Anxiolytic and Antidepressant Effects of a Leaf Extract of Palisota hirsuta K. Schum. (Commelinaceae) in Mice

Depression in Sub-Saharan Africa

Mood disorders can be considered among the most common and debilitating mental disorders. Major depression, as an example of mood disorders, is known to severely reduce the quality of life as well as psychosocial functioning of those affected. Its impact on the burden of disease worldwide has been enormous, with the World Health Organisation projecting depression to be the leading cause of mental illness by 2030. Despite several studies on the subject, little has been done to contextualise the condition in Africa, coupled with the fact that there is still much to be understood on the subject. This review attempts to shed more light on the prevalence of depression in Sub-Saharan Africa (SSA), its pathophysiology, risk factors, diagnosis and the experimental models available to study depression within the sub-region. It also evaluates the contribution of the sub-region to the global research output of depression as well as bottlenecks associated with full exploitation of the sub region's resources to manage the disorder.

Evaluation of anxiolytic potency of essential oil and S-(+)-linalool from Cinnamomum osmophloeum ct. linalool leaves in mice

Cinnamomum osmophloeum ct. linalool ( tǔ ròu guì) is one chemotype of the indigenous cinnamons in Taiwan. This study examined the anxiolytic potency of leaf essential oil (LEO) from C. osmophloeum ct. linalool and its main constituent on 4-week ICR mice using an open field test (OFT), a light-dark test (LDT) and an elevated plus maze test (EPT). After oral administration of corn oil, LEO (250 mg/kg and 500 mg/kg), S-(+)-linalool (500 mg/kg), R-(-)-linalool (500 mg/kg), and trazodone hydrochloride (75 mg/kg) for 14 days, the anxiolytic effects on mice behavior were evaluated. The results showed that LEO from C. osmophloeum ct. linalool leaves and S-(+)-linalool can significantly increase the time mice remained in the center area of the OFT, the illuminated area of the LDT and the open arms of the EPT without any side effects affecting motor activity, indicating excellent anxiolytic responses. Furthermore, results from the measurements of monoamines in mice brain revealed decreases in serotonin, dopamine, and norepinephrine, which are consistent with their anxiolytic effects in animal models. The findings obtained suggest that LEO from C. osmophloeum ct. linalool and its major compound, S-(+)-linalool, possess anxiolytic properties without any side effects and thus support their potential use in treatment of anxiety disorders.

Evaluation of anticonvulsant, sedative, anxiolytic, and phytochemical profile of the methanol extract from the aerial parts of Swertia corymbosa (Griseb.) wight ex C.B. Clarke

The objective of the present study was to evaluate the anxiolytic, antidepressant, and anticonvulsant activity of the methanolic extract of Swertia corymbosa (SCMeOH). After acute toxicity test, oral treatment with SCMeOH at doses of 125, 250, and 500 mg/kg behavioral models of open field, elevated-plus-maze, actophotometer, rotarod, pentylenetetrazole, isoniazid, and maximal electroshock induced seizure models were utilized. In open field test, SCMeOH (125, 250, and 500 mg/kg) (P < 0.01, P < 0.001) increased the number of rearings. However, the number of central motor and ambulation (P < 0.01, P < 0.001) were reduced. Likewise, the number of entries and the time spent in open arm were increased while the number of locomotion was decreased (P < 0.001) in elevated-plus-maze and actophotometer test, respectively. SCMeOH (125-500 mg/kg) protected the mice against the pentylenetetrazole and isoniazid induced convulsions; it causes significant (P < 0.01 and P < 0.001) dose dependent increase in latency of convulsion. Treatment with SCMeOH reduced the duration of the tonic hind limb extension induced by electroshock. Two major compounds such as gentiopicroside and swertianin were analyzed by HPLC system.

Antidepressant Effects of Mallotus oppositifolius in Acute Murine Models

Objective. Hydroalcoholic extract of leaves of Mallotus oppositifolius (MOE), a plant used for CNS conditions in Ghana, was investigated for acute antidepressant effects in the forced swimming (FST) and tail suspension tests (TST). Results. In both FST and TST, MOE (10, 30, and 100 mg kg(-1)) significantly decreased immobility periods and frequencies. A 3-day pretreatment with 200 mg kg(-1), i.p., para-chlorophenylalanine (PCPA), a tryptophan hydroxylase inhibitor, reversed the decline in immobility and the increase of swimming score induced by MOE in the modified FST. Pretreatment with reserpine alone (1 mg kg(-1)), α -methyldopa alone (400 mg kg(-1), i.p.), or a combination of both drugs failed to reverse the decline in immobility or the increase in swimming score caused by the extract in the modified FST. The extract potentiated the frequency of head twitch responses induced by 5-hydroxytryptamine. Pretreatment with d-serine (600 mg kg(-1), i.p.), glycine/NMDA agonist, abolished the behavioural effects of MOE while d-cycloserine (2.5 mg kg(-1), i.p.), a glycine/NMDA partial agonist, potentiated it in both TST and modified FST. Conclusion. The extract exhibited antidepressant effects in mice which is mediated by enhancement of serotoninergic neurotransmission and inhibition of glycine/NMDA receptor activation.

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.

Pharmacological evaluation of Potentilla alba L. in mice: adaptogenic and central nervous system effects

CONTEXT

Potentilla alba L. (Rosaceae) rhizomes have anti-inflammatory, antioxidant, and adaptogenic effects and are used for the treatment of diarrhea and intestinal colic. However, the data concerning the adaptogenic and central nervous system activities of P. alba are fragmentary.

OBJECTIVES

To determine the effect of oral administration of dried P. alba extract on the swimming endurance, light/dark exploration, and open-field tests for mice.

MATERIALS AND METHODS

The mice were orally administered Rhodiola rosea extract (RR group); dry extract of P. alba at doses of 12, 36, or 72 mg/kg (groups: PA12, PA36, and PA72); or distilled water (control group) for 7 consecutive days.

RESULTS

The swimming times of the RR, PA36, and PA72 groups were significantly longer than those of the control group. The administration of P. alba significantly increased the light time, latency time, and the number of rearings in a dose-dependent manner. In the open-field test, the P. alba extract at a dose of 12 mg/kg produced a significant increase in the frequency of head dipping and the number of squares crossed and a significant decrease in grooming compared with the control treatment.

CONCLUSION

The current findings demonstrate that P. alba extracts significantly increased swimming endurance time and have anxiolytic-like action with a predominant locomotor component.

Behavioral properties of Balanites aegyptiaca in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Balanites aegyptiaca is a native plant from the dry tropical areas of Africa and Arabia. It has been used in traditional medicine to treat psychoses, epilepsy, rheumatism and for the management of cough, liver and spleen conditions for many years. The plant is also used as antihelmintic and molluscicide.

AIM OF THE STUDY

The present studies aimed at investigating the behavioral properties of ethanol extract of the root of this medicinal plant, which is already in common applications in the Nigerian traditional medicine.

MATERIALS AND METHODS

The intraperitoneal and oral mean lethal dose (LD(50)) of the extract was determined using the Lorke's method. The preliminary phytochemical screening of the extract was carried out to identify the secondary metabolites in the extract. Furthermore, the behavioral properties of the extract were evaluated using diazepam-induced sleep, open field test, staircase test and beam walking assay all in mice.

RESULTS

The extract significantly (p<0.001) prolonged the duration diazepam (20mg/kg i.p)-induced sleep in mice dose dependently. However, the extract showed no significant effect on the onset of diazepam-induced sleep. In the open field test, the extract (150 and 300 mg/kg) and diazepam (0.05 mg/kg) produced a significant (p<0.05, p<0.005 and p<0.001) decrease in the number of square crossings. There was no significant effect on the number of centre square crossing following the administration of the extract. The extract (75 and 150 mg/kg) and diazepam (0.05 mg/kg) produced a significant (p<0.05) decrease in the number of rearing suggestive of sedation. In the staircase experiment there was a decrease in the number of upward step climbing as well as number of rearing suggesting anxiolytic and sedative properties of the extract. In the beam walking assay the extract did not produce any significant increase in the time taken to complete task as compared to diazepam 1mg/kg which was significant at p<0.05. Furthermore, 30 mg/kg of the extract and diazepam 1mg/kg showed significant (p<0.05) mean number of foot slips, suggesting that the central nervous system depressant activity might not necessarily due to peripheral neuromuscular blockade.

CONCLUSION

The result indicates that the extract of Balanites aegyptiaca possess biologically active compound(s) that have anxiolytic and sedative properties, which support the ethnomedicinal use of the plant as antipsychotic and antiepileptic agents.