Chemistry of Natural Compounds最新文献

A previously unreported acyclic monoterpene, zanthungeanumol A (1), and eleven known alkaloids 2–12 were isolated from the pericarps of Zanthoxylum bungeanum. The activity evaluation showed that compound 7 exhibited potent antibacterial activities against Staphylococcus aureus, while compound 8 exhibited significant antimicrobial activity against Escherichia coli 140 with a MIC value of 6.25 μg/mL, and their activities were comparable to the plant-derived antibacterial drug berberine.

N-Substituted derivatives of the alkaloid (–)-cytisine and its thioanalogue were synthesized via a two-step ‘alkylation-thionation’ chemical transformation sequence. The ability of the obtained compounds to inhibit metabolic activity of conditionally normal (HEK293, human embryonic kidney cells) and cancerous cells (A549, lung adenocarcinoma; MCF-7, breast cancer) was assessed. It was found that N-hexyl-, -nonylcytisine and N-heptyl-, -octyl-, -nonyl- and -benzyl-thiocytisine demonstrated moderate cytotoxic properties. The hit-compound (1R,5S)-3-benzyl-1,2,3,4,5,6-hexahydro-8H-1,5-methanopyrido[1,2-a][1,5]diazocine-8- thione (22) was identified with IC₅₀ values of 12.83 ± 1.2 μM (A-549) and 35.75 ± 7.43 μM (MCF-7). It was shown that the antiproliferative properties of compound 22 might be associated with alterations of cell cycle regulation in tumor cells (A549 and MCF-7), exhibiting mainly cytostatic effect, whereas in conditionally normal cells (HEK293), 22 promotes apoptosis, thus triggering the cytotoxic mechanisms.

Hybrid molecules based on 18β-glycyrrhetic acid (GLA), i.e., conjugates of GLA methyl ester 3-O-hemisuccinate with methyl/ethyl esters of L-amino acids (isoleucine, leucine, phenylalanine), were synthesized in 50–55% yields using N-hydroxysuccinimide–N,N′-dicyclohexylcarbodiimide. The conjugate with L-leucine methyl ester (5) showed pronounced antiviral activity against human adenovirus type 5.

The new pyrrolizidine alkaloid helasine (1) and known heliotrine (2), lasiocarpine N-oxide (3), trachelanthamine (4), and echinatine (5) were isolated from the plant Heliotropium lasiocarpum. Alkaloids 4 and 5 were observed for the first time in H. lasiocarpum. The absolute configurations of isolated alkaloids 2–4 were established by X-ray crystal structure analyses. The insecticidal activity of the CHCl₃, n-BuOH, and H₂O parts of the H. lasiocarpum extract against Callosobruchus maculates and Sitophilus oryzae was examined. The CHCl₃ extract at a dose of 10 mg/L had the highest activity.

A novel flavonolignan, named 3,3′,4′,5-tetrahydroxy-3′′′,5′′′-dimethoxy-9′,9′′′dihydroxymethyl-4- hydroxyphenyl-4′′′-hydroxy-3′′′,5′′′-dimethoxyphenylflavonolignan (1), together with five known flavonolignan derivatives (2–6) were isolated from Hippophae rhamnoides L. for the first time. Their structures were determined by extensive and comprehensive IR, UV, NMR, MS spectra, as well as reported references. Compounds 1–6 were evaluated for their hepatoprotective activities on APAP-treated HepG2 cells. As a result, compounds 1 and 2 exhibited moderate hepatoprotective activities.

1,3-Dipolar cycloaddition of benzyl azides to the propargyl ether of the 9-hydroxymethyl derivative of the quinolizidine alkaloid methylcytisine under CuAAC conditions synthesized 9-conjugates of it with 1-benzyl-, 1-(4-methoxybenzyl)-, 1-(2,3-dimethoxybenzyl)-, 1-(3,4-dimethoxybenzyl)-, 1-(2-fluorobenzyl)-, 1-(2-chlorobenzyl)-, 1-(4-bromobenzyl)-, 1-(2,4-dichlorobenzyl)-, and 1-(3-nitrobenzyl)-substituted 1,2,3-triazoles. The structures of the synthesized compounds were confirmed by physicochemical analysis, including elemental analysis and NMR spectroscopy.

In this study, two new pyrroloisoquinolines, cigarpyrro A and B (1 and 2), together with five known pyrroloisoquinolines (3–7) were isolated from the cigar-tobacco-derived endophytic fungus Aspergillus puniceus. Their structures were determined by means of HR-ESI-MS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1 and 2 were evaluated for their antibacterial activities against five pathogenic strains (Staphylococcus aureus (SEA), Escherichia coli (EPEC), Streptococcus pyogenes (GAS), Bacillus subtilis (QST713), and Proteus spp.). Interestingly, compounds 1 and 2 exhibited notable antibacterial activity with a bacteriostatic diameter within the range 15.4 ± 1.8 – 25.2 ± 1.6 mm against the above strains, and most of the bacteriostatic diameters are higher than that of the positive control. In addition, the potential values for compounds 1 and 2 used as antiseptic agents were also evaluated, and they have the potential value for use as antiseptic agents for cigarette-tipping paper.