Effect of methanol aqueous extract of Satureja montana and two of its bioactive components on memory in rats

Abstract

Purpose: To investigate the effect of Satureja montana Lamiaceae extract on cognition in rats.
 Methods: A total of 128 male, 8-week-old Wistar rats were used in this study. The rats were randomly and equally assigned to 16 groups (n = 8), which were orally given either saline and olive oil (two negative and two positive controls), S. montana Lamiaceae (250 and 500 mg/kg), RA (15 mg/kg), or carvacrol (500 mg/kg). For each experimental model, acute cold stress and chronic unpredictable mild stress models were used to induce memory impairment in rats. A new object recognition test was used to investigate cognition.
 Results: Acute stress did not produce a significant impact on cognition (p > 0.05). However, S. montana at a dose of 500 mg/kg significantly increased the discrimination index, relative to positive control rats (p = 0.001), while the lower dose of dry extract and RA had significant impacts only on time spent on new object investigation (p = 0.025 and p = 0.014, respectively). Chronic stress significantly reduced the duration of new object investigation but not the discrimination index (p = 0.037 and p = 0.009). Both doses of Satureja montana and RA increased levels of all studied parameters when compared to positive saline group, as well as novel object recognition when compared to RA and carvacrol (p < 0.05).
 Conclusion: Satureja montana and RA (but not carvacrol) have moderate effects on cognition abilities in rat models of acute and chronic stress. More research is required to establish the specific biochemical processes through which S. montana and RA affect memory.