Tryptanthrin from microwave-assisted reduction of isatin using solid-state-supported sodium borohydride: DFT calculations, molecular docking and evaluation of its analgesic and anti-inflammatory activity

Tryptanthrin is a potent natural alkaloid with good in vitro pharmacological properties. Herein, we report the synthesis of the compound via a new method involving the reduction of isatin with solid-state-supported sodium borohydride under microwave irradiation. The title compound has been tested for its analgesic and anti-inflammatory activity. The results showed that tryptanthrin dose dependently inhibits oedema and pain formation in all the models used. The agent also exhibited significant higher effects in its anti-inflammatory and analgesic activities better than positive drugs (aspirin and indomethacin) being currently used in the treatment and in the management of acute and chronic forms of pain and inflammatory disorders. The inhibitory potential of the compound was investigated by molecular docking using the software AutoDock Vina. The docking results were used to better rationalize the action and prediction of the binding affinity of tryptanthrin. Density Functional Theory (DFT) calculations at the B3LYP/6-311++G (2df, 2pd) level of theory showed that compared to ascorbic acid, tryptanthrin shows higher antioxidant activity which may be improved upon by functionalizing the aromatic core to enhance its solubility in polar solvents. The calculated electronic and thermodynamic properties obtained for tryptanthrin compete well with the standard ascorbic acid.

Repeated psychosocial stress causes glutamic acid decarboxylase isoform-67, oxidative-Nox-2 changes and neuroinflammation in mice: Prevention by treatment with a neuroactive flavonoid, morin

Psychosocial stress and biological predispositions are linked to mood and personality disorders related to psychiatric behaviors. Targeting neuroinflammation and oxidative stress has been recognized as a potential strategy for the prevention of psychosocial stress-induced psychiatric disorders. Morin, a bioactive compound isolated from mulberry leaf has been shown to produce antiamnesic, antipsychotic and anti-inflammatory effects relative to ginseng, a well-known adaptogen. Hence, the present study investigated the effect of morin on social-defeat stress (SDS)-induced behavioral, neurochemical, neuroimmune and neurooxidative changes in mice using intruder-resident paradigm. The intruder male mice were distributed into 6 groups (n = 10). Groups 1 (normal-control) and 2 (SDS-control) received normal saline, groups 3-5 had morin (25-100 mg/kg) while group 6 received ginseng (50 mg/kg) intraperitoneally daily for 14 days. Thirty minutes after treatment from days 7-14 onwards, mice in groups 2-6 were exposed to SDS for 10 min physical and psychological confrontations respectively with aggressive-resident mice. Neurobehavioral effects (locomotor activity, cognitive performance, anxiety- and depressive-like behavior) were assessed on day 14. Biomarkers of oxidative/nitrergic stress and neuroinflammation; acetylcholinesterase (AChE) and glutamic-acid decarboxylase-67 (GAD₆₇) were measured in the striatum, prefrontal-cortex and hippocampus. Behavioral deficits induced by SDS were attenuated by morin and ginseng. Both morin and ginseng decreasedmalondialdehyde, nitrite levels and increased glutathione concentrations in the brain regions. They also reduced inflammatory mediators (TNF-α, IL-6, COX-2 and NF-κB), AChE activity and Nox-2 expression in the specific brain regions. However, morin increased the levels of GAD₆₇ in the striatum, prefrontal-cortex and hippocampus in contrast to ginseng. Our results suggest that morin mitigates SDS-induced neurobehavioral deficits through enhancement of GAD₆₇, inhibition of AChE activity, oxidative stress, Nox-2 and neuroinflammatory pathways.

Curcumin induces secretion of glucagon-like peptide-1 through an oxidation-dependent mechanism

Curcumin shows antiglycemic effects in animals. Curcumin is chemically unstable at physiological pH, and its oxidative degradation products were shown to contribute to its anti-inflammatory effects. Since the degradation products may also contribute to other effects, we analyzed their role in the antiglycemic activity of curcumin. We quantified curcumin-induced release of glucagon-like peptide 1 (GLP-1) from mouse STC-1 cells that represent enteroendocrine L-cells as a major source of this anti-diabetic hormone. Curcumin induced secretion of GLP-1 in a dose-dependent manner. Two chemically stable analogues of curcumin that do not readily undergo degradation, were less active while two unstable analogues were active secretagogues. Chromatographically isolated spiroepoxide, an unstable oxidative metabolite of curcumin with anti-inflammatory activity, also induced secretion of GLP-1. Stable compounds like the final oxidative metabolite bicyclopentadione, and the major plasma metabolite, curcumin-glucuronide, were inactive. GLP-1 secretion induced by curcumin and its oxidative degradation products was associated with activation of PKC, ERK, and CaM kinase II. Since activity largely correlated with instability of curcumin and the analogues, we tested the extent of covalent binding to proteins in STC-1 cells and found it occurred with similar affinity as N-ethylmaleimide, indicating covalent binding occurred with nucleophilic cysteine residues. These results suggest that oxidative metabolites of curcumin are involved in the antiglycemic effects of curcumin. Our findings support the hypothesis that curcumin functions as a pro-drug requiring oxidative activation to reveal its bioactive metabolites that act by binding to target proteins thereby causing a change in function.

Safety effect of fractions from methanolic leaf extract of Ocimum gratissimum on reproduction in male wistar rats

This study evaluates the reproductive toxicity of ethyl acetate and butanolic fractions from crude methanolic leaf extract of Ocimum gratissimum in male Wistar rats. Acute toxicity was assessed to determine the safety dose, Sub-chronic reproductive toxicity studies were carried out by administering daily 25, 100 and 400 mg/kg body weight doses of the fractions to respective group of animals and 1 ml of normal saline daily for the control group for 28 days. Blood, epididymis and testes were harvested for reproductive hormones, sperm parameters, and histopathologic analysis respectively. There was significant (P < 0.05) increase in serum levels of testosterone, body-weight gain, sperm count. There was also apparent increase in mean-testicular weight and preservation of testicular histology with increase spermatogenesis in both the ethyl acetate and butanolic fraction treated groups compared with control. Serum levels of luteinising hormone was however significantly (P < 0.05) decrease across the groups compared to control. These effects were more pronounced in the butanolic fraction group compared to the ethyl acetate treated group. Sperm motility was also significantly (P < 0.05) higher in the ethyl acetate treated group compared to control. Findings from this studies demonstrate that these fractions were non-toxic at the tested doses with regards to male reproduction but, rather, exhibited fertility enhancing effects which was better with the butanolic fraction. Our findings also shows that the ethyl acetate fraction may be safer than the butanolic fraction.

Morin decreases cortical pyramidal neuron degeneration via inhibition of neuroinflammation in mouse model of schizophrenia

Neuroinflammation plays a prominent role in the pathophysiology and progression of schizophrenia. Thus, suppression of neuroinflammation may retard the progression of the disease. This study was designed to investigate whether morin, a bioactive compound with antipsychotic-like activity could reduce biomarkers of neuroinflammation and neurodegeneration in lipopolysaccharide (LPS)- and ketamine (KET)-induced schizophrenic-like behavior in mice. Animals were treated once daily intraperitoneally with morin (100 mg/kg), haloperidol (1 mg/kg), risperidone (0.5 mg/kg), or saline (10 mL/kg) in combination with LPS (0.1 mg/kg) for 14 consecutive days. However, from days 8-14, overt schizophrenia-like episode was produced with i.p. injection of KET (20 mg/kg) once daily. Schizophrenic-like behaviors: positive (open-field test), negative (social-interaction and social-memory tests) and cognitive (Y-maze test) symptoms were assessed on day 14. Thereafter, the levels and expressions of biomarkers of neuroinflammation were estimated in the striatum (ST), prefrontal cortex (PFC) and hippocampus (HC) using spectrophotometry, ELISA and immunohistochemistry. The effects of morin on cortical pyramidal neurons were estimated using Golgi-impregnation staining technique. LPS in combination with KET significantly (p < 0.05) induced schizophrenia-like behaviors, which was attenuated by morin. Morin significantly (p < 0.05) decreased tumor necrosis factor-α, interleukine-6 levels and myeloperoxidase activity in the ST, PFC and HC of mice treated with LPS + KET. Moreover, morin reduced regional brain expressions of cyclooxygenase-2, inducible nitric oxide synthase and nuclear factor kappa-B, and also rescued loss of pyramidal neurons in the PFC. Taken together, these findings suggest that morin reduces schizophrenic-like symptoms induced by LPS + KET via mechanisms related to inhibition of the release of pro-inflammatory mediators and suppression of degeneration of cortical pyramidal neurons in mice.

Possible neuroprotective mechanisms of action involved in the neurobehavioral property of naringin in mice

Flavonoids are naturally occurring bioactive phytochemical metabolites widely known to prevent and suppress several human diseases, and are important sources of therapeutic compounds from plants. Evidence derived from previous studies suggests that naringin, a neuroactive flavonoid possess functional beneficial neurobehavioral effects including anxiolytic, antidepressant and memory enhancing properties. However, literature search revealed that no studies have been carried out to evaluate the possible biochemical mechanisms involved in the neurobehavioral property of naringin alone following repeated treatment. Hence, this study was designed to evaluate the possible neuro-biochemical mechanisms involved in the neurobehavioral property of naringin following repeated administration in mice. The effects of naringin (2.5, 5 and 10 mg/kg), diazepam (2 mg/kg), imipramine (15 mg/kg) and donepezil (1 mg/kg) or vehicle on neurobehavioral and biochemical effects were evaluated in mice following repeated intraperitoneal injection for 7 consecutive days. Neurobehavioral activities consisting of open-field (locomotor), elevated-plus maze (anxiolytic), forced swim and social interaction (antidepressant and social preference), and Y-maze (memory enhancing) tests were assessed. Thereafter, brains levels of biomarkers of oxidative, nitrosative and cholinergic parameters were determined. Repeated treatment with naringin produced increased locomotor activity, and demonstrated antidepressant-like effects evidenced by decreased immobility time in forced swim test and increased % social preference in the social interaction test relative to controls. Also, naringin induced anxiolytic-like effect and increased cognitive performance in mice. Mechanistically, naringin significantly increased the activities of superoxide dismutase and catalase, and glutathione concentration relative to vehicle-controls. However, naringin significantly decreased malondialdehyde and nitrite contents, and reduced brain acetylcholinesterase activity in mice brains in a significant manner relative to controls. Taken together, these findings suggest that treatment with naringin might be useful to produce functional behavioral effects via mechanisms related to enhancement of cholinergic transmission, antioxidant defense systems, inhibition of lipid peroxidation and nitrosative processes.

Probable mechanisms involved in the antipsychotic-like activity of morin in mice

Evidence derived from preliminary studies suggests that morin, a neuroactive flavonoid with proven antioxidant and antiinflammatory properties possess antipsychotic-like activity. The present study was designed to evaluate the probable mechanisms involve in the antipsychotic-like activity of morin in ketamine model of schizophrenia. The effects of morin, haloperidol and risperidone on neurobehavioral and anti-schizophrenia-like effects were evaluated in mice (n = 7) following intraperitoneal (i.p.) administration of morin (25-100 mg/kg), haloperidol (1 mg/kg) and risperidone (0.5 mg/kg) alone or in combination with ketamine (20 mg/kg, i.p.) for 10 days. Neurobehavioral and schizophrenia-like activities consisting of open-field (positive symptoms), Y-maze, novel-object recognition (cognitive symptoms), social interaction (negative symptoms) tests were assessed. Also, wood-block catalepsy and rota-rod tests were employed to evaluate extrapyramidal side effects of morin. Thereafter, brain levels of biomarkers of oxidative, nitrergic and acetylcholinesterase alterations as well as histomorphological changes in the striatum and prefrontal-cortex were determined. Administration of morin and risperidone alone but not haloperidol significantly (p > 0.05) prevented ketamine-induced hyperlocomotion, social withdrawal and cognitive impairments relative to controls, and were devoid of extrapyramidal side effects. Morin alone or in combination with ketamine significantly increased glutathione concentration, superoxide dismutase and catalase activities compared with saline- or ketamine-treated mice. Moreover, morin alone or in combination with ketamine also significantly decreased malondialdehyde, nitrite and acetylcholinesterase alterations in mice brains. Furthermore, morin prevented ketamine-induced brain neuronal alterations in the striatum and prefrontal-cortex. Together, our findings suggest that morin may demonstrate antipsychotic-like therapeutic effect via modulation of oxidative/nitrergic, cholinergic actions and neuroprotection.

Involvement of GABAergic, BDNF and Nox-2 mechanisms in the prevention and reversal of ketamine-induced schizophrenia-like behavior by morin in mice

GABAergic (Gamma-aminobutyric acid) and neurotrophic derangements have important implication in schizophrenia, a neuropsychiatric disease. Previous studies have shown that nicotinamide adenine dinucleotide phosphate oxidase (NADPH-oxidase) alters GABAergic and neurotrophic activities via inflammatory and oxidative pathways. Thus, it has been proposed that agents with anti-oxidant and anti-inflammatory properties might be beneficial for the treatment of the disease. Morin is neuroactive bioflavonoid compound, which has been reported to demonstrate antipsychotic and anti-oxidant/anti-inflammatory activities. In this study, we further evaluated its effects on the brain markers of GABAergic, neurotrophic and oxidative alterations in the preventive and reversal of schizophrenia-like behavior induced by ketamine (KET). In the prevention protocol, adult mice were treated intraperitoneally with morin (100 mg/kg/day), haloperidol (1 mg/kg/day), risperidone (0.5 mg/kg/day), or saline (10 mL/kg/day) for 14 consecutive days. In addition, the animals were administered KET (20 mg/kg/day) from the 8th to the 14th day. In the reversal protocol, the animals received KET or saline for 14 days. From 8th to 14th days mice were additionally treated with morin, haloperidol, risperidone or saline. Schizophrenic-like behaviors consisting of positive (stereotypy test), negative (behavioral despair in forced swim test) and cognitive (novel-object recognition test) symptoms were evaluated. Afterwards, brain levels of biomarkers of GABAergic (Glutamic acid decarboxylase-67, GAD₆₇), neurotrophic (Brain-derived neurotrophic factor, BDNF) and oxidative [NADPH-oxidase, superoxide dismutase, (SOD) and catalase (CAT)] alterations were determined in the striatum, prefrontal cortex (PFC) and hippocampus, respectively. Morin significantly (p < 0.05) prevented and reversed KET-induced increased stereotypy, behavioral despair and deficit in cognitive functions when compared with KET-treated mice respectively. Also, morin and risperidone but not haloperidol, significantly (p < 0.05) prevented and reversed the decreases in expressions of GAD₆₇ and BDNF immunoreactivity in the striatum, PFC and hippocampus caused by KET. Moreover, morin and risperidone significantly (p < 0.05) decreased regional brain expressions of NADPH-oxidase immunopositive cells and increased endogenous anti-oxidant enzymes (SOD and CAT) in the striatum, PFC and hippocampus relative to KET controls respectively. Taken together, these findings further suggest that the antipsychotic-like activity of morin may be mediated via mechanisms related to enhancement of GABAergic neurotransmission and neurotrophic factor, and suppression of NADPH-oxidase induced oxidative damage in mice.

Evaluation of the combination of Uvaria chamae (P. Beauv.) and amodiaquine in murine malaria

ETHNOPHARMACOLOGICAL RELEVANCE

The leaf and fruit of Uvaria chamae P. Beauv (Annonaceae) are used in antimalarial ethnomedical preparations. Therefore, they were investigated for antimalarial activities as well as possible herb-drug interaction with amodiaquine (AQ).

MATERIALS AND METHODS

The methanol extracts of the leaf (UCL) and fruit (UCF) were administered orally at 100-800mg/kg/day in mice infected with chloroquine (CQ)-sensitive Plasmodium berghei NK65 using the four-day, curative and prophylactic antimalarial test models. The UCL was further evaluated at 100-800mg/kg as twice-daily doses and combinations of UCL+AQ using the four-day test. Mice infected with CQ-resistant P. berghei ANKA were treated with UCL at 400mg/kg and AQ at 10mg/kg - [UCL400+AQ10]mg/kg - in the four-day and curative test models.

RESULT

At 800mg/kg/day, UCL, UCF gave chemosuppression of 42, 28% (four-day test), parasite clearance of 36.3, 49.5% on day 5 (curative test) and 64.3, 82.6% (prophylactic test), respectively. The twice-daily dose of UCL at 800mg/kg showed activity of 51.50% while the combination of [UCL200+AQ5]mg/kg exhibited chemosuppression of 91.66%, which was not significantly different (p>0.05) from AQ at 10mg/kg (85.41%). In the CQ-resistant P. berghei experiment, the combination gave a chemosuppression of 45.80%, significantly lower (p<0.05) than AQ (78.40%) while the parasite clearance was not significantly different from AQ (curative test).

CONCLUSION

The leaf extract showed moderate chemosuppressive activity. The lower-dose combination of the leaf extract and amodiaquine had better antimalarial activity in CQ-sensitive murine malaria. However, the tested combination had no beneficial antimalarial effect in CQ-resistant murine malaria.

Spectrophotometric studies of a novel Gedunin-2-Hydroxypropyl- β-cyclodextrin binary system

BACKGROUND

Gedunin, a limonoid, is linked with antimalarial, anticancer and anti-allergic activities. This study was aimed at preparing an inclusion complex of gedunin and 2-hydroxypropyl-p-cyclodextrin (HBD) to increase solubility of-gedunin in polar solvents which will increase absorption and bioavailability in vivo and thus enhance pharmacological effects.

MATERIALS AND METHODS

Gedunin was obtained from the hexane extract of Entandrophragma angolense heartwood by column and preparative thin layer chromatography. The structure was previously confirmed by spectroscopic means (NMR). The electronic absorption spectra data of the complexes formed between gedunin. and HBD in various solvents was determined using the UV-VIS spectrophotometer. The stoichiometry of inclusion was determined by Job's method of continuous variation.

RESULTS

Evidence of interaction was observed between gedunin and HBD in the various solvents but gedunin and its complex with HBD exhibited sharp absorption bands in acetate buffer (pH 3.5).The spectrophotometric titrations showed curves with a single point of inflexion when the experiment was carried'out at 25⁰C (298 K) and 37⁰C (310 K). A stoichiometric ratio of 1:1 for complex formation was obtained. The formation constants (K,) obtained at 25⁰C and 37⁰C.were 9.539 x.10³ M⁻¹ and .1.853 x 10⁴ M⁻¹ respectively. Thermodynamic considerations revealed hydrophobic interaction between gedunin and HBD.

CONCLUSION

A stable inclusion complex of gedunin and HBD was formed at room and body temperature. This complex formation involved trapping of poorly soluble gedunin into the hydrophobic core of the cyclodextrin and may enhance the pharmacological activity of gedunin in vivo.

Pharmacological properties of the extract and some isolated compounds of Clausena lansium stem bark: anti-trichomonal, antidiabetic, anti-inflammatory, hepatoprotective and antioxidant effects

ETHNOPHARMACOLOGICAL RELEVANCE

Clausena lansium (Fool's Curry Leaf) is used for various ethnomedical conditions in some countries, including bronchitis, malaria, viral hepatitis, acute and chronic gastro-intestinal inflammation, and as a spicy substitute of the popular Curry leaf tree (Murraya koenigii).

AIM OF THE STUDY

This study was to evaluate the ethnomedical uses of the stem bark in inflammatory conditions, hepatotoxicity and to determine the anti-diabetic and anti-trichomonal properties of the plant.

MATERIALS AND METHOD

Anti-trichomonal, in vivo and in vitro antidiabetic and insulin stimulating, anti-inflammatory, hepatoprotective and anti-oxidant activities using Trichomonas gallinae, glucose loaded rats and in vitro insulin secreting cell line (INS-1 cell), carrageenin-induced rat paw oedema, CCl(4)-induced hepatotoxicity and DPPH scavenging ability methods respectively for the extracts and some isolates were determined.

RESULTS

A dichloromethane extract was superior over methanolic extract with respect to an anti-trichomonal activity which was measured after 24 and 48 h. The isolated compounds imperatorin and 3-formylcarbazole had the main anti-trichomonal activity (LC(50)s of 6.0, 3.0 and 3.6, 9.7 microg/mL after 24 and 48 h, respectively). Methanolic extract (100 mg/kg) induced maximum and significant (p<0.05) anti-hyperglycaemic activity of 15.8% at 30 min and a 38.5% increase in plasma insulin at 60 min, compared to control. The increase in plasma insulin after 60 min, compared to 0 min, was 62.0% (p<0.05). The significant 174.6% increase of insulin release from INS-1 cells (in vitro) at 0.1 mg/ml indicates that it mediates its antidiabetic action mainly by stimulating insulin release. Imperatorin and chalepin were the major active constituents increasing in vitro insulin release to 170.3 and 137.9%, respectively. 100 mg/kg of the methanolic extract produced an anti-inflammatory activity after 4 h. A sedative effect was not observed. 100 and 200 mg/kg of methanolic extract administered i.p., reduced CCl4-induced hepatotoxicity firstly by 5.3 and 8.4% reduction in phenobarbitone-sleeping time respectively, secondly by reversing the reduction in serum liver proteins by 7.0-8.8%, serum AST, ALT and ALP activities by 27.7-107.9% and thirdly by diminishing increased values of plasma AST, ALT and ALP activities by 13.2-83.8%. The extract exhibited antioxidant activities.

CONCLUSION

The hepatoprotective activity of C. lansium is partly due to its anti-oxidant and anti-inflammatory properties and confirms its folkloric use in the treatment of gastro-intestinal inflammation, bronchitis and hepatitis. In addition the use of C. lansium stem bark would be useful in diabetes and trichomoniasis.

Clinical effects of Garcinia kola in knee osteoarthritis

Objectives

Over the past years, there has been a growing number of knee osteoarthritis (KOA) patients who are not willing to comply with long-term non-steroidal anti-inflammatory drugs (NSAID) treatment and wish to use herbal anti- rheumatic medicine. This study assessed the clinical effects of Garcinia kola (GK) in KOA patients.

Patients and methods

Prospective randomized, placebo controlled, double blind, clinical trial approved by the institutional medical ethics review board and written informed consent obtained from each patient. All KOA patients presenting at the Obafemi Awolowo University Teaching Hospital complex were recruited into the study. The patients were grouped into four (A = Placebo, B = Naproxen, C = Garcinia kola, D = Celebrex). The drugs and placebo were given twice a day per oral route. Each dose consisted of 200 mg of G. kola, Naproxen (500 mg), Celebrex (200 mg) and Ascorbic acid (100 mg). The primary outcome measure over six weeks study period was the change in mean WOMAC pain visual analogue scales (VAS). Secondary outcome measures included the mean change in joint stiffness and physical function (mobility/walking).

Results

143 patients were recruited, 84 (58.7%, males – 24, females – 60) satisfied the selection criteria and completed the study. The effect of knee osteoarthritis bilateralism among the subjects was not significant on their outcome (p > 0.05). The change in the mean WOMAC pain VAS after six weeks of G. kola was significantly reduced compared to the placebo (p < 0.001). Multiple comparisons of the mean VAS pain change of G. kola group was not lowered significantly against the naproxen and celebrex groups (p > 0.05). The onset of G. kola symptomatic pain relief was faster than the placebo (p < 0.001). However, it was slower than the active comparators (p > 0.05). The duration of therapeutic effect of Garcinia kola was longer than the placebo (p > 0.001). G. kola period of effect was less than naproxen and celebrex (p < 0.001). G. kola subjects had improved mean change mobility/walking after six weeks better than the control group(p < 0.001). The mean change in mobility of the G. kola group when compared to the active comparators was not significantly better (p < 0.05). The mean change of knee joint stiffness (p < 0.001) and the change of mean WOMAC score (p < 0.001) were improved on Garcinia kola as compared to the placebo. The mid term outcome of eleven Garcinia kola subjects after cessation of use had a mean pain relief period of 17.27 +/- 5.15 days (range: 9–26 days). There was no significant cardiovascular, renal or drug induced adverse reaction to Garcinia kola.

Conclusion

Garcinia kola appeared to have clinically significant analgesic/anti-inflammatory effects in knee osteoarthritis patients. Garcinia kola is a potential osteoarthritis disease activity modifier with good mid term outcome. Further studies are required for standardization of dosages and to determine long-term effects.

Antinociceptive and antiinflammatory effects of essential oil of Dennettia tripetala G.Baker (Annonaceae) in rodents

In this study we evaluated the analgesic and anti-inflammatory activities of the essential oil (EO) of the fruits of Dennettia tripetala in rodents. The plant is a tropical African plant and the fruits are commonly eaten as spices and consumed as a stimulant, and its various parts are used in the treatment of fever, cough and as anti-emetics.The analgesic effects of the oil was assessed in mice using the hot plate, acetic acid-induced writhings and formalin test, while carrageenan-induced paw oedema was used to study the antiinflammatory effects in rats. The EO at 25-50 mg/kg exhibited significant (p<0.05) antinociceptive effects comparable to a potent opioid agonist, morphine (10 mg/kg) and non-steroidal anti-inflammatory drugs such as, aspirin (100 mg/kg) and indomethacin (80 mg/kg). The antinociceptive effect of the EO was also blocked by naloxone (2 mg/kg) in all the models used. The EO demonstrated significant (p<0.05) anti-inflammatory effect in the carrageenan-induced paw oedema model of inflammation that is also comparable to dexamethasone (1 mg/kg) The results showed that the essential oil of D. tripetala possesses significant antinociceptive and antiinflammatory effects in the animal models used. The results also suggest that the analgesic effects may be mediated both centrally as well as peripherally, while the antiinflammatory activity may be effective in both early and late phases of inflammation. The results obtained may therefore be used to rationalize the use of the plant in the treatment of pain and fever in traditional medicine.

Anti-protozoan activities of Harungana madagascariensis stem bark extract on trichomonads and malaria

AIM OF THE STUDY

The ethanolic stem bark extract of Harungana madagascariensis (Hypericaceae), (Choisy) Poir were evaluated for their activities on Trichomonas gallinae (Rivolta) Stabler isolated from the pigeon (Columba livia). It was also tested for their anti-malarial activity on N67 Plasmodium yoelii nigeriensis (in vivo) in mice and on Plasmodium falciparum isolates in vitro.

MATERIALS AND METHODS

The anti-trichomonal screening was performed in vitro using Trichomonas gallinae culture. The minimum lethal concentration (MLC) is the lowest concentration of the test extract in which no motile organisms were observed. The anti-malarial effects were determined in-vivo for suppressive, curative and prophylactic activities in mice receiving a standard inoculum size of 1 x 10(7) (0.2 ml) infected erythrocytes of Plasmodium yoelii nigeriensis intraperitoneally, and the in vitro was performed against 3 isolates of Plasmodium falciparum in a candle jar procedures.

RESULTS

The IC(50) of the extract and metronidazole (MDZ) (Flagyl) on Trichomonas gallinae at 48 h are 187 and 1.56 microg/ml. The IC(50) of the extract, chloroquine (CQ) and artemether (ART) on Plasmodium falciparum are between 0.052 and 0.517 microg/ml for the extract and 0.021 and 0.0412 microg/ml for ART and CQ, respectively. The actions of the extract in in vivo study on Plasmodium yoelii nigeriensis showed that in both suppressive and prophylactic tests the percentages chemo-suppressive were between 28.6-44.8% and 30.2-78.2% respectively, while only 80 mg/kg of the extract reduced the parasitaemia level when compared to the control and the standard drugs in curative test.

CONCLUSIONS

Harungana madagascariensis stem bark extract therefore exhibited significant anti-protozoan effects against Trichomonas and Plasmodium both in vivo and in vitro.

CHANGES IN THE VISCERAL FUNCTIONS OF PLASMODIUM BERGHEI-INFECTED AND -UNINFECTED RATS FOLLOWING ADMINISTRATION OF ARTEMETHER

1. The effects of artemether (12.5, 25.0 and 50.0 mg/kg per day, i.m.), administered to different groups of Plasmodium berghei-infected and -uninfected adult Wistar rats for 1 week, were investigated. 2. The parameters evaluated were the feeding, drinking and urinating patterns of the rats and these were compared with those of rats that received normal saline. 3. Artemether caused a significant dose-dependent reduction in food consumption of both P. berghei-infected and -uninfected rats (P < 0.05). Food intake in infected rats was reduced by approximately 7 g/24 h. This reduction in food intake was further reduced during drug treatment with artemether. Artermether also reduced food intake in uninfected rats. The food consumption of rats that received 12.5 and 25.0 mg/kg artemether was restored after stopping treatment, in contrast with rats that received 50.0 mg/kg, in which the significant reduction in food consumption persisted 1 week after drug administration. 4. During treatment with artemether, the water intake of infected rats was significantly lower than that of uninfected rats in the 12.5 mg/kg artemether-treated group, but was significantly higher in infected rats than in uninfected rats dosed with 25.0 and 50.0 mg/kg artemether. 5. For all doses of artemether tested, a significant increase in urine output was observed in infected rats during treatment and 1 week after treatment, whereas in uninfected rats a significant increase in urine output was observed only following 25.0 and 50.0 mg/kg artemether 1 week after drug administration. 6. The present study confirms the anorexic activity of a high dose of artemether in both P. berghei-infected and -uninfected rats. It also indicates that high doses of the drug could cause impaired renal function in rats and that the significant increase in urine output could also be due to other effects of artemether, namely those on thirst, anti-diuretic hormone output and the osmotic pressure of the blood.

Antimicrobial and antioxidant activities of some Nigerian medicinal plants

Ten Nigerian plants suggested from their ethnomedical uses to possess antimicrobial and antioxidant activities were studied for their anti-microbial and anti-oxidant properties. Antimicrobial activity was tested against Escherichia coli NCTC 10418, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Candida albicans, Candida pseudotropicalis and Trichophyton rubrum (clinical isolate). Trichilia heudelotti leaf extract showed both antibacterial and antifungal activities and was the most active against all the strains of bacteria tested. Boerhavia diffusa, Markhamia tomentosa and T. heudelotti leaf extracts inhibited the gram negative bacteria E. coli and P. aeruginosa strains whereas those of M. tomentosa, T. heudelotti and Sphenoceutrum jollyamum root inhibited at least one of the fungi tested. At a concentration of 312 microg/ml, hexane and chloroform fractions of T. heudelotti extract inhibited 6 and 14% of the fifty multi-drug resistant bacteria isolates from clinical infections, respectively. At < or = 5 mg/ml, the CHCl(3) (64%) and aqueous (22%) fractions of T. heudelotti and those of CHCl(3) (34%) and EtOAC (48%) of M. tomentosa gave the highest inhibition that was stronger than their corresponding methanol extracts. The corresponding EC(50) of the extracts on M. acuminata, T. heudelotti, E. senegalensis and M. tomentosa were 4.00, 6.50, 13.33, and 16.50 ig/ml using the TLC staining and 1,1-dipheyl-2-picry-hydrazyl (DPPH) free radical scavenging assay. Therefore, leaf extracts of M. tomentosa and T. heudelotti, especially the latter, possess strong antimicrobial and antioxidant activities and should be further investigated. These activities justified the ethnomedical uses of these plants.

Anti-trichomonal, biochemical and toxicological activities of methanolic extract and some carbazole alkaloids isolated from the leaves of Murraya koenigii growing in Nigeria

The methanolic extract of Murraya koenigii leaf was screened for toxicological and biochemical effects on rats because of the folkloric uses as an anti-dysentery and anti-diabetes. The extract was moderately toxic (LD(50)=316.23 mg/kg body weight) to rats and had appreciable effect on the liver and kidney at higher doses leading to liver inflammation. It had little or no effect on haematology and relative organ weight of lungs, heart and spleen. Acute doses (500 mg/kg) reduced significantly serum globulin, albumin, urea, glucose, total protein, aspartate transaminase (AST), and increased cholesterol and alanine transaminase (ALT) indicating hepatic injury. However, chronic administration for 14 days gave a significant (p<0.05) reduction in the serum cholesterol, glucose, urea, bilirubin, ALT and AST showing that the plant has hypoglycaemic and hepatoprotective effects after prolonged use. The activity demonstrated by some of the isolated carbazole alkaloids and their derivatives against Trichomonas gallinae confirmed that the anti-trichomonal activity of the leaf may be due to its carbazole alkaloids. The order of activity was C(18)>C(23)>C(13). Girinimbine and girinimbilol with IC(50) values of 1.08 and 1.20 microg/ml were the most active. Acetylation of girinimbilol and mahanimbilol improved their activities to 0.60 and 1.08 microg/ml.

Sedative, antiepileptic and antipsychotic effects of Spondias mombin L. (Anacardiaceae) in mice and rats

In this study, we evaluated the effects of air-dried Spondias mombin leaves extracted with aqueous, methanol and ethanol solvents on hexobarbital-induced sleeping time and novelty-induced rearing (NIR) behaviours in mice and rats. We also studied the effect of the extracts on amphetamine- and apomorphine-induced stereotyped and picrotoxin-induced convulsive behaviour in rats. All residues from different extractions were dissolved in normal saline and administered intraperitoneally (i.p.). The methanolic and ethanolic extracts (12.5-100mg/kg i.p.) prolonged the hexobarbital-induced sleeping time and reduced the NIR in both mice and rat in a dose-dependent manner. The aqueous extract prolonged the hexobarbital-induced sleeping time and reduced (NIR) at doses of 50 and 100mg/kg. The inhibitory effect of the extracts on NIR was not reversed by atropine, yohimbine, naltrexone and flumazenil. However, the extracts blocked the facilitating effect of flumazenil. This suggests that NIR inhibitory effects of extracts of Spondia mombin are not mediated via muscarinic, alpha(2) adrenergic, and mu-opioid receptors, whereas, the extracts appear to facilitate GABAergic transmission. In addition the extracts blocked picrotoxin-induced convulsions. Phenolic compound(s) were present in the ethanolic and methanolic extracts, which exhibited anticonvulsant properties in the picrotoxin-induced convulsions model. The extracts decreased the amphetamine/apomorphine-induced stereotyped behaviour, which suggest that these extracts possess antidopaminergic activity. The effect of the extracts on hexobarbitone-induced sleeping time was blocked by flumazenil a GABA(A) antagonist, indicating that the extracts contain GABA(A) agonists. These results suggest that the leaves extracts of Spondias mombin possess sedative and antidopaminergic effects.

A study of theIn Vivo activity of the leaf extract ofAlchornea cordifolia against multiply antibiotic resistantS. aureus isolate in mice

The effect of a 50% aqueous ethanol extract of Alchornea cordifolia (Schum and Thonn) Muell. Arg. leaf was investigated in mice which had been infected intraperitoneally with 5.0 x 10(9) cfu of Staphylococcus aureus. Dose-dependent antibacterial activity was demonstrated and the rate of survival of infected mice was improved significantly by doses between 25 and 200 mg/kg of injected extract when compared with untreated infected controls. The intraperitoneal median lethal dose of the extract was found to be 800 mg/kg.

Pro- and Antioxidant Effects and Cytoprotective Potentials of Nine Edible Vegetables in Southwest Nigeria

Antioxidant and cytoprotective activities of boiled, cold, and methanolic extracts of nine edible vegetables in Southwest Nigeria were evaluated in the 1,1-diphenyl-2-picrylhydrazyl free radical assay and hemagglutination assay in bovine erythrocytes, respectively. Crassocephalum rubens showed the highest antioxidant activity (56.5%), Solanum americanum and Vernonia amygdalina exhibited moderate antioxidant activity (26.0-37.5% and 14.8-36.2%, respectively), Solanum macrocarpon, Telfaria occidentalis, Amaranthus hybridus, and Jatropha tanjorensis produced weak activity (1.6-15.8%, 1.6-7.7%, 2.8-6.62%, and 10.7-12.1%, respectively), while Celosia argentea and Talinum triangulare were pro-oxidants. It was also shown that extracts from all the vegetables are pro-oxidants at high concentrations of either 1 or 5 mg/mL or both. On the other hand, the studies on the cytoprotective effect showed that all the plant extracts demonstrated a very low hemagglutination titer value between 0.32 and 5.56 except S. americanum methanolic extract, which had a titer of 50.0. These results indicated correlation between the antioxidant properties and the hemagglutination values of these plant extracts; however, the membrane stabilizing capacity of the extracts supports the plants' antioxidant activity.

Antitrichomonal and antioxidant activities of Dorstenia barteri and Dorstenia convexa

Dorstenia barteri and D. convexa extracts and some isolated components of the former were investigated for effectiveness against Trichomonas gallinarum and compared with quercetin and quercitrin. The antioxidant activity of the extracts/compounds was also determined. The minimum lethal concentrations (MLCs) for the extract of D. barteri leaves and twigs at 24 h were found to be 15.625 and 15.625 microg/ml, respectively. However, the MLCs of the leaf and twig extract of D. convexa were 125 and 437.5 microg/ml, respectively. The prenylated and geranylated chalcones were as active as the prenylated flavones, 6-prenylapigenin and the diprenylated derivative 6,8-diprenyleridictyol. The order of the antitrichomonal activity of the compounds at 24 h was: quercetin (0.121 microg/ml) > quercitrin (0.244 microg/ml) > or = bartericin B (0.244 microg/ml) > bartericin A (0.73 microg/ml) > stigmasterol (0.98 microg/ml) > 6,8-diprenyleridictyol = isobavachalcone = dorsmanin F (31.25 microg/ml). D. barteri extracts, quercitrin, and bartericin A, and the prenylated flavonoids had potent antioxidant properties. The twig extract of D. barteri was more potent than the leaf extract. Moderate (EC50 >50 microg/ml) and high (EC50 <50 microg/ml) antioxidant activities were detected in the leaf and twig extracts of D. barteri and the prenylated flavonoids. Prenylated flavonoids and the isolated compounds with antioxidant properties described here may account for the anti-inflammatory action of these extracts. The antitrichomonal and antioxidant activities shown by the extracts and compounds in this study are consistent with the ethnomedicinal and local use of the Dorstenia species studied.

In vitro spasmolytic effect of aqueous extract of Calotropis procera on Guinea-pig trachea smooth muscle chain

The aqueous extract of Calotropis procera was evaluated for its spasmolytic effect using in vitro trachea smooth muscle chain of Guinea-pig. The extract (50, 100 and 200 microg/ml) showed a dose-dependent relaxant activity probably exhibited through the direct relaxant action on the smooth muscle.

Antinociceptive and anti-inflammatory effects of Dorstenia barteri (Moraceae) leaf and twig extracts in mice

The present study was undertaken to investigate the antinociceptive and anti-inflammatory activities of the leaf and twig extracts of Dorstenia barteri (Moraceae) in mice. Both the leaf and twig extracts of Dorstenia barteri at 50, 100 and 200 mg/kg showed significant (P < 0.05-0.01) antinociceptive activities in chemical-, mechanical- and thermal-induced pain test models. Intraperitoneal administration of the plant extracts at 50, 100 and 200 mg/kg significantly (P < 0.05-0.01) inhibited carrageenin-induced acute inflammation in oedema paw weight, pulmonary oedema and number of pleural leucocytes in a dose-dependent way. The twig extract was found to be more active than the leaf extract in all the experimental models used. The inhibitory effects of the plant extracts were comparable to those of the reference drugs acetylsalicyclic acid (ASA) and phenylbutazone (PBZ) at 100 mg/kg i.p. The significant reduction in acetic acid-induced abdominal contractions, the decrease in oedema paw weight as well as in the number of leucocytes in the pleural cavity exudates, and the significant increase in the reaction time and pain threshold of mice observed in this study suggest that Dorstenia barteri extracts possess both anti-inflammatory and antinociceptive activities. The present study, therefore, lend pharmacological support to the folkloric uses of Dorstenia barteri extracts in the treatment, control and/or management of arthritis, rheumatism, gout, headache and other forms of body pains in some parts of Africa.

Effects of autacoid inhibitors and of an antagonist on malaria infection in mice

The effects of p-chlorophenylalanine, an inhibitor of serotonin synthesis, indomethacin, an inhibitor of prostaglandin synthesis, cyproheptadine, a serotonin, bradykinin and histamine antagonist, were assessed separately and in combination with chloroquine (CQ) in Vom strains of Swiss albino mice (18-22 g) of either sex infected intraperitoneally with 1 x 10(7) Plasmodium yoelii nigeriensis-induced malaria. As prophylactic, these agents reduced from 31.9 +/- 4.5 to 16.1 +/- 8.1% the level of parasitemia relative to control but had no appreciable activity as curative agents when administered subcutaneously once daily for 4 days after 72 h of parasites innoculum in vivo. However, CQ alone and the combination of these agents with CQ in curative and prophylactic treatments significantly reduced (from 50.3 +/- 5.8 to 4.9 +/- 0.75%) the level of parasitemia (P < 0.05), which was taken only once 72 h after the parasites innoculum. The prophylactic result was shown to produce better results than the curative treatment. The data indicate that inhibitors and an antagonist can reduce the parasitemia load (the extent of damage and the severity of infection) as well as enhance the effects of CQ when combined with it for malaria therapy. The study reveals that the production of autacoids in established infection renders autacoid inhibitors and an antagonist ineffective for radical cure in malarial mice; however, selective inhibition of local hormones implicated in the pathological manifestations of malaria infection by autacoid inhibitors and an antagonist may be a possible pathway to reduce the severity of infection and the associated tissue damage and to enhance the efficacy of available anti-malarials.

An in vitro study of the effects of Cassia podocarpa fruit on the intestinal motility of rats

Folkloric evidence and scientific reports indicate the use of C. podocarpa fruit as a purgative recipe. This study attempts to find the in vitro effects of its aqueous infusion (ACPF) and methanolic extract (MCPF) on the motility of the intestine of albino rats of Wistar strain and to compare their effect with those of C. acutifolia fruit (ACAF and MCAF). MCPF relaxed both the ileum and colon dose dependently. Its effect was blocked by tolazoline (10(-9) M) and propranolol (10(-9) M). ACPF had no effect on the ileum, but contracted the colon dose-dependently. Its effect was blocked by nifedipine (2.8 x 10(-10) M) and drastically reduced by atropine (3.4 x 10(-6) M). MCAF has the same effect as ACPF on both ileum and colon and its effect was similarly affected by atropine (3.4 x 10(-6) M) and nifedipine (2.8 x 10(-8) M). ACAF relaxed the ileum, its effect was blocked by tolazoline (5.1 x 10(-7) M). MCAF was more potent than ACPF in contracting the colon, Hexamethonium (2.8 x 10(-8) M), chlorpheniramine (3.8 x 10(-8) M) and promethazine (3.2 x 10(-10) M) potentiated the effect of ACPF on the colon. The results suggest that both ACAF and MCPF have anti-diarrhoeal effect. MCPF acts via both alpha and beta adrenergic receptor stimulation, while ACAF stimulates alpha-receptor. ACPF and MCAF engage both the cholinergic system and calcium channel activation in causing purgation in the colon. The potentiation of the effect of ACPF by some blockers could be due to allosteric enhancement of the receptors involved in its action.

Studies on the acute and sub-chronic toxicity of the essential oil of Ocimum gratissimum L. leaf

Oral and intra-peritoneal acute toxicity and the sub-chronic intra-peritoneal toxicity of the essential oil of Ocimum gratissimum Linn, Lamiaceae (Ocimum oil), was investigated. The acute toxicity test involved the oral and intra-peritoneal administration of graded doses of Ocimum oil prepared as a 4% v/v emulsion to 2 groups each of 30 rats and mice. LD50 and LD100 were determined for both routes and species. In the sub-chronic toxicity study, 25 male Sprague-Dawley rats were randomized into 4 test groups (treated with three graded sub-lethal doses of Ocimum oil prepared as a 4% v/v emulsion) and a control. Organs and blood samples were taken for analyses after a 30 day treatment period. A dose-dependent sedative effect of Ocimum oil was observed during the acute toxicity study in mice and rats and in the sub-chronic test in rats. Evidence of treatment, route, and dose-dependent toxicity were detected in both studies. Changes in weight of the testes, hearts, kidneys, intestines and lungs of the rats were statistically insignificant (ANOVA P < 0.05). Data analyses of blood biochemical, haematological and histopathological findings showed significant differences between control and treated groups and revealed that Ocimum oil is capable of invoking an inflammatory response that transits from acute to chronic on persistent administration. While the study revealed that Ocimum oil might be better tolerated when administered orally for systemic delivery, the oil has toxic potentialities that should not be overlooked.

Evaluation of the antimalarial properties and standardization of tablets of Azadirachta indica (Meliaceae) in mice

The antimalarial activities of the tablet suspension of the bark and leaf of Azadirachta indica were evaluated on Plasmodium yoelli nigeriensis infected mice. The tablet suspensions exhibited high prophylactic, mode-rate suppressive and a very minimal curative schizonticidal effect. No animal was cured of the infection in the curative test and there was not much increase in the survival time of the animals compared with the control. The tablet suspensions from the leaf and bark at a concentration of 800 mg/kg and chloroquine at a concentration of 62.5 mg/kg body weight produced average percentage (%) parasitaemia of 79.6%, 68.2% and 99.5% for leaf, bark and chloroquine, respectively, in chemosuppression. Also in the prophylactic treatment, the tablet suspensions at 800 mg/kg and pyrimethamine at a concentration of 0.35 mg/kg gave an average parasitaemia reduction of 75.3%, 65.6% and 98.3% for the leaf, bark and pyrimethamine, respectively. There was a clear indication that both tablet suspensions from the leaf and bark possess antimalarial activity and a suspension from the former is relatively more effective than the bark. Extrapolation of the results from the antimalarial activity of the tablet suspension of the crude plant parts showed that an adult human would need to ingest a minimum of 48 g of the powdered plant material per day, an amount that is impracticable. A survival index value of 0.33 was obtained with the 800 mg/kg dose level, indicating that the tablet suspension has some moderate beneficial effect.

Analgesic, antipyretic, anti-inflammatory effects of methanol, chloroform and ether extracts of Vernonia cinerea less leaf

The chloroform, methanolic and ether extracts of Vernonia cinerea (Asteraceae; Less) leaf (100, 200 and 400mg/kg intraperitoneally) were tested in: acetic acid-induced writhing in mice, carrageenin-induced oedema and brewer's yeast-induced pyrexia in rats to assess their analgesic, anti-inflammatory, antipyretic and behavioral activities, respectively. The changes in writhings and behavioural activities in mice, the pyrexia and paw volumes in rats were reduced significantly (P<0.05) compared to the control. There was an increase in pain threshold on the oedematous right hind limb paw of the rats. These results indicate that the extracts could possess analgesic, antipyretic and anti-inflammatory properties. All these effects and the changes in the behavioural activities could be suggested as contributory effects to the use of V. cinerea leaf in the treatment of malaria.