Calamintha incana (Sm.) Helder: A New Phytoextract with In Vitro Antioxidant and Antidiabetic Action

This study aimed to assess the antioxidant and antidiabetic properties of ethanolic phytoextracts of Calamintha incana (Sm.) Helder leaves. Initially, the chemical characterization of the phytocomplex was performed using high-performance liquid chromatography (HPLC)/mass spectrometry (MS). The cytotoxicity of the ethanolic extract was assessed using an MTT assay in HepG2 cells. Subsequently, antioxidant activity was evaluated using a DPPH test. Finally, enzymatic tests with α-amylase, α-glucosidase, pancreatic lipase, and dipeptidyl peptidase IV (DPP-IV) were performed to evaluate their effects on glucose metabolism. The chemical composition of the extract is p-linolenic acid (13.2%), myristic acid (12.1%), and p-cymene (10.5%). The extract demonstrated low toxicity, with none of the tested concentrations inducing 50% cell death. Furthermore, the ethanolic extract revealed potent antioxidant activity using DPPH (IC50 was 35.9 ± 0.7 µg/mL) and reducing power capacity (IC50 was 90.3 ± 0.8 µg/mL). Regarding the antidiabetic activity, the extract caused a significant inhibition of α-amylase, α-glucosidase (IC50 46.3 ± 0.2, 56.8 ± 0.1 μg/mL, respectively), weak inhibition of pancreatic lipase and no notable inhibition of dipeptidyl peptidase IV. In conclusion, C. incana has antioxidant and antidiabetic properties and appears to exert insulin-independent hypoglycemic action.