Extracts of PELARGONIUM SIDOIDES, commonly known as EPs 7630, are produced by extraction of milled roots with 11 % (w/w) ethanol in water. This solvent leads to a spectrum of constituents which differs significantly from extracts obtained by extraction with non-polar solvents. EPs 7630 is composed of six main groups of constituents, namely unsubstituted and substituted oligomeric prodelphinidins, monomeric and oligomeric carbohydrates, minerals, peptides, purine derivatives and highly substituted benzopyranones. The oligoprodelphinidins, frequently supposed to be compounds with unspecific tanning interactions, show, in contrast to other polyphenols, an amazing variety of substructures and connectivities which results in an uncommon diversity even at a low degree of polymerization. Three distinct purine derivatives, second messengers and probably intermediates of DNA synthesis, were identified and characterized by phytochemical means. The main benzopyranones of EPs 7630 are highly oxygenated at the phenyl moiety (three to four oxygens) and in addition sulfated at distinct positions. A disulfate of 6,7,8-trihydoxybenzopyranone has been identified for the first time in plants. Taken together, these constituents amount to about 70 to 80 % of the total weight of EPs 7630, the active ingredient of the phytopharmaceutical Umckaloabo (Iso Arzneimittel Ettlingen).

The distribution of unpaired electron spin over all regions of the organic ligands was extracted from the large positive and negative 1H and 13C NMR paramagnetic shifts of the title complexes. Owing to benevolent line broadening and to very high sensitivities of approximately 254,000 and approximately 201,000 ppm/(unpaired electron spin) for Co(II) and Ni(II), respectively, at 298 K in these pseudotetrahedral bis(N,N'-chelates), spin transmission through the sigma- (and orthogonal pi)-bonding system of the ligands could be traced from the chelate ring over five to nine sigma bonds. Most of those "experimental" spin densities DeltarhoN (situated at the observed nuclei) agree reasonably well with quantum chemical DeltarhoDFT (DFT = density functional theory) values and provide an unsurpassed number of benchmark values for the quality of certain types of modern density functionals. The extraction of DeltarhoN became possible through the unequivocal separation of the nuclear Fermi contact shift components from the metal-centered pseudocontact shifts, which are proportional to the anisotropy Deltachi of the magnetic susceptibility: Experimental Deltachi values were obtained in solution from measured deuterium quadrupole splittings in the 2H NMR spectra of two deuterated model complexes and were found to be nonlinear functions of the reciprocal temperature. This provided the reliable basis for predicting metal-centered pseudocontact shifts for any position of a topologically well-defined ligand at varying temperatures. The related ligand-centered pseudocontact shifts were sought by using the criterion of their expected nonlinear dependence on the reciprocal temperature. However, their contributions could not be differentiated from other small effects close to the metal center; otherwise, they appeared to be smaller than the experimental uncertainties. The free activation energy of N-aryl rotation past a vicinal tert-butyl substituent in the Ni(II) vinamidine bis(N,N'-chelates) is DeltaG++(+74 degrees C) approximately 17.0 kcal/mol and past a vicinal methyl group DeltaG++(-6 degrees C) approximately 13.1 kcal/mol.

Investigation of the benzopyranones from the roots of PELARGONIUM SIDOIDES led to the identification of 15 benzopyranones, among them the novel compounds 12 and 14. Furthermore, benzopyranones 4 and 15 were detected in PELARGONIUM SIDOIDES for the first time. Structure determinations were performed by one- and two-dimensional NMR spectroscopy. An HPLC system for the discrimination of these benzopyranones has been developed.

SummaryIsovanillin was oxidized with magnesium monoperoxyphthalate to 4-methoxyresorcinol (2) and the latter was reacted with 3-0x0-propionic acid ethylester prepared in siru to give scopoletin (1). These reactions can be achieved in kg scale in high yields.

The low temperature photooxygenation of the furocoumarins 1 a -e, the naphthofurans 1 f -h, and the furoquinoline 1 i afforded the corresponding dioxetanes 2 in good yields, except the linearly annulated naphthofuran 1 f, which led exclusively to the allylic hydroperoxide 5f by ene reaction with singlet oxygen. The dioxetanes 2 were rigorously purified by means of low temperature silica gel chromatography and fully characterized. Thermolysis of the furocoumarin dioxetanes 2a -e led to the expected cleavage products 3a-e (acetyloxy-and acetyl-substituted coumarins), while the naphtho-and quinolinofuran dioxetanes 2 g -i gave in addition to the cleavage products 3g -i also the spiroepoxides 4 g -i. Intramolecular electron transfer from the aromatic moiety to the dioxetane ring, with subsequent cyclization of the radical-ion species and fragmentation is postulated as mechanism for the formation of this novel rearrangement product of dioxetanes. On heating in chloroform the spiroepoxides 4g,h rearranged into the 1,3-dioxole 6g, but heating of 4 g in methanol gave the dioxine 7 g by trapping of the dipolar intermediate. -The furocoumarin dioxetanes 2a, c.d showed high mutagenic activity in the Salmonella typhimurium strain TA 100 but not in the strain TA 2638. The naphtho-and quinolinofuran dioxetanes 2h,i and the spiroepoxides 4g.h were nonmutagenic in the TA 100 strain. Epoxide-like DNA damage appears to be responsible for the mutagenicity of the furocoumarin dioxetanes Our investigations on the photogenotoxicity of 1,2-dioxetanes -efficient chemical sources of triplet excited carbony1 compounds -revealed that indeed DNA can be damaged when treated with dioxetanes under physiological conditions. With isolated DNA pyrimidine dimers were detected 1,233), while with superhelical PM2 DNA and pyrimidine dimer-specific repair endonucleases a correspondence between the amount of dimer formation and triplet excitation flux of different alkyl-substituted dioxetanes was observed4). However, in bacteria and mammalian cells the main damage were single strand breaks, which were presumably caused by active oxygen species2). It was, therefore, surprising that these dioxetanes were not mutagenic in several Salmonella thypimurium strains (Ames test). Nevertheless, recently we observed4) that benzofuran dioxetanes 2 (Scheme 1) were highly mutagenic in S. thyphimurium TA 100; thus, these derivatives are the first known dioxetanes with potent mutagenicity.To obtain insight into the mechanism of their mutagenic activity, we prepared some isomeric furocoumarin-, naphthofuran-and furoquinoline-annulated 1,2-dioxetanes. O n the one hand, because of their marked planar geometry, these dioxetanes should exhibit a high affinity to DNA through intercalation; on the other hand, the availability ofstructural isomers with distinct intercalating abilities should allow to draw conclusions on their mutagenic mode of action.Presently we report on the synthesis and characterization of the dioxetanes 2 by photooxygenation of the corresponding furocouma...