Chromane Derivatives from Underground Parts of Iris tenuifolia and Their In Vitro Antimicrobial, Cytotoxicity and Antiproliferative Evaluation.

Phytochemical investigation of the ethanol extract of underground parts of Iris tenuifolia Pall. afforded five new compounds; an unusual macrolide termed moniristenulide (1), 5-methoxy-6,7-methylenedioxy-4-O-2'-cycloflavan (2), 5,7,2',3'-tetrahydroxyflavanone (3), 5-hydroxy-6,7-dimethoxyisoflavone-2'-O-ß-d-glucopyranoside (9), 5,2',3'-dihydroxy-6,7-dimethoxyisoflavone (10), along with seven known compounds (4-8, 11-12). The structures of all purified compounds were established by analysis of 1D and 2D NMR spectroscopy and HR-ESI-MS. The antimicrobial activity of the compounds 1-3, 5, 9, and 10 was investigated using the agar diffusion method against fungi, Gram-positive and Gram-negative bacteria. In consequence, new compound 3 was found to possess the highest antibacterial activity against Enterococcus faecalis VRE and Mycobacterium vaccae. Cell proliferation and cytotoxicity tests were also applied on all isolated compounds and plant crude extract in vitro with the result of potent inhibitory effect against leukemia cells. In particular, the newly discovered isoflavone 10 was active against both of the leukemia cells K-562 and THP-1 while 4-6 of the flavanone type compounds were active against only THP-1.

Five new flavonoids and their pharmacological activities from Iris tenuifolia Pall.

Five new components including two new isoflavones, 5, 7, 2', 3'-tetrahydroxy-6-methoxyisoflavone (1), 5, 7, 2', 3'-tetrahydroxy-8-methoxyisoflavone (2), one flavonol 3, 5, 3', 4'-tetrahydroxy-7, 2'-dimethoxyflavonol (3), one flavanone (2S)-5, 7, 3'-trihydroxy-2'-methoxyflavanone (4), and one flavanonol (2R, 3R)-3, 5, 3', 4'-tetrahydroxy-7, 2'-dimethoxyflavanonol (5), along with nine known flavonoids (6-14) were isolated from under ground parts of Iris tenuifolia Pall. Their structures were elucidated by NMR and HRESIMS data and by comparison of CD spectra with compounds having similar structure. The separated compounds were evaluated for in vitro antioxidant activities by DPPH and ABTS. The α-glucosidase inhibitory activity of the compounds were evaluated with the pNPG method, the results indicated flavonoids were potential inhibitors of α-glucosidase. Moreover, in vitro anti-oxidative assay using flow cytometry indicated that compounds 1-5 showed strong oxidation resistance ability on C8D1A cells without affecting the cell viability.