In vitro antiplasmodial activity of indole alkaloids from the stem bark of Geissospermum vellosii

Ethnopharmacological relevance

The stem bark of Geissospermum vellosii has been traditionally used by the native population of northern South America to treat malaria. Indole alkaloids have been previously isolated from this plant, but the antiplasmodial constituents have not yet been described. As part of our ongoing investigations of new bioactive compounds with activity against malaria parasites, we tested the in vitro antiplasmodial activity of isolated fractions and purified alkaloids from Geissospermum vellosii.

Materials and methods

Indole alkaloids were isolated and identified from a methanolic crude extract of Geissospermum vellosii bark using a combination of high performance counter current chromatography, mass spectrometry and nuclear magnetic resonance technologies. The methanolic extract, the crude alkaloid fractions and the purified compounds were tested for in vitro antiplasmodial activity against the chloroquine-sensitive strain of Plasmodium falciparum (D10).

Results

An indole alkaloid (4) along with four known indole alkaloids, geissolosimine (1), geissospermine (2), geissoschizoline (3), and vellosiminol (5) were isolated and structure elucidated. The antiplasmodial activity (IC₅₀) of the methanolic crude extract was 2.22 μg/mL, while for the isolated compounds it ranged from 0.96 μM to 13.96 μM except for (5) which showed a low activity (157 μM). Geissolosimine (1) showed the highest antiplasmodial activity (0.96 μM).

Conclusions

This study provides evidence to support the use of Geissospermum vellosii as an antimalarial agent, as used by the native populations. Geissolosimine (1) is a lead molecular structure for possible antimalarial drug development.     

Acute and subchronic oral toxicity assessment of the aqueous extract from the stem bark of Erythrina senegalensis DC (Fabaceae) in rodents

Aim of the study

The decoction of the stem bark of Erythrina senegalensis (EAES) is traditionally used in the Western region of Cameroon against liver disorders. The present study evaluated the potential toxicity of this decoction after acute and sub-chronic administration in rodents.

Materials and methods

In acute study, a single administration of EAES was given orally to mice at doses ranging from 1.25 to 12.5 g/kg. General behaviour, adverse effects and mortality were determined for up to 14 days post treatment. In the sub-chronic study, EAES was given orally as a single administration to Wistar rats at doses of 300, 600 and 1200 mg/kg/day for 28 days. Animal body weight was observed throughout the experimental period while haematological and biochemical parameters of blood and urine, as well as kidney and liver tissues histology were evaluated at the end of the experiment.

Results

In the acute study in mice, none of the doses used induced mortality or significant behavioural changes. In the sub-chronic study in rats, daily oral administration of EAES at the dose of 600 mg/kg resulted in a significant increase in the relative body weight at the last week of treatment. The relative weights of organs were not affected by the treatment. No haematological changes were observed a part of a significant increase in WBC count at the dose of 600 mg/kg. Serum AST, ALT, ALP, total protein, total cholesterol and triglycerides decreased significantly while total and conjugated bilirubin significantly increased. Renal function indices assay in blood showed significant modification in all the treated groups compared to control while, in urine, only urea excretion markedly reduced at a dose of 1200 mg/kg. Histological analysis did no show any liver or kidney alteration.

Conclusion

These results demonstrated that there is a wide margin of safety for the therapeutic use of EAES and further corroborated the traditional use of this extract as a hepatoprotective agent.     

Acute and sub-chronic oral toxicity studies of an aqueous stem bark extract of Pterocarpus soyauxii Taub (Papilionaceae) in rodents

Pterocarpus soyauxii Taub (Papilionaceae) is used in Cameroonian traditional medicine and pharmacopoeia to treat hypertension, diabetes, gastrointestinal parasitizes and cutaneous diseases.

Aim of the study

The present investigation was carried out to evaluate the safety of an aqueous stem bark extract of Pterocarpus soyauxii by determining toxicity after acute and sub-chronic oral administration in male and female rodents.

Materials and methods

The acute toxicity test was conducted in mice. An aqueous extract of barks was administrated by gavage in single doses of 2.5-12.5 g/kg. General behaviour and mortality were examined for up to 7 days. The sub-chronic toxicity test was performed in rats. The plant extract was administered by daily gavage of 150-600 mg/kg for 42 days. Body weight, food and water intakes were followed weekly. Haematological, biochemical and organ parameters were determined at the end of the 42-day administration.

Results

In the acute study in mice, oral administration of the aqueous extract of Pterocarpus soyauxii caused dose-dependent general behaviour adverse effects and mortality. The no-observed adverse effect level (NOAEL) of the extract was 5.0 g/kg. The lowest-observed adverse effect level (LOAEL) was 7.5 mg/kg. Mortality increased with the dose, LD₅₀ was > 10.75 g/kg for the mouse. In the sub-chronic study in rats, daily oral administration of the aqueous extract of Pterocarpus soyauxii did not result in death or significant changes in haematological or biochemical parameters, excepted increased hepatic catalase activity (P < 0.05) at the dose of 600 mg/kg. No alteration was observed in body weight, food and water intake. Liver, kidney, lung and pancreas histopathology did not reveal morphological alteration.

Conclusions

The results showed that the aqueous stem bark extract of Pterocarpus soyauxii Taub had very low toxicity in oral acute high dose administration and no toxicity in oral sub-chronic low dose administration and indicate that the plant could be considered safe for oral medication.     

Further studies on the antinociceptive action of aqueous seed extract of Aframomum melegueta

This study presents the results of further investigations on the antinociceptive profiles of an aqueous seed extract of Aframomum melegueta in rodents. The antinociceptive activity of the intraperitonal doses of 25-100 mg/kg of Aframomum melegueta was assessed using the formalin-induced paw licking, Randall-Selitto paw pressure and hot plate models of pain. The extract was found to produce a significant dose-dependent inhibition of the inflammatory but not the neurogenic pains associated with the formalin test. In the Randall-Sellito paw pressure test, the extract significantly reduced the nociceptive responses elicited by compression of inflamed hind paw of rats in a dose-related manner. However, Aframomum melegueta did not alter the pain threshold in non-inflamed paw and also failed to prolong the reaction time of the animals to noxious heat in the hot plate test. Taken together, these findings suggest that the aqueous seed extract of Aframomum melegueta possess peripheral analgesic activity.     

Acute and chronic toxicity of the aqueous extract of Artemisia afra in rodents

Artemisia afra (Jacq. Ex. Willd), "African Wormwood" is widely used traditionally in South Africa with no literature evidence substantiating its safety. The aim of this study was to investigate the safety of the aqueous extract of Artemisia afra by determining its pharmaco-toxicological effects after acute and chronic administration in mice and rats, respectively. The aqueous extract mimicked the traditional decoction dosage form of Artemisia afra. In mice, single intraperitoneal injections of Artemisia afra-extract (1.5-5.5g/kg) induced a regular dose-dependent increase in the death rate and incidence of general behaviour adverse effects, while with single oral doses (2-24g/kg) the increases in incidence of general behaviour adverse effects and mortality rate were dose-independent. The LD(50s) after acute intraperitoneal and oral doses were 2.45 and 8.96g/kg, respectively. Rats given oral doses of Artemisia afra-extract (0.1 or 1g/kg/day) survived the 3 months of dosing (i.e. LD(50) much higher than 1g/kg), experienced no significant changes in general behaviour and haematological and biochemical parameters, except for transient decrease in AST activity. No significant changes were observed in organ weights, and histopathological results showed normal profile suggesting no morphological alterations. Collectively, the results indicate that Artemisia afra-extract is non-toxic when given acutely, has low chronic toxicity potential and, in high doses, may have a hepatoprotective effect.     

Antidiarrheal activity of Pyrenacantha staudtii Engl. (Icacinaceae) aqueous leaf extract in rodents

Ethnopharmacological relervance

Pyrenacantha staudtii Engl. (Icacinaceae) is a plant which is traditionally used for the treatment of blemnorrhea, hernia, insomnia, intestinal pain and diarrhea in Nigeria. Therefore the core aim of the present study is to evaluate antidiarrheal activity of Pyrenacantha staudtii aqueous extract (PSE).

Materials and methods

The antidiarrheal activity was evaluated using castor oil-induced diarrhea method. The effects of Pyrenacantha staudtii aqueous extract on gastrointestinal motility, intestinal transit and enteropooling were also examined in rodents. The acute toxicity effect of the aqueous extract of Pyrenacantha staudtii was also investigated.

Results

Pyrenacantha staudtii aqueous extract (PSE, 100-400 mg/kg, p.o.) produced dose-dependent and significant (P < 0.05-0.01) protection of rats and mice against castor oil-induced diarrhea, inhibited intestinal transit, and delayed gastric emptying. PSE, produced dose-dependent and significant (P < 0.05-0.01) antimotility effect, caused dose-related inhibition of castor-oil-induced enteropooling in animals, comparable to atropine (1 mg/kg, p.o.). Like loperamide (10 mg/kg, p.o.), PSE, dose-dependently and significantly (P < 0.05-0.01) delayed the onset of castor-oil induced diarrhea, decreased the frequency of defecation, and reduced the severity of diarrhea in the rodents. Compared with control animals, PSE, dose-dependently and significantly (P < 0.05-0.01) decreased the volume of castor oil-induced intestinal fluid secretion, and reduced the number, weight and wetness of fecal droppings.

Conclusion

The findings of this study indicate that PSE possesses antidiarrheal property in rats and mice. These findings confirm the ethnomedicinal use of Pyrenacantha staudtii leaf as a valuable natural remedy for the treatment, management and/or control of diarrhea.     

Acute and sub-acute toxicity of the methanolic extract of Pteleopsis hylodendron stem bark

Ethnopharmacological relevance

Pteleopsis hylodendron is one of the most popular medicinal plants in Cameroon where it is used to treat measles, chickenpox, sexually transmitted diseases, female sterility, liver and kidney disorders as well as dropsy. To date there is no documented evidence corroborating its safety. This study thus aimed to determine the toxicity profile of the methanolic extract of Pteleopsis hylodendron.

Materials and Methods

The acute and sub-chronic toxicity of the methanolic extract of Pteleopsis hylodendron were investigated by employing established methods. The acute toxicity study was done by administering single doses (2-8 g/kg body weight) of plant extract to adult mice. For the sub chronic toxicity study, doses (85-680 mg/kg bw) of plant extract were administered daily to adult rats during 28 days after which the effect on organs, the hematological and biochemical parameters was assessed.

Results

In mice, single oral administrations of the methanolic extract of Pteleopsis hylodendron caused dose-dependent general behaviour adverse effects and mortality. The LD50 values were 3.00 and 3.60 g/kg bw for males and females respectively. In rats, daily single oral doses of the methanolic extract of Pteleopsis hylodendron provoked significant (p < 0.05) growth retardation in rats at all tested doses after 28 days of dosing. Haematological parameters showed a significant decrease in white blood cells count and significant increases red blood cells count; irrespective of the sex, all biochemical parameters studied, except triglycerides significantly (p < 0.001) increased with dose. However, a dose-dependent significant (p < 0.007) increase in HDL was observed only in male rats. Increases in liver enzymes (ALT and AST), proteins and creatinine levels correlate the observed histopathological damages (i.e. inflammation and vascular congestions) in the liver and kidneys.

Conclusions

The overall results of this study indicate that the methanolic extract of Pteleopsis hylodendron stem bark possesses hepatotoxic and nephrotoxic effects at doses ≥85 mg/kg bw, suggesting that this plant should be used with caution.     

In vivo analgesic activity,toxicity and phytochemical screening of the hydroalcoholic extract from the leaves of Psidium cattleianum Sabine

Ethnopharmacological relevance

Psidium cattleianum Sabine is extensively used in Brazilian traditional medicine to treat several diseases including painful disorders. Aim of the study to investigate the toxicity and the possible analgesic activities of the hydroalcoholic extract from the leaves of Psidium cattleianum Sabine (ELPCS), to support its use in folk medicine. To screen the major phytochemical constituents of this extract and evaluate their antioxidant activity.

Materials and methods

ELPCS was assessed for its antioxidant activity using the DPPH model. Its analgesic activity was examined using mouse models of acetic acid-induced writhing and hot plate paw licking models. The major phytochemical constituents of the extract were screened; their toxicity on LLC-MK2 mammalian cells was evaluated.

Results

ELPCS exhibited significant peripheral analgesic activity at doses of 60, 80, 100, 200 and 400 mg/kg in mice, but it did not display central analgesic activity and not was toxic to LLC-MK2 cell (LD₅₀>400 µg/mL). The extract exhibited free radical scavenging activity as evidenced by IC₅₀ values (15.9 µg/mL) obtained by the DPPH method. Phytochemical screening detected flavonoids, saponins, cardiac glycosides, anthraquinones, and tannins.

Conclusions

The results of the experimental studies proved the analgesic activity of ELPCS and supported the traditional use of this plant.     

Anti-diarrhoeal activity of the aqueous extract of Mezoneuron benthamianum Baill (Caesalpiniaceae)

The effect of the aqueous extract of Mezoneuron benthamianum (MB) on experimentally induced diarrhoea, intestinal propulsive movement (IPM) and intestinal fluid accumulation (enteropooling) were investigated in rats and mice. The extract (400, 800 and 1600 mg/kg, orally) produced a significant (p<0.05) and dose-dependent reduction in propulsion in the castor oil-induced intestinal transit in mice. The mean peristaltic index (%) for these doses of extract, control, (distilled water, 10 ml/kg, p.o.) and morphine, (10 mg/kg, s.c.) were 73.48, 69.34, 57.27, 89.93 and 31.56, respectively. The effect of the extract at the highest dose was significantly (p<0.05) lower than that of the standard drug. This effect was antagonised by yohimbine (1mg/kg, s.c.). In a dose-dependent manner, the extract delayed the onset of diarrhoea, produced a significant decrease in the frequency of defaecation, severity of diarrhoea and protected the mice treated with castor oil. Total diarrhoea scores were 12.0+/-0.63, 10.3+/-2.06, 8.5+/-2.15, 7.1+/-0.91 and 5.8+/-0.79 for control, extract (400, 800 and 1600 mg/kg) and morphine, respectively. The extract significantly decreased the volume (ml) of intestinal fluid secretion induced by castor oil (1.75+/-0.02 to 0.93+/-0.04) compared with 1.90+/-0.05 for control. The inhibitory effect on fluid accumulation by the extract was also attenuated by yohimbine (1.0 mg/kg). Preliminary phytochemical screening revealed the presence of flavonoids, tannins, cardiac glycosides, anthraquinones and saponins. Administration of the extract up to 2 g/kg (orally) did not produce any toxic effect in the acute toxicity studies in mice. The LD(50) of the extract when given intraperitoneally was 1021.31 mg/kg. The results obtained show that MB possesses anti-diarrhoeal activity due to its inhibitory effects on gastrointestinal propulsion and intestinal fluid accumulation. The antagonistic actions of yohimbine in the experiments suggest a role for the a(2)-adrenergic receptor system.     

Anti-inflammatory and analgesic activity of aqueous extract of Flos populi

Ethnopharmacological relevance

Flos populi is an important traditional Chinese medicine prepared from the male inflorescence of Populus tomentosa Carr. or Populus canadensis Moench (Salicaceae family). Flos populi is mainly used for the treatment of various inflammatory diseases and anti diarrhea in East Asian countries. The objective of this study was to investigate the anti-inflammatory and analgesic properties of the aqueous extract of Flos populi (FPAE).

Materials and methods

Cotton pellets-induced granuloma, carrageenan-induced paw oedema, arachidonic acid-induced right ear oedema and xylene-induced ear oedema were used to assess anti-inflammatory activity of FPAE and analgesic activity was evaluated by hot plate test, acetic acid-induced abdominal writhing test and formalin test.

Results

FPAE produced significant dose–response anti-inflammatory activity against cotton pellets-induced granuloma. FPAE at dosages of 50, 100 and 200 mg/kg b w. significantly reduced carrageenan-induced paw edema by 48.84% (P<0.05), 54.95% (P<0.05), and 62.05% (P<0.05) at 5 h after carrageenan injection, respectively. FPAE significantly (P<0.05) reduced the ear oedema induced by arachidonic acid and peaked at the dose of 200 mg/kg b w. (40.78%). A significant (P<0.05) dose dependent inhibition of xylene-induced oedema was produced by FPAE and peaked at the highest dose of 200 mg/kg b w. (23.95%). FPAE (50, 100 and 200 mg/kg b w.) produced significant dose–response analgesic activity in the hot-plate test. However, the low percentage inhibition (<50%) suggests that it is not a centrally acting analgesic. Extract at dosages of 50, 100 and 200 mg/kg b w., p.o. significantly reduced acetic acid-induced writhing by 39.6% (P<0.05), 45.4% (P<0.05), and 51.8% (P<0.05), respectively. The extract also caused marked dose-dependent inhibition of formalin-induced pain in the second phase (P<0.05).

Conclusion

The findings in this study suggest that the aqueous extract of Flos populi possesses anti-inflammatory and analgesic activities. These results may support the fact that this plant is used traditionally to cure inflammatory diseases.     

Teratogenic effects, acute and sub chronic toxicity of the leaf aqueous extract of Ocimum suave Wild (Lamiaceae) in rats

The aqueous extract from the leaves of Ocimum suave was evaluated for acute and sub chronic toxicity and teratogenic effects. Swiss mice were administered single oral doses of 2000, 4000, 6000 and 8000 mg/kg and monitored for death and body weight gained for 7 days (acute toxicity). In sub-acute toxicity, experimental rats, received daily doses of 250, 500 and 1000 mg/kg for 42 consecutive days and the toxic effects were assessed using biochemical and haematological data and histology of vital organs. In a teratogenic study, 1-day pregnant rats were administered orally 500 and 1000 mg/kg of extract daily for 21 consecutive days and 14th day corpora lutea and foetal implants and litter size at birth were noted. Reproductive performance of F(1) generation rats was studied by crossing them at maturity and recording the number, birth weight and physical presentation of the young offspring. Acute intake of extract up to 8000 mg/kg did not produce mortality or significant changes in general behaviour. Sub chronic treatment did not show any change in body and organ weights, feeding habits or behaviour between the control and the treated groups of both sexes. Haematological analysis and blood biochemistry revealed no toxicity effects of the extract. No gross abnormalities or histological changes were observed. Teratogenic and fertility studies did not reveal any toxic manifestations or foetal abnormalities. The leaf aqueous extract of Ocimum suave is non toxic in acute and sub chronic intake.     

Acute and sub-chronic oral toxicity profiles of the aqueous extract of Polygala fruticosa in female mice and rats

Polygala fruticosa (P.J. Bergius) is one of the most popular medicinal plants in South Africa but to date there is no documented evidence corroborating its safety. This study thus aimed to determine the toxicity profile of the aqueous extract of Polygala fruticosa by determining its effects after acute and sub-chronic oral administration in female mice and rats, respectively. In adult mice, single oral administrations of the aqueous extract of Polygala fruticosa (2–20 g/kg body weight) induced an increase in the incidence of general behavioural adverse effects. The mortality rate also increases with increasing dosage (LD₅₀ = 10.8 g/kg). In rats, daily single oral doses of Polygala fruticosa aqueous extract (0.1 and 1 g/kg) were well tolerated behaviourally after 31 days of dosing (LD₅₀ much higher than 1 g/kg) and induced no significant changes in body and organs weights. However, haematological and biochemical parameters showed a significant decrease in platelet count and significant increases in ALT, AST and creatinine levels suggesting disturbances of haemopoiesis, liver and kidney functions.     

Antinociceptive and anti-inflammatory effects of Thespesia populnea bark extract

The ethanolic extract of Thespesia populnea bark (TPE) was investigated for anti-inflammatory and analgesic activity at the doses (p.o.) of 100, 200 and 400mg/kg body weight. For evaluation of inflammation carrageenan-, histamine- and serotonin-induced paw edema served as acute models and formaldehyde-induced arthritis served as a chronic model in rats. The acetic acid-induced writhing response and formalin-induced paw licking time in the early and late phases of mice were used to assess analgesic activity. The higher doses of TPE (200 and 400mg/kg, p.o.) were inhibiting carrageenan, histamine and serotonin-induced paw edema as well as formaldehyde-induced arthritis successfully. In addition, TPE (200 and 400mg/kg, p.o.) significantly attenuated the writhing responses induced by an intraperitoneal injection of acetic acid and late phase of pain response induced by an subplantar injection of formalin in mice. Furthermore, our phytochemical studies indicated that the ethanolic extract of bark contains alkaloids, carbohydrates, protein, tannins, phenols, flavonoids, gums and mucilage, saponins and terpenes. From acute oral toxicity studies (OECD-423 guidelines), no mortality was observed even at highest dose of TPE (2000mg/kg, p.o.).     

In vivo antiulcer activity of the aqueous extract of Bauhinia purpurea leaf

Ethnopharmacological relevance

Bauhinia purpurea (Fabaceae) is a medicinal plant traditionally used to treat various ailments, including ulcers. In order to establish pharmacological properties of the leaf of Bauhinia purpurea, studies were performed on antiulcer activity of the plant's aqueous extract.

Materials and methods

The Bauhinia purpurea aqueous extract (BPAE) was prepared in the doses of 100, 500 and 1000 mg/kg. Antiulcer activity of BPAE was evaluated by absolute ethanol- and indomethacin-induced gastric ulcer, and pyloric ligation models. Acute toxicity was also carried out.

Results

BPAE, at the dose of 5000 mg/kg, did not cause any signs of toxicity to rats when given orally. Oral administration of BPAE exhibited antiulcer activity (p < 0.05) in all models used. However, the dose-dependent activity was observed only in the absolute ethanol-induced gastric ulcer model. Histological studies supported the observed antiulcer activity of BPAE. In pyloric ligation assay, BPAE increased the gastric wall mucus secretion.

Conclusions

The BPAE exhibits antiulcer activity, which could be due to the presence of saponins or sugar-free polyphenols, and, thus, confirmed the traditional uses of Bauhinia purpurea in the treatment of ulcers.     

Evaluation of antinociceptive activity of Casearia sylvestris and possible mechanism of action

The antinociceptive properties of Casearia sylvestris Sw. (Flacourtiaceae) were investigated in various models of pain-related behavior in mice. The hydroalcoholic crude extract of the plant (30-300mg/kg, per os) clearly inhibited nocifensive responses induced by ovalbumin (hindpaw licking) or acetic acid (writhes) in graded fashion. At 300mg/kg, the extract reduced nocifensive behaviors (from 71.1+/-13.3 to 14.8+/-9.3s; from 31.3+/-4.5 to 3.3+/-1.2 writhes, respectively) to similar extents as indomethacin (5mg/kg; 5.7+/-1.1s and 3.3+/-1.2 writhes, respectively). Significant antinociceptive effects in the hot plate test were only detected following administration of the highest extract dose, but this analgesic action appeared to be specific as the extract failed to change motor and exploratory activities. The antinociceptive effect of Casearia sylvestris extract in the acetic acid test was prevented by prior treatment with the non-selective opioid receptor antagonist naloxone (1mg/kg; 5.8+/-4.2 and 31.5+/-3.1 writhes in vehicle-treated and naloxone-treated groups, respectively), indicating that the endogenous opioid system is involved in its analgesic mechanism of action. Thus, our investigation suggests a potential therapeutic benefit of Casearia sylvestris Sw. in treating conditions associated with inflammatory pain.     

Antinociceptive activity of aqueous extract and isolated compounds of Lithrea molleoides

Ethnopharmacological relevance

Lithrea molleoides (Vell.) Engl. (Anacardiaceae) is a medicinal plant commonly used in traditional medicine in South America.

Aim of the study

In the present study, the in vivo antinociceptive effect of L. molleoides' aqueous extract and its isolated compounds has been investigated.

Materials and Methods

Antinociceptive activity was evaluated through writhing, formalin and hot plate tests in mice. The phytochemical analysis was performed.

Results

The extract produced significant inhibition on nociception induced by acetic acid (ED50: 8.7 mg/kg, i.p.) and formalin (ED50: 7.7 mg/kg, i.p.) administered intraperitoneally and also orally. Yohimbine diminished the activity of the extract in the acetic acid test meanwhile haloperidol enhanced its effect. Two majority compounds, shikimic and vanillic acid were active in chemical nociceptive models used in this work, producing the highest inhibition of the writhing response at a dose of 30 mg/kg i.p. (55.4% and 57.1%, respectively) meanwhile at 100 mg/kg p.o. produced a slight response (23.3% and 23.9%, respectively).

Conclusions

These results suggest that L. molleoides' aqueous extract produced antinociception possibly related to the presence of shikimic and vanillic acid. The adrenergic and dopaminergic systems seem to be involved in the mechanism of antinociception of the extract.     

Aqueous root extracts from Mimosa albida Humb. & Bonpl. ex Willd display antinociceptive activity in mice

Ethnopharmacological relevance

In this work, we study whether aqueous extracts from the roots of Mimosa albida Humb. & Bonpl. ex Willd, a plant known in the Highlands of Chiapas, Mexico as “Lotóm chíx” are endowed with both antinociceptive and anxiolytic effects.

Materials and methods

ICR mice were systemically treated with aqueous extracts from Mimosa albida and the reference compounds (diazepam, dipyrone and/or fentanyl) and their behavior was evaluated in several behavioral tests.

Results

Administration of aqueous extracts from the roots of Mimosa albida resulted in a reduction of the nociception elicited in mice by both the hot plate (12.5, 25 and 50 mg/kg; i.p.) and the acetic acid-induced writhing (25 and 50 mg/kg; i.p.) tests. No effects were however observed both in the elevated plus-maze and hole board test (3.2, 12.5 and 25 mg/kg; i.p.). In contrast, both locomotion (open field test) and motor coordination (rotarod test) were affected at doses (50, 100 y 200 mg/kg; i.p.) higher than those having antinociceptive effects.

Conclusion

These data suggest that in mice the systemic administration of low doses of aqueous extracts from the roots of Mimosa albida results in antinociceptive effects in several models of pain through mechanisms that do not involve the opioid system pathway. These results support the ethnopharmacological use of Mimosa albida in popular medicine.     

Anti-anaemic potentials of aqueous extract of Sorghum bicolor (L.) moench stem bark in rats

The effects of oral administration of aqueous extract of Sorghum bicolor (L.) Moench stem bark at the doses of 200, 400 and 800 mg/kg body weight on iron sufficient and iron deficient weaning rats were investigated. Weaning rats of 21 days old were maintained on iron sufficient and iron deficient diets for 6 weeks before the administration of the aqueous extract of Sorghum bicolor stem bark at various doses for 7 days. Proximate analysis of the iron sufficient and iron deficient diets showed that they were similar except in the amount of iron. Phytochemical screening of the extract revealed the presence of alkaloids and saponins. Extract administration produced significant increase in haemoglobin, packed cell volume and red blood cells in iron sufficient and iron deficient groups (P < 0.05). There was also significant increase (P < 0.05) in the catalase activity of the rat liver and kidney without any significant change (P > 0.05) in the serum catalase activity. The results revealed that extract administration has restored the anaemic condition in the iron deficient group and thus lend credence to its use in folklore medicine in the management of anaemia.     

Anti-inflammatory and antinociceptive activities of extract, fractions and populnoic acid from bark wood of Austroplenckia populnea

Austroplenckia populnea (Reiss) Lund is a Brazilian plant from "cerrado", which belongs to Celastraceae family, popularity know as "marmelinho-do campo, mangabeira-brava, mangabarana, vime and maria-mole". This plant is used in folk medicine to treat dysenteries and inflammatory disorders, such as rheumatism. Austroplenckia populnea bark hydroalcoholic crude extract, and its hexane, chloroform and ethyl acetate fractions, obtained by partition, as well as the isolated populnoic acid were investigated for their anti-inflammatory (carrageenan, dextran and histamine-induced rat paw oedema, histamine-induced increase in vascular permeability, and granulomatous tissue induction) and analgesic activities (writhing and hot plate tests). The ED(50) (oral) of the crude extract for the inhibition of carragenan-induced rat paw oedema assay was determined to be 200 mg/kg, which was also used in the assays with the extract and its fractions in all other experiments. Populnoic acid was administered in the dose of 50 mg/kg. Crude extract, hexane and chloroform fractions (200 mg/kg), and indomethacin (10 mg/kg) inhibited significantly (p<0.05) the formation of the carrageenan-induced rat paw oedema, measured in third hour of experiment (peak of oedema formation) by 43.2%, 37.3%, 31.1% and 59.3%, respectively. There was a significant reduction (p<0.05) in dextran-induced rat paw oedema in all groups, while in the assay using histamine as the oedematogenic agent, only the groups treated with populnoic acid (50 mg/kg) and cyproheptadine (10 mg/kg) displayed significant reduction (p<0.05). The populnoic acid and cyproheptadine reduced the peak of oedema formation (1st hour) by 41.3% and 34.7%, respectively. Only for the groups treated with populnoic acid (50 mg/kg) and cyproheptadine (10 mg/kg) it was observed a significant (p<0.05) reduction in histamine-induced increase in vascular permeability (44.8% and 80.3%, respectively). Granulomatous tissue formation was significantly inhibited (p<0.05) by both hexane fraction (46.0%) and dexamethasone (66.2%). In the analgesic assays, the crude extract and its hexane and chloroform fractions, as well as indomethacin diminished significantly the number of writhings (p<0.05) by 69.6%, 47.2%, 44.8% and 62.8%, respectively. On the other hand, none assayed sample displayed significant result in the hot plate test. Based on the obtained results it is suggested that extracts of Austroplenckia populnea bark and populnoic acid display anti-inflammatory activity, supporting its folkloric use to treat inflammatory disorders.     

Characterization of the antinociceptive and anti-inflammatory activities from Cocos nucifera L. (Palmae)

Aim of the study

Cocos nucifera cultivated in Brazil is known as “coco-da-Bahia” or “coqueiro-da-Índia”. The tea from the husk fiber is widely used to several inflammatory disorders. Crude extract and fractions obtained from Cocos nucifera “common variety” were evaluated to test the anti-inflammatory and antinociceptive activities.

Materials and methods

Crude extract (CE, 50, 100, and 150 mg/kg), fraction 1 (F1, molecular weight lesser than 1 kDa, 1, 10, and 50 mg/kg), fraction 2 (F2, molecular weight higher than 1 kDa, 1, 10, and 50 mg/kg), and the references drugs morphine (5 mg/kg), acetilsalicilic acid (200 mg/kg), prometazine (30 mg/kg), and metisergide (5 mg/kg) were evaluated on models of analgesia and inflammation.

Results

CE, F1, and F2 significantly develop peripheral and central antinociceptive activity but with less effect on supra-spinal regions of the brain. Administration of the opioid antagonist, naloxone (5 mg/kg) inhibited the antinociceptive effect indicating that Cocos nucifera crude extract and fractions may be acting in opioid receptors. CE and F1 also inhibited rat paw edema induced by histamine, and serotonin.

Conclusions

results demonstrated that Cocos nucifera and its fractions have antinociceptive and anti-inflammatory activities which confirm the popular use of this plant in several inflammatory disorders.