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1,4-Epidioxy-bisabola-2,12-diene (3) and aromatic hydroperoxides (4, 5) were prepared by photoxidation of gamma-curcumene (1). Reduction and esterification of 6 and 7 afforded compounds 9 to 10. All compounds were tested in vitro for antimalarial activity. The activity could not be increased significantly, compared with 3. The most active compounds, 3 and 9, did not show in vivo antimalarial activity in mice.

A so far unknown 4-methyl-7-hydroxyphthalideglycoside has been isolated from the methanol extract of the bark of Quillaja saponaria molina. Its structure has been established from NMR experiments as 7-O(-)[beta-glucopyranosyl-(1-->6)-beta-arabinopyranosyl]-7-hydrox y-4-methy l -1[3H]-isobenzofuranone. Two known compounds, 3,4,5-trimethoxyphenyl-beta-D-glucopyranoside and lyoniresinol-3 alpha-O-beta-D-glycopyranoside were also identified.

Two previously undescribed elemanolide esters, the 2-methylpropanoate and 2-methyl-2-propenoate of 11,13-dehydromelitensin, were isolated in the course of a bioassay-guided fractionation from the aerial parts of Centaurea chilensis Hook. et Arn., used traditionally to treat 'gout and rheumatism'. The mixture of both substances exhibits anti-inflammatory activity in the carrageenan-induced paw edema assay.

Hydrolysis of the crude saponin extracted from the leaves of Panax notoginseng (Burk.) F. H. Chen yields five sapogenins which are separated by column chromatography. Two of these are identified to be panaxadiol and panaxatriol whose structures were elucidated earlier. The third sapogenin ist found to be Dammar-20(22)en-3beta, 12beta,-26-triol by carbon-13 NMR. The structure of the fourth sapogenin is established by X-ray diffractometry and carbon-13 NMR to be 20 ( R)-Dammaran-3beta, 12beta, 20, 25-tetrol.

An alkaloid of the molecular formula C (21)H (19)NO (6) was isolated from the roots of berberis actinacantha. Substructures were derived from proton and carbon-13-NMR data. Single-crystal x-ray diffractometry identified the alkaloid as 15( R,S)-3,4-dimethoxy-11,12-methylenedioxy-8,14-dioxo-hexahydro- ISO-homoprotoberberin. ORTEP plots, bond angles, assigned carbon-13 and proton NMR data are given.

Hydrolysis of the crude saponin isolated from the leaves of PANAX NOTOGINSENG (Burk.) F. H. Chen yields five sapogenins which are separated by column chromatography. The structures of four of those were elucidated earlier to be panaxadiol, panaxatriol, dammar-20(22)en-3beta, 12beta,26-triol and 20(R)-dammaran-3beta, 12beta,20,25-tetrol. The fifth sapogenin is identified as an oxepane derivative probably arising from acid catalyzed dehydration and rearrangement of panaxadiol. The structure as proposed from NMR data was confirmed by single-crystal X-ray diffractometry.

From Sulfolobus solfataricus, a sulfur-oxidizing thermophilic member of archaebacteria, three unusual benzothiophenquinones were isolated. Detailed NMR studies on these quinones, including multipulse mono-dimensional and two-dimensional techniques, were performed to obtain carbon and proton assignments, one-bond, geminal and vicinal coupling constants and T1 relaxation times. This report extends the known quinone composition of thermophilic archaebacteria and further supports the concept that these biomolecules can serve as a useful chemotaxonomic tool.

The alga Ankistrodesmus braunii was grown with [14N]nitrate under optimized conditions of a large-scale mass cultivation. 19.7% of the dried algae were isolated as a mixture of amino acids. The 15N-labelled amino acids (15N content up to 98%) were separated by ion exchange chromatography using pyridine acetate gradients. The 15N cotent of the analytically pure amino acid was determined by combined gas-liquid chromatography-mass spectrometry of the trifluoroacetylated methylesters and by emission spectroscopy in the 15N analysator. Using pulse Fourier transform 13C nuclear magnetic resonance, the pH dependence of the 13C-15N coupling constants of Asp, Pro, Ser, Glu, Gly, Ala, Val, Ile and Leu was determined in aqueous solutions. Increasing coupling constants were found with pH and decreasing electron density, respectively. The relation of Binsch et al. (Binsch, G., Lambert, J.B., Roberts, B.W. and Roberts, J.D. (1964) J.Am. Chem. Soc. 86,5564-5570) between the coupling constant and the product of the S-part of the 13C and 15N hybridization SC - SN = 80 - J (13C-45X) fits best in acidic medium. The magnitude of coupling constants correlates well with the electron densities calculated by Del Re et al. (Del Re, G., Pullman, B. and Yonezawa, T. (1963) Biochim. Biophys. Acta 75, 153-182). The recording of 13C nuclear magnetic resonance spectra over the entire pH range revealed no change in the sign of the 13C-15N coupling constants of the amino acids.

Nuclear magnetic resonance spin-lattice relaxation times (T1) of tissue water protons are elevated in samples from tumors when compared to the corresponding normal tissues. In order to exclude differences between the normal and the tumorous tissue samples other than transformation as far as possible the T1values of cells infected by temperature sensitive transforming mutants of Rous sarcoma virus were measured. In this model genetic homogeneity of the host cells as well as identity of the viruses in the normal and transformed state is assured. In the transformed cells the protons relaxed more slowly than in the cells of normal phenotype which were kept at an only slightly higher incubation temperature.