Chemistry of Natural Compounds最新文献

New conjugates of lupane triterpenoids bound through a 1,2,3-triazole linker with gallate derivatives were prepared via Cu-catalyzed cycloaddition reactions of [3β,28-diacetoxy-20(29)-lupen-30-yl]azide and 3β-acetoxylup-20(29)-en-30-azido-28-oic acid with gallate derivatives with propargyl substituents in various positions. Conjugate 4 based on betulin with a modified gallate substituent containing a dioxolane moiety possessed potent antioxidant properties and anti-inflammatory activity (suppression of NO hyperexpression).

A new naphtho[2,3-c]furan-1(3H)-one derivative, 6,8,9-trihydroxynaphtho[2,3-c]furan-1(3H)-one (1), has been isolated from the stem bark of Rhamnus kanagusukii, together with eight known compounds, chrysophanol (2), emodin (3), rhamnazin (4), kaempferol (5), apigenin (6), taxifolin (7), ferulic acid (8), and gallic acid (9). The structure of new compound 1 was determined using spectroscopic and MS analyses. Among the isolated compounds, 6,8,9-trihydroxynaphtho[2,3-c]furan-1(3H)-one (1), kaempferol (5), apigenin (6), and taxifolin (7) showed potent inhibition with IC₅₀ values of 19.48 ± 1.52, 20.48 ± 1.84, 16.47 ± 1.25, and 15.44 ± 1.02 μM, respectively, against LPS-induced NO generation. In addition, compounds 5, 6, 7, 8, and 9 also showed potent DPPH radical scavenging activities with IC₅₀ values of 21.11 ± 1.84, 22.47 ± 2.04, 13.02 ± 1.07, 14.54 ± 1.35, and 13.48 ± 1.16 μM respectively.

Pyridin-3-ylmethylylidene derivatives of methyl betulonate were synthesized. Six new Pd(II) complexes of them were obtained. The effects of these compounds on A549 (non-small-cell lung carcinoma) and HCT116 cell lines (colon cancer) were assessed by the MTT assay. 3-{(E)-[28-Methoxy-3,28-dioxolup-20(29)-en-2-ylidene]methyl}-1-methylpyridinium tetrafluoroborate exhibited potent cytotoxic activity on HCT116 cell line (IC₅₀ = 7.21 μM).

A new ester compound, ethyl-(9E)-8,11,12-trihydroxyoctadecenoat (1), and five known compounds comprising a mixture of 3-hydroxy-3-methyl-5-hexanolide (2A) and leucine (2B), indole-3-aldehyde (3), 3β,7α-dihydroxy-6-cholest-5-ene (4), cholest-5-ene-3β,7β-diol (5), and saringosterol (6) were isolated from the dichloromethane extract of male Carica papaya flowers. Their structures were determined by NMR, MS spectra and comparison with the reported data.

A water-soluble polysaccharide based on glucoarabinogalactan GAG-Sa was isolated from the aerial part of Scutellaria adenostegia. The monosaccharide composition of the glucoarabinogalactan included arabinose, glucose, and galactose in a 1.0:10.9:7.6 mole ratio. GAG-Sa was characterized as a branched polysaccharide with a main chain of β-1,6-bound β-D-galactopyranose residues. The side chains of GAG-Sa consisted of 1,3-bound β-D-galactopyranose, α-D-glucopyranose, and α-L-arabinofuranose residues. The aqueous extract of the aerial part of S. adenostegia was shown to have anti-inflammatory activity.

Taiwanin A, a natural naphthalide lignan isolated from the heartwoods of Taiwania cryptomerioides Hayata, has previously been reported to have cytotoxicity against human tumor cells. In this study, a series of taiwanin A derivatives were synthesized and evaluated for their structure–activity relationship. Among the eleven taiwanin A derivatives, four compounds showed higher in vitro cytotoxic activity than taiwanin A. The biological evaluation of the synthesized compounds illustrated that the introduction of an electron-donating group in aryl ring A contributed to the antiproliferative potency, while in aryl ring B, it attenuated the cytotoxic activity. Compound 20 demonstrated excellent anticancer activity with an IC₅₀ value of 0.5 μM against HONE-1 human carcinoma cell lines, indicating that it could be a promising lead compound for further drug development studies.

A new terpenoid, nornemoralisin D was isolated from the leaves of Aphanamixis polystachya. The structure of the isolated compound was elucidated by various spectroscopic methods, including 1D and 2D NMR experiments.

A novel flavonolignan, named 3-hydroxy-7-O-β-D-glucopyranosyl-7′′-(4′′-methoxyphenyl)-8′′-(9′′-ethyl acetate)-flavonolignan (1), along with eight known flavonolignan derivatives (2–9) were isolated from Citrus medica var. sarcodactylis (Siebold ex Hoola van Nooten) Swingle for the first time. These compounds (1–9) were determined by extensive and comprehensive IR, UV, NMR, MS spectral analyses and compared with the reported references. Compounds 1–9 were evaluated for their inhibitory effects against the increases in AST and ALT levels on H₂O₂-induced HepG2 cells. As a result, compounds 1 and 2 displayed moderate hepatoprotective activities.