Moroccan antidiabetic medicinal plants: Ethnobotanical studies, phytochemical bioactive compounds, preclinical investigations, toxicological validations and clinical evidences; challenges, guidance and perspectives for future management of diabetes worldwide

Background: Moroccan flora is rich with medicinal plants that are widely used in traditional medicine for the treatment of various diseases including diabetes. These plants possess several classes of bioactive molecules, which belong to different chemical families such as phenolic acids, flavonoids, terpenoids and alkaloids. Scope and approach: This review highlights the published reports on the antidiabetic properties of Moroccan medicinal plants. The mechanism of action of these plants and their secondary metabolites were discussed in detail. Clinical trials on the antidiabetic active constituents were summarized demonstrating the potential application of these natural treasures to be developed as potent antidiabetic agents. Key findings and conclusions: were reported to be used in the treatment of diabetes in Morocco. Among these medicinal plants, the antidiabetic activity was evaluated for 15 species in vitro and 30 species in vivo. The in vitro studies showed significant inhibition of enzymes involved in the intestinal metabolism of carbohydrates. The in vivo reports revealed that the extracts and essential oils of these plants exhibited several antidiabetic effects such as a decrease of blood glucose and an increase of insulin secretion. Phytochemical analysis of the active plants revealed the presence of 148 secondary metabolites. These compounds belong to different chemical classes such as terpenoids, flavonoids, alkaloids, phenolic acids, and fatty acids. Among the identified compounds, 95 were evaluated for their antidiabetic activity. The results showed that these compounds manage diabetes by several mechanisms such as enzymatic inhibition, interference with glucose and lipid metabolism signaling pathways, and the inhibition and/or the activation of gene expression involved in glucose homeostasis. Eighteen active compounds reached clinical trials and showed impressive results in controlling diabetes and its manifestations.