Nuno Alvares Pereira

Plant natural products active against snake bite — the molecular approach

The article surveys the substances identified in plants reputed to neutralize the effects of snake venoms. Protective activity of many of them against the lethal action of the venom of the jararaca (Bothrops jararaca) snake was confirmed by biological assays. It was shown that all belong to chemical classes capable of interacting with macromolecular targets--receptors and enzymes. In a few cases it has been shown that exogenous natural micromolecules can mimic the biological activity of endogenous macromolecules. From the evidence presented, it can be inferred that micromolecules which neutralize the action of snake venoms mechanistically replace endogenous antitoxic serum proteins with venom neutralizing capacity such as produced by some animals.

Pharmacological screening of plants recommended by folk medicine as anti-snake venom: I. Analgesic and anti-inflammatory activities

We have observed that several plants used popularly as anti-snake venom show anti-inflammatory activity. From the list prepared by Rizzini, Mors and Pereira some species have been selected and tested for analgesic activity (number of contortions) and anti-inflammatory activity (Evans blue dye diffusion--1% solution) according to Whittles technique (intraperitoneal administration of 0.1 N-acetic acid 0.1 ml/10 g) in mice. Previous oral administration of a 10% infusion (dry plant) or 20% (fresh plant) corresponding to 1 or 2 g/kg of Apuleia leiocarpa, Casearia sylvestris, Brunfelsia uniflora, Chiococca brachiata, Cynara scolymus, Dorstenia brasiliensis, Elephantopus scaber, Marsypianthes chamaedrys, Mikania glomerata and Trianosperma tayuya demonstrated analgesic and/or anti-inflammatory activities of varied intensity.

Anti-inflammatory and immunologically active polysaccharides of Periandra mediterranea.

Three polysaccharides, glucans with mean M(r)s of 1.5 x 10(5), 3.6 x 10(4) and 2.1 x 10(4), were isolated from dried roots of Periandra mediterranea by fractionation on Sephacryl S-300 HR and Sephadex G-25. Chemical and spectroscopic studies indicated that they have a highly branched glucan type structure composed of alpha-(1-->4) linked D-glucopyranose residues with both (3-->4) and (4-->6) branching points. The polysaccharides enhance phagocytosis in vivo, and exhibit anti-inflammatory activity.

Chamaedrydiol, an ursane triterpene from Marsypianthes chamaedrys

A mixture containing a new triterpene, chamaedrydiol (urs-12-ene-2α,3β-diol), and three known triterpenes (lup-20(29)-ene-2α,3β-diol, castanopsol and epigermanidiol) was isolated from Marsypianthes chamaedrys. The components in the mixture were identified using spectroscopic methods. In addition, a mixture of four less polar known triterpenes consisting of α-amyrin, β-amyrin, lupeol and germanicol, was also isolated.

Effect of leaf essential oil from Piper solmsianum C.DC. in mice behaviour.

The essential oil from Piper solmsianum leaves and its major compound (sarisan) were tested to verify their influences upon mice behaviour. The essential oil was obtained by hydrodistillation in a modified Clevenger extractor and analysed by GC/ MS. This analysis revealed in the oil the presence of monoterpenes, sesquiterpenes and of arylpropanoids. The compound sarisan, a myristicin analogue, was isolated from the oil to perform the pharmacological tests. Emulsions of the oil and of sarisan (5.0 and 10.0% v/v) were used in the tests. Pentobarbital (30 mg/ kg s.c.) or diazepam (2.5 mg/ kg s.c.) were tested as standard drugs to verify depressant or anxiolytic effects, respectively. Both essential oil and sarisan showed to have exciting and depressant effects in the tested animals.

Molluscicidal constituents of Marsypianthes chamaedrys.

Marsypianthes chamaedrys is a common herb that occurs in the North and Northeast regions of Brazil. Phytochemical studies showed this plant to be rich in triterpenoids. The hexane extract of M. chamaedrys yielded, after chromatographic separations, two mixtures: the first containing monohydroxylatedcompounds (α‐amyrin, β‐amyrin, lupeol and germanicol) and the second, dihydroxylated compounds (chamaedrydiol, castanopsol, 2α‐hydroxylupeol and epigermanidiol). Molluscicidal tests were performed for the crude hexane extract and for mixtures I and II. Mixture II showed high activity. Copyright

Tongue angioedema in vivo: Antagonist response of anti-inflammatory drugs

Introduction. The toxicity of Dieffenbachia picta, an ornamental plant, arises from its ability to cause painful edema of oral mucous membranes, buccal ulcerations, and tongue hypertrophy after chewing on the stem or contact with the sap. Objectives. We compared the anti-inflammatory effect of eugenol (2-methoxy-4-(2-propenyl)phenol) to different drugs, and investigated the role of oxalate crystals in the development of the inflammation reaction. Methods. Tongue edema in live mice were measured with a digital tachymeter, 2 h after topical application (0.1 mL) or tissue injection (0.05 mL) of D. picta sap. The mice were treated by intraperitoneal or topical application of drugs, 15 min after edema induction. Vascular permeability was quantified based on abdominal skin plasma extravasation of Evans blue dye in response to intradermal administration of D. picta sap. The proteolytic assay was carried out as previously described (Kunitz M. Crystalline soybean trypsin inhibitor. General properties. J Gen Physiol 1947; 30:291–310.). Results. Arachidonate cascade antagonists and eugenol showed anti-edematogenic effects. High doses of eugenol (50 μg/kg) and sodium cromoglycate (100 mg/kg), but not a combination of the two, inhibited plasma extravasations. The sap without crystals, its methanol extract, or the ethanol-washed crystals in saline-reconstituted solution did not reproduce the tongue edema seen with the original sap. Topical application of 10% sodium bicarbonate completely abolished the tongue edema. Conclusions. The inflammatory response induced by D. picta may be due to mechanical tissue damage resulting from the physical presence of calcium oxalate crystals. We were, however, unable to exclude the possibility of an insoluble toxicity present within the sap as an etiological agent. We realized that emergency treatment should also aim to inhibit antidromic vasodilation and axon reflex flare, reducing mastocyte degranulation and release of tachykinins from nerve endings. We speculate that eugenol showed better antiedematogenic results because it seems to function not only as a classic non-steroidal anti-inflammatory drug, but also as a local anesthetic, blocking neurotransmission in the damaged tissue.

Atividade inibidora da absorção intestinal da glicose do epicarpo da Romã (Punica granatum, L.)

When glucose at 0,1% was perfused into intestinal segment of the anesthetized rats, presents constant rate of absorption.The association of the pomegranate infusion in the glucose solution inhibits glucose absorption. The pomegranate extract previously IP injected also inhibits absorption of perfused glucose.

Estudo do mecanismo tóxico em Dieffenbachia picta

These are the results we have got with the experiences on buccal edem provoked by the raphides of Dieffenbachia picta which were washed with water or ether.The raphides washed with water and suspendend in water have no longer provoked the edem. The raphides washed with water have presented a red colorin by the SUDAM III while those wasched with ether do not get colored any more.

Influência do chá da caá-heê, Stevia rebaudiana (Bert.) Bertoni, sobre o peso dos órgãos sexuais isolados de camundongos jovens

The infusion of the dried caa-hee leaves reduced the male and female mouse sexual organ weight (the latest principaly). After the administration of the infusion at 1% for period of 30 days (for females) and 60 days (male testicles) this effect was more evident. The inhibitory influence of the dried caa-hee leaves chaged with the dose (Concentration of the infusion) and with the duration of the treatment.