Abstract
Patients with mild cognitive impairment eventually progress to Alzheimer's disease (AD) causing a strong impact on public health. Rosmarinus officinalis has long been known as the herb of remembrance and can be a potential cognition enhancer for AD. The aim of this review was to summarize the qualitative and quantitative aspects of R. officinalis and its active constituents in enhancing cognition. A structured search was conducted on Google Scholar and PubMed to find relevant studies that assessed the effect of R. officinalis extract or any of its active constituents on cognitive performance in animals. The following information was extracted from each study: 1) article information; 2) characteristics of study animals; 3) type of intervention: type, dose, duration, and frequency of administration of R. officinalis; and 4) type of outcome measure. Data were analyzed using Review Manager and meta-analysis was performed by computing the standardized mean difference. Twenty-three studies were selected for qualitative analysis and fifteen for meta-analysis. From the fifteen included papers, 22 with 35 comparisons were meta-analyzed. Effect sizes for intact and cognitively impaired animals were 1.19 (0.74, 1.64) and 0.57 (0.19, 0.96), indicating a positive effect on both groups. The subgroup analyses showed substantial unexplained heterogeneity among studies. Overall, R. officinalis improved cognitive outcomes in normal and impaired animals, and results were robust across species, type of extract, treatment duration, and type of memory. However, studies had a considerable amount of heterogeneity, and subgroup analyses failed to find any heterogeneity moderator.
Highlights
Mild cognitive impairment is a deficit in memory and cognition with no physical limitation in daily activities
Twenty-eight papers met our inclusion requirements, out of which twenty-one [34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54] focusing on the cognitive impact of R. officinalis on animal models were included in the qualitative study and 15 from those were further chosen for quantitative analysis [34,35,36,37,38,39,40,41,42,43,44,45,46,47,48]
The studies were conducted between 2004 and 2020 in different countries and had in total 35 comparisons; one study was performed with zebra fish as the study animal, 11 studies used rats, and 10 studies were performed on mice
Summary
Mild cognitive impairment is a deficit in memory and cognition with no physical limitation in daily activities. This impairment advances with age and is expected to increase in the future with an increasing older population worldwide. It is necessary to delay this progression for which there are many strategies including the use of cognitive enhancers ( referred as nootropics). N-methyl-d-aspartic acid receptor antagonist (memantine) [4,5]. These drugs are the mainstay of treatment, but their effectiveness is controversial, and each has its own set of adverse effects and limitations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
