An investigation of Serjania salzmanniana for biologically active substances has led to the isolation of two novel saponins, salzmannianoside A (3-O-[[beta-D- glucopyranosyl-(1-->4)]-[alpha-L-rhamnopyranosyl-(1-->2)]-alpha-L- arabinopyranosyl] gypsogenin) [3] and salzmannianoside B (3-O-[[beta-D-glucopyranosyl-(1-->4)]-[alpha-L- arabinopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)] -alpha-L-arabinopyranosyl] hederagenin) (4). Two known saponins, pulsatilla saponin D (3-O-[[beta-D- glucopyranosyl-(1-->4)]-[alpha-L-rhamnopyranosyl-(1-->2)]-alpha-L- arabinopyranosyl] hederagenin) (1) and 3-O-[[beta-D-glucopyranosyl-(1-->4)]-[alpha-L-rhamnopyranosyl-(1-->2)]-a lpha-L- arabinopyranosyl] oleanolic acid (2) were also isolated from this plant. The structures of 3 and 4 were elucidated by FABMS and 2D NMR techniques. All these four saponins were mollusicidal, causing 70-100% mortality at 10 ppm against Biomphalaria alexandrina, a vector of Schistosoma mansoni in the Nile Valley. The saponins also showed antifungal activity against Cryptococcus neoformans and Candida albicans at minimal inhibitory concentrations of 8 and 16 micrograms/mL, respectively.
Phosphorus-31 nuclear magnetic resonance studies of a number of phospholipids and related phosphate monoand diesters indicate that hydrogen bonding occurs in organic solutions of phospholipids. This interpretation is based primarily on the observation that phosphatidylethanolamine (PE), lysophosphatidylethanolamine (lyso-PE), phosphatidylserine (PS), lysophosphatidylserine (lyso-PS), sphingomyelin (SPH), and lysophosphatidylcholine (lyso-PC) all give rise to resonances in the same region of the spectrum; this region is downfield of the chemical shift of phosphalidylcholine (PC) by ca. 30 Hz. The chemical shifts of PE, lyso-PE, PS, lyso-PS, SPH, and lyso-PC are consistent with deshielding of the phosphorus nuclide by hydrogen bonding interactions of P hosphorus-31 nuclear magnetic resonance ( nmr) is proving particularly useful in studies on biological systems for a number of reasons, numbered among which are the relative simplicity of the spectra, the relatively large range of chemical shifts, the sensitivity of the phosphate shift to the presence of metal ions, and the relatively high sensitivity of this 100% naturally abundant nuclide.Phosphorus data of the type obtained in the present work are already finding application in the study of lipid-lipid and lipid-protein interactions in biology. For example, Michaelson et al. (1973) used the differences in chemical shifts of phosphatidylglycerol and phosphatidylcholine to determine the sidedness of cosonicated vesicles. In addition we have applied the differences in chemical shifts of phosphatidylcholine and other phospholipids in studies on the structure of human serum lipoproteins (Glonek et al., 1973a).We recently reported the application of *lP nmr to the detection, estimation, and identification of alkylphosphonic acid derivatives in biological materials (Glonek et ul., 1970;Hilderbrand et a/., 1971 ;Henderson et al., 1972). During the course of these and subsequent studies, we consistently found that lipid fractions from a wide variety of sources in either Grants USPHS-11702 (T. C. M.) and USPHS-NS-9354 (T. 0. H.), amine, amide, or hydroxyl protons with a phosphate oxygen.In the case of PC, however, the opportunity for hydrogenbond-induced deshielding of the phosphorus is minimized due to the absence of the requisite dissociable proton in the molecule. The chemical shift of PC was displaced downfield by 25 Hz when methanol was added to chloroform solutions; the chemical shifts of PE and lyso-PC which contain a dissociable proton were altered to a lesser extent. The contribution of the quaternary nitrogen function of choline to the chemical shifts of PC was assessed by determining the chemical shifts of appropriate phosphate mono-and diesters in aqueous solutions and lyso-PC and lyso-PE in organic solution. This shift contribution was found to be ca. 15 Hz. organic or aqueous solvents gave rise to two absorption bands in the orthophosphate region of the nmr spectrum (cf. Figure 1, spectrum A for the spectrum of a bovine liver lipid extract). Similar spectra...
Whole human blood was examined by 31p nuclear magnetic resonance spectroscopy. Individual phosphates (a,O,-y) In this study, we have used 31P nuclear magnetic resonance spectroscopy (31P NMR) to identify phosphorus compounds in intact human erythrocytes and to record metabolic changes directly in intact erythrocytes incubated in vitro. We have detected the individual phosphate groupings (a,,By) of ATP in intact erythrocytes and have determined that there may be at least two microenvironments for this molecule. In addition, changes in 2,3-diphosphoglycerate were followed immediately after withdrawal of blood, as well as during incubation of aged cells in the presence of added inosine and pyruvate at 250.Recently, Moon and Richards (1) applied the technique of a1P NMR to the study of rabbit whole blood and hemolysates, and were able to estimate the intracellular pH of carbon monoxide-treated rabbit erythrocytes by measuring the pHinduced changes in chemical shifts of the 2-and 3-phosphates of 2,3-diphosphoglycerate. MATERIALS AND METHODSThe spectrometer used was a Bruker HFX-5 operating at 36.43 MHz for 31p (21 KGauss) (2-4) and incorporating facilities for Fourier transform signal-averaging and broadband heteronuclear 1H decoupling.
A paramagnetic quenching reagent, Mn-2+/EDTA (1:2.2), was developed for the purpose of investigating the phospholipid phosphate groupings of human serum low and high density lipoproteins through the quenching effect of the reagent on the 31-P nuclear magnetic resonance signals from these complexes. Systems investigated included native low and high density serum liproteins (LDL, HDL2, and HDL3), egg phosphatidylcholine vesicles together with appropriate phosphodiester model systems, diethyl phosphate in aqueous buffer, and phosphatidylcholine and sphingomyelin both in anhydrous methanol. The results of these studies indicated that ca. 50 percent of the phospholipid-phosphorus signal of LDL is quenched upon titration as compared to an 80-85 percent figure observed for HDL2 and HDL3. In all cases the spectral effects were totally reversible upon removalof the paramagnetic ion by dialysis. The results of the titration studies indicated a similar but not an identical behavior between HDL2 and HDL3. The results are consistent with model structures of HDL and LDL particles derived from low angle X-ray diffraction.
Advanced methods of phosphorus-31 nuclear magnetic resonance spectroscopy provided a method whereby biological phosphonates and phosphates can be determined on simple lipid fractions of biological origin. The spectra consist of two easily distinguished resonance bands; one corresponds to families of phosphonates, and the other corresponds to families of orthophosphates.
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