Hymenaea stigonocarpa Mart. ex Hayne: A Brazilian medicinal plant with gastric and duodenal anti-ulcer and antidiarrheal effects in experimental rodent models

Ethnopharmacological relevance

Hymenaea stigonocarpa Mart. ex Hayne (Fabaceae) is a medicinal species commonly found in the Brazilian savannah. The stem bark of this medicinal plant, popularly known as “jatobá-do-cerrado”, is widely used in tea form to treat gastric pain, ulcers, diarrhoea and inflammation, whereas its fruits pulp is edible.

Aim of the study

The aim of this study was to investigate the antidiarrheal and anti-ulcer effects of a methanolic extract derived from the stem bark (MHs) and diet with fruit pulp of H. stigonocarpa.

Materials and methods

The antidiarrheal action of MHs was measured against the intestinal motility and diarrhoea induced by castor oil in mice. The preventive action of MHs (50, 100, 150 and 200 mg/Kg, by oral route (p.o.)) against peptic ulcers was evaluated in experimental rodent models challenged with absolute ethanol, non-steroidal anti-inflammatory drugs (NSAIDs), ischemia–reperfusion (I/R) (200 mg/Kg, p.o.) and cysteamine (200 mg/Kg, p.o.). The main anti-ulcer mechanisms of action of MHs were analysed as follows: evaluation of the gastric juice parameters, assessment of mucus adherence to the gastric wall, determination of the role of nitric oxide (NO) and sulfhydryl compounds (SH), glutathione (GSH) levels and myeloperoxidase (MPO) activity. The healing effects from MHs (200 mg/Kg) and diet with fruit pulp (10%) against gastric and duodenal ulcers induced by acetic acid were also evaluated by treating rats over 7 or 14 consecutive days of treatment.

Results

The phytochemical profile of MHs and fruit pulp indicated the presence of phenolic compounds (mainly flavonoids and condensed tannins). MHs (200 mg/Kg, p.o.) displayed an antidiarrheal effect and were able to protect gastric mucosa against absolute ethanol (68% protection) and also against the injurious effect of NSAIDs (86% protection) when compared to the group treated with vehicle. These results were accompanied by the prevention of GSH depletion and an inhibition of MPO activity when compared to animals treated with vehicle (P<0.05). MHs markedly protected duodenal mucosa against injuries caused by cysteamine (98%) and also against I/R induced gastric ulceration (80%) when compared to the group treated with vehicle. Furthermore, MHs also prevented the GSH depletion of gastric mucosa relative to the control group treated with vehicle. NO appeared to be involved in this gastroprotective effect. MHs and diet with fruit pulp clearly demonstrated gastric healing actions after treatment for 7 (MHs – 53% inhibition) or 14 days (MHs – 60% inhibition and fruit pulp – 61% inhibition). Treatment with diet with fruit pulp for 7 days demonstrates a significant duodenal healing effect (71% inhibition) without any signs of toxicity.

Conclusions

MHs clearly demonstrate antidiarrheal, gastroprotective and cicatrising effects in experimental gastric and duodenal ulcers, and the diet with fruit pulp displays duodenal healing effects. The observed effects may be associated with the antioxidant effect, which may be due the presence of condensed tannins and flavonoids in the bark and fruit of H. stigonocarpa.     

In vivo antimalarial activities of Enantia polycarpa stem bark against Plasmodium berghei berghei in mice

Ethnopharmacological relevance

Enantia polycarpa (PC) Engl. Et Diels (Annonaceae) is used in traditional medicine as an antimalarial remedy in Southern Nigeria.

Aim of the study

The antimalarial activities of ethanolic stem bark extracts of Enantia polycarpa was studied in vivo, in mice infected with Plasmodium berghei berghei.

Materials and methods

The ethanolic stem bark extract of Enantia polycarpa was administered at doses ranging from 200 to 600 mg/kg/day to Plasmodium berghei infected mice in both early and established models of antiplasmodial studies.

Results

The extract of Enantia polycarpa exhibited promising antimalarial activity against both early and established infections. At a dose of 600 mg/kg the extract achieved a 75.8% and 72% chemosuppression of parasitaemia in the study of acute and established infections, respectively. The extract also prolonged mean survival time of Plasmodium berghei infected mice during the study of established infection. The mean survival time of mice administered Enantia polycarpa extract at 600 mg/kg/day (27 days) was significantly longer than infected/untreated control (12 days). For the acute toxicity study the extract had an intraperitoneal LD₅₀ of 186 mg/kg but caused no mortality when administered orally at doses as high as 2,000 and 4,000 mg/kg.

Conclusions

Collectively, the results indicate that Enantia polycarpa is safe when administered orally and possesses promising antimalarial activity, thus supporting its use in traditional medicine for the treatment of malaria.     

Evaluation of mechanisms involved in the antinociception of the ethanol extract from the inner bark of Caesalpinia pyramidalis in mice

Ethnopharmacological relevance

Caesalpinia pyramidalis Tul. (Fabaceae) is an endemic tree of the Northeast region of Brazil, mainly in the Caatinga region. More commonly, inner bark or flowers are traditionally used to treat many painful and inflammatory processes. A common use of this plant is made by macerating a handful of its stem bark in a liter of wine or sugarcane brandy. It is drunk against stomachache, dysenteries, and diarrheas.

Materials and methods

The ethanol extract of Caesalpinia pyramidalis inner bark was used in mice via oral route, at the doses of 10, 30, and 100 mg/kg, in behavioral models of nociception and investigates some of the mechanisms underlying this effect.

Results

The ethanol extract (30 and 100 mg/kg, P<0.001), given orally, produced dose dependent inhibition of acetic acid-induced visceral pain. The ethanol extract also caused significant and dose-dependent inhibition of capsaicin-(100 mg/kg, P<0.001) and glutamate-(10, 30, and 100 mg/kg, P<0.01) induced pain. The antinociception caused by the ethanol extract (30 mg/kg) in the abdominal constriction test was significantly attenuated (P<0.001) by intraperitoneal treatment of mice with l-arginine (600 mg/kg).

Conclusions

Collectively, the present results suggest that the ethanol extract of Caesalpinia pyramidalis produced dose-related antinociception in several models of pain through mechanisms that involved both glutamatergic system and/or the l-arginine–nitric oxide pathway, supporting the folkloric usage of the plant to treat various painful processes.     

Phytochemical study guided by the myorelaxant activity of the crude extract,fractions and constituent from stem bark of Hymenaea courbaril L.

Ethnopharmacological relevance

Hymenaea courbaril L. (Caesalpinoideae) is used in Brazilian folk medicine to treat anemia, kidney problems, sore throat and other dysfunctions of the respiratory system, such as bronchitis and asthma, although such properties are yet to be scientifically validated.

Aim of the study

In order to give a scientific basis to support the traditional use of Hymenaea courbaril, this study was designed to evaluate antioxidant, myorelaxant and anti-inflammatory properties of the ethanol extract from stem bark and its fractions. The myorelaxant effect of astilbin, a flavonoid isolated from the bioactive ethyl acetate fraction (EAF), has also been evaluated.

Material and methods

In the present study ethanol extract from stem bark (EEHC) and fractions were analyzed using bioassay-guided fractionation. The following activities were investigated: antioxidant by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, myorelaxant on rat tracheal smooth muscle, and anti-inflammatory using ovalbumin-induced leukocytosis and airway hyperresponsiveness in rats.

Results

The results of the present investigation show that the whole extract of Hymenaea courbaril and some of its fractions strongly scavenged DPPH radical. The extract showed myorelaxant activity on rat trachea, being EAF its highest efficient fraction. Bio-guided study allowed the isolation of astilbin, a well-known flavonoid. The activity induced by this compound indicates that it may be partly responsible for the myorelaxant effect of EAF. EAF reduced contractions that depended on divalent cation inflow through voltage-operated Ca²⁺ channels (VOCCs) or receptor-operated Ca²⁺ channels (ROCCs), but it was more potent to inhibit VOCC- than ROCC-dependent contraction induced by Ca²⁺ addition in ACh-enriched Ca²⁺-free medium. Oral pretreatment of antigen-challenged animals with EAF prevented airway hyperresponsiveness on KCl-induced contraction and reduced the number of total white cells, particularly eosinophils and neutrophils in bronchoalveolar lavage.

Conclusions

This study provided scientific basis that Hymenaea courbaril presents potential antioxidant, myorelaxant and anti-inflammatory actions, which support its use in folk medicine to treat inflammatory airway diseases.     

Protective effect of ethyl acetate fraction of Acacia ferruginea DC. against ethanol-induced gastric ulcer in rats

Ethnopharmacological relevance

In traditional systems of medicine, stem bark of Acacia ferruginea DC. is used for the treatment of itching, leucoderma, ulcers, stomatitis and diseases of the blood. In the present study, we determined antioxidant and anti-ulcerogenic activities of Acacia ferruginea stem bark.

Materials and methods

Acetone extract and its sub-fractions of Acacia ferruginea stem bark were subjected to assess their antioxidant potential using various in vitro systems such as DPPH^•, ABTS^•+ scavenging, FRAP and phosphomolybdenum reduction activities. Based on the antioxidant potential, the ethyl acetate fraction was used to evaluate the protective effect of ethanol-induced gastric damage in rat model. Enzyme activities such as superoxide dismutase, glutathione, catalase and lipid peroxidation were also determined in the stomach tissues.

Results

Ethyl acetate fraction (AFE) of Acacia ferruginea stem bark registered higher antioxidant and free radical scavenging activities than the crude acetone extract and other fractions. In addition, AFE exhibited that the IC₅₀ values of DPPH (2.5 µg/ml) and ABTS (1.8 µg/ml) were lower when compared to the standard quercetin (12.4 µg/ml and 4.7 µg/ml, respectively). In ethanol induced gastric ulcer, administration of AFE at doses of 10 mg/kg, 50 mg/kg and 100 mg/kg body weight prior to ethanol ingestion significantly protected the stomach ulceration. Consequently significant changes were observed in enzyme activities such as SOD, CAT, GSH and LPO in the stomach tissues when compared with ethanol control group.

Conclusion

It is concluded that the ethyl acetate fraction of Acacia ferruginea stem bark possessed higher antioxidant and anti-ulcerogenic activities. Based on the results, we suggest that Acacia ferruginea stem bark has potential to provide a therapeutic approach to ethanol mediated ulcer as an effective anti-ulcer agent.     

Antidiarrheal and intestinal antiinflammatory activities of a methanolic extract of Qualea parviflora Mart. in experimental models

Ethnopharmacological relevance

An ethnopharmacological survey indicated that the bark from Qualea parviflora Mart. (Vochysiaceae) could be used to treat gastrointestinal disorders, such as diarrhea and intestinal inflammation. The objective of this study was to evaluate the effects of a methanolic extract from the bark of Qualea parviflora (QP) in an experimental model of diarrhea and intestinal inflammation induced in rodents.

Material and methods

The antidiarrheal and antispasmodic effects of QP were investigated by measuring intestinal motility, diarrhea, and intestinal fluid accumulation in rodents after challenging with a cathartic agent. In addition, the effects of QP on the contractility of the isolated mice-ileum preparation were determined. Acute intestinal inflammation was induced in male Wistar rats by the rectal administration of trinitrobenzenesulfonic acid (TNBS) in 50% ethanol (0.25 mL). QP was administered orally (for 5 days) prior to the induction of inflammation. The colonic injury and extent of inflammation were assessed by macroscopic damage scores and lesion length. The enhanced colonic mucosal injury, inflammatory response, and oxidative stress were evaluated by myeloperoxidase (MPO) activity; the tumor necrosis factor alpha (TNF-α), interleukin 1β (IL1-β), and malondialdehyde (MDA) levels; and the glutathione (GSH) content.

Results

Oral treatment with QP (500 mg/kg) delayed the onset of diarrhea, reduced the amount of liquid stool, and decreased the severity of the diarrhea and the evacuation index in rodents challenged with castor oil (p<0.01). Additionally, QP (150–500 µg/mL) demonstrated effective antispasmodic activity against carbachol-induced contractions of mouse ileum in vitro. Oral treatment (25 and 50 mg/kg/day) with QP significantly reduced the intestinal inflammation induced by TNBS in rats (52% and 45%, respectively). Improvement of colonic mucosal injury by treatment with QP was demonstrated by a decrease in MDA levels and an increase in GSH content in colonic tissue. QP also prevented intestinal inflammation as evidenced by reduced cytokine levels (TNF-α and IL1-β) and low MPO activity.

Conclusions

The ethnopharmacological usefulness of the bark from Qualea parviflora against diarrhea containing blood and mucus was supported by the observed antidiarrheal, antispasmodic, and intestinal antiinflammatory properties of this medicinal plant.     

Evaluation of anxiolytic and sedative effects of 80% ethanolic Carica papaya L. (Caricaceae) pulp extract in mice

Ethnopharmacological relevance

Carica papaya has been used in the Ethiopian traditional medicine to relieve stress and other disease conditions.

Aim of the study

The present study was undertaken to evaluate the anxiolytic and sedative effects of 80% ethanolic Carica papaya (Caricaceae) pulp extract in mice.

Materials and methods

Carica papaya pulp extract was screened for anxiolytic effect by using elevated plus maze, staircase and open field tests, and ketamine-induced sleeping time test for sedation at doses of 50, 100, 200, 400 mg/kg. Distilled water and Diazepam were employed as negative and positive control groups, respectively.

Results

Carica papaya pulp extract 100 mg/kg significantly increased the percentage of open arm time and entry, and reduced the percentage of entry and time spent in closed arm in elevated plus maze test; reduced the number of rearing in the staircase test; and increased the time spent and entries in the central squares while the total number of entries into the open field were not significantly affected, suggesting anxiolytic activity without altering locomotor and sedative effects. A synergistic reduction in the number of rearing and an inverted U-shaped dose response curves were obtained with important parameters of anxiety

Conclusions

The results of this study established a support for the traditional usage of Carica papaya as anxiolytic medicinal plant.     

Nigella sativa inhibits intestinal glucose absorption and improves glucose tolerance in rats

Aim of the study

Nigella sativa L. (Ranunculaceae) seeds have been used traditionally for centuries, notably for treating diabetes.

Materials and methods

We studied the effects of the crude aqueous extract of Nigella sativa seeds on intestinal glucose absorption in vitro using a short-circuit current technique and in vivo using an oral glucose tolerance test.

Results

The aqueous extract of Nigella sativa (0.1 pg/ml to 100 ng/ml) exerted dose-dependent inhibition of sodium-dependent glucose transport across isolated rat jejunum. Maximal inhibition exceeded 80% and IC₅₀ was close to 10 pg/ml. An oral glucose tolerance test was carried out in rats after the initial dose and after a 6-week treatment of Nigella sativa (2 g/(kg day)), and compared to metformin (300 mg/(kg day)). Chronic Nigella sativa treatment improved glucose tolerance as efficiently as metformin. Nigella sativa and metformin also reduced body weight without any toxic effect.

Conclusions

To our knowledge, this is the first demonstration that Nigella sativa directly inhibits the electrogenic intestinal absorption of glucose in vitro. Together with the observed improvement of glucose tolerance and body weight in rats after chronic oral administration in vivo, these effects further validate the traditional use of Nigella sativa seeds against diabetes.     

Inhibitory effects of Geijigajakyak-Tang on trinitrobenzene sulfonic acid-induced colitis

Aim of the study

Water extract of Geijigajakyak-Tang (GJT) consisting of five crude drugs [dried root of P. lactiflora Peony (Paeoniaceae), dried trunk bark of C. cassia Blume (Lauraceae), seed of Z. jujube var. inermis Mill (Rhamnaceae), fresh root of Z. officinale Rocoe (Zingiberaceae) and dried trunk bark of G. uralensis Fish (Leguminosae)] is a folk medicine used for the treatment of chronic colitis. This study was designed to further elucidate the effect of GJT on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats.

Materials and methods

GJT orally given to mice before and after TNBS intoxication, and their clinical and morphological changes, myeloperoxidase (MPO) activity and malondialdehyde (MDA) levels in colon tissues, were evaluated on Day 8 post-TNBS. Furthermore, the effect of six major constituents of individual herbs on ileum smooth muscle contraction and neutrophil chemotaxis was studied.

Results

GJT had a significant anti-inflammatory effect based on clinical and morphologic changes, MPO activity and MDA levels in colon tissues as compared with sham control. GJT and 5 major active constituents of individual herbs, paeoniflorin, cinnamaldehyde, jujuboside A, jujubogenin, and diammonium glycyrhhizinate significantly inhibited neutrophil chemotaxis. GJT significantly inhibited muscle contraction (IC₅₀; 2.10 ± 0.11 mg/ml), and 1,8-cineol has the most spasmolytic activity (IC₅₀; 0.10 ± 0.03 mg/ml).

Conclusion

GJT has significant anti-inflammatory effects on TNBS-induced colitis via inhibitions of smooth muscle contraction and neutrophil chemotaxis.     

The effect of the aqueous extract of Helietta parvifolia A. Gray (Rutaceae) stem bark on carrageenan-induced paw oedema and granuloma tissue formation in mice

Aims of study

Despite the ethnopharmacological relevance of Helietta parvifolia A. Gray (Rutaceae) in Mexico, we found no significant pharmacological studies of this plant in the scientific literature. The aim of the present study was to establish the anti-inflammatory effect of an aqueous extract of the stem bark of Helietta parvifolia in mice.

Materials and methods

The anti-inflammatory activity of the aqueous extract of the stem bark of Helietta parvifolia was evaluated using carrageenan-induced paw oedema in mice, and the cotton pellet granuloma method.

Results

An extract dose ranging from 20 to 80 mg/kg p.o. showed a non-significant effect over the initial phase of carrageenan-induced oedema. However, it showed a significant inhibition of oedema after 3 h, which can be related to the inhibition of the release of kinin-like substances. An ID₅₀ value of 47.4 mg/kg was obtained for the plant extract. The extract also suppressed granulomatous tissue formation during chronic inflammation. The inhibitory values were 19.2, and 22.2, corresponding to 40 and 80 mg/kg doses of extract respectively.

Conclusions

Aqueous extract showed a statistically significant anti-inflammatory effect in mice during the late phase of acute inflammation and during chronic inflammation. However, the exact mechanism(s) of anti-inflammatory effects of Helietta parvifolia observed in this study remains unclear.     

Sub-acute toxicity of the chloroformic extract of Rapanea melanophloeos (L.) Mez in rats

Ethnopharmacological relevance

Cape beech (Rapanea melanophloeos) is an important medicinal plant that is widely used in most of Africa. Currently, little toxicological information is available on its safety following prolonged use.

Aim of the study

In this study, we sought to evaluate the oral sub-acute toxicity of Rapanea melanophloeos stem bark chloroformic extract using Sprague Dawley rats.

Materials and methods

Six-week old rats were orally administered with the extract at dosage levels of 100 mg/kg, 300 mg/kg and 1000 mg/kg for 28 days. Clinical signs, hematological and clinical chemistry parameters were monitored, while organ weights and organ pathology were evaluated at the end of the study.

Results

The extract caused a significant reduction in bodyweight at 1000 mg/kg. The hematological profiles of animals at this dose showed an increase in the erythrocyte count and the hematocrit that were accompanied by decrease in the mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. Biochemical parameters were not altered in a dose-related manner when compared to the controls. There were time associated alterations on both hematological and biochemical parameters, but pathological examination did not reveal any treatment related changes in any of the organs.

Conclusion

Our results demonstrate that the chloroformic stem bark extract of Rapanea melanophloeos may be of no toxicological concern at dosage levels up to 1000 mg/kg. Rapanea melanophloeos can therefore be used confidently in African traditional medicine at these or lower dosage levels.     

Antimalarial and safety evaluation of extracts from Toddalia asiatica (L) Lam. (Rutaceae)

Ethnopharmacological relevance

Toddalia asiatica (L) Lam. (Rutaceae) is a medicinal plant traditionally used in Kenya by many communities for the treatment of malaria and other ailments. All parts of the plant are claimed to have medicinal value, but the root bark in particular is believed to be more potent. Decoctions or infusions of the roots are taken orally to treat malaria, fever and stomach ache.

Aim of the study

To evaluate antimalarial activity of aqueous and organic extracts prepared from Toddalia asiatica and determine in vitro and in vivo safety of the extracts.

Materials and methods

Aqueous, ethyl acetate, hexane and methanol extracts were obtained from Toddalia asiatica root bark, fruits and leaves. In vitro antiplasmodial activity was done using chloroquine-sensitive (D6) and chloroquine-resistant (W2) Plasmodium falciparum strains and the concentration causing 50% inhibition of radioisotope incorporation (IC₅₀) was determined. In vivo assay was done by administering mice infected with Plasmodium berghei four consecutive daily doses of the extracts through oral route following Peters 4-Day suppressive test. The percentage suppression of parasitaemia was calculated for each dose level by comparing the parasitaemia in untreated control with those of treated mice. Quinine hydrochloride was used as positive control while double distilled water or 20% Tween-80 was used as a negative control. In vivo acute toxicity was determined in mice using standard procedures. In vitro cytotoxicity assay was carried out using actively dividing sub-confluent Vero cells.

Results

Inhibitory concentrations of ethyl acetate extract of Toddalia asiatica fruits showed high activity against chloroquine resistant (W2) strains of Plasmodium falciparum (IC₅₀=1.87 μg/ml), followed by root bark aqueous extract (IC₅₀=2.43 μg/ml). Tested in vivo against Plasmodium berghei, the fruit ethyl acetate extract (500 mg/kg) and root bark aqueous extract (250 mg/kg) reduced malaria parasitaemia by 81.34% and 56.8% respectively. Higher doses were found to be less effective in vivo. Acute toxicity and cytotoxictiy of the tested extracts, with the exception of hexane extract from the roots, showed LD₅₀>1000 mg/kg and CC₅₀>100 μg/ml respectively.

Conclusions

The results obtained contribute to the validation of traditional use of Toddalia asiatica and provides in vivo and safety data of the plant extracts tested for the first time. Ethyl acetate extract of the fruits was active against chloroquine resistant Plasmodium falciparum as well as against Plasmodium berghei. These findings confirm the suitability of Toddalia asiatica as a good candidate for further tests to obtain a prototype for antimalarial medicine.     

n-Butanol soluble fraction of the water extract of Chinese toon fruit ameliorated focal brain ischemic insult in rats via inhibition of oxidative stress and inflammation

Aim of the study

Toona sinensis Roem. (Meliaceae; Toona sinensis; Chinese toon) is a type of arbor that is widely distributed in Asia. The fruits of Toona sinensis Roem has been traditionally recognized for treatment of cerebrovascular diseases. To evaluate the potential clinical use of the fruits of Toona sinensis Roem, we determined the dose dependence of the neuroprotective efficacy in a focal cerebral ischemic reperfusion model of rats and explored the underlying mechanisms.

Materials and methods

Rats were subjected to occlusion of the middle cerebral artery (MCAO) by a nylon filament and treated with different doses (20 mg/kg and 30 mg/kg) of n-butanol soluble fraction of the water extract of Chinese toon fruit or the vehicle for 1 week before induction of ischemia, s.i.d..

Results

n-Butanol soluble fraction of the water extract of Chinese toon fruit reduced in a dose-dependent manner the ischemia-induced cerebral infarct and edema volume and attenuated neurological deficits observed at 6 h point after ischemia. n-Butanol soluble fraction of the water extract of Chinese toon fruit reduced the levels of nitrate, nitrite, lipid peroxidation, cyclooxygenase-1, thromboxane in post-ischemic brain. n-Butanol soluble fraction of the water extract of Chinese toon fruit adjusted the elevation of the activity of glutathione peroxidase and superoxide dismutase in ischemic brain.

Conclusions

The present study was the first evidence of effectiveness of n-butanol soluble fraction of the water extract of Chinese toon fruit in the rat stroke models, as it reduced infarct volume, inhibited the oxidative stress and inflammation.     

Pharmacological evidence favouring the use of Nauclea latifolia in malaria ethnopharmacy: Effects against nociception,inflammation, and pyrexia in rats and mice

Aim of the study

Nauclea latifolia Smith is used traditionally in the treatment of uncomplicated malaria and painful conditions among its several other applications. The objective of this study is to investigate the pharmacological activities of the plant relevant to the symptomatic treatment of malaria fever and other painful conditions as an initial step towards developing an effective therapy for the symptomatic management of malaria fever and relief of other painful conditions.

Materials and methods

Various concentrations of the aqueous extract of the root bark of this plant were evaluated for its anti-nociceptive, anti-inflammatory and anti-pyretic activities in mice and rats. Investigation of the anti-nociceptive activities was performed using the acetic acid-induced abdominal constriction and hot-plate tests in mice and formalin-induced pain test in rats, as models of nociception. The extract was also investigated for its effect against inflammation induced by egg-albumin and pyrexia induced by yeast in rats.

Results

Our data showed that the aqueous extract of Nauclea latifolia root bark (50–200 mg/kg p.o.) significantly (P < 0.05) attenuated writhing episodes induced by acetic acid and increased the threshold for pain perception in the hot-plate test in mice, dose-dependently. The product also remarkably decreased both the acute and delayed phases of formalin-induced pain in rats and also caused a significant reduction in both yeast-induced pyrexia and egg-albumin-induced oedema in rats. These effects were produced in a dose-dependent manner.

Conclusion

The results suggest the presence of biologically active principles in the extract with anti-nociceptive, anti-inflammatory and anti-pyretic activities that justifies its use in malaria ethnopharmacy and subsequent development for clinical application.     

In vitro and in vivo anti-Helicobacter pylori activity of Calophyllum brasiliense Camb.

Aims of the study

Calophyllum brasiliense (Camb.) is a medicinal tree that grows particularly in the hilly and forested regions of Brazil. Preparations from its stem bark are popular remedies for the treatment of chronic ulcers. Since earlier investigations on bark extracts evidenced gastroprotective and gastric acid inhibitory properties, this study evaluated the effects of hydroethanolic extract (HEECb) and the dichloromethanic fraction (DCMF), from Calophyllum brasiliense stem bark, against Helicobacter pylori, in vitro and in vivo.

Materials and methods

The in vitro assays were performed using the disk diffusion and broth microdilution methods to determine the minimum inhibitory concentration (MIC) values. The test substances were evaluated in vivo taking into account the delay in the gastric ulcer healing in Wistar rats, infected with Helicobacter pylori.

Results

DCMF appeared the most active and potent in vitro against Helicobacter pylori growth with an MIC of 31 μg/mL. In the in vivo assays, rats ulcerated by acetic acid, and inoculated with Helicobacter pylori showed a marked delay in ulcer healing. Treatment with HEECb (50, 100 and 200 mg/kg) and DCMF (100 and 200 mg/kg) reduced the ulcerated area in a dose-dependent manner. While DCMF, at 200 mg/kg, increased the prostaglandin E₂ (PGE₂) level, both HEECb and DCMF decreased the number of urease-positive animals, as confirmed by the reduction of Helicobacter pylori presence in histopathological analysis.

Conclusion

The results suggest that the antiulcer activity of Calophyllum brasiliense is due, in part, to its anti-Helicobacter pylori action, validating the popular use of this species.     

Anti-inflammatory, anti-hyperalgesic, antiplatelet and antiulcer activities of Byrsonima japurensis A. Juss. (Malpighiaceae)

Ethnopharmacological relevance

Decoctions or infusions of the stem bark of Byrsonima japurensis A. Juss. (Malpighiaceae) are widely used as an anti-inflammatory drug in folk medicine of Amazonas State (Brazil).

Aim of the study

To evaluate the pharmacological potential of an aqueous extract of the stem bark of Byrsonima japurensis (BJEA) to scientifically verify of its traditional use.

Materials and methods

Anti-inflammatory, antihyperalgesic and antiulcer activities were evaluated in Wistar rats, a Hippocratic screening was performed in Swiss mice to evaluate the toxic effects, and antiplatelet evaluation was performed in human platelet rich plasma assay. Additionally, antioxidant activity was evaluated by superoxide radical scavenging method and β-carotene bleaching test.

Results

Anti-inflammatory, antihyperalgesic and gastroprotective activities were observed in rats treated orally with different doses of BJEA. While signals of toxicity were observed in the mice treated with a very high dose of extract (5000 mg/kg), no death occurred. BJEA also showed expressive antiplatelet and antioxidant activities in vitro.

Conclusion

According to our results, it was concluded that stem bark of Byrsonima japurensis has significant and safe anti-inflammatory activity, which is closely related with their potent antioxidant activity, supporting the folk medicinal use of this species.     

Antidiabetic activity of Ficus amplissima Smith. bark extract in streptozotocin induced diabetic rats

Ethnopharmacological relevance

Ficus amplissima commonly known as kal-itchchi have a long history of use in Ayurveda, Siddha and Unani herbal preparations in Indian traditional system of medicine. It has been used in folklore medicine for the treatment of diabetes.

Aim

The aim of the present study was to evaluate the effect of methanolic extract of the bark of Ficus amplissima (FAB) in streptozotocin-induced diabetic rats.

Materials and methods

Oral administration of FAB bark at the doses of 50 mg/kg, 100 mg/kg and 150 mg/kg was studied in normal, glucose-loaded and STZ—induced diabetic rats.

Results

The three doses caused significant reduction in blood glucose levels in all the models. The effect was more pronounced in 50 mg/kg and 100 mg/kg than 150 mg/kg. FAB also showed significant increase in serum insulin and body weight. The glycogen content in liver, skeletal muscle, total protein contents were markedly increased and marker enzymes of hepatic function of STZ-induced diabetic rats while there was significant reduction in the levels of serum triglyceride and total cholesterol. FAB also showed significant anti-lipid peroxidative effect in the pancreas of STZ-induced diabetic rats. The anti-diabetic effect of FAB was compared with glibenclamide, a well known hypoglycemic drug. Histological analysis showed the regenerative effect of FAB on the β-cells of diabetic rats.

Conclusion

Results of this experimental study indicated that FAB possessed anti-diabetic and antioxidant activities. Hence it could be used as a natural source of antidiabetic (Type-I) and antioxidant drug.     

Antiprotozoal screening and cytotoxicity of extracts and fractions from the leaves,stem bark and root bark of Alstonia congensis

Ethnopharmacological relevance

To evaluate the antiprotozoal activity and cytotoxicity of extracts and fractions from the leaves, root bark and stem bark of Alstonia congensis (Apocynaceae), used in traditional medicine against parasitic diseases.

Materials and methods

The aqueous and 80% MeOH extracts, and a series of fractions and subfractions from the leaves, stem and root bark of Alstonia congensis were tested in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, Trypanosoma cruzi, Lesihamania infantum and the chloroquine and pyrimethamine-resistant K1 strain of Plasmodium falciparum. Their cytotoxicity on MRC-5 cells (human lung fibroblasts) was evaluated as well.

Results

The aqueous and 80% MeOH extracts and a series of subfractions of each plant part exhibited pronounced antiprotozoal activity against the K1 strain of Plasmodium falciparum with IC₅₀ values ranging from 2 to 5 µg/ml, and good activity against Trypanosoma brucei brucei and Trypanosoma cruzi with IC₅₀ values ranging between 5 and 10 µg/ml. The residual 80% MeOH extract from the leaves, and the total alkaloid extract from stem and root bark were the only subfractions active against Leishmania infantum with IC₅₀ values <10 µg/ml. None of the samples from the root bark was cytotoxic against MRC-cell lines (CC₅₀>64 µg/ml). In general, the aqueous extract (traditional decoction) showed the highest selectivity, especially against Plasmodium falciparum.

Conclusion

These results can partly support and justify the traditional use of these plant parts of Alstonina congensis as raw materials for the preparation of traditional remedies to treat parasitic diseases such as malaria and trypanosomiasis.