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The present study deals with two ethnobotanical surveys carried out in two different segments of the Brazilian population: the first among the Krahô Indians living in Tocantins State, a Cerrado region, and the second one among the descendants of former black slaves, the Quilombolas, living in Mato Grosso State. Both populations use plants which may have effects on the central nervous system (CNS) in their ritual healing ceremonies. Field work was performed during two years by one of the authors (E. Rodrigues) utilizing methods from botany and anthropology. Information was obtained on a total of 169 plants which were utilized in the preparation of 345 prescriptions for 68 ailments seemingly of the CNS, classified as tonics, analgesics, anorectics, hallucinogens, and anxiolytics. The taxonomic families of plants used, the more common therapeutic indications and types of healing rituals are discussed.

The aim of the present study was to document the use of plants, probably acting on the central nervous system (CNS), in rituals carried out by the Kraho Indians, who occupy the cerrado biome in the central region of Brazil. The 2 years of fieldwork were guided by methods of anthropology and botany. The local shamans have indicated 286 formulas, consisting of 138 plant species in 50 uses that could be associated with some type of action on the CNS; of which 98 formulas, 87 plants and 25 uses, appear to involve psychoactive properties, such as: 'to get slow', 'stimulant effect', 'to calm down', 'to enhance memory', 'to reduce anxiety' and 'to induce sleep'. Phytochemical and pharmacological literature data were queried to establish any correlation between indigenous knowledge and scientific indications, for each one of the 138 plant species. Studies were available for 11 of these plants; and for two of them, scientific data coincided with indigenous information., (Copyright 2005 John Wiley & Sons, Ltd.)

This study focused on an ethnopharmacological survey among a group of Brazilian Quilombolas (descended from runaway slaves living in hideouts up-country) whose therapeutic practices involve a combination of healing ceremonies and prescription of medicinal plants consisting of the use of, at least, 48 plants with possible effect on the central nervous system (CNS), cited in 53 formulas prescribed for 17 therapeutic indications, the main ones being: to fortify the brain, for insomnia, as a sedative, for insanity, weight loss, and rejuvenation. The formulas consist of one to ten plants, and each plant may be recommended for up to seven different therapeutic indications, with evidence of non-specificity in the use of plants in this culture. Of these 48 plants, only 31 could be identified to the species level as belonging to 20 taxonomic families, with the Asteraceae, Malpighiaceae, Cyperaceae, and Myrtaceae as the most important families. Only eleven of these species have been previously studied and appear in scientific literature. Some of these plants are at present under study in the Department of Psychobiology of the Federal University of Sao Paulo., (Copyright (c) 2004 John Wiley & Sons, Ltd.)

This review article draws the attention to the many species of plants possessing activity on the central nervous system (CNS). In fact, they cover the whole spectrum of central activity such as psychoanaleptic, psycholeptic and psychodysleptic effects, and several of these plants are currently used in therapeutics to treat human ailments. Among the psychoanaleptic (stimulant) plants, those utilized by human beings to reduce body weight [Ephedra spp. (Ma Huang), Paullinia spp. (guaraná), Catha edulis Forssk. (khat)] and plants used to improve general health conditions (plant adaptogens) were scrutinized. Many species of hallucinogenic (psychodysleptic) plants are used by humans throughout the world to achieve states of mind distortions; among those, a few have been used for therapeutic purposes, such as Cannabis sativa L., Tabernanthe iboga Baill. and the mixture of Psychotria viridis Ruiz and Pav. and Banisteriopsis caapi (Spruce ex Griseb.) C.V. Morton. Plants showing central psycholeptic activities, such as analgesic or anxiolytic actions (Passiflora incarnata L., Valeriana spp. and Piper methysticum G. Forst.), were also analysed.Finally, the use of crude or semipurified extracts of such plants instead of the active substances seemingly responsible for their therapeutic effect is discussed.

The plant Heteropteris aphrodisiaca O. Machado is widely employed in Brazilian popular medicine as a stimulant, a tonic and a remedy for nervous debility. Several other plant products with similar therapeutic applications may have such effects based on the antioxidant content of polyphenols (gallates, cathecols, etc.) and flavonoids. The aim of this work was to investigate the effects of Heteropteris aphrodisiaca O. Machado extracts on the antioxidant defences and oxidative stress of young and old rat brains. Tests of lipoperoxidation in vitro, comparing H. aphrodisiaca extracts with butylhydroxytoluene (BHT), a classic antioxidant, showed an efficient inhibition of lipoperoxidation (Q(1/2) = 3.3 microg/mL). Chronic treatment of young and old rats with 50 mg plant extract/kg body weight resulted in a significant increase in superoxide dismutase (SOD) activities (40%) in the brain of old rats, but no changes in catalase and glutathione peroxidase (GPX). No significant variations in antioxidant enzyme activities were observed in the brains of young rats. However, significantly lower levels of lipoperoxidation (30%) were detected in the brain of young rats upon plant extract administration, suggesting that H. aphrodisiaca extracts reduced the oxidative stress to brain lipids., (Copyright 2001 John Wiley & Sons, Ltd.)

The effects on toxic and behavioral levels of guarana (Paullinia cupana) were assessed in rats and mice subsequent to acute and chronic administrations and were compared to those produced by Ginseng (Panax ginseng). Experimental parameters included tests for antioxidant capacity in vitro and measured in vivo, toxicological screening, progress in weight, motor activity, death rate, and histopathological examination of the viscera. Guarana showed an antioxidant effect because, even at low concentrations (1.2 microg/ml), it inhibited the process of lipid peroxidation. In high doses of 1000-2000 mg/kg (i.p. and p.o.) it did not induce significant alterations in parameters for toxicological screening. No effects on motor activity were observed, neither did guarana alter the hypnotic effect of pentobarbital. Ginseng (250-1000 mg/kg i.p.), however, elicited reductions in motor activity, eyelid ptosis and bristling fur. Consumption of liquids containing guarana or ginseng and progress in weight of the animals remained at levels similar to the controls, even after prolonged administration. The percentage mortality was equivalent in control and in treated groups. The absence of toxicity of guarana was also demonstrated by histopathological examination, with no alteration being detected in heart, lungs, stomach, small and large intestine, liver, pancreas, kidneys, bladder and spleen.

Paulinia cupana (guarana) is a Brazilian plant given great prestige in popular medicine, for example as being a potent stimulator of brain functions. The authors assessed the effects of the long-term administration of guarana on the cognition of normal, elderly volunteers. Forty-five volunteers were studied, with a random distribution in three experimental groups: placebo (n = 15), caffeine (n = 15), and guarana (n = 15), in a double-blind study. There were no significant cognitive alterations in these volunteers.

The authors studied the acute effects of "Guaraná", when compared to caffeine and placebo, (double blind study) on cognition, anxiety and sleep in 30 normal volunteers. Although results were negative it cannot be concluded that "Guaraná" is harmless. Other studies shall be undertaken, administering "Guaraná" on a long term basis, as popularly proclaimed.

Leaves of Maytenus species are used in the popular medicine of Brazil for their reported antacid and antiulcerogenic activity. The present work examined the effects of a boiling water extract of equal parts of M. aquifolium and M. ilicifolia leaves on acute administration in rats and mice, in an attempt to detect any general depressant, hypnotic, anticonvulsant and analgesic effects. General depressant and hypnotic effects were seen only after intraperitoneal administration. After chronic administration, the overall behavior of animals did not change and they continued to gain weight at the same rate as controls. Several biochemical and hematological parameters as well as pathological examination of different organs did not show any significant alterations after 3 months of treatment. A search for the potential effects of the extract on the fertility of female and male rats and on the course of pregnancy as well as a search for potential teratogenic effects did not reveal any significant differences from controls. Taken together, the results indicate that these Maytenus species may be safe for human use and deserve further investigation.

Leaves of Maytenus species are commonly used in Brazil for the treatment of gastric ulcers, dyspepsias and other gastric problems. The present study evaluated the antiulcerogenic potential of a boiling water extract of equal parts of M. aquifolium and M. ilicifolia leaves against ulcer lesions induced by indomethacin and cold-restraint stress in rats. Ranitidine and cimetidine were used as reference drugs. The oral and intraperitoneal administration of the extract had a potent antiulcerogenic effect against both types of ulcers. The extract was shown to cause an increase in volume and pH of gastric juice of the animals with the pH effects comparable to those of cimetidine. The results tend to confirm the popular use of the plant.

A herbal tea (called an abafado in Brazil) prepared from the dried leaves of lemongrass was administered to healthy volunteers. Following a single dose or 2 weeks of daily oral administration, the abafado produced no changes in serum glucose, urea, creatinine, cholesterol, triglycerides, lipids, total bilirubin, indirect bilirubin, GOT, GPT, alkaline phosphatase, total protein, albumin, LDH and CPK. Urine analysis (proteins, glucose, ketones, bilirubins, occult blood and urobilinogen) as well as EEG and EKG showed no abnormalities. There were slight elevations of direct bilirubin and of amylase in some of the volunteers, but without any clinical manifestation. These results taken together indicate that lemongrass as used in Brazilian folk medicine is not toxic for humans. The eventual hypnotic effect of lemongrass was investigated in 50 volunteers who ingested samples of lemongrass and a placebo under double-blind conditions. The parameters (i.e. sleep induction, sleep quality, dream recall and rewakening) did not show any effect of lemongrass as compared to the placebo. Eighteen subjects with high scores of trait-anxiety were submitted to an anxiety-inducing test following taking lemongrass or placebo under double-blind conditions. Their anxiety levels were similar, indicating that the abafado of the plant does not have anxiolytic properties. It is concluded that lemongrass, one of the most popular Brazilian herbal medicines, used for its alleged CNS-depressant effects, is atoxic but lacks hypnotic or anxiolytic properties.

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.

An infusion (abafado) prepared from leaves of lemongrass (Cymbopogon citratus Stapf) administered orally to adult rats for 2 months, in doses up to 20 times larger than the estimated corresponding human dosage, did not induce any effect which could be taken as evidence of toxicity. An absence of effects was also noted in male and female rats and in their offspring when the abafado was administered prior to mating or during pregnancy. These data strongly suggest that lemongrass, as used in Brazilian folk medicine, has no toxic properties.

Cymbopogon citratus is one of the most used plants in Brazilian folk medicine for the treatment of nervous and gastrointestinal disturbances. It is also used in many other places to treat feverish conditions. The usual way to use it is by ingesting an infusion made by pouring boiling water on fresh or dried leaves (which is called "abafado" in Portuguese). Abafados obtained from lemongrass harvested in three different areas of Brazil (Ceará, Minas Gerais and São Paulo States) were tested on rats and mice in an attempt to add experimental confirmation to its popular medicinal use. Citral, the main constituent of the essential oil in Brazilian lemongrass, was also studied for comparison. Oral doses of abafados up to 40 times (C40) larger than the corresponding dosage taken by humans, or of 200 mg/kg of citral, were unable to decrease body temperature of normal rats and/or rats made hyperthermic by previous administration of pyrogen. However, both compounds acted when injected by intraperitoneal route. Oral administration of doses C20 -C100 of abafados and 200 mg/kg of citral did not change the intestinal transit of a charcoal meal in mice, nor did it decrease the defecation scores of rats in an open-field arena. Again, by intraperitoneal route both compounds were active. The possible central nervous system depressant effect of the abafados was investigated by using batteries of 12 tests designed to detect general depressant, hypnotic, neuroleptic, anticonvulsant and anxiolytic effects. In all the tests employed, oral doses of abafados up to C208 or of citral up to 200 mg/kg were without effect. Only in a few instances did intraperitoneal doses demonstrate effects. These data do no lend support to the popular oral therapeutic use of lemongrass to treat nervous and intestinal ailments and feverish conditions.