Nardostachys jatamansi extract prevents chronic restraint stress-induced learning and memory deficits in a radial arm maze task

Nardostachys jatamansi is traditionally used in alternative medicine for treatment of neuropsychiatric disorders. We investigated the potential of N. jatamansi extract (NJE) in protecting against chronic stress-induced impairments in spatial learning and memory. The rats were exposed to 21 days of chronic restraint stress and simultaneously received 100 mg or 200 mg/kg body weight of NJE following which acquisition and retention of hippocampus-dependent spatial memory were tested in a partially-baited eight arm radial maze. Animals treated with 200 mg/kg body weight NJE had learning curves comparable to control unstressed animals, made significantly more correct choices (38%, P < 0.001), and fewer reference memory errors (53%, P < 0.01) on the eighth day of training compared to untreated stressed animals as well as stressed animals which received vehicle or a lower dose (100 mg/kg) of NJE. NJE-treated animals also made significantly higher correct choices (31%, P < 0.001) than untreated animals in a retention test 10 days after the training period. We propose that NJE has a protective effect of stress-induced impairments in hippocampus-dependent learning and memory behavior in rats.