Evidence that L-carnitine and selenium supplementation reduces oxidative stress in phenylketonuric patients.

It is well established that the involvement of reactive species in the pathophysiology of several neurological diseases, including phenylketonuria (PKU), a metabolic genetic disorder biochemically characterized by elevated levels of phenylalanine (Phe). In previous studies, we verified that PKU patients (treated with a protein-restricted diet supplemented with a special formula not containing L-carnitine and selenium) presented high lipid and protein oxidative damage as well as a reduction of antioxidants when compared to the healthy individuals. Our goal in the present study was to evaluate the effect of Phe-restricted diet supplemented with L-carnitine and selenium, two well-known antioxidant compounds, on oxidative damage in PKU patients. We investigated various oxidative stress parameters in blood of 18 treated PKU patients before and after 6 months of supplementation with a special formula containing L-carnitine and selenium. It was verified that treatment with L-carnitine and selenium was capable of reverting the lipid peroxidation, measured by thiobarbituric acid-reactive species, and the protein oxidative damage, measured by sulfhydryl oxidation, to the levels of controls. Additionally, the reduced activity of glutathione peroxidase was normalized by the antioxidant supplementation. It was also verified a significant inverse correlation between lipid peroxidation and L-carnitine blood levels as well as a significant positive correlation between glutathione peroxidase activity and blood selenium concentration. In conclusion, our results suggest that supplementation of L-carnitine and selenium is important for PKU patients since it could help to correct the oxidative stress process which possibly contributes, at least in part, to the neurological symptoms found in phenylketonuric patients.

HPLC quantitation of kaurane diterpenes in Xylopia species.

Xylopia frutescens is a tree native to the Brazilian Amazon whose seeds are rich in kaurenoic acid, a diterpene that showed in vitro activity against Trypanosoma cruzi. Aiming to find out alternative sources for kaurenoic acid, the content of some kaurane diterpenes was evaluated in X. aromatica and X. brasiliensis, species occurring in the Cerrado area of Minas Gerais, and also in X. frutescens. A reversed phase HPLC isocratic method was developed and validated to perform the assays. Kaurenoic acid was found to be the most abundant diterpene within the analyzed species, with a 3.16+/-0.97% content in the seeds of X. frutescens, which also presented the highest amount of xylopic acid (1.09+/-0.33%). The highest concentration of 16-alpha-hydroxykauranoic acid (1.96+/-1.58%) was found in the stems of X. aromatica.

Screening Brazilian plant species for in vitro inhibition of 5-lipoxygenase.

Plants from the Brazilian flora were evaluated for the inhibition of 5-lipoxygenase. The species were selected based on their traditional use and on a chemosystematic approach. In total, 19 species belonging to 13 families have been investigated. Hedychium coronarium J. Koenig (Zingiberaceae), Xylopia frutescens Aubl. (Annonaceae) and Hymenaea courbaril L. (Leguminosae) presented a high 5-lipoxygenase inhibitory activity. Some hypothesis about the nature of the active compounds are discussed, based on reports of the chemical constitution of these species or other species from the same botanical family.

Screening the Brazilian flora for antihypertensive plant species for in vitro angiotensin-I-converting enzyme inhibiting activity.

The evaluation of several antihypertensive activity of Brazilian plant species was performed using in vitro inhibition of the angiotensin I-converting enzyme (ACE). Nineteen species belonging to 13 families were investigated. Plants were selected based on their use as diuretics and on a chemosystematic consideration. Extracts of the following species presented the highest ACE inhibition rate, at concentrations of 0.33 mg/ml: Ouratea semiserrata (Mart. & Nees) Engl. stems (68%), Cuphea cartagenesis (Jacq.) Macbride leaves (50%) and Mansoa hirsuta DC. leaves (54%). Some hypotheses about the nature of the compounds that may be responsible for the activity of these species are discussed in the paper.

Trypanosomicidal kaurane diterpenes from Wedelia paludosa.

The diterpenes ent-kaur-16-en-19-oic acid, ent-kaur-9(11),16(17)-dien-19-oic acid and 3 alpha-angeloiloxy-ent-kaur-16-en-19-oic acid were identified as trypanosomicidal compounds of the ethanolic extract from the aerial parts of Wedelia paludosa D.C. (Asteraceae), showing activity up to the lowest dose of 0.68 mg/mL in the in vitro assay against trypomastigotes of T. cruzi, the causative agent of Chagas' disease (American trypanosomiasis). The other isolates, friedelan-3 beta-ol, ent-kaur-16 alpha-ol-19-oic acid, beta-amyrin acetate and (22-E)-stigmasta-5,22-dien-3 beta-ol, were inactive. This is the first report on the trypanosomicidal activity of ent-kaur-9(11),16(17)-dien-19-oic acid and 3 alpha-angeloiloxy-ent-kaur-16-en-19-oic acids; this effect was already known for ent-kaur-16-en-19-oic acid.

Screening of Asteraceae (Compositae) plant extracts for larvicidal activity against Aedes fluviatilis (Diptera:Culicidae).

Ethanol extracts of 83 plants species belonging to the Asteraceae (Compositae) family, collected in the State of Minas Gerais, Brazil, were tested for larvicidal activity against the mosquito Aedes fluviatilis--Diptera: Culicidae). The extract from Tagetes minuta was the most active with a LC90 of 1.5 mg/l and LC50 of 1.0 mg/l. This plant has been the object of several studies by other groups and its active components have already been identified as thiophene derivatives, a class of compounds present in many Asteraceae species. The extract of Eclipta paniculata was also significantly active, with a LC90 of 17.2 mg/l and LC50 of 3.3 mg/l and no previous studies on its larvicidal activity or chemical composition could be found in the literature. Extracts of Achryrocline satureoides, Gnaphalium spicatum, Senecio brasiliensis, Trixis vauthieri, Tagetes patula and Vernonia ammophila were less active, killing more than 50% of the larvae only at the higher dose tested (100 mg/l).

Grossamide and N-trans-caffeoyltyramine from Annona crassiflora seeds.

Grossamide, and N-trans-caffeoyltyramine, were isolated for the first time from the seeds of Annona crassiflora Mart, and in the Annonaceae family.

Brine shrimp lethality assay as a prescreening system for anti-Trypanosoma cruzi activity.

With the aim of finding an acceptable method for selecting plant extracts to be assayed against the infective blood form of Trypanosoma cruzi, the causative agent of Chagas' disease (American trypanosomiasis), two different strategies were compared: a) screening only medicinal species and b) pre-screening random collected species in the brine shrimp lethality assay (BSLA). Fifty-two plants belonging to the Asteraceae family, including eighteen medicinal species, were collected and their ethanol extracts assayed against both T. cruzi and Artemia salina (brine shrimp). The proportion of trypanocidal extracts among the medicinal species and among the random collection did not differ significantly. On the other hand, the proportion of trypanocidal extracts among those that presented LC(50) of less than 100 ppm to A. salina was four times higher than among the medicinal species.

Inhibition of drug-induced contractions of guinea-pig ileum by Annona crassiflora seed extract.

A hydro-alcoholic extract of dried Annona crassiflora seeds (AR.1) showed a non-specific inhibitory effect on drug-induced contractions of guinea-pig ileum. Maximum responses to histamine, acetylcholine and bradykinin were reduced increasingly with increasing doses of AR.1. Affinities of the gut to the above agonists, expressed as respective pD2 values were not changed by AR.1. Dose-response curves of calcium-induced contractions in depolarized preparations were shifted to the right but maximum responses were not changed by AR.1. It is suggested that the inhibitory effect of AR.1 is due to a decrease in membrane permeability to calcium. This inhibitory effect may be responsible for the effect of Annona crassiflora as a remedy against snake venom.

Screening in vitro of natural products against blood forms of Trypanosoma cruzi.

Transmission of Chagas disease by blood transfusion is a major health problem in Central and South America. The annual incidence of transfusion-transmitted Chagas disease in Brazil is about 20,000 cases. Crystal violet is the only trypanosomicidal agent available at present, but there are some restrictions on its use. In a search for possible new chemoprophylactic agents, several natural products of different structural types were tested in vitro against infective blood trypomastigotes of Trypanosoma cruzi. Four compounds had high activity at a concentration of 5 x 10(-4) M: the diarylpropanoids (3R)-claussequinone, (R)-4-methoxydalbergione and (S)-4,4'-dimethoxy-dalbergione, and 15-deoxygoyazensolide, a sesquiterpenelactone. Haemoculture and serology of mice inoculated with infected blood treated with these active compounds were negative after 3 and 6 months. The benzoquinone moiety seemed to be important for this activity since lapachol and related naphthoquinones are known to be trypanosomicidal. 15-Deoxygoyazensolide has previously been recognized as a schistosomicide.

Psychopharmacological effects of the essential oil fraction and of the hydrolate obtained from the seeds of Licaria puchury-major.

An essential oil fraction obtained from powdered seeds of Licaria puchury-major contained 51.3% of safrol, 3.3% of eugenol and 2.9% of methyleugenol, among other substances. Fifty to 800 mg/kg of this fraction reduced motor activity and anesthetized mice; it also protected the animals against transcorneal electroshock. A hydrolate obtained from the powder, contained 0.2 mg of essential oil fraction per ml: 0.1 and 0.2 ml/10 g of this hydrolate reduced motor activity and potentiated barbiturate sleeping time of mice; 2.5-10 ml/kg given to rats produced a drop in body temperature. The hydrolate, however, did not anesthetize and did not protect mice against convulsions induced by electrical shock. These amounts of the hydrolate corresponded to dosing the animals with 2-4 mg/kg of the essential oil (or 1-2 mg/kg of safrol), doses which were inactive per se. This suggested that the pharmacological activity of the hydrolate was not due to its essential oil content. Corroborating this possibility the hydrosoluble portion of the hydrolate mimicked all of its effects: reduced motor activity, potentiated barbiturate sleeping time of mice and decreased body temperature of rats. The hydrosoluble material, as the hydrolate, was also incapable of anesthetizing and protecting mice against electroshock induced convulsions.