Effective nodulation of rhamnaceous actinorhizal plants induced by air dry soils

Air dry soil samples stored at room temperature for more than one and a half years, were used as inocula for actinorhizal plants. Seedlings of Colletia paradoxa, Discaria americana, D. articulata and D. trinervis (Rhamnaceae) cultivated in nitrogen-free nutrient solution, were inoculated by adding dry soil to the solution. All the soil samples tested were able to induce nodulation, showing the presence of infective propagules of Frankia. Healthy growth of nodulated plants suggested the occurrence of nitrogen fixation.     

Flavonoids from Rhamnus pallasii

A new dihydroflavonol, pallasiin, together with kaempferol, quercetin, isorhamnetin, mearnsetin, aromadendrin, eriodictyol and taxifolin, has been isolated from the bark of Rhamnus pallasii and its structure elucidated as 2,3-dihydromyricetin 4′-O-methyl ether.     

New peptide alkaloids from Hovenia dulcis and H. tomentella

From the root bark of Hovenia dulcis Thunb. and H. tommentella (Makino) Nakai (Rhamnaceae), three peptide alkaloids, frangulanine, hovenins-A and -B have been isolated. Hovenin-A has been shown to be des-N-methylfrangulanine (II).     

Diversification of the North American shrub genus Ceanothus (Rhamnaceae): conflicting phylogenies from nuclear ribosomal DNA and chloroplast DNA

Ceanothus comprises ～55 morphologically and ecologically diverse species of woody perennials endemic to North America. Interpretations of the natural history of Ceanothus have served as a general model of evolution for woody perennials with simple entomophilous pollination systems, but these interpretations lacked explicit phylogenetic context. We used cladistic analysis of sequences of the chloroplast-encoded matK and the internal transcribed spacers (ITS) and 5.8S coding region of nuclear ribosomal DNA (nrDNA) to reconstruct the phylogeny of Ceanothus. The nuclear and organellar phylogenies exhibited very low levels of both topological and character congruence. Subgenera Ceanothus and Cerastes are monophyletic sister taxa in both phylogenies, but both data sets suffer from a lack of resolution below the level of subgenus. Lack of taxonomic congruence between the two data sets may be a result of introgression and/or lineage sorting. The ITS tree was accepted as the better estimate of a species phylogeny for Ceanothus, on the assumption that nuclear markers are less prone to introgression. Three of five polytypic species in the ITS data set were paraphyletic, and four of six polytypic species in the matK data set were paraphyletic. This study demonstrates the degree to which matched independent data sets can produce conflicting summaries of evolutionary history.     

Naphthoquinone-lactones and extended quinones from Ventilago calyculata

New quinones have been isolated from the root bark of Ventilago calyculata. Ventilatones A and B are benzisochromanquinones, related to the ventiloquinones, which have an additional fused lactone ring while ventileins A and B are benzisochroman dimers having a dihydroxy-peri-xanthenoxanthenequinone chromophore.     

Benzisochromanquinones in ventilago species

From the acetone extract of the root bark of Ventilago maderaspatana eight new benzisochromanquinones; ventiloquinones A, B, C, D, E, F, G and H, have been isolated. Ventiloquinones I, J and K are three more new benzisochromanquinones isolated from the root bark of V. calyculata. The majority are 3,4,5,10-tetrahydro-cis-1,3-dimethyl-1H-naphtho[2,3-c]pyran-5,10-quinones related to eleutherin, but F, H, I, J and K are 6,9-quinones related to ventilagone.     

Sativanine-C: A cyclopeptide alkaloid from the bark of Zizyphus sativa

From the bark of Zizyphus sativa a previously undescribed 13 membered cyclopeptide alkaloid, sativanine-C has been isolated. The structure of this new compound was elucidated by spectroscopic methods, its transformation product and by chemical degradation.     

Triterpenoids of Colletia spinosissima

The neutral components from the stems of Colletia spinosissima Gmel. include lupenone, sitosterol lupeol, daucosterine. Acid hydrolysis of the glycoside fraction afforded ethyl sinapate and two homologous degradation products from the corresponding sapogenins. Mild hydrolysis of the glycoside fraction afforded the intact sapogenins, which have been tentatively assigned the structures (VIIb) and (VIIIb). The chemistry of the latter compounds has been explored.