Flavans from Iris tenuifolia and their effects on β-amyloid aggregation and neural stem cells proliferation in vitro.

Two new flavans (1, 2) and a new flavanone (3), together with three known compounds (4-6), were isolated from the roots of Iris tenuifolia. Their structures were elucidated by means of spectroscopic methods including 1D and 2D NMR techniques and mass spectrometry. Compounds 1, 4, and 6 were further confirmed by single-crystal X-ray diffraction analysis. Biological evaluation showed that compounds 1 and 4 were positive in inhibiting β-amyloid (Aβ) aggregation and promoting neural stem cells (NSCs) proliferation, respectively.