Lecturer, University of Lagos, Nigeria
Medicinal plants are often employed in traditional medicine for the treatment of various diseases. Medicinal plants have been recognized as potential drug candidates because they possess drug-like properties. Medicinal plants have been shown in literature to possess neuropharmacological activity in animal models and beneficial effects in human studies. The research is focused on investigating the neuropharmacological activity and safety of medicinal plants claimed to be used for managing mental disorders in indigenous Traditional medicine practice using experimental mouse models. This involves preparing a suitable extract from the medicinal plant of interest, administering it at varying doses to groups of mice. Thereafter, the mice are examined for their behaviour on test apparatus such as the Elevated plus maze, open field box, hole board and forced swim test. The results of these tests will be compared with those of other mice groups treated with water (negative control) and that of a reference drug (positive control) to determine if treatment with the medicinal plant extract gave a significant effect relative to control on the mice. This study will give some details as to justify the use of such plants in Traditional medicine practice and their neuropharmacological properties and safety profile. The study will also lead to the development of standardized phytomedicine and discovery of potential sources of phytomolecule(s)/lead compound(s) with potential therapeutic effect in the treatment of CNS disorders.
Abstract: The efficacy of current antidepressant drugs has been compromised by adverse effects, low remission and delay onset of action necessitating the search for alternative agents. Methyl jasmonate (MJ), a bioactive compound isolated from Jasminum grandiflorum has been shown to demonstrate antidepressant activity but its mechanism of action remains unknown. Thus, the role of monoaminergic systems in the antidepression-like activity of MJ was investigated in this study.Mice were given i.p. injection of MJ (5, 10 and 20mg/kg), imipramine (10mg/kg) and vehicle (10mL/kg) 30min before the forced swim test (FST) and tail suspension test (TST) were carried out. The involvement of monoaminergic systems in the anti-depressant-like effect of MJ (20mg/kg) was evaluated using p-chlorophenylalanine (pCPA), metergoline, yohimbine, prazosin, sulpiride and haloperidol in the TST.MJ significantly decrease the duration of immobility in the FST and TST relative to control suggesting antidepressant-like property. However, pretreatment with yohimbine (1mg/kg, i.p., an α2-adrenergic receptor antagonist) or prazosin (62.5μg/kg, i.p., an α1-adrenoceptor antagonist) attenuated the antidepressant-like activity of MJ. Also, pCPA; an inhibitor of serotonin biosynthesis (100mg/kg, i.p) or metergoline (4mg/kg, i.p., 5-HT2 receptor antagonist) reversed the anti-immobility effect of MJ. Sulpiride (50mg/kg, i.p., a D2 receptor antagonist) or haloperidol (0.2mg/kg, i.p., a dopamine receptor antagonist) reversed the anti-immobility effect of MJ.The results of this study suggest that serotonergic, noradrenergic and dopaminergic systems may play a role in the antidepressant-like activity of MJ.
Pub.: 19 Aug '17, Pinned: 30 Nov '17
Abstract: Different parts of Murraya paniculata have been used traditionally for treating several ailments including mental disorders. The present study was designed to evaluate the antianxiety and antidepressant potential of M. paniculata leaves using elevated plus maze model and forced swim test, respectively.Extracts of M. paniculata made with petroleum ether (60-80 °C), chloroform, ethanol and water were evaluated for antianxiety and antidepressant activity. The anxiolytic chloroform extract was subjected to column chromatography, yielding five fractions (F1-F5). Fraction F5 (100 mg/kg), which showed notable anxiolytic activity, was further chromatographed to get four subfractions (F5.1-F5.4). Simultaneously, the ethanol extract was partitioned with ethyl acetate to obtain ethyl acetate soluble fraction (EASF) and ethyl acetate insoluble fraction. Phytochemical screening of bioactive extracts/fractions and detection of mahanimbine in M. paniculata leaf extract by thin-layer chromatography was also carried out.Fraction F5.3 (25 mg/kg) and EASF (20 mg/kg) showed significant anxiolytic and antidepressant activity, respectively. Thin-layer chromatography and phytochemical screening demonstrated the absence of mahanimbine in M. paniculata leaves. Coumarins were observed to be responsible for the anxiolytic activity.The results validate the traditional use of M. paniculata leaves in the treatment of mental disorders.
Pub.: 01 Jul '17, Pinned: 30 Nov '17
Abstract: Ginsenoside Rb1, a 20 (S)-protopanaxadiol, is a major active ingredient of Panax ginseng C.A. Meyer, which as the King of Chinese herbs, has been wildly used for the treatment of central nervous system diseases. Previous studies have shown that 20 (S)-protopanaxadiol possesses a novel antidepressant-like effect in the treatment of depression, whereas ginsenoside Rb1 in depression has been rarely reported.The present study was to investigate the antidepressant-like effect of ginsenoside Rb1 and its relevant mechanisms.The whole experiment was divided into two parts: one part we examined the antidepressant-like effect of ginsenoside Rb1 with open-field test (OFT), tail suspension test (TST), forced swim test (FST), 5-HTP induced head-twitch and reserpine response in mice, another part we used chronic unpredicted mild stress (CUMS) model to further explore the antidepressant-like effect of ginsenoside Rb1 with caffeine, fluoxetine and p-Chlorophenylalanine (PCPA) in rats. Furthermore, the levels of monoamine neurotransmitters of NE, 5-HT, DA and their metabolites 5-HIAA, DOPAC, HVA were all measured by ELISA kits after the CUMS protocol.Our data indicated that 7 days treatment with ginsenoside Rb1 (4, 8, 10mg/kg, p.o.) significantly decreased immobility time in the FST and TST in mice, and played important roles in mice which were induced by 5-HTP (200mg/kg, i.p.) and reserpine (4mg/kg, i.p.). On the basis of CUMS model, 21 days treatment with ginsenoside Rb1 not only had effective interactions with caffeine (5mg/kg, i.p.), fluoxetine (1mg/kg, i.p.) and PCPA (100mg/kg, i.p.), but also significantly up-regulated the 5-HT, 5-HIAA, NE and DA levels in CUMS rats' brain, whereas HVA and DOPAC had no significant difference. Moreover, there was no alteration in spontaneous locomotion in any experimental group.These results suggest that ginsenoside Rb1 exhibits significant antidepressant-like effect in behavioral tests, chronic animal model and drug interactions, its mechanisms mainly mediated by central neurotransmitters of serotonergic, noradrenergic and dopaminergic systems.
Pub.: 17 Apr '17, Pinned: 30 Nov '17