Flavoniods from aerial parts of Astragalus hoantchy

Four new flavonoids, astragaisoflavans A-D (1-4), along with thirteen known ones (5-17) were isolated from the aerial parts of Astragalus hoantchy. Their structures were established by the extensive spectroscopic analyses including one- and two-dimensional NMR, HRESIMS, IR, and UV results. The absolute configurations of 1-4 were deduced based on circular dichroism. Compounds 1-3 all possessed a rare modified A-ring and compound 4 was a dimeric isoflavan. Compound 5 was first identified from genus Astragalus and 6-17 were found from A. hoantchy for the first time. Compound 1 and 4 were evaluated for their antifungal activity against Alternaria solani (a phytopathogenic fungus), with the result that 1 failed to exhibit significant antifungal activity at the testing concentration of 100μg/mL and the IC₅₀ value of 4 was 173.3μg/mL.