Jose Angelo Silveira Zuanazzi

Antiinflammatory and antinociceptive activities of extracts and isolated compounds from Stachytarpheta cayennensis

The alcoholic and n-butanolic extracts of dried leaves of Stachytarpheta cayennensis (L.C. Rich) Vahl (Verbenaceae) was assessed in antiinflammatory and antinociceptive models. Intraperitoneal pretreatment with the dried extracts at doses ranging from 100 to 200 mg/kg, significantly inhibited carrageenin inducing edema formation. The active extracts were then fractionated and monitored with the same bioassay. The iridoid ipolamiide and the phenylethanoid glycoside acteoside were isolated from the active fraction and showed inhibitory effect on histamine and bradykinin induced contractions of guinea-pig ileum. The compounds also showed in vivo antiinflammatory activity when administered orally to rats mainly in the fourth hour after the administration of the phlogistic agent (70.22% and 93.99%, respectively). These results indicate that S. cayennensis shows antiinflammatory properties which seems to be due, at least partly, to the inhibition of bradyknin and histamine. The extracts also exhibited antinociceptive activity measured by the hot-plate test both i.p. and p.o. in doses ranging from 100 to 300 mg/kg.

Production of Sinorhizobium meliloti nod gene activator and repressor flavonoids from Medicago sativa roots

During symbiosis between leguminous plants and rhizobia, flavonoids exuded by the plants act as chemoattractants and nodulation (nod) gene regulators in the other partner. To better understand the role of these compounds during the early steps of the alfalfa-Sinorhizobium meliloti symbiosis and the regulation of their production we have isolated nod gene inducers from alfalfa roots. All the compounds that we identified in this study as nod gene inducers in the root are flavonoids, indicating that other compounds with nod gene activator capacity may have little contribution, if any, to nod gene activation. Most of the intermediates of the flavonoid pathway were found in Medicago sativa roots and nodules, but only end products of the flavonoid pathway were identified in the root exudate. We have also studied flavonoid production in different parts of the root and found that it is developmentally regulated during root growth. Finally, we have shown that coumestrol and medicarpin, present in the exudates and ...

Brachycerine, a novel monoterpene indole alkaloid from Psychotria brachyceras

Brachycerine (1), an unusual alkaloid from the leaves of Psychotria brachyceras, was characterized through spectroscopic data interpretation and its stereochemistry established by NOE difference techniques. Brachycerine (1) was found to be restricted to shoots in rooted cuttings of P. brachyceras (0.018 +/- 0.004% dry weight), and accumulation was unaffected by root induction treatment with auxin.

Screening for cytotoxic activity of extracts and isolated alkaloids from bulbs of Hippeastrum vittatum

The dichloromethane and n-butanol extracts obtained from fresh bulbs of Hippeastrum vittatum (Amaryllidaceae), collected in Southern Brazil, were evaluated for their cytotoxic activity in vitro against five human cell lines (HT29 colon adenocarcinoma, H460 non-small cell lung carcinoma, RXF393 renal cell carcinoma, MCF7 breast cancer, and OVCAR3 epithelial ovarian cancer), using the sulphorhodamine B assay. Both extracts showed potential antiproliferative activity. From CH(2)Cl(2) fraction, three alkaloids were isolated: lycorine, vittatine and montanine. The two last compounds were submitted to the antiproliferative assay and the highest level of cytotoxicity was found for the alkaloid montanine.

A quantitative resazurin assay to determinate the viability of Trichomonas vaginalis and the cytotoxicity of organic solvents and surfactant agents

Trichomonas vaginalis causes trichomonosis, the most common, non-viral sexually transmitted disease. To test anti-Trichomonas agents, usually many with low water solubility, organic solvents and surfactant agents should be used. Therefore, the minimal inhibitory concentration (MIC) of acetone, methanol, ethanol, isopropanol, DMSO, Tween 20, Tween 80, and Triton X-100 was determined against T. vaginalis isolates using the quantitative resazurin method. Our results showed that solvents and surfactant agents can be employed as vehicles to test bioactive compounds at lower concentrations than MIC values and we suggest acetone and DMSO as preferential. Moreover, a new methodology is established to substitute or to complement the counting of viable trophozoites. The amount of resazurin reduced by T. vaginalis can be quantified by fluorescence spectroscopy, making the test a quantitative determination of cell viability. These results contribute for pharmacological investigations of bioactive compounds that need the use of solvents as solubilization vehicles to test anti-Trichomonas activity.

Effect of isoquinoline alkaloids from two Hippeastrum species on in vitro acetylcholinesterase activity.

The treatment of neurological disorders and neurodegenerative diseases is related to the levels of acetylcholine (ACh) through the inhibition of acetylcholinesterase (AChE). Galanthamine, an important alkaloid isolated from the Amaryllidaceae family, is approved for the pharmacological treatment of Alzheimers disease (AD) and acts by inhibiting the acetylcholinesterase (AChE) activity. In the present study, Ellmans method was used to verify the inhibition of AChE activity of some isoquinolines alkaloids such as galanthamine, montanine, hippeastrine and pretazettine. At the concentrations 1mM, 500 microm and 100 microm, galanthamine presented an AChE inhibition higher than 90%. Montanine inhibited, in a dose-dependent manner, more than 50% of the enzyme at 1mM concentration. With the concentrations 500 microm and 100 microm, 30-45% of AChE activity inhibition was detected. The alkaloids hippeastrine and pretazettine presented no significant inhibition of the AChE activity. The results demonstrate that montanine significantly inhibits AChE activity at the tested concentrations, suggesting the necessity of further investigations on this alkaloid use in treating neurological disorders.

Lycorine induces cell death in the amitochondriate parasite, Trichomonas vaginalis, via an alternative non-apoptotic death pathway

In this study, the mechanism of action of the pro-apoptotic alkaloid lycorine on an amitochondriate cell, the parasite Trichomonas vaginalis, was investigated. The cytotoxicity of lycorine against T. vaginalis was studied from 2.5 to 1000μM and several important ultrastructural alterations were observed by electron microscopy. Lycorine arrested the T. vaginalis cell cycle, although no hallmarks of apoptosis, such as apoptotic bodies, were observed. Consequently, the underlying mechanism of action fails to completely fulfill the criteria for apoptosis. However, some similarities to paraptotic cell death were observed.

Alkaloids of Erythroxylum (Erythroxylaceae) species from Southern Brazil

A new alkaloid identified as 3beta,6beta-ditigloyloxynortropane as 3beta,7beta-ditigloyloxynortropane, 4-hydroxyhygrinic acid, methylecgonidine and tropacocaine have been isolated from the leaves of Erythroxylum argentinum. The new structure was established by means of spectroscopic techniques. Four other species E. deciduum, E. microphyllum, E. pelleterianum and E. cuneifolium collected in the state of Rio Grande do Sul were screened for methylecgonidine and tropacocaine by CG/MS. Two of these plants contain tropacocaine and two contain methylecgonidine. GC/MS analysis of all 5 species for cocaine proved fruitless. The chemotaxonomic significance of these results is discussed.

Alkaloids from Hippeastrum papilio.

Galanthamine, an acetylcholinesterase inhibitor marketed as a hydrobromide salt (Razadyne®, Reminyl®) for the treatment of Alzheimer’s disease (AD), is obtained from Amaryllidaceae plants, especially those belonging to the genera Leucojum, Narcissus, Lycoris and Ungernia. The growing demand for galanthamine has prompted searches for new sources of this compound, as well as other bioactive alkaloids for the treatment of AD. In this paper we report the isolation of the new alkaloid 11β-hydroxygalanthamine, an epimer of the previously isolated alkaloid habranthine, which was identified using NMR techniques. It has been shown that 11β-hydroxygalanthamine has an important in vitro acetylcholinesterase inhibitory activity. Additionally, Hippeastrum papilio yielded substantial quantities of galanthamine.

Composição química e atividade antioxidante do óleo volátil de eupatorium polystachyum dc.

The essential oil obtained from leaves and flowers of Eupatorium polystachyum DC. (Asteraceae) collected in Rio Grande do Sul State, Brazil, was characterized by GC-MS and its antioxidant activity was assessed by DPPH assay. The yield of essential oil, relative to fresh material, was 1.6 and 0.9% for leaves and flowers, respectively. Both oils are constituted exclusively by terpenic compounds. Leaf oil contains great quantity of monoterpenes (66.4%); on the other hand, inflorescence oil contains comparable quantities of mono- and sesquiterpenes (51.8 and 47.7%, respectively). The same compounds are majority in both oils: b-pinene (14.7 and 9.8%), b-myrcene (15.3 and 10.8%) and limonene (22.8 and 20.5%) among monoterpenes and b-caryophyllene (10.4 and 15.4%), germacrene D (7.2 and 9.4%) and bicyclogermacrene (12.0 and 19.2%) among sesquiterpenes. The oils had antioxidant activity by DPPH assay in 1:10 dilution in ethyl ether (v/v).