial activities. During structural definition of a FAD isolated from Croton pullei, the possibility of a heterologous series made this definition difficult. In this regard, computational simulations were performed using theoretical calculations at DFT level to predict Infrared (IR) and Nuclear Magnetic Resonance (NMR) data. The IR and NMR (13)C and (1)H data were compared with the theoretical calculations performed for three structural possibilities of a heterologous series. The theoretical results were compared with the experimental data through linear regression in order to define the most probable structure and showed satisfactory values.

Flavonoids, antioxidant potential and antimicrobial activity of Myrcia rufipila mcvaugh leaves (myrtaceae).

This paper reports the first chemical study of the non-volatile compounds, antioxidant capacity and antimicrobial effect of the methanol extract of the leaves of Myrcia rufipila McVaugh. Samples of the leaves were collected in Maracanã Municipality, Pará, Brazil. The chemical investigation led to the identification of the triterpenoids ß- and α-amyrin, the flavonoids 4'-O-galloyldihydromyricetin, myricetin, myricitrin, desmantin-I, myricetin-3-O-(3"-O-galloyl)-α-L-rhamnopyranoside and isovitexin, in addition to gallic acid. The methanol extract showed antioxidant capacity (>90%) against DPPH radical (IC50 356.3 ± 3.1 µg.mL-1) and was active only at high concentrations against the tested microorganisms, including the chloramphenicol resistant E. coli CCMB261 and S. aureus CCMB285 and a nystatin resistant C. parapsilosis CCMB 288. This study shows that M. rufipila, like other Myrcia species, is another source of flavonoids such as desmantin-I and myricitrin which have shown hypoglycemic potential, besides triterpenes and phenolic acids.

Chemical characterisation of the constituents of Eugenia protenta McVaugh and leishmanicidal activity of dimethylxanthoxylin.

The chemical study of Eugenia protenta McVaugh extracts performed by classical and high-performance liquid chromatography techniques and spectral methods has led to the identification of known triterpenoids, flavonoids and an acetophenone derivative (dimethylxanthoxylin). The effect of dimethylxanthoxylin on Leishmania (Leishmania) amazonensis was evaluated against the promastigotes forms after 96 h of treatment. Dimethylxanthoxylin reduced 57 and 59% of the promastigotes growth when treated with 50 and 100 µg/mL solutions, respectively (IC50 117.35 µg/mL or 52.3 µM). Cytotoxicity experiments using MTT assays showed that this substance did not promote cell death after 24 h of treatment. Dimethylxanthoxylin was active on the promastigotes and could be a promising agent for treating leishmaniasis.

Chemical constituents and allelopathic and antioxidant activities of Alchorneopsis floribunda Müll. Arg. (Euphorbiaceae).

Chemical investigation of extracts from the stems and leaves of Alchorneopsis floribunda Müll. Arg., collected in the Amazon region, was performed. The main isolated compounds were triterpenes (α-amyrin, ß-amyrin, lupeol, betulin, betulinic acid, uvaol, erythrodiol and oleanolic acid) and phenolic acid derivatives from 4-hydroxybenzoic acid (gallic and protocatechuic acids and isocorilagin). In the germination assays, high inhibitory allelopathic effects of the extracts and isocorilagin were observed and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of isocorilagin was higher than those of the standards used (Trolox and butylated hydroxyanisole). This is the first chemical study of the genus Alchorneopsis (Euphorbiaceae).

Anti-inflammatory and opioid-like activities in methanol extract of Mikania lindleyana, sucuriju

Mikania lindleyana DC., Asteraceae (sucuriju), grows in the Amazon region, where is frequently used to treat pain, inflammatory diseases and scarring. This study was carried out to investigate phytochemical profile accompanied by in vivo antinociceptive and anti-inflammatory screening of n-hexane (HE), dichloromethane (DME) and methanol (ME) extracts obtained from the aerial parts of the plant. The oral administration of ME (0.1, 0.3, 1 g/kg) caused a dose-related reduction (16.2, 42.1 e 70.2 percent) of acetic acid-induced abdominal writhing while HE and DME (1 g/kg, p.o.) were ineffective. In the hot plate test, ME (300 mg/kg, p.o.) increased the latency of heat stimulus between 30 and 120 min and inhibited the first (45 percent) and second (60 percent) phases of nociception in the formalin test. The antinociception induced by ME or positive control fentanyl (150 µg/kg, s.c.) in hot plate and formalin tests was prevented by naloxone (3 mg/kg, s.c.). When submitted to the carrageenan-induced peritonitis test, ME (0.5, 1.0, 2.0 g/kg, p.o.) impaired leukocyte migration into the peritoneal cavity by 46.8, 59.4 and 64.8 percent respectively, while positive control dexamethasone (2 mg/kg, s.c.), inhibited leukocyte migration by 71.1 percent. These results indicate that the antinociception obtained after oral administration of methanol extract of M. lindleyana involves anti-inflammatory mechanisms accompanied with opioid-like activity which could explain the use of the specie for pain and inflammatory diseases.

Biflavones and triterpenoids isolated from Ouratea castaneifolia (DC.) Engl., Ochnaceae / Biflavonas e triterpenóides isolados de Ouratea castaneifolia (DC.) Engl., Ochnaceae

This paper presents the chemical investigation of the leaves and stems of Ouratea castaneifolia (DC.) Engl.. There are no chemical or pharmacological studies with this species. Classic phytochemical investigation of the organic extracts together with high pressure liquid chromatography (HPLC) procedures lead to the identification of seventeen metabolites: seven triterpenes (friedelin, 3β-friedelinol, α-amyrin, β-amyrin, lupeol, germanicol and taraxerol), four steroids (sitosterol, stigmasterol and the glycosides sitosteryl 3-O-β-D-glucopyranoside and stigmasteryl 3-O-β-D-glucopyranoside), one isoflavone (5,7,4'-trimethoxyisoflavone), one flavone (5,4'-dihydroxy-7,3',5'-trimethoxyflavone) and four biflavones (amenthoflavone, 7,7"-O-dimethylamenthoflavone, heveaflavone and tetramethylamenthoflavone). The structures of the compounds were established by the analysis of ¹H, 13C NMR spectra including bidimensional techniques. The classes of the identified metabolites are in agreement with previous studies of the Ouratea genus.

O presente trabalho trata da investigação química das folhas e caule da espécie Ouratea castaneifolia (DC.) Engl., sobre a qual não há registros de estudos químicos ou farmacológicos anteriores. O estudo fitoquímico clássico dos extratos orgânicos do caule e das folhas de O. castaneifolia foi aliado à técnica da cromatografia líquida de alta eficiência (CLAE) e resultou na identificação de dezessete metabólitos: sete triperpenos (friedelina, 3β-friedelinol, α-amirina, β-amirina, lupeol, taraxerol e germanicol), quatro esteróides (sitosterol, estigmasterol e os glucosídeos sitosteril 3-O-β-D-glicopiranosídeo e estigmasteril 3-O-β-D-glicopiranosídeo), uma isoflavona (5,7,4´-trimetoxiisoflavona), uma flavona (5,4´-diidroxi-7,3´,5´-trimetoxiflavona), quatro biflavonas (amentoflavona, 7,7"-O-dimetil-amentoflavona, heveaflavona e tetrametilamentoflavona). A identificação das substâncias foi feita com base na análise de espectros de RMN de ¹H, 13C e técnicas bidimensionais. As classes dos metabólitos identificados estão de acordo com aquelas citadas em estudos químicos do gênero Ouratea.

Evaluation of antinociceptive and antiinflammatory effects of Croton pullei var. glabrior Lanj. (Euphorbiaceae) / Avaliação dos efeitos antinociceptivo e antiinflamatório de Croton pullei var. glabrior Lanj. (Euphorbiaceae)

Croton pullei var. glabrior Lanj. (Euphorbiaceae) é uma liana, amplamente distribuída na Floresta Amazônica. Na medicina popular, diversas plantas do gênero Croton têm sido utilizadas com fins terapêuticos em patologias que envolvem dor e inflamação, o que justifica este trabalho. O objetivo deste estudo foi investigar as atividades antinociceptiva e antiinflamatória do extrato metanólico das folhas de C. pullei (MECP). O MECP reduziu, de forma dose-dependente, o número de contorções abdominais (1,2 por cento) em camundongos, sugerindo uma atividade antinociceptiva da planta. Por outro lado, o MECP não alterou significativamente a reatividade ao estímulo térmico no teste da placa quente e a reatividade à estimulação química na primeira fase do teste da formalina, indicando um mecanismo não-opioidérgico. O MECP reduziu a nocicepção na segunda fase do teste da formalina, inibiu o edema de orelha induzido pelo óleo de croton e reduziu a migração leucocitária no teste da peritonite induzida por carragenina, indicando uma atividade antiinflamatória. Apesar dos mecanismos responsáveis pelos efeitos da planta ainda não estarem completamente esclarecidos, estes resultados parecem justificar o uso medicinal potencial de Croton pullei var. glabrior Lanj. em patologias que envolvam dor e inflamação.

Croton pullei var. glabrior Lanj. (Euphorbiaceae) is a liana, vastly distributed in the Amazonian Forest. In the folk medicine, several plants of the Croton genus have been used with therapeutic purposes in pathologies that involve painful and inflammatory diseases which justify this work. The aim of this study was to investigate the antinociceptive and antiinflammatory activities of the C. pullei leaves methanol extract (MECP). MECP reduced in a dose-dependent manner the number of acetic acid-induced abdominal writhing (1.2 percent) in mice, suggesting an antinociceptive activity of the plant. On the other hand, MECP did not significantly modify the reactivity to the thermal stimulation in the hot-plate test and the reactivity to the chemical stimulation in the formalin test first phase, indicating a non-opioid mechanism. MECP reduced the formalin-induced nociception in the second phase, inhibited the croton oil-induced ear edema and reduced the leukocytes migration in the test of the carrageenan-induced peritonitis, indicating an antiinflammatory activity. Although the mechanisms that underlie these plant effects are not completely elucidated, these results appear to support the potential medicinal use of Croton pullei var. glabrior Lanj. against painful and inflammatory diseases.

Antraquinonas e naftoquinonas do caule de um espécime de reflorestamento de Tectona grandi (Verbenaceae) / Anthraquinones and naphtoquinones from the bark of Tectona grandis (Verbenaceae) reforestation specimen

O fracionamento do extrato hexânico do caule de um espécime de reflorestamento de Tectona grandis (Verbenaceae), através de procedimentos fitoquímicos clássicos, levou ao isolamento das naftoquinonas lapachol e desidro-a-lapachona e das antraquinonas tectoquinona e obtusifolina. As estruturas das substâncias foram caracterizadas através da análise de métodos espectrométricos de RMN. Este é o primeiro estudo fitoquímico de um espécime de reflorestamento de Tectona grandis, no Brasil, sendo o objetivo principal deste trabalho a comprovação da presença de tectoquinona em espécimes cultivados.

The hexane extract of the bark of Tectona grandis (Verbenaceae) afforded two anthraquinones and two naphtoquinones. Their caracterizations were obtained through NMR spectroscopic techniques. This is the first phytochemical study of the bark of Tectona grandis reforestation specimen in Brazil. The main interest in this work is proving the presence of tectoquinone in reforestation specimen.