Screening On Antitumor Fractions Of Inonotus Obliquus And Its Chemical Constituents

In this paper, different concentrations (10,20,40,60,80 μg/ml) of ethanol extract (IOET), petroleum ether extract (IOPE), ethyl acetate extract (IOEE), n-butanol extract (IOBT) and residual water extract (IOAT) from Inonotus obliquus were tested on three tumor strains (HepG2,SGC-7901, A549), the cell growth rate were detected by MTT method. IC50 values were calculated. The ethanol extract (IOET) the petroleum ether fraction (IOPE) and ethyl acetate fraction (IOEE) from Inonotus obliquus have antitumor activity, with IC50 values of 56 μg/ml,28μg/ml,47 μg/ml, respectively.The constituents were isolated repeatedly through silica gel, ODS and Sephadex LH-20 column chromatography, then structurally elucidated by spectral analysis (MS, 1H-NMR,13C-NMR). Twenty-one compounds were isolated from antitumor fractions of Inonotus obliquus and 12 compounds were identified, namely lanosterol (2), 3 β-hydroxy-lanosta-8,24-dien-21-al(3),inotodiol(4),betulin(5),5a,8a-epidioxyergosta-6, 22-dien-3β3-ol (7), ergosta-4,6,8 (14),22-tetraene-3-one (9), stigmast-4-en-3-one (10), uvariol (12), inonotsuoxides B (13), inonotsutriols A (14), daucosterol (19). Twenty-one identified compounds were known compounds, among which 9 and 19 were firstly reported from Inonotus obliquus.MTT method was used to test the anti-tumor activity of the compounds from Inonotus obliquus. Among tested compounds, lanosterol (2), inotodiol(4), 5a,8a-epidioxyergosta-6,22-dien-3β-ol(7) and inonotsuoxides B (13) show antitumor activity, whereas 3β-hydroxy-lanosra-8,24-dien-21-al(3),botulin(5),ergosta-4,6,8 (14), 22-tetraen-3-one (9) and stigmast-4-en-3-one (10) have not antitumor activity on tested tumor strains.Inotodiol (4),5a,8a-epidioxyergosta-6,22-dien-3β-ol (7), inonotsuoxides B (13) have strong antitumor activity, with IC50 value less than 100 μmol/L, whereas antitumor activity of lanosterol (2) was weak with its IC50 value more than 100 μmol/L.