causing three major metabolites it the predominant one cor

analysis of the 2D COSY correlations between 2E Heq, 2E Hax, 4E H and 3E H and their coupling constants helped us to ascertain the D digitoxose stereochemistry, 9 and 11 being recognized as demycarosyl 3D T D digitoxosyl mithramycin SK and demycarosyl 3D B D digitoxosylmithramycin SDK, respectively. In and as it was anticipated, strain S. argillaceus M3W1 pMP3 Celecoxib BII produced new compounds combining changes at the 3 carbon side chain and in the glycosylation profile : ingredient 9 a 2 hydroxy 1 methoxy 3 oxobutyl side chain, while 10 and 11 a 1 methoxy dioxobutyl side chain ;5 in addition, in compounds 9 and 11 the D mycarose residue was replaced by D digitoxose, and in 10 the third sugar in the trisaccharide chain was absent. The expression of plasmid pKOL in mutant strain S. argillaceus M3W1, resulting in recombinant strain S. argillaceus M3W1 pKOL created a few mithramycin type substances, like the acknowledged metabolites 4 and 3 Endosymbiotic theory and demycarosyl mithramycin SK. 5,29 The two new compounds, not contained in extracts of S. argillaceus M7W1, showed somewhat faster and mithramycin form UV absorptions retention times compared to 3 and 4, with masses of 14 amu significantly less than their 4 counterparts and 3, indicating the substitution of an unmethylated dideoxysugar at E position APCIMS. A 10L fermentation of S. argillaceus M3W1 pKOL gave sufficient amounts of the new substances, of determined through HR ESI mass spectrometry and 1D and 2D NMR spectroscopy as substance 9 and 11. Antitumor activity of new mithramycin analogues Antitumor activity of selected new mithramycin analogues was initially tested against a panel of three tumor cell lines. Fostamatinib Only compounds 9 to 11, which mix modifications both in the sugar moiety and C3 side chain within their buildings, showed high antitumor activity, with normal GI50 values between 0. 3 and 1. 3 uM. The anticancer action of compounds 9 to 11 were tested in the National Cancer Institutes cell possibility display applying 60 cancer cell lines derived from different liquid and solid tumors. Like a reference, substance 2, with only modifications within the glycosylation pattern, was also tested. Data are shown in Dining table 1. All three new compounds showed high antitumor activity against all human tumor cell lines tested, with GI50 values between 10 nM and 1 uM, except in ovarian tumor cell line NCI/ADR RES where GI50 values for compounds 9 and 10 are more than 10 uM. Compounds 9 and 11 showed the highest antitumor action, being in average about 5 fold more effective than 10. A comparison of the values of compounds 9 and 11 with those of substance 2, which only is significantly diffent from them within the structure of the 3 carbon side chain, revealed an increase of activity for 9 and 11 for several of cell lines. Compared with 1 that has average GI50 of 18 nM, 9 and 11 were minor less potent, while 10 is considerably less potent, with average GI50 at 158 nM.