Cognition enhancing effect of rosemary (Rosmarinus officinalis L.) in lab animal studies: a systematic review and meta-analysis

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.

Alzheimer's disease: In silico study of rosemary diterpenes activities

“…Numerous medicinal, spice, and aromatic plants exhibit remarkable biological properties. Among these, rosemary, thriving abundantly in Mediterranean climates ( Hussain et al, 2022 , Filiptsova et al, 2017 ), stands out as a versatile herb attributed with preventing “brain weakness”. Regarded as “the herb of remembrance” ( Dehghan et al, 2022 ), studies have reported positive impact on memory in both humans and animals from inhalation of rosemary aroma (whether from burning rosemary or heated essential oils extracted from rosemary) ( Dehghan et al, 2022 , Petiwala et al, 2013 , Habtemariam, 2016 ).…”

Efficacy and safety of herbal medicine on dementia and cognitive function: An umbrella review of systematic reviews and meta‐analysis

“…This method can help summarize the evidence from multiple systematic reviews and meta‐analyses, assessing the strength of evidence and extent of possible biases to ascertain the quality of evidence. To date, several systematic reviews and meta‐analyses (SRMAs) focusing on the antidementia effects of herbal medicines and medicinal plants have been recently reported (Hussain et al, 2022; Liao et al, 2020; Wang et al, 2020; Zhu, Mei, Zhang, Xie, & Lang, 2019). To synthesise the most updated comprehensive evidence, we performed the umbrella review to systematically summarize the effects of various types of herbal medicines used for improving cognitive function in healthy volunteer or patients with dementia for determining benefits of each herb from previously published systematic reviews and meta‐analyses to provide the wide picture for real‐world clinical practice.…”