Mexican hypoglycemic medicinal plants: extraction advances and microencapsulation challenges for antidiabetic applications

Abstract México is home to one of the richest medicinal floras in the world. However, only a small fraction of this vast resource has been successfully translated from ethnobotanical knowledge into stable, bioactive antidiabetic preparations. This review aims to address and explore this significant gap. In adherence to the PRISMA 2020 guidelines, a total of 124 species native to Mexico with documented hypoglycemic activity were identified. Among these, only 32 species have undergone microencapsulation, and notably, only three— Myrtillocactus geometrizans, Phaseolus lunatus, and Tecoma stans —have had their glucose-lowering activity experimentally confirmed in the final microcapsule form. Flavonoids (52.4% of species) and phenolic acids (35.5%) dominate the phytochemical profiles, exerting their effects primarily through the inhibition of α-amylase and α-glucosidase, suppression of hepatic gluconeogenesis, and modulation of GLUT4 translocation. Maceration, infusion, and decoction dominate the extraction methods reported, even for compounds like chlorogenic acid and rutin, whose ester and glycosidic bonds are hydrolyzed under the specific heat and prolonged contact times characteristic of these techniques. Spray drying is similarly the predominant encapsulation method, with maltodextrin, gum arabic, and their blends being the most commonly used wall materials. Encapsulation efficiencies range from 19.9 to 99%, and average particle sizes vary from approximately 190 nm–27.2 µm. The evidence presented here suggests that extraction polarity, compound stability, and wall composition should be considered simultaneously rather than sequentially. Based on this, a set of compound-class-specific workflows, integrating extraction and encapsulation processes, is proposed.