Methyl 2-naphthoates with anti-inflammatory activity from Morinda officinalis.

Chemical fractionation of the EtOH extract of the roots of a traditional Chinese herb, Morinda officinalis, afforded an array of methyl 2-naphthoate derivatives (1-9) including four pairs of enantiomers (1-4), two pimarane diterpenes and two ursane triterpenoids. Among them, eight compounds (1a/1b-3a/3b, 11 and 13) were reported in the current work for the first time. The structures of the new compounds, including their absolute configurations, were defined by spectroscopic analyses in combination with quantum chemical electronic circular dichroism (ECD) and gauge-independent atomic orbital (GIAO) NMR calculations. All the isolates were evaluated for their inhibitory effect on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in murine RAW264.7 macrophage cells, and the enantiomers 1a and 3b exhibited moderate activity with IC50 values of 41.9 and 26.2 µM. Meanwhile, compound 3b also dose-dependently inhibited the secretion of two pro-inflammatory cytokines TNF-α and IL-6 in the same cell model.

Bioactive pentacyclic triterpenoids from the whole plants of Pterocephalus hookeri.

Eight undescribed triterpenoids (pterohoonoids A-H) including four oleananes, one nor-oleanane and three nor-ursanes, along with seven known analogues, were isolated from the whole plants of Pterocephalus hookeri (Dipsacaceae). The structures with relative stereochemistries of these molecules were elucidated mainly by spectroscopic analyses, and the absolute configurations of the undescribed ones were assigned by a variety of methods, including time-dependent density functional theory (TD-DFT) based electronic circular dichroism (ECD) calculation, Rh2(OCOCF3)4-induced ECD experiment and chemical transformation. The inhibitory effects toward the diabetes target α-glucosidase of all the isolates were assessed, and four of them exhibited pronounced activity with IC50 values ranging from 6.8 to 55.8 µM. In addition, four compounds also showed inhibition against the nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 macrophage cells (IC50 = 12.4-63.7 µM). Further assays demonstrated that the most active compound pterohoonoid A inhibited the release of two key pro-inflammatory cytokines TNF-α and IL-6 in a dose-dependent manner.

Two new naphthylisoquinoline alkaloids from stems and leaves of Ancistrocladus tectorius.

Two new alkaloids, 4'-O-demethylhamatine (1) and ancistrotectoriline C (2), were isolated from the stems and leaves of Ancistrocladus tectorius. These two compounds represent one 5,1'-coupled and one 7,6'-coupled naphthylisoquinoline alkaloid, respectively. Their structures were elucidated by 1D- and 2D-NMR spectra and other spectroscopic studies.

Constituents from Clausena excavata.

Three new coumarins containing a C(10) terpenoid side chain, clauslactones R - T (1 - 3), together with 14 known coumarins (4 - 17) and 11 known carbazole alkaloids (18 - 28), were isolated from the leaves and stems of Clausena excavata. Their structures were established by detailed spectroscopic analyses. Furthermore, the stereochemistry of 1 was confirmed by single-crystal X-ray diffraction analysis, which was the first example among coumarins with a C(10) terpenoid side chain. Additionally, compounds 22 and 27 were found to show moderate topoisomerase II inhibitory effects at 50 microM.