In Vitro Screening of Medicinal Plants Used in Mexico as Antidiabetics with Glucosidase and Lipase Inhibitory Activities

This work shows the inhibitory effect on glucosidase and lipase enzymes of 23 medicinal plants described as traditional treatments for diabetes in several Mexican sources. Hydroalcoholic extracts of selected plants were evaluated at 1 mg/mL for glucosidase and 0.25 mg/mL for lipase inhibitory activities, respectively. Camellia sinensis, acarbose, and orlistat were used as positive controls. Dose-response curves were done with the most active species. Sixty percent of all tested extracts inhibited more than 25% of α-glucosidase activity. C. sinensis displayed an inhibition of 85% (IC(50) = 299 μg/mL), while Ludwigia octovalvis and Iostephane heterophylla showed the highest inhibition (82.7 %, IC(50) = 202 μg/mL and 60.6%, CI(50) = 509 μg/mL, resp.). With respect to lipase activity, L. octovalvis and Tecoma stans were the most inhibiting treatments (31.4%, IC(50) = 288 μg/mL; 27.2%, IC(50) = 320 μg/mL), while C. sinensis displayed 45% inhibition (IC(50) = 310 μg/mL). These results indicate that a high proportion of plants used in Mexico as treatment for diabetes displays significant inhibition of these digestive enzymes.