Semi-synthesis, α-amylase inhibition, and kinetic and molecular docking studies of arylidene-based sesquiterpene coumarins isolated from Ferula tunetana Pomel ex Batt.

Despite all the significant progresses made to enhance the efficacy of the existing bank of drugs used to manage and cure type II diabetes mellitus, there is still a need to search and develop novel bioactive compounds with superior efficacy and minimal adverse effects. This study describes the valorization of the natural bioactive sesquiterpene coumarin via the semi-synthesis of new analogs and the study of their α-amylase inhibition activity. The sesquiterpene coumarin named coladonin (1) was quantitatively isolated from the chloroform extract of endemic Ferula tunetana roots. Subsequently, the oxidation of 1via the Jones oxidation reaction, used as a key reaction, afforded precursor 2. The condensation of oxidized coladonin (2) with various aryl aldehydes provided a series of new arylidene-based sesquiterpene coumarin derivatives (3a-m), which were characterized by NMR and ESI-HRMS experiments. All derivatives evaluated in vitro for their α-amylase inhibitory potential showed interesting α-amylase inhibition with IC50 values ranging from 7.24 to 28.98 µM. Notably, compounds 3k and 3m exhibited lower IC50 values (7.24 µM and 8.38 µM, respectively) compared to the standard (acarbose: IC50 = 9.83 µM). In addition, the structure-activity relationship (SAR) for all the compounds was studied. The most active compounds were found to be mixed-type inhibitors, which was revealed by kinetic studies. Furthermore, molecular in silico docking studies were established for all synthesized analogs with the binding site for the α-amylase enzyme.

Chemical Composition and In Vitro Evaluation of Antimicrobial, Antioxidant and Antigerminative Properties of the Seed Oil from the Tunisian Endemic Ferula tunetana Pomel ex Batt.

Essential oil of the seeds from the endemic Tunisian plant Ferula tunetana Pomel ex Batt. was analyzed for its chemical composition and screened for its antimicrobial, antioxidant and antigerminative properties. The chemical composition of the isolated oil is reported for the first time. According to the GC/FID, GC/MS and 13 C-NMR analysis results; 18 compounds were identified accounting for 84.6% of the total oil. The chemical composition of this essential oil was characterized by the presence of a high proportion of monoterpene hydrocarbons (77.3%) followed by oxygenated sesquiterpenes (4.1%) and sesquiterpene hydrocarbons (3.2%). α-Pinene (39.8%), ß-pinene (11.5%) and (Z)-ß-ocimene (7.5%) were the predominant compounds. Moreover, the isolated oil was tested for its antimicrobial activity using the disc-diffusion and the microdilution assays against six Gram-positive and five Gram-negative bacteria as well as towards two Candida species. The isolated oil was tested also for its antioxidant activity against DPPH, ABTS, O2∙ and hydrogen peroxide (H2 O2 ), and for its antigerminative potential. It was found that it exhibited interesting antimicrobial activity against Salmonella typhimurium LT2 DT104 (inhibition zone (IZ) 16.2 ± 1.0 mm) and Bacillus cereus ATCC 14579 (IZ 15.8 ± 1.0 mm). However, it exerted a moderate antioxidant activity against H2 O2 (IC50 78.2 ± 2.98 µg/ml) and towards O2∙ (IC50 89.2 ± 3.82 µg/ml). The antigerminative effect of this oil was also evaluated in this work. Results showed a toxic effect.

Synthesis, cytotoxic, anti-lipoxygenase and anti-acetylcholinesterase capacities of novel derivatives from harmine.

We synthesized two series of new hydrazide harmine derivatives. The reaction of harmine 1 with ethyl acetate chloride afforded the corresponding ethyl ester 2. The treatment of 2 with hydrazine hydrate gave the hydrazide 3 which further converted into hydrazones 4a-j and dihydrazides 5a-c. A series of new triazoles 7a-f has also been prepared from the suitable propargyl harmine 6. The synthesized derivatives were characterized by 1H-NMR, 13C-NMR, and HRMS and evaluated for their activities against MCF7, HCT116 OVCAR-3, acetylcholinesterase and 5-lipoxygenase. The most hydrazones derivatives 4a-j have a good cytotoxic activity against all cell lines, when 4a, 4d, 4f and 4 g are more active than 1 (against OVCAR-3 IC50 16.7-2.5 µM). The compound 6 was the most active (IC50 = 1.9 µM) against acetylcholinesterase. Some compounds exhibited significant activity against 5-lipoxygenase (IC50 = 30.9-63.1 µM).

Synthesis of New Harmine Isoxazoles and Evaluation of their Potential Anti-Alzheimer, Anti-inflammatory, and Anticancer Activities.

Harmine 1 was extracted from the seeds of Peganum harmala. From this natural molecule, a new series of isoxazole derivatives with complete regiospecificity were prepared using 1,3-dipolar cycloaddition reactions with various arylnitrile oxides. Harmine and its derivatives were characterized by (1)H NMR, (13)C NMR and HRMS. The evaluation of their anti-acetylcholinesterase (AChE), anti-5-lipoxygenase (5-LOX), anti-xanthine oxidase (XOD) and anticancer activities were studied in vitro against AChE, 5-LOX and XOD enzymes, respectively, and in HTC-116, MCF7 and OVCAR-3 cancer cell lines. The prepared derivatives were shown to be inactive against the XOD enzyme (0-38.3 ± 1.9% at 100 µM). Compound 2 exhibited the best anti-AChE activity (IC50=1.9 ± 1.5 µM). Derivatives 3a, 3b and 3d had moderate cytotoxic activities (IC50=5.0 ± 0.3 µM (3a) and IC50=6.3 ± 0.4 µM (3b) against HCT 116 cells, IC50=5.0 ± 1.0 µM (3d) against MCF7 cells).

Synthesis of new isoxazoline derivatives from harmine and evaluation of their anti-Alzheimer, anti-cancer and anti-inflammatory activities.

In our study, a series of new harmine derivatives has been prepared by cycloaddition reaction using various arylnitrile oxides and evaluated in vitro against acetylcholinesterase and 5-lipoxygenase enzymes, MCF7 and HCT116 cancer cell lines. Some of these molecules have been shown to be potent inhibitors of acetylcholinesterase and MCF7 cell line. The greatest activity against acetylcholinesterase (IC50 = 10.4 µM) was obtained for harmine 1 and cytotoxic activities (IC50 = 0.2 µM) for compound 3a. Two derivatives 3e and 3f with the thiophene and furan systems, respectively, showed good activity against 5- lipoxygenase enzyme (IC50 = 29.2 and 55.5 µM, respectively).