Effects of piperine on memory and behavior mediated via monoamine neurotransmiters

Abstract

Cure of cognitive disorders such as amnesia, attention deficit and Alzheimer's disease is still a nightmare in the field of medicine. Nootropic agents such as piracetam, aniracetam and choline esterase inhibitors like Donepezil^® are being used for improving memory, mood and behavior, but the resulting side effects associated with these agents have made their applicability limited. Oxygen free radical, the harmful byproduct of oxidative metabolism is known to cause organic damage of living system. They are implicated in various pathological events such as mutagenesis, ageing and neurodegenerative disorder. Indian system of medicine emphasizes use of herbs, and nutraceuticals or life style changes for controlling age related neurodegenerative disorders.
In the present study, the effect of isolated piperine from Piper nigrum fruits on memory and behavior mediated via monoamine neurotransmitters was investigated. Elevated plus maze and passive avoidance paradigms were used as exteroceptive behavioral models, where as scopolamine induced amnesia was the interoceptive behavioral model. The effects on lithium induced head twitches, clonidine-induced hypothermia, and halperidol-induced catalepsy were also observed to study the effect on serotonin, noradrenaline and dopamine mediated behavior, respectively. Piperine isolated from P. nigrum exhibited prominent nootropic activity, reversed clonidine-induced hypothermia, decreased lithium induced head twitches and significantly delayed haloperidol induced catalepsy at a dose of 10 mg/kg. The alkaloid modified 5-HT and NA mediated behavior. Hence, piperine from the fruits of P. nigrum can be employed as a potential nootropic agent.