Rosemary (Rosmarinus officinalis L.) improves biochemical outcomes in diabetes mellitus: a systematic review and meta-analysis of animal studies

We report on the systematic review and meta-analysis concerning the efficacy of R. officinalis in treating diabetes mellitus (DM) in animals. This study followed the PRISMA guideline and the protocol was registered in PROSPERO (CRD42021250556). The research was duplicated in the PubMed, Scopus, ScienceDirect, Web of Science, and Virtual Health Library (VHL) databases until December 31st, 2022. No restrictions have been set for language publication. Twenty-three (23) experimental studies of type-1 diabetes mellitus (T1DM) met the eligibility criteria and were included in the qualitative analysis, whereas eighteen (18) underwent a meta-analysis. The R. officinalis derivatives significantly decreased fasting plasma glucose (MD: −120.84 [95% CI; −157.09, −84.59]); increased insulin release (MD; +3.73 [95% CI; +3.17, +4.29]); dwindled blood urea nitrogen (MD: −24.84 [95% CI; −34.78, −14.90]) and creatinine (MD: −0.40 [95% CI; −0.74, −0.06]) levels; and ameliorated liver function or repaired liver damage by decreasing ALT (MD: −36.42; [95% CI; −55.69, −17.14]) and AST (MD: −24.05 [95% CI; −37.84, −10.27]) enzyme levels compared to vehicle control group. Moreover, R. officinalis derivatives improved the lipid profile of diabetic animals by reducing LDL-c levels (MD: −11.74 [95% CI; −21.27, −2.21]). R. officinalis is a nutraceutical that may help in the management of T1DM and its complications. However, some gaps need to be taken into account for this evidence. Greater attention is needed for an analytical standardization of Rosemary extracts besides the demand for high-quality clinical studies dealing with the efficacy of this phytomedicine.