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

Effect of solvents extraction on phytochemical components and biological activities of Tunisian date seeds (var. Korkobbi and Arechti)

Abstract Background The interest in natural antioxidants, especially polyphenols, is growing more and more thanks to their positive contribution to human health. Thus, the prevention from the harmful action of oxidative stress which has been involved in many diseases such as cancer, inflammation diabetes, and cardiovascular illness. Recent research proved the bioactive compounds richness of date seeds which could be a good biological matrix of natural antioxidants. Unfortunately, an important quantity of Tunisian dates seed is discarded yearly. Methods In this study, different solvents extraction (water, methanol, absolute acetone and aqueous acetone 80%) were used and the evaluation of its effect on phytochemical level, in vitro antioxidant activities, in vitro hyperglycemia key enzymes inhibition and in vivo anti-inflammatory proprieties were established for Tunisian date seeds. Results The result revealed that the polar solvent exhibited the highest amount of bioactive compounds. The correlation between polyphenol compounds and the antioxidant potentiality explains the powerful effect of used polar solvents on inflammation, TBARS and hyperglycemia inhibition. Furthermore, it showed its higher capacity to scavenge radicals. Conclusions Therefore, this big waste of Tunisian seeds could be used as cheap source of natural antioxidant compounds which are considered as a health challenge for the poor countries

Chemical composition and biological activities of Eruca vesicaria subsp. longirostris essential oils

Context To date, there are no reports to validate the Tunisian traditional and folklore claims of Eruca vesicaria (L) Cav. subsp. longirostris (Brassicaceae) for the treatment of disease. Objective Investigation of the chemical composition antimicrobial and antioxidant activity of essential oils from Eruca longirostris leaves, stems, roots and fruits. Materials and methods The essential oils of E. longirostris from leaves, stems, roots and fruits were obtained after 4 h of hydrodistillation. Chemical compositions were determined using a combination of GC/FID and GC/MS. The in vitro antimicrobial activity of the volatile constituents of E. longirostris was performed in sterile 96-well microplates against three Gram-positive, four Gram-negative bacteria and one strain as yeast. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values were reported. Furthermore, the antioxidant activity was evaluated by DPPH and ABTS assays. Results The main compound for fruits, stems and roots was the erucin (96.6%, 85.3% and 83.7%, respectively), while β-elemene (35.7%), hexahydrofarnesylacetone (23.9%), (E)-β-damascone (15.4%), erucin (10.6%) and α-longipinene (9.6%) constituted the major compounds in the essential oil of the leaves. The experimental results showed that in all tests, essential oil of fruits showed the better antioxidant activity than the others. On the other hand, the oils of stems, fruits and roots showed significant antimicrobial activity with MIC values ranging from 0.125 to 0.31 mg/mL against Candida species, Gram-positive and Gram-negative bacteria, mainly Salmonella enterica. Conclusions The present results indicate that essential oils of E. longirostris can be used as a source of erucin

Additional file 1: of Effect of solvents extraction on phytochemical components and biological activities of Tunisian date seeds (var. Korkobbi and Arechti)

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