Ismail O. Ishola

Antidepressant and anxiolytic effects of amentoflavone isolated from Cnestis ferruginea in mice

The root decoction of Cnestis ferruginea (CF) Vahl DC (Connaraceae) is used in traditional African medicine in the management of psychiatric disorders. This study presents the antidepressant and anxiolytic effects of amentoflavone (CF-2) isolated from the root extract of C. ferruginea. The antidepressant effect was studied using the forced swimming (FST) and tail suspension tests (TST) while the hole-board, elevated plus maze (EPM) and light/dark tests were used to evaluate the anxiolytic effect. Acute treatment with CF extract and amentoflavone significantly (p<0.001) reduced the duration of immobility in FST and TST with peak effects observed at 100 and 50mg/kg respectively in comparison to control treated. Antidepressant effects of CF and amentoflavone were significantly higher (p<0.05) when compared to imipramine in FST but comparable to the fluoxetine treated group in TST. The pretreatment of mice with metergoline (4mg/kg, i.p., a 5-HT2 receptor antagonist), prazosin (62.5μg/kg, i.p., an α1-adrenoceptor antagonist), and yohimbine (1mg/kg, i.p., an α2-adrenoceptor antagonist), but not sulpiride (50mg/kg, i.p., a dopamine D2 receptor antagonist), cyproheptadine (3mg/kg, i.p., a 5-HT2 receptor antagonist), atropine (1mg/kg, i.p., a muscarinic receptor antagonist) 15mins before the administration of amentoflavone (50mg/kg; p.o.) significantly prevented its antiimmobility effect in the FST. CF extract and CF-2 significantly (p<0.05) attenuated anxiety by increasing the number of head-dips in the hole-board test, the time spent on the open arms in the EPM, and the exploration of the light chamber in the light/dark test. Pretreatment with flumazenil (3mg/kg, i.p., ionotropic GABA receptor antagonist) 15min before oral administration of amentoflavone (25mg/kg) significantly reduced the time spent in the open arms in EPM. It is concluded from the results obtained that amentoflavone produces its antidepressant effect through interaction with 5-HT2 receptor and α1-, and α2-adrenoceptors while the anxiolytic effect involved the ionotropic GABA receptor.

Analgesic and anti-inflammatory activities of Cnestis ferruginea Vahl ex DC (Connaraceae) methanolic root extract

ETHNOPHARMACOLOGICAL RELEVANCE Cnestis ferruginea Vahl ex DC (Connaraceae) is a shrub widely used in traditional African Medicine (TAM) for the treatment of various painful and inflammatory conditions. AIM OF THE STUDY The objective of this study was to investigate the analgesic and anti-inflammatory properties of the methanolic root extract of Cnestis ferruginea. MATERIALS AND METHODS Analgesic activity was evaluated using the acetic acid-induced writhing, formalin, tail clip, and hot plate tests in mice. The carrageenan- and egg albumin-induced rat paw oedema, formaldehyde-induced arthritis inflammation, and xylene-induced ear oedema tests were used to investigate the anti-inflammatory actions of Cnestis ferruginea. RESULTS The methanolic root extract of Cnestis ferruginea (100, 200, and 400mg/kg; p.o.) produced significant (P<0.05) dose-dependent inhibition of pain response elicited by acetic acid and formalin while also increasing the nociceptive reaction latency in the tail clip and hot plate tests. In respect of anti-inflammatory activity, Cnestis ferruginea caused significant (P<0.05) dose-dependent inhibition of oedema development in the carrageenan, egg albumin, formaldehyde, and xylene-induced inflammation tests. The effects of the extract in the various models were generally comparable to those of the standard drugs used. CONCLUSION The findings in this study suggest that the methanolic root extract of Cnestis ferruginea possesses analgesic and anti-inflammatory activities possibly mediated through peripheral and central mechanisms involving inhibition of release and/or actions of vasoactive substances (histamine, serotonin and kinins) and prostaglandins. The results justify the use of the extract in TAM for the treatment of painful and inflammatory conditions.

Mechanisms of analgesic and anti-inflammatory properties of Annona muricata Linn. (Annonaceae) fruit extract in rodents.

Unripe fruit of Annona muricata Linn. (Annonaceae) (soursop) is used in traditional African medicine for the treatment of neuralgia, rheumatism, and arthritic pain. This study sought to investigate the analgesic and anti-inflammatory effects of lyophilized fruit extract of Annona muricata (AM) in rodents. The analgesic activity was evaluated using the mouse writhing, formalin, and hot-plate tests while the anti-inflammatory action was investigated using the carrageenan-induced rat paw edema and xylene-induced ear edema tests. Pretreatment with AM (50, 100, and 200 mg/kg, p.o.) produced dose-dependent (P<.001) inhibition of writhes and formalin-induced pain in the late phase. AM and morphine produced time-course increase in pain threshold in hot-plate test. However, the analgesic effect elicited by AM was reversed (P<.05) by naloxone pretreatment. Similarly, the time-dependent increase in paw circumference induced by carrageenan was inhibited by AM treatment with peak effect (0.23±0.10 cm; P<.001, 200 mg/kg; 6 h), which was comparatively similar to that of diclofenac treated. Further, the xylene-induced ear edema was significantly reduced by AM (50 or 100 mg/kg) pretreatment; however, the anti-inflammatory effect elicited by AM was prevented by pretreatment of mice with N(G)-nitro-l-arginine (20 mg/kg, i.p., nitric-oxide synthase inhibitor) 15 min before AM (200 mg/kg, p.o.). The in vitro cyclooxygenase assay also showed that AM produced concentration-dependent inhibition of both cyclooxygenase (COX)-1 and COX-2 activity by 39.44%±0.05% and 55.71%±0.12%, respectively, at 100 μg/mL. In conclusion, A. muricata possesses analgesic effect through interaction with opioidergic pathway and anti-inflammatory property through inhibition of chemical mediators of inflammation.

Bioactivity guided isolation of analgesic and anti-inflammatory constituents of Cnestis ferruginea Vahl ex DC (Connaraceae) root.

ETHNOPHARMACOLOGICAL RELEVANCE Cnestis ferruginea (CF) Vahl ex DC (Connaraceae) is a shrub widely used in Traditional African Medicine (TAM) for the treatment of various painful and inflammatory conditions. AIM OF THE STUDY To isolate the active pharmacological constituents responsible for the anti-inflammatory and antinociceptive properties of the methanolic root extract of C. ferruginea. MATERIALS AND METHODS The crude methanolic root extract of CF was sequentially fractionated into four sub extracts (chloroform, ethylacetate, n-butanol and the remaining aqueous fraction). The aqueous-butanol fractions, having showed significant inhibition of inflammation and pain, were subjected to fractionation through successive column chromatography on silica gel 60-120 mesh, eluted with a gradient of CHCl(3)-MeOH. Sixty five fractions were collected; fractions with similar TLC profiles were grouped into seven major fractions (1-7). Fraction 4 being the most active in bioassay was rechromatographed to obtain CF-2. Analgesic activity was evaluated using the acetic acid-induced writhing and hot plate tests in mice while carrageenan induced paw oedema test was used to investigate the anti-inflammatory actions of the fractions obtained. RESULT Amentoflavone (CF-2) was isolated from the aqueous/n-butanol fraction. CF-2 (12.5, 25 and 100 mg/kg; p.o) produced significant (P<0.05) dose dependent inhibition of pain response elicited by acetic acid and increased nociceptive reaction latency in hot plate test. In addition it produced significant (P<0.05) dose-dependent inhibition of oedema in the carrageenan-induced inflammation. CONCLUSION This study showed that amentoflavone is responsible for the analgesic and anti-inflammatory activity of Cnestis ferruginea.

Protective effect of Cnestis ferruginea and its active constituent on scopolamine-induced memory impairment in mice: A behavioral and biochemical study

Abstract Context: Cnestis ferruginea Vahl ex DC (Connaraceae) (CF) is used in traditional African medicine in the management of CNS disorders. The degeneration and dysfunction of cholinergic neurons is closely associated with the cognitive deficits of Alzheimer’s disease (AD) and oxidative stress has been implicated in its pathogenesis. However, the influence of C. ferruginea on the cholinergic system and oxidative stress parameters has not been explored. Objective: The present study investigates the effect of methanol root extract of C. ferruginea and its active constituent amentoflavone (CF-2) on memory, oxidative stress and acetylcholinesterase (AChE) activity in scopolamine-induced amnesia. Materials and methods: Mice were orally treated with CF (25–200 mg/kg), CF-2 (6.25–25 mg/kg) for three days and memory impairment was induced by intraperitoneal injection of scopolamine (3 mg/kg). Memory function was evaluated by passive avoidance and Morris water maze tests. Biochemical parameters of oxidative stress and cholinergic function were estimated in brain after the completion of behavioral studies. Results: Scopolamine caused memory impairment along with increased AChE activity and oxidative stress in mice brain. Oral administration of CF and CF-2 significantly prevented scopolamine-induced memory impairment, inhibited AChE and enhanced antioxidant enzyme activity in the brain following scopolamine injection as compared to vehicle administration in scopolamine (i.p.)-treated mice that were comparable to the effect of tacrine. Discussion and conclusion: The study demonstrated that C. ferruginea and its constituent have significant protective effect against scopolamine-induced memory deficits in mice that can be attributed to their antioxidant and antiAChE activity.

Novel action of metformin in the prevention of haloperidol-induced catalepsy in mice: Potential in the treatment of Parkinson's disease?

Metformin is widely used to treat type II diabetes and other metabolic syndromes. In addition, it has been shown to increase neurogenesis, spatial memory formation and reduce the risk of Parkinsons disease. On this basis, the aim of the present study was the investigation of the protective potential of metformin in the haloperidol-induced catalepsy model of Parkinsons disease in mice. The effect of metformin (20 - 100mg/kg, p.o) on motor coordination was assessed using rotarod and forced swimming tests (FST), while the effect on memory function was evaluated using the Y-maze test. The neuroprotective activity was investigated in acute/chronic (21days) haloperidol-induced catalepsy in mice. On the 21st day, biochemical estimation of nitrosative and oxidative stress parameters was carried out. Metformin (50 or 100mg/kg, p.o.) did not affect motor coordination in rotarod test and FST but significantly reversed haloperidol-induced memory deficit (+35.50%) at 100mg/kg. Importantly, metformin significantly reduced the duration of catalepsy score during acute and chronic catalepsy tests as compared to trihexylphenidyl (reference standard). Intraperitoneal chronic injection of haloperidol (1mg/kg) significantly increased malondialdehyde and nitrite levels, while it significantly attenuated the activity of reduced glutathione, catalase and superoxide dismutase. Moreover, oral chronic administration of metformin significantly attenuated the haloperidol-induced increase of malondialdehyde and nitrite, as well as the deficit of glutathione and catalase. These findings suggest that metformin protects against haloperidol-induced catalepsy through inhibition of oxidative/nitrosative stress and has the potential for adjuvant action in the management of Parkinsons disease.

Combretum mucronatum and Capparis thonningii prevent scopolamine-induced memory deficit in mice

Context: Roots of Combretum mucronatum Schumach. & Thonn. (Combretaceae) and Capparis thonningii Schum. (Capparaceae) are used in southwest Nigeria in the treatment of inflammatory disorders and mental illness. Objective: This study evaluated the antidementic effect of the methanol root extracts of C. mucronatum and C. thonningii on scopolamine (3 mg/kg, i.p.) induced memory impairment in mice. Materials and methods: The effect of C. mucronatum and C. thonningii (50–200 mg/kg) administered orally for 3 days on memory impairments induced in mice by scopolamine was assessed in the passive avoidance and Morris water maze test and compared with that of tacrine (5 mg/kg, i.p.). The activities of acetylcholinesterase (AchE) and antioxidant enzymes were estimated in the brain after the completion of behavioral studies. Results: C. mucronatum and C. thonningii root extracts (50–200 mg/kg) reversed scopolamine-induced memory deficit with significant (p < 0.05) increase in transfer latency in passive avoidance test. Similarly, the extracts (200 mg/kg) ameliorated memory deficit as a result of significant (p < 0.001) decrease in escape latency and path length in Morris water maze test. The increased AChE activity induced by scopolamine was significantly (p < 0.05) inhibited by C. mucronatum and C. thonningii (100 and 200 mg/kg) treatment which was similar to the effect of tacrine. Both extracts significantly (p < 0.05) attenuated scopolamine-induced increase in oxidative stress parameters as well as restoration of glutathione activity. Discussion and conclusion: C. mucronatum and C. thonningii extracts possess significant anticholinesterase, antioxidant and antidementic properties, which may be useful in the management of Alzheimer’s disease.

Potential of novel phytoecdysteroids isolated from Vitex doniana in the treatment depression: Involvement of monoaminergic systems

Vitex doniana Sweet (Verbanaceae) is used in traditional African medicine for the treatment of neurological disorders including depression. In our previous studies, three new phytoecdysteroids were isolated from methanol stem bark extract of V. doniana (VD) (11β-hydroxy-20-deoxyshidasterone, 21-hydroxyshidasterone, and 2,3-acetonide-24-hydroxyecdysone) along with known ecdysteroids. This study was designed to investigate antidepressant-like effect of VD and the isolated phytoecdysteroids in behavioral models of despair, forced-swim test (FST) and tail-suspension test (TST) in mice. VD (100 and 200mg/kg, p.o.) treatment reduced (P<0.05) the duration of immobility in both tests without affecting the locomotor activity and exploratory behavior as observed in the open field test. Similarly, 21-hydroxyshidasterone, 11β-hydroxy-20-deoxyshidasterone, ajugasterone and 24-hydroxyecdysone acute oral treatments significantly reduced immobility time with peak effect at 10mg/kg, which was similar to the effect of conventional antidepressants (imipramine and fluoxetine) in the FST. Conversely, pretreatment of mice with yohimbine (1mg/kg, i.p., α2-adrenoceptor antagonist), ketanserin (5mg/kg, i.p., 5-HT2A/2C receptor antagonist) or sulpiride (dopamine D2 receptor antagonist) prevented the antidepressant-like effect of 21-hydroxyshidasterone while the effects of 11β-hydroxy-20-deoxyshidasterone and 24-hydroxyecdysone were blocked by yohimbine or ketanserin in the FST. Moreover, the anti-immobility effect elicited by ajugasterone was prevented by prazosin (62.5μg/kg, i.p., α1-adrenoceptor antagonist) pretreatment. Our findings demonstrated that V. doniana and its phytoecdysteroids constituents elicited antidepressant-like effect in behavioral paradigm of despair. Furthermore, 21-hydroxyshidasterone produces its antidepressant-like effect through interaction with α2-adrenoceptor, 5-HT2A/2C receptor and dopamine D2-receptors but 11β-hydroxy-20-deoxyshidasterone and 24-hydroxyecdysone effects depend on interaction with α2-adrenoceptor and 5-HT2A/2C receptors while ajugasterone produces its action through interaction with post-synaptic α1-adrenoceptors. Thus, phytoecdysteroids could play a pivotal role in the treatment of major depression.

Hepatoprotective and antioxidant activities of Hepacare®, a herbal formulation against carbon tetrachloride-induced liver injury.

BACKGROUND Hepacare(®) is a herbal formulation used to treat patients with sickle-cell anaemia complicated with jaundice, also recommended as a protective agent against liver damage due to chronic ingestion of alcohol. METHODS In vitro antioxidant properties of Hepacare(®) was determined using 1, 1- diphenyl-2-picryl-hydrazyl (DPPH), total antioxidant capacity, reducing power ability, and nitric oxide assays. Hepatoprotective effect of Hepacare(®) (50-400 mg/kg/day for 7 days, p.o.) was investigated in male Sprague Dawley rats against carbon tetrachloride (CCl(4) /olive oil, 1:1, 0.7 ml/kg, i.p.)-induced liver damage. At the end of the study, blood samples and liver tissue were assayed for biochemical and antioxidants parameters. RESULTS Hepacare produced concentration dependent inhibition of DPPH and nitric oxide activity with IC(50) of 48.50 and 55.00 µg/ml, respectively, it suppressed the absorbance of ABTS(.+) with total antioxidant capacity of 423.47±8.37 mg QUE/g. CCl(4) administration induced significant (P<0.001) elevation of serum aspartate transaminase (1.70 fold), alanine transaminase (1.60 fold), alkaline phosphatase (2.90 fold) and bilirubin (2.00 fold) in comparison to control. The increase in serum biomarker were dose-depen-dently reversed by Hepacare(®) pretreatment. More-over, CCl(4) pretreatment increased (P<0.001) malondialdehyde (MDA) (73.98%) and decreased (P<0.001) antioxidant enzymes level but Hepacare pretreatment produced dose-dependent attenuation of the increased MDA (3.84 fold) with enhancement of glutathione (3.08 fold), superoxide dismutase (2.08 fold), and catalase (3.14 folds) levels in comparison to CCl(4) treated group, similar to those of silymarin reference standard. CONCLUSION Hepacare was beneficial in the prevention of CCl(4)-induced hepatocellular injury, possibly by scavenging reactive free radicals, and boosting endogenous antioxidant systems.

Cyclooxygenase inhibitory compounds from Gymnosporia heterophylla aerial parts

Gymnosporia heterophylla (Celastraceae) is an African medicinal plants used to treat painful and inflammatory diseases with partial scientific validation. Solvent extractions followed by repeated chromatographic purification of the G. heterophylla aerial parts led to the isolation of one new β-dihydroagarofuran sesquiterpene alkaloid (1), and two triterpenes (2-3). In addition, eight known compounds including one β-dihydroagarofuran sesquiterpene alkaloid (4), and six triterpenes (5-10) were isolated. All structures were determined through extensive analysis of the NMR an MS data as well as by comparison with literature data. These compounds were evaluated for the anti-inflammatory activities against COX-1 and -2 inhibitory potentials. Most of the compound isolated showed non selective COX inhibitions except for 3-Acetoxy-1β-hydroxyLupe-20(29)-ene (5), Lup-20(29)-ene-1β,3β-diol (6) which showed COX-2 selective inhibition at 0.54 (1.85), and 0.45 (2.22) IC50, in mM (Selective Index), respectively. The results confirmed the presence of anti-inflammatory compounds in G. heterophylla which are important indicators for development of complementary medicine for inflammatory reactions; however, few could be useful as selective COX-2 inhibitor.