Antimalarial and cytotoxic constituents of Xylaria cf. cubensis PK108.

Xylaria cf. cubensis PK108 was identified by its distinctive morphological characteristics and its internal transcribed spacers sequence analysis. The chromatographic separation and structural elucidation based on spectroscopic analysis of fungal crude extracts led to 10 compounds; tryptoquivaline L (1), fiscalin C (2), epi-fiscalin C (3), cytochalasin D (4), ergosterol (5), ergosterol peroxide (6), chevalone C (7), xylaranol B (8), helvolic acid (9) and cyclo-(L-Pro-L-Leu) (10).

Potential antimalarial derivatives from astraodorol.

Astraodorol, a major lanostane-type triterpene isolated from the edible mushroom Astraeus odoratus, was subjected to chemical modifications. Ten derivatives have been synthesized and their biological activities were evaluated. Compounds 5, 6, 7a, 7c, 7e, 7f, and 7 g exhibited strong antimalarial activity with IC50 values of 4.

Chemical constituents, and their cytotoxicity, of the rare wood decaying fungus Xylaria humosa.

Samples of Xylaria humosa, a rare species of Xylariaceae, were collected during an investigation into the diversity of the fungus in the Phu Khieo Wildlife Sanctuary, Thailand. Nine compounds were isolated from the species and their structures elucidated by spectroscopic methods. The compounds were ergosterol (1), ergosterol peroxide (2), two meroterpenoids, chevalone B and C (3-4), together with five indole alkaloids, tryptoquivaline L (5), tryptoquivaline M (6), fiscalin A (7), epi-fiscalin A (8) and epi-fiscalin C (9).

Cofractionation of HMGB proteins with histone dimers.

An effective and flexible method is presented that can be used to investigate cofractionation of groups of nuclear proteins. The method was used to analyze chromatin-related proteins, of which high-mobility group B (HMGB) proteins consistently cofractionated by cation-exchange chromatography with the histone dimer (H2A-H2B). This led to the hypothesis that the two form a complex, further suggested by gel filtration, in which the HMGBs with core histones eluted as a defined high-molecular-weight peak.

Astraodoric acids A-D: new lanostane triterpenes from edible mushroom Astraeus odoratus and their anti-Mycobacterium tuberculosis H37Ra and cytotoxic activity.

Tuberculosis (TB) is one of the chronic infectious diseases caused by Mycobacterium tuberculosis that causes about 2-3 million deaths per year. Isoniazid and rifampicin are examples of first line drugs used for TB treatment; however, they are potentially hepatotoxic. More effective and safer drugs are urgently needed, especially from natural products.

The oxidised histone octamer does not form a H3 disulphide bond.

A H3 dimer band is produced when purified native histone octamers are run on an SDS-PAGE gel in a beta-mercaptoethanol-free environment. To investigate this, native histone octamer crystals, derived from chicken erythrocytes, and of structure (H2A-H2B)-(H4-H3)-(H3'-H4')-(H2B'-H2A'), were grown in 2 M KCl, 1.35 M potassium phosphates and 250-350 microM of the oxidising agent S-nitrosoglutathione, pH 6.

Bitungolides A-F, new polyketides from the Indonesian sponge Theonella cf. swinhoei.

Six new polyketides, bitungolides A-F (1-6), have been isolated from the Indonesian sponge Theonella cf. swinhoei and their structures elucidated by spectroscopic data and X-ray diffraction analysis. The bitungolides are a new class of Theonella metabolites that inhibit dual-specificity phosphatase VHR.