Antiamnesic evaluation of C. phlomidis Linn. bark extract in mice / Avaliação da atividade antiamnésica da casca de C. phlomidis Linn. em camundongos

Clerodendron phlomidis Linn. (Verbenaceae) is known as Agnimantha in sanskrit. Bark of the plant is used in treating various nervous disorders. In the present study C. phlomidis was investigated for its potential as a nootropic agent in mice. The aqueous extract of the C. phlomidis (100 and 200 mg/kg, p.o.) was administered for 6 successive days to both young and aged mice. Exteroceptive behavioral models such as elevated plus maze and passive avoidance paradigm were employed to evaluate short term and long term memory respectively. Scopolamine (0.4 mg/kg, i.p.), diazepam (1 mg/kg, i.p.) were employed to induce amnesia in mice. To delineate the mechanism by which C. phlomidis exerts nootropic action, its effect on brain acetyl cholinesterase levels were determined. Piracetam (200 mg/kg, i.p.) was used as a standard nootropic agent. Pretreatment with C. phlomidis (100 and 200 mg/kg, p.o.) for 6 successive days significantly improved learning and memory in mice. It reversed the amnesia induced by scopolamine, diazepam and natural ageing. It also decreased the acetyl cholinesterase levels in the whole brain. The bark of C. phlomidis can be of enormous use in the management of treatment of cognitive disorders such as amnesia and Alzheimer's disease.

Clerodendron phlomidis Linn. (Verbenaceae) é conhecida como Agnimantha em sânscrito. A casca da planta é utilizada no tratamento de várias disfunções neurológicas. No presente estudo, C. phlomidis foi investigada pelo seu potencial como agente nootrópico em camundongos. O extrato aquoso de C. phlomidis (100 e 200 mg/kg, p.o.) foi administrado por seis dias consecutivos tanto para camundongos jovens quanto para idosos. Modelos comportamentais exteroceptivos, tais como labirinto em cruz elevada e paradigma de esquiva passiva foram empregados para avaliar memória recente e tardia, respectivamente. Escopolamina (0,4 mg/kg i.p.), diazepam (1 mg/kg i.p.) foram empregados para induzir amnésia em camundongos. A fim de delinear o mecanismo pelo qual C. phlomidis exerce ação nootrópica, determinaram-se seus efeitos nos níveis cerebrais de acetilcolinesterase. Utilizau-se piracetam (200 mg/kg i.p.) como nootrópico padrão. O pré-tratamento com C. phlomidis (100 e 200 mg/kg, p.o.) por seis dias sucessivos melhorou, significativamente, o aprendizado e a memória em camundongos. Ela reverteu a amnésia induzida por escopolamina, diazepam e pelo envelhecimento normal. Também, diminuíram-se os níveis de acetilcolinesteraseem todo o cérebro. A casca de C. phlomidis pode ser de grande uso no tratamento de disfunções cognitivas, como amnésia e doença de Alzheimer.

Evaluation of the antiamnesic effects of Phyllanthus amarus in mice / Evaluación de los efectos antiamnésicos de Phyllanthus amarus en ratones

Alzheimer’s disease is a progressive neurodegenerative disorder characterized by a gradual decline in memory. Phyllanhus amarus is commonly known as bhumi amla in India and is traditionally used since centuries in ayurveda medicine. The present study was undertaken to investigate the effects of Phyllanhus amarus (PA) on cognitive functions and brain cholinesterase activity in mice. Elevated plus maze and passive avoidance paradigm were employed to evaluate learning and memory parameters. Three doses (50, 100 and 200 mg/kg, p.o.) of aqueous extract of PA were administered for 8 successive days to both young and aged mice. PA (50, 100 and 200 mg/kg) produced a dose-dependent improvement in memory scores of young and older mice. PA also reversed successfully the amnesia induced by scopolamine (0.4 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.). Interestingly, brain acetyl cholinesterase activity was also reduced. The underlying mechanism of action for the observed nootropic effect may be attributed to pro-cholinergic activity exhibited by PA in the present study. Therefore, it would be worthwhile to explore the therapeutic potential of PA in the management of patients with cognitive disorders.

La enfermedad de Alzheimer es un desorden neuro-degenerativo progresivo que se caracteriza por una disminución gradual de la memoria. El Phyllanhus amarus (PA), se conoce comúnmente como bhumi amla en la India, y tradicionalmente se ha usado durante siglos en la medicina ayurvédica con diversas indicaciones. Este estudio se hizo para investigar los efectos del PA en las funciones cognitivas y en la actividad de la colinesterasa cerebral. Se emplearon las pruebas de laberinto complejo y el paradigma de evitación pasiva a fin de evaluar los parámetros de memoria y aprendizaje. Se administraron tres dosis (50, 100 y 200 mg/kg vía oral) de extracto acuoso de PA durante 8 días sucesivos, tanto a ratones jóvenes como adultos. El PA (50, 100 y 200 mg/kg) produjo una mejoría que depende de la dosis en los puntajes de memoria en los ratones jóvenes y en los adultos. EL PA también revirtió con éxito la amnesia inducida por escopolamina (0.4 mg/kg, i.p.) y diazepam (1 mg/kg, i.p.). Es de interés anotar que asimismo disminuyó la actividad de la acetil colinesterasa cerebral. El mecanismo de acción subyacente para el efecto nootrópico observado se puede atribuir a la actividad pro-colinesterasa demostrada en el presente estudio. Por tanto, se justificaría explorar el potencial terapéutico del PA en el manejo de pacientes con desórdenes cognitivos.

Evaluation of nootropic potential of Ocimum sanctum Linn. in mice.

Dementia is one of the age related mental problems and a characteristic symptom of various neurodegenerative disorders including Alzheimer's disease. Certain drugs like diazepam, barbiturates and alcohol disrupt learning and memory in animals and man. However, a new class of drugs known as nootropic agents is now used in situations where there is organic disorder in learning abilities. The present work was undertaken to assess the potential of O. sanctum extract as a nootropic and anti-amnesic agent in mice. Aqueous extract of dried whole plant of O. sanctum ameliorated the amnesic effect of scopolamine (0.4 mg/kg), diazepam (1 mg/kg) and aging induced memory deficits in mice. Elevated plus maze and passive avoidance paradigm served as the exteroceptive behavioral models. O. sanctum extract decreased transfer latency and increased step down latency, when compared to control (piracetam treated), scopolamine and aged groups of mice significantly. O. sanctum preparations could of beneficial in the treatment of cognitive disorders such as dementia and Alzheimer's disease.