Chemical Characterization of Plant Extracts and Evaluation of their Nematicidal and Phytotoxic Potential.

ranks among the "top ten" plant-parasitic nematodes of phytosanitary importance. It causes significant losses in commercial interest crops in America and is a potential risk in the European Union. The nematicidal and phytotoxic activities of seven plant extracts against and were evaluated in vitro, respectively.

Complete 1H NMR assignments of pyrrolizidine alkaloids and a new eudesmanoid from Senecio polypodioides.

Chemical investigation of the aerial parts of Senecio polypodioides lead to the isolation of the new eudesmanoid 1β-angeloyloxyeudesm-7-ene-4β,9α-diol (1) and the known dirhamnosyl flavonoid lespidin (3), while from roots, the known 7β-angeloyloxy-1-methylene-8α-pyrrolizidine (5) and sarracine N-oxide (6), as well as the new neosarracine N-oxide (8), were obtained. The structure of 1 and 8 was elucidated by spectral means. Complete assignments of the (1)H NMR data for 5, 6, sarracine (7), and 8 were made using one-dimensional and two-dimensional NMR experiments and by application of the iterative full spin analysis of the PERCH NMR software.

New saponins from Sechium mexicanum.

The chemical study of Sechium mexicanum roots led to the isolation of the two new saponins {3-O-beta-D-glucopyranosyl (1 --> 3)-beta-D-glucopyranosyl-2beta,3beta,16alpha,23-tetrahydroxyolean-12-en-28-oic acid 28-O-alpha-L-rhamnopyranosyl-(1 --> 3)-beta-D-xylopyranosyl-(1 --> 4)-alpha-L-rhamnopyranosyl-(1 --> 2)-alpha-L-arabinopyranoside} (1) and {3-O-beta-D-glucopyranosyl (1 --> 3)-beta-D-glucopyranosyl-2beta,3beta,16alpha,23-tetrahydroxyolean-12-en-28-oic acid 28-O-alpha-L-rhamnopyranosyl-(1 --> 3)-beta-D-xylopyranosyl-(1 --> 4)-[beta-D-apiosyl-(1 --> 3)]-alpha-L-rhamnopyranosyl-(1 --> 2)-alpha-L-arabinopyranoside} (2), together with the known compounds {3-O-beta-D-glucopyranosyl-(1 --> 3)-beta-D-glucopyranosyl-2beta,3beta,6beta,16alpha,23-pentahydroxyolean-12-en-28-oic acid 28-O-alpha-L-rhamnopyranosyl-(1 --> 3)-beta-D-xylopyranosyl-(1 --> 4)-alpha-L-rhamnopyranosyl-(1 --> 2)-alpha-L-arabinopyranoside} (3), tacacosides A(1) (4) and B(3) (5). The structures of saponins 1 and 2 were elucidated using a combination of (1)H and (13)C 1D-NMR, COSY, TOCSY, gHMBC and gHSQC 2D-NMR, and FABMS of the natural compounds and their peracetylated derivates, as well as by chemical degradation. Compounds 1-3 are the first examples of saponins containing polygalacic and 16-hydroxyprotobasic acids found in the genus Sechium, while 4 and 5, which had been characterized partially by NMR, are now characterized in detail.