Rhodiola rosea L- Standardized Extract on Passive Avoidance in Rats

Background: Rhodiola rosea L. originates from the plant family Crassulaceae and is known as an adaptogen increasing resistance to various stressors. The present study aimed to evaluate the effects of a commercially available standardized Rhodiola rosea L. extract administered intraperitoneally on cognitive processes in naive rats by using two passive avoidance tests. Methodology/Principal findings: Male Wistar rats were pre-treated for 10 days with extract from Rhodiola in doses 50 mg/kg or 100 mg/kg. Step-through and step-down tests were used. Following two days of training memory retention tests were performed on the 3rd and 10th day. A criterion for step-through test was latency of reaction 180 s and for step-down test latency of reaction 60 s. The statistical evaluation was done in SPSS17.0. In step-down test rats with both doses of extract decreased latency time during learning session and on long memory retention test, compared to the same day controls. In step-trough test rats with the high dose of the extract decreased significantly the latency time during two days of learning session and on short and long memory retention tests, compared to the same day controls. Conclusions: Based on our results it can be speculated that the studied extract of Rhodiola influences passive avoidance condition stimuli reactions in dose-dependent manner. To clarify the exact influence of the studied extract more behavioral tests should be performed with higher doses of the studied extract. Our observations reveal some stimulating effect of Rhodiola standardized extract on the formation of memory traces.