Immunomodulatory effects of 1-(6-hydroxy-2-isopropenyl-1-benzofuran-5-yl)-1-ethanone from Petasites hybridus and its synthesized benzoxazepine derivatives

Liquid-liquid chromatography isolation of Petasites hybridus sesquiterpenes and their LC-HR-MS/MS and NMR characterization

Petasites hybridus L. (butterbur, Asteraceae) is a well-known medicinal plant traditionally used as a remedy for neurological, respiratory, cardiovascular, and gastrointestinal disorders. Eremophilane-type sesquiterpenes (petasins) are considered to be the major bioactive constituents of butterbur. However, efficient methods to isolate high-purity petasins in sufficient amounts for further analytical and biological testing are lacking. In this study, various sesquiterpenes were separated from a methanol rootstock extract of P. hybridus with liquid-liquid chromatography (LLC). The appropriate biphasic solvent system was selected using the predictive thermodynamic model COSMO-RS and shake-flask experiments. After the selection of the feed (extract) concentration and operating flow rate, a batch LLC experiment was performed with n-hexane/ethyl acetate/methanol/water 5/1/5/1 (v/v/v/v). For those LLC fractions containing petasin derivatives with purities < 95%, a preparative high-performance liquid chromatography purification step followed. All isolated compounds were identified by state-of-the-art spectroscopic methods, i.e., liquid chromatography coupled with high-resolution tandem mass spectrometry and nuclear magnetic resonance techniques. As a result, six compounds were obtained, namely 8β-hydroxyeremophil-7(11)-en-12,8-olide, 2-[(angeloyl)oxy]eremophil-7(11)-en-12,8-olide, 8α/β-H-eremophil-7(11)-en-12,8-olide, neopetasin, petasin, and isopetasin. The isolated petasins can be further used as reference materials for standardization and pharmacological evaluation.

One-pot synthesis of benzofurans via heteroannulation of benzoquinones

Three different reactions were explored leading to the synthesis of various benzofurans. All reactions took place under AcOH catalysis in a one-pot manner. As a result, benzoquinone derivatives underwent heteroannulation with either itself or cyclohexanones to produce furanylidene-benzofuran or benzofuran structures, respectively.

New antimicrobial and cytotoxic benzofuran glucoside from Senecio glaucus L

The ethyl acetate fraction of the dried aerial parts of Senecio glaucus L. exhibited significant antimicrobial activity against some of selected bacteria and fungi. Also, it showed potent cytotoxicity against PANC-1 cancer cell lines under glucose deficient medium. The ethyl acetate fraction was subjected to different chromatographic techniques for isolation of the bioactive compounds. A new benzofuran glucoside; 2,3-dihydro-3β-hydroxyeuparin 3-O-glucopyranoside (1) was isolated. Additionally, two known flavonoid compounds isorhamentin 3-O-β-D-glucoside (2), and isorhamentin 3-O-β-D-rutinoside (3) were first identified in S. glaucus. Compound 1 exhibited potent antimicrobial activities against two Gram-positive bacteria, one Gram-negative bacteria, and two fungi. Also, it displayed potent cytotoxic activity against PANC-1 cancer cell lines under glucose deficient medium (IC50 7.5 μM). However, the isolated flavonoid glycosides (2 & 3) showed moderate antimicrobial activities against two Gram-positive bacteria, two Gram-negative bacteria, four fungi, and did not show any cytotoxic activity against PANC-1.

Molecular docking studies, biological evaluation and synthesis of novel 3-mercapto-1,2,4-triazole derivatives

Synthesis of bioactive heterocyclic compounds having effective biological activity is an essential research area for wide-ranging applications. In this study, a conventional methodology has been developed for the synthesis of a series of new 3-mercapto-1,2,4-triazole derivatives 4a-f. The purity and structure of the synthesized molecules were confirmed by ¹H NMR, ¹³C NMR and elemental analysis. In addition, the prepared compounds were screened for their anti-proliferative activity against three human cancer cell lines including A549 (lung cancer), MCF7 (breast cancer) and SKOV3 (ovarian cancer) using MTT reduction assay. All the tested compounds demonstrated remarkable cytotoxic activity with IC₅₀ values ranging from 3.02 to 15.37 µM. The heterocyclic compound bearing 3,4,5-trimethoxy moiety was found to be the most effective among the series displaying an IC₅₀ of 3.02 µM specifically against the ovarian carcinoma cancer cell line (SKOV3). Moreover, Annexin V-FITC/propidium iodide staining assay indicated that this compound can induce apoptosis in SKOV3 cells. Furthermore, cell cycle assay showed a significant cell cycle arrest at the G2/M phase in a dose-dependent manner for this compound. The molecular docking results was showed binding modes of potent compound 4d perfectly corroborated the suggestion of binding to the colchicine site. The entire results conclude that 3-mercapto-1,2,4-triazole derivatives can be synthesized by a green method for biological and pharmacological applications. New analogs of 3-mercapto-1,2,4-triazole potential derivatives for anti-proliferative activity were synthesized. Cytotoxic activity of all synthesized compounds was evaluated against tree human cancer cell lines: lung (A549), breast (MCF7) and ovarian (SKOV3).

Identification of some benzoxazepines as anticancer agents inducing cancer cell apoptosis

AIM

Using cytotoxic agents with apoptosis induction may represent one of new strategies for cancer treatment to overcome the increased resistance of the disease.

METHODOLOGY

Two series of benzo[f][1,4]oxazepine-3,5(2H,4H)-diones (compounds 5, 6a-f) and 3-phenylbenzo[f][1,4]oxazepin-5(4H)-ones (compounds 10, 11a-f) were synthesized and screened for their cytotoxicity against leukemia K-562 and breast T-47D cancer cell lines as well as normal fibroblasts WI-38.

RESULTS

The tested compounds revealed good cytotoxicity and selectivity toward cancer cell lines relative to the normal cells, especially compounds 6f, 10 and 11e, f. These compounds were screened for cell cycle disturbance and apoptosis induction. They were found to cause PreG1 apoptosis and complete cell growth arrest at G2/M. They induce apoptosis via caspase-3 and Bax activation and downregulation of Bcl2.

CONCLUSION

benzo[f][1,4]oxazepine represents a scaffold for further optimization to obtain promising anticancer agents.

Green synthesis and antioxidant activity of novel series of benzofurans from euparin extracted of Petasites hybridus

A novel class of benzofuran derivatives is prepared from the isocyanide-based MCR, euparin and aldehydes in the presence of ZnO-nanorods as a catalyst in excellent yields at room temperature under solvent-free conditions as a green reaction medium. Also, the antioxidant activities of some synthesised compounds such as 4a, 4b, 10a and 10b were evaluated by DPPH radical scavenging and ferric reduction activity potential (FRAP) assays. Compound 10b, was shown moderate radical scavenging activity and very good reducing activity compared to standards (BHT and TBHQ).

A Fluorination/Aryl Migration/Cyclization Cascade for the Metal-Free Synthesis of Fluoro-Benzoxazepines

Fluorinated organic molecules are of high interest for many applications across chemical and medical disciplines. Efficient methods for the synthesis of such compounds are thus needed. Within this work, application of the bench-stable cyclic hypervalent iodine(III) fluoro reagent 1 facilitated the development of an efficient, metal-free method for the preparation of the novel class of 4-fluoro-1,3-benzoxazepines starting from readily available styrenes. The efficacy and broad applicability of this concept is demonstrated by the synthesis of 20 structurally diverse congeners in high yields, regio-, and diastereoselectivities. The presented method provides complementary chemoselectivity when compared to the common, commercially available electrophilic fluorination reagents, such as selectfluor. First mechanistic investigations with isotopically labeled substrates reveal a complex reaction mechanism, proceeding via an unusual fluorination/1,2-aryl migration/cyclization cascade.