A systematic and comprehensive review on current understanding of the pharmacological actions, molecular mechanisms, and clinical implications of the genus Eucalyptus

The interest in the use of Eucalyptus genus members, in parallel with preclinical studies has been steadily growing over the last few decades in the field of pharmaceuticals, agriculture, cosmetics, food, etc. Eucalyptol (1,8-cineole or cineole), the main terpenoid constituent in Eucalyptus species, has been studied in both preclinical and clinical settings for its various pharmacologic activities. Investigations into the pharmacological activities of the genus Eucalyptus revealed that it manifests astounding potential in the treatment and management of respiratory disorders, COVID-19, pain, oral health, infectious diseases, cancer, etc. This review congregates and discusses the hitherto scattered data on Eucalyptus species morphology, chemical composition, some of its profusely investigated multifaceted therapeutic applications with insights into their molecular mechanisms, and clinical studies. The current understanding of the molecular mechanisms arising from cell lines, animal models, and clinical trials are emphasized. Lattermost, this review sheds light on various reported Eucalyptus-based formulations and relevant patents. Overall, this review aims to summarize and bridge the lacunae in the current research and offer a plethora of opportunities for the researchers engaged in the validation of the traditional claims and development in Eucalyptus utilization for safe and effective treatment of various diseases The systematic and comprehensive review was carried out by adhering to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements. PubMed, Scopus, ScienceDirect, Google Scholar, and Google patents databases were used to explore literature published till April 2021 by using relevant keywords. The systematic search retrieved 306 papers that were potentially relevant and after the selection procedure, 103 studies were included in this review and discussed. The evidence reviewed herein suggested that several Eucalyptus species possess anti-inflammatory, anti-microbial, anti-viral, anti-oxidant, anti-nociceptive, anti-cancer, anti-diabetic, etc., activities. Preclinical and clinical studies have shown that the Eucalyptus plant and its chemical constituents have enormous potential for disease prevention and treatment. Eucalyptus, an ancient and underutilized ally with its diverse therapeutic applications can give rise to a paradigm shift in the treatment regime of several diseases in this era of modern science.