Toxicity and safety of rosemary (Rosmarinus officinalis): a comprehensive review

Background

Rosemary (Rosmarinus officinalis) contains alkaloids, phenolic acids, saponins, tannins, diterpenes, flavonoids, and essential oils and has antioxidant, anti-inflammatory, antibacterial, anticancer, neuroprotective, cardioprotective, and hepatoprotective effects. While rosemary is generally considered safe for consumption and topical application, allergic reactions and dermatitis have been reported in some individuals. This paper provides an in-depth review of the current studies on rosemary toxicity, shedding light on its potential adverse effects and underlying mechanisms.

Methods

Google Scholar, PubMed, Scopus, and Web of Science were used to perform extensive research from the inception of these databases until February 2024.

Results

The toxicological effects explored include affecting several organs such as the liver and kidney by causing atrophic and degenerative changes, increasing blood urea nitrogen (BUN), aspartate aminotransferase (AST), and reducing total serum protein levels. Rosemary may induce reproductive toxicity by decreasing spermatogenesis in the testes, testosterone, sperm density, and motility. It might also trigger genotoxicity and anomalies in fetuses by increasing cytoplasmic membrane shrinkage, the formation of apoptotic bodies, internucleosomal deoxyribonucleic acid (DNA) fragmentation, and DNA ladder formation.

Conclusion

While rosemary is considered safe for food preservation, caution is warranted regarding chronic and high doses due to potential adverse effects on the kidneys, liver, reproductive system, and teratology. Additionally, it underscores the significance of considering drug interactions. The article also highlights the importance of considering toxicological data in realistic exposure situations and discusses the relevance of these findings for human health. Hence, further research is recommended to enhance our understanding of the toxicity profile associated with rosemary.