Chemistry of Natural Compounds最新文献

In this study, two new benzochromones (1 and 2), together with four known ones (3–6), were isolated from Nicotiana tabacum-derived Aspergillus niger. Their structures were determined by means of HR-ESI-MS and extensive 1D and 2D NMR spectroscopic studies. All compounds were evaluated for their antibacterial activities against five nitrosobacteria strains (Nitrosomonas communis, Nitrosomonas nitrosa, Nitrosospira multiformis, Nitrobacter winogradskyi, and Nitrospira inopinata). Interestingly, compounds 1–6 exhibited notable antibacterial activity with bacteriostatic diams in the range of 11.8 ± 1.6 ~ 19.6 ± 2.3 mm against five nitrosobacteria strains, and most of the bacteriostaticic diams were close to that of the positive control. Due to the nitrosobacteria having the ability in tobacco to convert nitrogen components into nitrite, and then convert that into tobacco-specific nitrosamines (TSNAs), the above compounds have the potential to reduce TSNAs in tobacco by inhibiting nitrosobacteria during the fermentation process of tobacco leaves.

The structures of metabolic products of echinochrome, the substance of the medicine histochrome, were established by high-resolution GC-MS using a deuterium label. Their structures were compared with those of the metabolic products of its inactive trimethyl ether. This suggested that the cardioprotective activity of the histochrome drug could be determined by echinochrome, its 2(3)-methoxy derivatives, their monoglucuronides, and (trihydroxyethyl)naphthoquinonyl urea. The research significantly narrowed the list of metabolites responsible for the biological properties of histochrome drug.

4-(1′,2′-Dihydroxyethyl)-2-methylpyridine (1) and ((2-methylpyridin-4-yl)oxy)methanol (2), two new pyridine alkaloids, have been isolated from the roots of Annona cherimola Mill. (Annonaceae). The structure was characterized and identified by spectral analysis.

Two new coumarins 1 and 2 and known compounds 3–12 were isolated from the herb of Phlojodicarpus sibiricus (Fisch.) Koso-Pol. (Apiaceae) growing in Mongolia. The new compounds were identified as (+)-(3′S)-lomatin 3′-O-(6′′-O-β-D-apiofuranosyl)-β-D-glucopyranoside (phlojosibiriside VIII, 1) and (1′S,2′S)-phlojodicarpin 1′-O-β-D-glucopyranoside (phlojosibiriside IX, 2) using UV and NMR spectroscopic and mass spectrometric data.

The fruits of Vietnamese Garcinia schomburgkiana were subjected to chemical investigation, leading to the isolation and characterization of a previously unreported benzoylphloroglucinol, 8-benzoyl-2-(4-methylpenten-3-yl)-chromane-5,7-diol (1), along with two known compounds, 8-benzoyl-2-(4-methylpenten-3-yl)-chromane-3,5,7-triol (2) and 5-benzoyl-1,1,4a-trimethyl-2,3,4,4a,9,9a-hexahydro-1H-xanthene-6,8-diol (3). The structural elucidation was achieved through extensive spectroscopic methods, including NMR and HR-ESI-MS. Compound 1 exhibited good α-glucosidase inhibition with an IC₅₀ value of 30.2 ± 5.3 μM.

Lipids from the aerial part (leaves, 1; rosettes, 2) of Pulmonaria obscura Dumort. (Boraginaceae) collected at the start of vegetation were studied. The contents of neutral (NL) and polar lipids (PL) in 1 and 2 were isolated and determined. NL were separated into esters of triterpene and aliphatic alcohols (ETAs) and acylglycerides (AcGl). The composition of polyunsaturated fatty acids (PUFAs) was established. The main amounts of α-linoleic (α-18:2) and α-linolenic (α-18:3) were shown to occur in AcGl; γ-linolenic (γ-18:3) and stearidonic acids (18:4), in ETAs. The composition and content of lipophilic components were found. The antioxidant activity of lipids from 1 and 2 was determined. Lipids from 1 possessed more pronounced iron-reducing properties than 2 in the FRAP model.

A new pyridine, 4-(1′-acetoxyethyl)-2-methylpyridine (1) as well as 7,8-dihydro-8-hydroxyberberine, oxyberberine, berberine, palmatine, jatrorrhizine, and columbamine, were isolated from the roots of Mahonia oiwakensis. The structure of the new pyridine was elucidated by chemical and physical evidence.

A novel lactone derivative, named antrozon A (1), and three known compounds (2–4) were isolated from cultures of the basidiomycetes Antrodiella zonata. Antrozon A (1) represented an unprecedented lactone derivative with a long fatty chain inlaid with a cyclopropane. Their structures were established through extensive spectroscopic studies.