In-vitro antioxidant and antidiabetic potential of <i>Ephedra gerardiana</i> stem extract

Introduction: Gymnosperms hold significant economic and ethnomedicinal importance with diverse bioactivities, including antimicrobial, antioxidant, and anticancer properties. Ephedra gerardiana is traditionally used as an antidiabetic remedy. This study aimed to estimate the total phenolic and flavonoid contents, antioxidant activity, and antidiabetic potential of E. gerardiana. Methods: The plant’s stem powder was extracted in methanol and fractionated using hexane, dichloromethane, and aqueous. The extracts’ total phenolic and flavonoid contents were determined using Folin-Ciocalteu’s reagent and aluminium chloride method, respectively. The antioxidant and antidiabetic potential were assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and α-glucosidase inhibition assays. The toxicity of the fraction was evaluated in brine shrimp larvae. Results: The aqueous fraction contained a high phenolic content of 123.27 µg GAE (gallic acid equivalent), while the dichloromethane fraction had a high flavonoid content of 35.43 µg QE (quercetin equivalent). The aqueous fraction exhibited high antioxidant activity by scavenging DPPH with a half inhibitory concentration (IC50) value of 25.04 ± 1.57 µg/mL. Additionally, it showed strong antidiabetic activity by inhibiting α-glucosidase with an IC50 value of 4.33 ± 0.11 µg/mL. It was non-toxic to the brine shrimp nauplii. Conclusion: Ephedra gerardiana aqueous extract is rich in phenolic and flavonoid compounds and possesses strong antioxidant and antidiabetic properties. Thus, this plant might be used to prepare antidiabetic drugs after complementary trials.