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

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

Chemical composition and biological evaluation of the Tunisian Achillea cretica L. essential oils

The essential oils (EOs) of different organs (flowers, vegetative parts (stems + leaves) and roots) of Achillea cretica were investigated. Antioxidant and antimicrobial activity of the essential oils were also evaluated. They have been analyzed by a combination of GC and GC/MS. Twenty-five, twenty-nine and twenty-five compounds, accounting for 97.9%, 98.80% and 96.20% of the root, (stem + leaf), and flower oils, were identified, respectively. The EOs were rich in monoterpenes (camphor, borneol, camphene and 1,8-cineola) and camphor was identified as a major constituent. Furthermore, the antioxidant activity was evaluated by DPPH, ABTS and ferric reducing assays. The isolated oils showed significant radical-scavenging activity evidenced by IC50 value for ABTS radical (in between IC50 =62 µg/mL and IC50 = 70 µg/mL). The antibacterial activity was tested against two Gram-positive and three Gram-negative bacteria using the broth dilution method. The flowers essential oil shows an excellent inhibitory effect on S. aureus

Semi-synthesis of new antimicrobial esters from the natural oleanolic and maslinic acids

International audienc