Alpha-amylase Inhibitory Activity of Extracts from Algerian Calamintha nepeta (L.)

Background: Calamintha nepeta is a plant from the Lamiaceae family that is known for its traditional use to treat diabetes among Algerian populations. However, till now, there has been no research work to confirm this activity. Objectives: This work aimed to evaluate the amylase inhibitory activity of essential oils and phenolic compounds from both methanolic and aqueous extracts of Algerian Calamintha nepeta (L.). Methods: The essential oil was obtained by hydrodistillation and analyzed using GC and then GC/MS. Aqueous and methanolic extracts were obtained from the remains of the hydrodistillation. Total phenolic compounds were quantified using the Folin-Ciocalteu method. The amylase inhibitory activity of the extracts was determined by testing their ability to inhibit alpha-amylase. Results: The extraction yield was 0.67 % (w/w) for the essential oil, and 11.85 and 4.38 % (w/w) for the aqueous and methanolic extracts, respectively. The essential oil analysis revealed that menthone, menthol, pulegone, and pulegone oxide were the main components of the oil. The total phenolic compounds in the aqueous and methanolic extracts were 41.81 and 32.92 mg GAE/g DW, respectively. The extracts inhibited α-amylase activity with IC50 values of 24.46, 31.54, and 115.47 mg/ml for the methanolic extract, essential oil, and aqueous extract, respectively. Conclusion: The different extracts of Calamintha nepeta showed an interesting composition and significant amylase inhibitory activity, emphasizing their successful use in traditional medicine.