Alpha-glucosidase and amylase inhibitory effects of Eruca vesicaria subsp. longirostris essential oils: synthesis of new 1,2,4-triazole-thiol derivatives and 1,3,4-thiadiazole with potential inhibitory activity

Abstract

Context: The substantial increase in the number of diabetics has encouraged the search for new pharmacological strategies to face this problem. In this regard, triazole and its derivatives have attracted considerable attention for the past few decades due to their pharmacological significance. Objective: Evaluation of the inhibitory activity of α-glucosidase and α-amylase in essential oils extracted from plant Eruca vesicaria (L) Cav. subsp. longirostris (Brassicaceae) (EVL) and to verify whether the triazoles and thiadiazol bearing the lipophilic 4-methylthiobutyl group synthesized from the essential oil contribute to this activity. Materials and methods: The essential oils were extracted by hydrodistillation from leaf, stem, root, and fruit of EVL, and their chemical compositions were analyzed by gas chromatography and gas chromatography-mass spectrometry. We present here the synthesis of three new types of 1,2,4-triazole-thiol and 1,3,4-thiadiazol and the structures were confirmed by NMR, mass spectrometry. The α-glucosidase and α-amylase inhibitory activities were investigated in vitro. Results: The main compound in fruit, stem, and root was erucin (96.6, 85.3, and 83.7%, respectively). The three essential oils of the fruit, stem, and root have strong inhibitory activity on α-glucosidase and α-amylase; IC50 values of roots were 0.81 ± 0.02 μg/mL and 0.13 ± 0.01 μg/mL, respectively. Derivatives 1 b, 2 b, 3 b, and 2c showed remarkable inhibitory activity against α-glucosidase with potencies better than that of acarbose with IC50 values ranging between 0.49 and 1.43 μM. Conclusions: Current results indicate that ECL fruit essential oil can be used as a natural precursor for the synthesis of triazoles as potential hypoglycemic agents.