Chemical Composition, Antiprotozoal and Cytotoxic Activities of Indole Alkaloids and Benzofuran Neolignan of Aristolochia cordigera.

This is a comparative study on the intraspecific chemical variability of species, collected in two different regions of Brazil, Biome Cerrado (semiarid) and Biome Amazônia (coastal). The use of GC-MS and statistical methods led to the identification of 56 compounds. A higher percentage of palmitone and germacrene-D in the hexanes extracts of the leaves of plants from these respective biomes was observed.

4,5-seco-guaiane and a nine-membered sesquiterpene lactone from Holostylis reniformis.

Root extracts of Holostylis reniformis (Aristolochiaceae) yielded three new natural sesquiterpenes, a sesquiterpene with an unusual carbon skeleton, 4,5-seco-guaiane (7-epi-11-hydroxychabrolidione A, 1), a nine-membered lactone with new carbon skeleton (holostylactone, 2), and a new megastigmane [(6S,7E)-6,9-dihydroxy-10-(2'-hydroxy-ethoxy)-4,7-megastigmadien-3-one, 3], together with bulnesol and sitosterol-3-O-β-D-glucopyranoside. The structures of these compounds were determined by spectroscopic analyses and B3LYP/STO-3G** theoretical studies.

A nonionic porphyrin as a noninterfering DNA antibacterial agent.

The increasing interest in clinical bacterial photodynamic inactivation has led to the search for photosensitizers with higher bactericidal efficiency and less side effects on the surrounding tissues. We present a novel nonionic porphyrin, the 5,10,15-tris(2,6-dichlorophenyl)-20-[4-N-(6-amino-hexyl)sulfonamido)phenyl]-porphyrin (ACS769F4) with substantial improvements in the efficiency of nonionic sensitizers. This porphyrin causes eradication of both Escherichia coli and Staphylococcus aureus by the photodynamic effect but in higher concentrations compared with 5,10,15,20-tetrakis (4-N,N,N-trimethylammoniumphenyl)-porphyrin p-tosylate (TTAP(4+)), a known bactericidal tetracationic porphyrin.

Unconstrained mining of transcript data reveals increased alternative splicing complexity in the human transcriptome.

Mining massive amounts of transcript data for alternative splicing information is paramount to help understand how the maturation of RNA regulates gene expression. We developed an algorithm to cluster transcript data to annotated genes to detect unannotated splice variants. A higher number of alternatively spliced genes and isoforms were found compared to other alternative splicing databases.

Biosynthesis of antimalarial lignans from Holostylis reniformis.

Holostylis reniformis biosynthesizes 8-8' linked lignans without 9,9'-oxygenation. To elucidate the biosynthetic pathways to these lignans, the reputed precursors [U-(14)C]phenylalanine, [9-(3)H(1)]coniferyl alcohol, and [9-(3)H(1)]isoeugenol were administered to roots of the plant, which led to the incorporation of (3)H and (14)C into ten 2,7' linked-lignans (aryltetralone lignans) and two 7,7'-epoxylignans (furan lignans). These administration experiments demonstrated that the lignans were propenylphenol-derived and that H.

Antiplasmodial activity of aryltetralone lignans from Holostylis reniformis.

Extracts from Holostylis reniformis were tested in vivo against Plasmodium berghei and in vitro against a chloroquine-resistant strain of Plasmodium falciparum. The hexane extract of the roots was the most active, causing 67% reduction of parasitemia in vivo. From this extract, six lignans, including a new (7'R,8S,8'S)-3',4'-methylenedioxy-4,5-dimethoxy-2,7'-cyclolignan-7-one, were isolated and tested in vitro against P.

Aryltetralol and aryltetralone lignans from Holostylis reniformis.

Aryltetralol and aryltetralone lignans were isolated from the hexane extracts of the roots of Holostylis reniformis. Their structures were determined by spectroscopic methods and chemical transformations.

Aryltetralone lignans and 7,8-seco-lignans from Holostylis reniformis.

Aryltetralone lignans and two 7,8-seco-lignans were isolated from the acetone and hexane extracts of the roots of Holostylis reniformis, together with (-)-galbacin. Their structures were determined by spectroscopic methods.