Julianeli Tolentino de Lima

Plants with anticonvulsant properties: a review

Seizures are resistant to treatment with currently available anticonvulsant drugs in about 1 out of 3 patients with epilepsy. Thus, there is a need for new, more effective anticonvulsant drugs for intractable epilepsy. However, nature is a rich source of biological and chemical diversity and a number of plants in the world have been used in traditional medicine remedies, i.e., anticonvulsant, anxiolytic, analgesic, antidepressant. This work constitutes a literature review on medicinal plants showing anticonvulsant properties. The review refers to 16 Brazilian plants and a total 355 species, their families, geographical distribution, the utilized parts, method and references. Some aspects of research on medicinal plants and a brief review of the most common animal models to discover antiepileptic drugs are discussed. For this purpose over 170 references were consulted.

Antinociceptive effect of citronellal in mice

Citronellal is a monoterpene reported to be a major component of the essential oils in various aromatic species of plants. The present study evaluated the central nervous system depressant and antinociceptive properties of citronellal through behavioral experimental models. Following intraperitoneal injection, citronellal induced the reduction of spontaneous activity, ataxia, analgesia, and sedation. In pentobarbital-induced hypnosis, CTL (citronellal) at 50, 100, and 200 mg/kg (i.p.) significantly increased sleeping time (88.0 ± 11.4, 100.2 ± 16.4, and 119.5 ± 20.9 min) when compared to vehicle solution injections (43.0 ± 6.1). Citronellal (100 and 200 mg/kg, i.p.) significantly reduced the number of writhes (66.4 and 81.9%) in a writhing test and the number of paw licks during phase 1 (47.0 and 66.8%) and phase 2 (71.1 and 79.2%) of a formalin test when compared to control group animals. In addition, the results of a hot plate test showed central analgesic properties for citronellal (p < 0.05). These results indicate depressant, hypnotic, and antinociceptive properties of this monoterpene.

Antinociceptive effect of ethanolic extract of Selaginella convoluta in mice.

BackgroundSelaginella convoluta (Arn.) Spring (Selaginellaceae), commonly known as “jericó”, is a medicinal plant found in northeastern Brazil. S. convoluta is used in folk medicine as an antidepressant, aphrodisiac, diuretic, analgesic, anti-inflammatory and it is used to combat amenorrhea, coughing and bleeding. This study was performed to evaluate the antinociceptive effects of ethanolic extract from S. convoluta in mice exposed to chemical and thermal models of nociception.MethodsPreliminary phytochemical analysis of the ethanolic extract was performed. The ethanolic extract from Selaginella convoluta (Sc-EtOH) was examined for its intraperitoneal (i.p.) antinociceptive activity at the doses of 100, 200 and 400 mg/kg body weight. Acetic acid-induced writhing, formalin injection and hot plate tests were used to evaluate the antinociceptive activity of Sc-EtOH extract. The rota-rod test was used to evaluate motor coordination.ResultsA preliminary analysis of Sc-EtOH revealed that it contained phenols, steroids, terpenoids and flavonoids. In the acetic acid-induced writhing test, mice treated with Sc-EtOH (100, 200 and 400 mg/kg, i.p.) exhibited reduced writhing (58.46, 75.63 and 82.23%, respectively). Secondly, Sc-EtOH treatment (100, 200 and 400 mg/kg, i.p.) decreased the paw licking time in mice during the first phase of the formalin test (by 44.90, 33.33 and 34.16%, respectively), as well as during the second phase of the test (by 86.44, 56.20 and 94.95%, respectively). Additionally, Sc-EtOH treatment at doses of 200 and 400 mg/kg increased the latency time in the hot plate test after 60 and 90 minutes, respectively. In addition, Sc-EtOH did not impair motor coordination.ConclusionOverall, these results indicate that Sc-EtOH is effective as an analgesic agent in various pain models. The activity of Sc-EtOH is most likely mediated via the inhibition of peripheral mediators and central inhibitory mechanisms. This study supports previous claims of traditional uses for S. convoluta.

Antiulcer activity of ethanolic extract of Encholirium spectabile Mart. ex Schult & Schult f. (Bromeliaceae) in rodents

This study evaluated the antiulcer activity of an ethanolic extract of Encholirium spectabile (ES-EtOH) by using different standard experimental models of induced acute gastric ulceration. ES-EtOH (100 mg/kg p.o) protected the gastric mucosa against ulceration that was induced by absolute ethanol (53%), ethanol/HCl (75%), ibuprofen (52 %) and ischemia/reperfusion (43 %). It also restored catalase activity and non-protein sulfhydryl group concentration in the gastric wall of mice that had been treated with ethanol. The pre-treatment of mice with N-nitro-L-arginine (70 mg/kg i.p.) abolished the protective activity of ES-EtOH, which indicates that prostaglandins, antioxidant compounds and nitric oxide synthase activity are involved in the gastroprotective activity of the extract.

Biological Oxidations and Antioxidant Activity of Natural Products

Oxygen is the most prevalent element in the earth’s crust. It exists in air as a diatomic molecule, O2. Except for a small number of anaerobic bacteria, all living organisms use O2 for energy production and it is essential for life as we know it. Energy production by organisms from food material requires “oxidation”, which implies the loss of electrons. However the potential of O2 to oxidize also makes it toxic. Oxidation can inactivate important enzymes, and anaerobes that do not have antioxidant mechanisms do not survive in an O2 environment (Magder, 2006).

Spasmolytic Action of Diplotropin, a Furanoflavan from Diplotropis ferruginea Benth., Involves Calcium Blockade in Guinea-Pig Ileum

Diplotropis ferruginea Benth. (Fabaceae) is a tree popularly known in Northeastern Brazil as “sucupira-preta”. In the present work, the isolation, identification and pharmacological activity of a furanoflavan-type flavonoid (2,3-trans-3,4-trans)-3,4,5,8-tetramethoxy-(6,7,2”,3”)-furanoflavan, which received the trivial name diplotropin is reported. The structure was determined by means of spectroscopic techniques, especially EIMS and 1D and 2D NMR. Diplotropin (10−8 −3 · 10−4 M) inhibited the phasic contractions induced by both acetylcholine (IC50 = 4.6±0.8 · 10−5 M) and histamine (IC50 = 2.3±1.1 · 10−5 M) in guinea-pig ileum. Diplotropin relaxed the ileum pre-contracted with KCl (EC50 = 3.9±1.1 · 10−6 M), acetylcholine (EC50 = 3.7±1.6 · 10−6 M) and histamine (EC50 = 4.4±1.4 · 10−5 M) in a concentration-dependent manner. As the maintenance of tonic contraction induced by these contractile agents involves Ca2+ influx through voltage-dependent Ca2+ channels, it is suggestive that this relaxation may be due to the blockade of Ca2+ influx through those channels. This hypothesis was confirmed by the observation that diplotropin antagonized (pD’2 = 4.83±0.37) CaCl2 induced contractions in Ca2+-free depolarizing medium (IC50 = 1.5±0.8 · 10−5 M).

Bioassay-guided evaluation of central nervous system effects of citronellal in rodents

The central nervous system (CNS) depressant and anticonvulsant activities of citronellal (CT) were investigated in animal models. The CT in doses of 100, 200 and 400 mg/kg injected by i.p. route in mice caused a significant decrease in the motor activity of animals when compared with the control group. The highest dose of CT significantly reduced the remaining time of the animals on the Rota-rod apparatus up to 2 h. Additionally, CT at doses 100, 200 and 400 mg/ kg (i.p.) was also capable to promote an increase of latency for development of convulsions induced by pentylenetetrazole (PTZ). It was efficient in prevents the tonic convulsions induced by maximal electroshock (MES) in doses of 200 and 400 mg/kg, resulting in 30 and 40% of protection, respectively. This compound was also capable to promote an increase of latency for development of convulsions induced by picrotoxin (PIC) at 400 mg/kg. In the same way, the anticonvulsant effect of CT was affected by pretreatment with flumazenil, a selective antagonist of benzodiazepine site of GABAA receptor. These results suggest a possible CNS depressant and anticonvulsant activities.

Antinociceptive Activity of Ethanol Extract from Duguetia chrysocarpa Maas (Annonaceae)

The ethanol extract from the fruits of Duguetia chrysocarpa was evaluated for its antinociceptive activity in chemical and thermal models of nociception in mice. The intraperitoneal administration of the ethanol extract (100, 200, and 400 mg/kg body weight) showed a dose-dependent inhibition of acetic-acid-induced abdominal writhes. The extract also produced a significant inhibition of both phases of the formalin test in all doses tested and increased the reaction time in hot-plate test at dose of 200 mg/kg. The data obtained suggest that the antinociceptive effect of the extract may be mediated via both peripheral and central mechanisms. The phytochemical investigation yielded the isolation of the benzenoid derivative 3-methoxy-4-ethoxy benzoic acid which is being reported for the first time in this genus.

Evaluation of the anti-inflammatory and antinociceptive effects of the essential oil from leaves of Xylopia laevigata in experimental models.

Xylopia laevigata (Annonaceae) is a medicinal plant used in folk medicine to treat pain and inflammation. Thus, we investigated the possible antioxidant, antinociceptive, and anti-inflammatory effects of X. laevigata leaf essential oil (EOX) in animal models. Our EOX sample showed the presence of γ-muurolene (17.78%), δ-cadinene (12.23%), bicyclogermacrene (7.77%), and α-copaene (7.17%) as main compounds. EOX presented a strong antioxidant potential according to the DPPH, TBARS, and nitrite production tests. Additionally, pretreatment with EOX, in mice, also significantly produced (P < 0.05 or P < 0.001) antinociceptive effect by reduction of nociceptive behavior (in formalin and writhing tests). The EOX showed c-Fos label in the olfactory bulb, piriform cortex, and periaqueductal gray. Acute administration of EOX exhibited a significant (P < 0.01 or P < 0.001) anti-inflammatory profile in the carrageenan-induced peritonitis and by the carrageenan-induced hindpaw edema tests in mice. Our results provide evidence for the use of X. laevigata by traditional medicine practitioners in the management of pain and inflammatory disorders.

Phytochemical screening and anti‑inflammatory activity of Cnidoscolus quercifolius (Euphorbiaceae) in mice

Background: Cnidoscolus quercifolius is a species popularly known as favela and faveleira, and belonging to the Caatinga biome (semi-arid vegetation, Brazil), where is used in folk medicine as an anti-inflammatory. Objective: The aim was to evaluate the anti-inflammatory effect of the ethanolic extract from barks (Cqb-EtOH) and leaves (Cql-EtOH) of C. quercifolius in mice using experimental models of inflammation. Materials and Methods: The preliminary phytochemical analysis of the ethanolic extract was performed. The activity was evaluated by paw edema induced by carrageenan and leukocytes migration to the peritoneal cavity induced by carrageenan methods. Results: A preliminary analysis of Cqb-EtOH revealed that it contained coumarins, flavonoids, monoterpenes/diterpenes and naphthoquinones, while the Cql-EtOH showed positive reaction to coumarins, anthracene derivatives, flavonoids, lignans and triterpenes/steroids. Cqb-EtOH and Cql-EtOH (100, 200 and 400 mg/kg) inhibited significantly (P < 0.01) the increase in the edema volume after administration of carrageenan. In the peritonitis test, acute pretreatment with Cqb-EtOH and Cql-EtOH (100, 200 and 400 mg/kg) inhibited the leukocyte migration. Conclusions: It can be concluded that extracts from the barks and leaves of C. quercifolius have anti-inflammatory activity, which supports the popular use of this plant to treat inflammation. Thus, extracts has significant anti-inflammatory properties, which are related probably to inhibition of release of mediators of the inflammatory process.