Coumaronochromones, flavanones, and isoflavones from the twigs and leaves of Erythrina subumbrans inhibit PTP1B and nitric oxide production

Isoflavones isolated from the fruits of Ficus altissima and their anti-proliferative activities

Ficus altissima, also known as lofty fig, is a monoecious plant from the Moraceae family commonly found in southern China. In this study, we isolated and identified one new isoflavone (1), three new hydroxycoumaronochromones (2a, 2b and 3a) and 12 known compounds from the fruits of F. altissima. Their chemical structures were determined using spectroscopic analysis methods. We also tested all the isolated compounds for their anti-proliferative activities against eight human tumour cell lines (A-549, AGS, K562, K562/ADR, HepG2, HeLa, SPC-A-1 and CNE2) using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Our experiments showed that compound 6 exhibited obvious anti-proliferative activity against the K562 cell line with an IC50 value of 1.55 μM. Additionally, compounds 8 and 9 showed significant anti-proliferative activities against the AGS and K562 cell lines, respectively. Moreover, compound 6 induced apoptosis in K562 cells through the caspase family signalling pathway.

Coriaceumins A-D, the First Nitrogen-Containing Crenulide Diterpenoids from the Brown Alga Dictyota coriacea Collected in the East China Sea

A phytochemical investigation of an East China Sea collection of the brown alga Dictyota coriacea has led to the isolation of four novel nitrogen-containing crenulide diterpenoids, named coriaceumins A-D (1-4), two rare nitrogenous xenicane diterpenoids, dictyolactams C (5) and D (6), and one known crenulide diterpenoid, hydroxycrenulide (7). The structures of the new compounds were elucidated by detailed spectroscopic data analyses, including HRESIMS and 1D/2D NMR. The absolute configurations were determined by a comparison of the experimental ECD spectra with the spectra computed by DFT-based quantum chemical calculations. Coriaceumins A-D (1-4) represent the first examples of nitrogen-containing crenulide diterpenoids. In a bioassay, compounds 2, 3, 5, and 7 were found to exhibit different levels of inhibitory effects against protein tyrosine phosphatase 1B (PTP1B) with IC50 values ranging from 7.3 to 19 μM. In addition, the primary structure-activity relationships of all the isolates were summarized.