Facile green in situ hemisynthesis of new chiral chromeno-pyrimidine derivatives: antibacterial, antioxidant activities and molecular docking study.

A hemisynthesis 'in situ' reaction of (thio)barbituric acids with an α,ß-unsaturated aldehyde using perillaldehyde from Ammodaucus leucotrichus essential oil, afforded chromeno-pyrimidine derivatives B-1 and B-2. The reaction was carried out in water and water/ethanol medium without a catalyst. The obtained pyrimidines were identified by their spectral 1H,13C, Dept-135, HMBC, HSQC, COSY, and NOESY 2D. The antioxidant activity of both compounds was evaluated using different in vitro methods (DPPH, ABTS, and CUPRAC). The hemisynthesized molecules exhibited a bacteriostatic effect against ten tested gram (+) and gram (-) strains. According to the molecular docking analysis, B-1 showed lower binding energies compared to B-2 against (PDB: 1HD2) and (PDB: 1KZN) targets, which is in agreement with the ABTS and E. Coli assays. Furthermore, a probable promising anti-HIV activity was noticed against reverse transcriptase (PDB: 2RKI), a key enzyme for HIV replication. The ADME properties calculations showed no Lipinski's rule violation for both compounds.

6"'-O-acetylisospinosin, a new C-glycosylflavone and known compounds from the aerial parts of Cladanthus mixtus.

A new C-glycosylflavone, identified as 6"'-O-acetylisospinosin (1), was isolated from the aerial parts of Cladanthus mixtus together with 30 known compounds. The structures of these compounds were established by interpretation of their spectral data, mainly UV, 1D and 2D NMR spectroscopic methods including (1H and 13C NMR, COSY, ROESY, HSQC and HMBC experiments), ESI-MS, and by comparison with the literature data.

Isolation and characterisation of cytotoxic compounds from Euphorbia clementei Boiss.

A new phorbol-type diterpene ester, 4,20-dideoxy-4α-phorbol-12ß-acetate-13α-isobutyrate, in addition to 11 known compounds were isolated from the latex and roots of Euphorbia clementei Boiss. Structure elucidation was performed by comprehensive 1D and 2D NMR analyses (1H and 13C NMR, COSY, ROESY, HSQC and HMBC experiments), mass spectrometry (HR-ESI-MS) and by comparison with literature data. The inhibitory activity of all isolated compounds was evaluated against promyelocytic leukemia HL60 and human erythromyeloblastoid leukemia K562 cell lines and seven of these compounds exhibited a weak cytotoxicity with IC50 values ranging from 40 to 97 µM.

Chemical composition, antioxidant and antibacterial activities of Tamarix balansae J. Gay aerial parts.

A previously undescribed phenolic sulphate ester, potassium 34-dihydroxy-3-methoxybenzoic acid methyl ester-5-sulphate (1), along with nine known flavonoids, kaempferol-3-O-potassium sulphate-4',7-dimethyl ether (2), kaempferol-4',7-dimethyl ether (3), rhamnocitrin-3-O-potassium sulphate (4), rhamnocitrin (5), kaempferol (6), quercetin (7), afzelin (8), quercetin-3-O-α-l-rhamnopyranoside (9) and luteolin-3'-O-potassium sulphate (10) were isolated from the aerial parts of Tamarix balansae. Structures elucidation was performed by comprehensive 1D and 2D NMR analyses, mass spectrometry and by comparison with literature data. The antibacterial assay against Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa bacteria showed a good activity for 2, 3, 7 and 9, with MICs ranging from 62.5 to 250 µg/mL. The abilities of these compounds to scavenge the DPPH were evaluated. Compounds 1, 7, 9 and 10 exhibited a good antiradical activity potential with IC50 values ranging from 3.0 to 115.5 µg/mL, compared with ascorbic acid (IC50 7.4 µg/mL) which was used as positive control.