Conformational recognition of RA-XII by 80S ribosomes. A differential line broadening study in 1H NMR spectroscopy.

Abstract

1H NMR spectroscopy has been used to demonstrate specific binding of rat 80S ribosomes to the major conformer of an antitumor bicyclic hexapeptidic glucoside, RA-XII, isolated from Rubia cordifolia, in a fast exchange process.

Bioactive Constituents from Chinese Natural Medicines. XI. Inhibitors on NO Production and Degranulation in RBL-2H3 from Rubia yunnanensis: Structures of Rubianosides II, III, and IV, Rubianol-g, and Rubianthraquinone

“…The acid hydrolysis of 2 and 3 liberated D-glucose, which was identified by HPLC analysis using an optical rotation detector, 1,15) and rubiarbonols A (13) 1,19) and F (14) 1,19) as their aglycons, respectively. The 1 H-NMR (pyridine-d 5 ) and 13 C-NMR (Table 1) spectra 14) of 2 and 3 showed the presence of the following functions: a rubiarbonol A part in 2 {seven methyls [d 0.97, 1.10 (3H each, both d, were also determined by HMBC, which showed long-range correlation was observed between the 1Ј-proton and 3-carbon ( Fig. 2).…”

“…The 1 H-NMR (pyridine-d 5 ) and 13 C-NMR (Table 1) spectra 14) of 1 showed signals assignable to eight methyls [ as its aglycon and D-glucose, which was identified by HPLC analysis using an optical rotation detector. 1,15) The proton and carbon signals in the 1 H-and 13 C-NMR spectra of 1a were similar to those of rubiarbonol A (13), except for the signals due to the 28-methyl group.…”

“…The 1 H-NMR (pyridine-d 5 ) and 13 C-NMR (Table 1) spectra 14) of 1 showed signals assignable to eight methyls [ as its aglycon and D-glucose, which was identified by HPLC analysis using an optical rotation detector. 1,15) The proton and carbon signals in the 1 H-and 13 C-NMR spectra of 1a were similar to those of rubiarbonol A (13), except for the signals due to the 28-methyl group. The 1 H-1 H correlation spectroscopy ( 1 H- 1 cidated using nuclear Overhauser enhancement spectroscopy (NOESY), which showed the NOE correlations between the following proton pairs: H -3 and H-5, H 3 -23; H-5 and H-7, H 3 -23; H-7 and H 3 -26; H-8 and H 3 -25, 27; H-18 and H-21, H 3 -26; H-19 and H 3 -27, 28; H 3 -24 and H 3 -25; H 3 -27 and H 3 -28.…”

“…The aqueous acetone extract from the roots of R. yunnanensis (purchased in Kunming, Yunnan Province, China) was partitioned into an ethyl acetate (EtOAc)-water mixture to furnish the EtOAc-soluble and H 2 O-soluble fractions as previously described. 1) The EtOAc-soluble fraction was subjected to normal-phase and reverse-phase silica gel column chromatography and repeated HPLC to give rubianosides II (1, 0.0006% from the natural medicine), III (2, 0.011%), and IV (3, 0.0035%), rubianol-g (4, 0.0021%), and rubianthraquinone (5, 0.0043%) together with 16 7,8) (0.0016%), 17 7,8) (0.22%), 18 7,8) (0.062%), 5Ј-methoxylariciresinol (20, 9) 0.00048%), 2-methyl-1,6-dihydroxy-9,10-anthraquinone 3-O-(6Ј-acetyl)-a -L-rhamnopyranosyl(1®2)-b -D-glucopyranoside (24,10) 0.18%), rubinaphthin A (25, 11) 0.028%), and RA-XII (28, 12,13) 0.021%).…”

9,10‐Anthraquinones and Other Biologically Active Compounds from the Genus Rubia

“…In the course of a continuing search for antitumor substances from crude extract of Rubia, it was established that the bicyclic hexapeptides showed potent antitumor activities against various experimental murine tumors in vivo and cultured cells in vitro. The cyclic hexapeptides showed potent antitumor activity by binding to eukaryotic 80S ribosomes, resulting in inhibition of aminoacyl-tRNA binding and peptidyl-tRNA translocation, thus leading to the stopping of protein synthesis [88] [102]. The treatment of human colon cancer DLD-1 cells with RA-VII (138) induces cellgrowth inhibition associated with a partial G1 arrest and a rapid decrease (below 2 h) in the level of cyclin D1 protein, and, hence, RA-VII (138) or O-Me-deoxybouvardin is known to inhibit protein biosynthesis in vitro and in vivo [103].…”