Maria Célia de Oliveira Chaves

Gastric and Duodenal Antiulcer Activity of Alkaloids: A Review

Peptic ulcer disease is a deep gastrointestinal erosion disorder that involves the entire mucosal thickness and can even penetrate the muscular mucosa. Numerous natural products have been evaluated as therapeutics for the treatment of a variety of diseases, including this one. These products usually derive from plant and animal sources that contain active constituents such as alkaloids, flavonoids, terpenoids, tannins and others. The alkaloids are natural nitrogen-containing secondary metabolites mostly derived from amino acids and found in about 20% of plants. There has been considerable pharmacological research into the antiulcer activity of these compounds. In this work we review the literature on alkaloids with antiulcer activity, which covers about sixty-one alkaloids, fifty-five of which have activity against this disease when induced in animals.

The Antinociceptive and Anti-Inflammatory Activities of Caulerpin, a Bisindole Alkaloid Isolated from Seaweeds of the Genus Caulerpa

The antinociceptive and anti-inflammatory activity of caulerpin was investigated. This bisindole alkaloid was isolated from the lipoid extract of Caulerpa racemosa and its structure was identified by spectroscopic methods, including IR and NMR techniques. The pharmacological assays used were the writhing and the hot plate tests, the formalin-induced pain, the capsaicin-induced ear edema and the carrageenan-induced peritonitis. Caulerpin was given orally at a concentration of 100 μmol/kg. In the abdominal constriction test caulerpin showed reduction in the acetic acid-induced nociception at 0.0945 μmol (0.0103–1.0984) and for dypirone it was 0.0426 μmol (0.0092–0.1972). In the hot plate test in vivo the inhibition of nociception by caulerpin (100 μmol/kg, p.o.) was also favorable. This result suggests that this compound exhibits a central activity, without changing the motor activity (seen in the rotarod test). Caulerpin (100 μmol/kg, p.o.) reduced the formalin effects in both phases by 35.4% and 45.6%, respectively. The possible anti-inflammatory activity observed in the second phase in the formalin test of caulerpin (100 μmol/kg, p.o.) was confirmed on the capsaicin-induced ear edema model, where an inhibition of 55.8% was presented. Indeed, it was also observed in the carrageenan-induced peritonitis that caulerpin (100 μmol/kg, p.o.) exhibited anti-inflammatory activity, reducing significantly the number of recruit cells by 48.3%. Pharmacological studies are continuing in order to characterize the mechanism(s) responsible for the antinociceptive and anti-inflammatory actions and also to identify other active principles present in Caulerpa racemosa.

Piperdardine, a piperidine alkaloid from Piper tuberculatum☆

Abstract A new piperidine alkaloid 1-[7-(1,3-benzodioxol-5-yl)-1-oxo-2, 4-heptadienyl]piperidine, piperdardine, was isolated from hexane and chloroform extracts of Piper tuberculatum var. tuberculatum. A combination of 1D and 2D NMR, together with other spectroscopic methods, led to the unambiguous assignments of all protons and carbons of the molecule.

Antinociceptive activities of crude methanolic extract and phases, n-butanolic, chloroformic and ethyl acetate from Caulerpa racemosa (Caulerpaceae)

Neste estudo, tentamos identificar a atividade antinociceptiva do extrato metanolico bruto e das fases n-butanolica, cloroformica e acetato de etila provenientes da alga Caulerpa racemosa. Esta alga e cosmopolita no mundo, principalmente em regioes tropicais. O extrato metanolico bruto e as fases n-butanolica, cloroformica e acetato de etila foram administrados por via oral, na concentracao de 100 mg/kg. Estes foram capazes de reduzir a nocicepcao produzida pelo acido acetico, sendo 47,39%, 70,51%, 76,11% e 72,24%, respectivamente. No ensaio da placa quente as fases cloroformica e acetato de etila foram ativas neste modelo. Na fase neurogenica do teste de formalina, foi observado que o extrato metanolico bruto (51,77%), fase n-butanolica (35,12%), fase cloroformica (32,70%) e indometacina (32,06%) foram eficazes em inibir a resposta nociceptiva. Na fase inflamatoria, apenas a fase acetato de etila (75,43%) e indometacina (47,83%) foram capazes de inibir significativamente a resposta nociceptiva. Com base nestes dados, podemos sugerir que o a fase acetato de etila apresenta um significativo efeito anti-inflamatorio, cuja potencia ainda nao foi determinada. No entanto, estudos farmacologicos e quimicos serao necessarios, a fim de caracterizar o mecanismo responsavel pela acao antinociceptiva e tambem para identificar outros principios ativos presentes na alga Caulerpa racemosa.

SYNTHESIS OF NATURAL AMIDE ALKALOID PIPERDARDINE AND A NEW BIOACTIVE ANALOGUE

Piperdardine, (E,E)-1-[7-(1,3-benzodioxol-5-yl)-1-oxo-2,4-heptadienyl]-piperidine, isolated from the stem of Piper tuberculatum, was synthesized in 21% overall yield by an efficient pathway, in which safrole, an abundant Brazilian essential oil from Ocotea pretiosa, was used as starting material.

Antinociceptive and anti-inflammatory effects of flavonoids PMT1 and PMT2 isolated from Piper montealegreanum Yuncker (Piperaceae) in mice

In this study, we identified the antinociceptive and anti-inflammatory effects of two flavonoids (PMT1 and PMT2) from Piper montealegreanum. The antinociceptive effect was evaluated using the classical tests: acetic acid-induced writhing, formalin and hot plate test. PMT1 and PMT2 (0.1, 1, 30 and 100 μmol/kg, i.p.) reduced the writhings, with an ID50 of 0.58 and 0.44 μmol/kg, respectively. Moreover, these flavonoids (100 μmol/kg, i.p.) inhibited paw-licking time in the neurogenic phase of the formalin test, but only PMT2 was active in the inflammatory phase. However, PMT1 and PMT2 (100 μmol/kg, i.p.) did not increase the latency time of the animals in the hot plate. In order to evaluate the anti-inflammatory effect of these flavonoids, capsaicin-induced ear oedema was carried out. Both flavonoids (100 μmol/kg, i.p.) were active in this model. These results suggest that PMT1 and PMT2 have antinociceptive and anti-inflammatory activities.

Isolation of Monoterpene Dihydrochalcones from Piper montealegreanum Yuncker (Piperaceae)

Four new compounds were isolated from the branches of Piper montealegreanum Yuncker, a shrub found in the Amazon rainforest, including two new dihydrochalcones named claricine (1) and maisine (2), a cinnamic acid derivative 3 and a phenylalkanoid 4, along with a porphyrin identified as the known compound phaeophytin a (5). The structures were established using spectroscopic experiments, including 1D and 2D NMR and HRESIMS experiments, performed on the two monoterpene dihydrochalcones and their monoacetyl derivatives. The structural diversity of these substances is very important for the Piper genus chemotaxonomy.

Burchellin: study of bioactivity against Aedes aegypti

BackgroundThe dengue mosquito Aedes aegypti Linnaeus, 1762 is a widespread insect pest of serious medical importance. Since no effective vaccine is available for treating dengue, the eradication or control of the main mosquito vector is regarded as essential. Since conventional insecticides have limited success, plants may be an alternative source of larvicidal agents, since they contain a rich source of bioactive chemicals. The aim of this study was to evaluate the larvicidal activity of the neolignan burchellin isolated from Ocotea cymbarum (Lauraceae), a plant from the Amazon region, against third instar larvae of A. aegypti.MethodsBurchellin obtained from O. cymbarum was analyzed. The inhibitory activity against A. aegypti eggs and larvae and histological changes in the digestive system of treated L3 larvae were evaluated. In addition, nitric oxide synthase activity and nitric oxide levels were determined, and cytotoxicity bioassays performed.ResultsThe data showed that burchellin interfered with the development cycle of the mosquito, where its strongest toxic effect was 100% mortality in larvae (L3) at concentrations ≥ 30 ppm. This compound did not show target cell toxicity in peritoneal macrophages from BALB/c mice, and proved to have molecular stability when dissolved in water. The L3 and L4 larvae treated with the compound showed cellular destruction and disorganization, cell spacing, and vacuolization of epithelial cells in small regions of the midgut.ConclusionThe neolignan burchellin proved to be a strong candidate for a natural, safe and stable phytolarvicidal to be used in population control of A. aegypti.

Flavonóides de Piper carniconnectivum C. DC Piperaceae

The flavonoids 5,3’,4’-trihydroxy-7-methoxyflavone, 5,3’-dihydroxy-7-4’-dimethoxyflavone, 5,4’-dihydroxy-7-methoxyflavone and steroids mixture (β-sitosterol and stigmasterol) were isolated from the dried aerials parts of Piper carniconnectivumC.DC. Their structures were established by spectroscopic analyses (UV, IV and 1H, 13C NMR, including 1D and 2D NMR).

FLAVONOIDES DE Piper glandulosissimum Yuncker (Piperaceae)

Three flavanones, two chalcones and one dihydrochalcone were isolated from the branches of Piper glandulosissimum. All isolated compounds were characterized based on IR, UV, 1H and 13C NMR, including 2D NMR analyses (HMQC, HMBC, COSY and NOESY) and comparison with the literature. The compound 7-hydroxy-5,8-dimethoxyflavanone displayed antimicrobial activity against Staphylococcus aureus, S. epidermidis, Trichophyton mentagrophytes and Microsporum canis.