Biological evaluation of selected 3,4-dihydro-2(1H)-quinoxalinones and 3,4-dihydro-1,4-benzoxazin-2-ones: Molecular docking study.

In order to investigate new potential therapeutically active agents, we investigated the biological properties of two small libraries of quinoxalinones and 1,4-benzoxazin-2-ones. The results obtained showed that compounds 5, 9-11 have good cytotoxic activity against HeLa cells where the lowest IC50 value (10.46 ± 0.82 µM/mL) was measured for compound 10. Additionally, the most active compounds (5, 9-11) showed much better selectivity for MRC-5 cells (up to 17.4) compared to cisplatin. In vitro evaluation of the inhibition of the enzyme α-glucosidase showed that compounds 10 and 11 exert significant inhibition of the enzyme at 52.54 ± 0.09 and 40.09 ± 0.49 µM, respectively. Competitive experiments with ethidium bromide (EB) indicated that all tested compounds have affinity to displace EB from the EB-DNA complex through intercalation, suggesting good competition with EB (Ksv = (3.1 ± 0.2), (5.1 ± 0.1), (5.6 ± 0.2), and (6.3 ± 0.2) × 103 M-1 ). A molecular docking study was also performed to better understand the binding modes and to conclude the structure-activity relationships of the synthesized compounds.

Chemical Composition, Antimicrobial and Cytotoxic Activity of Heracleum verticillatum Pancic and H. ternatum Velen. (Apiaceae) Essential Oils.

In this work, the chemical composition, antimicrobial and cytotoxic activity of Heracleum verticillatum Pancic and H. ternatum Velen. root, leaf, and fruit essential oils were investigated. The composition was analyzed by GC and GC/MS. Heracleum verticillatum and H. ternatum root oils were dominated by monoterpenes, mostly ß-pinene (23.5% and 47.3%, respectively). Heracleum verticillatum leaf oil was characterized by monoterpenes, mainly limonene (20.3%), and sesquiterpenes, mostly (E)-caryophyllene (19.1%), while H. ternatum leaf oil by the high percentage of phenylpropanoids, with (Z)-isoelemicin (35.1%) being dominant constituent. Both fruit oils contained the majority of aliphatic esters, mostly octyl acetate (42.3% in H. verticillatum oil and 49.0% in H. ternatum oil). The antimicrobial activity of the oils was determined by microdilution method against eight bacterial and eight fungal strains. The strongest effect was exhibited by H. verticillatum root oil, particularly against Staphylococcus aureus, Salmonella typhimurium (MICs = 0.14 mg/ml, MBCs = 0.28 mg/ml), and Trichoderma viride (MIC = 0.05 mg/ml, MFC = 0.11 mg/ml). Cytotoxic effect was determined by MTT test against malignant HeLa, LS174, and A549 cells (IC50 = 5.9 - 146.0 µg/ml), and against normal MRC-5 cells (IC50 > 120.1 µg/ml). The best effect was exhibited by H. verticillatum root oil on A549 cells (IC50 = 5.9 µg/ml), and H. ternatum root oil against LS174 cells (IC50 = 6.7 µg/ml).