Two new glycosides from Stachys geobombycis C.Y.Wu.

Two new compounds geobomlin A (1) and geobomlin B (2) were isolated from the roots of Stachys geobombycis C. Y. Wu. Structural determinations were established principally by two-dimensional NMR and MS data analyses. Geobomlin B showed moderate inhibitory activity against α-glucosidase with IC50 = 248.77 µM. We have also determined the mechanism by which geobomlin B elicit its inhibitory effect on α-glucosidase, for which we have established a competitive inhibition mode. Docking studies confirmed our results on geobomlin B α-glucosidase inhibitory properties.

Two new cyclopeptides from Stachys geobombycis C. Y. Wu.

Two new cyclic peptides, named as cyclogeobomptides A (1) and B (2) were isolated from the roots of Stachys geobombycis C. Y. Wu. Compounds 1 and 2 are both made up of eight amino acids. The structures of them were established on the basis of the spectral data, including mass spectrometry, 2D NMR, and X-ray crystallography. Cyclogeobomptides A and B were proved to have obvious inhibitory activities against α-glucosidase with the IC50 values of 26.00 and 19.16 µM, respectively.

A new oleanane-type triterpenoid saponin with α-glucosidase inhibitory activity from Camellia nitidissima.

A new oleanane-type triterpenoid saponin, 21ß, 22α-di-O-angeloyl-15α, 16α, 28-trihydroxyolean-12-ene 3ß-O-α-L-rhamnopyranosyl-(1→3)-α-D-xylopyranosyl-(1→3)-ß-D-glucopyranoside (1), together with five known compounds (2-5), were isolated from Camellia nitidissima. Their structures were elucidated based on spectroscopic methods, including extensive NMR and MS spectra. Compound 1 showed potential inhibitory activity on α-glucosidase with the IC50 values of 185.9 ± 44.5 µmol/L.

Two new dammarane triterpenoid saponins from the leaves of Cyclocarya paliurus.

Two undescribed dammarane triterpenoid saponins, cypaliurusides O and P (1 and 2), were isolated from the ethanol extracts of the leaves of Cyclocarya paliurus. Bioactivity assay results showed that compound 1 has potential cytotoxic activities against selected human cancer cell lines in vitro, with IC50 values ranging from 14.55 ± 0.55 to 22.75 ± 1.54 µM. Compound 1 showed better antitumor activity against HepG2 cells with IC50 of 14.55 ± 0.55 µM. In addition, compound 2 showed no obvious antitumor activity.

A new glucopyranoside from the leaves of Microsorium fortunei.

A new compound, 2-hydroxy-4-[3',5'-dihydroxyhexyl]phenyl-ß-D-glucopyranoside (1), together with five known compounds (2-6), were isolated from the leaves of Microsorium fortunei. Their structures were determined by spectroscopic techniques, especially 2D NMR and MS data analyses. All of these compounds are phenolic glycosides and were isolated from this plant for the first time. In addition, compound 1 showed moderate inhibitory activity against α-glucosidase with IC50 value at 0.111 ± 0.061 mg/mL.