Establishment and validation of a 384-well antibacterial assay amenable for high-throughput screening and combination testing.

A 384-well-based antibacterial assay amenable for high-throughput screening and combination testing is described. The assay uses 100-500nL of test compounds and tolerates up to 2.5% dimethyl sulfoxide concentrations.

Leporizines A-C: epithiodiketopiperazines isolated from an Aspergillus species.

Three new compounds named leporizines A-C have been isolated from an Aspergillus sp. strain. Their structures were elucidated by analysis of 1D and 2D NMR spectra.

Isolation and characterization of antimicrobial compounds in plant extracts against multidrug-resistant Acinetobacter baumannii.

The number of fully active antibiotic options that treat nosocomial infections due to multidrug-resistant Acinetobacter baumannii (A. baumannii) is extremely limited. Magnolia officinalis, Mahonia bealei, Rabdosia rubescens, Rosa rugosa, Rubus chingii, Scutellaria baicalensis, and Terminalia chebula plant extracts were previously shown to have growth inhibitory activity against a multidrug-resistant clinical strain of A.

Neopyrrolomycins with broad spectrum antibacterial activity.

Three new antibiotics, neopyrrolomycins B (1), C (2), and D (3), with potent activity against Gram-positive pathogens were discovered. They exhibited MIC values < 1 microg/mL versus a number of resistant strains. The compounds were obtained from the ethyl acetate extracts of a Streptomyces sp.

Mutactimycin E, a new anthracycline antibiotic with gram-positive activity.

Resistance to currently available antibiotics has become a widely recognized crisis in the medical community. To address this, many companies and researchers are refocusing their attention towards natural products, which have an excellent track record of producing effective antibacterial drugs. The AMRI natural product library was screened for activity against multi-drug resistant Staphylococcus aureus (MDRSA).

Citreamicins with potent gram-positive activity.

Two new xanthone antibiotics, citreamicin delta (1) and epsilon (2), with potent activity against Gram-positive pathogens including multidrug-resistant Staphylococcus aureus (MDRSA) were discovered. Compounds 1 and 2 exhibited MIC values < 1 microg/mL versus a number of resistant strains. The compounds were obtained from EtOAc extracts of Streptomyces vinaceus and were purified by countercurrent chromatography and reversed-phase HPLC.

Auxarthrol A and auxarthrol B: two new tetrahydoanthraquinones from Auxarthron umbrinum.

Two new 1,2,3,4-tetrahydroanthraquinones, auxarthrol A (compound 1) and auxarthrol B (2), along with three known pyrrolyloctatetraenyl-alpha-pyrone pigments, auxarconjugatin A (3), auxarconjugatin B (4) and rumbrin (5), were isolated from the fungus Auxarthron umbrinum. Structure elucidation of new compounds 1 and 2 was accomplished by spectroscopic data analysis while identification of the known pigments (3-5) was achieved by LC-MS-photodiode array detection.

14'-Hydroxymytoxin B and 16-hydroxyroridin E, two new cytotoxic trichothecenes from Myrothecium roridum.

Two new trichothecenes, 14'-hydroxymytoxin B (1) and 16-hydroxyroridin E (3), were isolated from a fermentation extract of Myrothecium roridum. The structures of 1 and 3 were determined by spectral data interpretation. Both compounds showed potent cytotoxic activity against primary soft-tissue sarcoma cells.