Two new diketopiperazine dimers, WIN 64821 (la) and WIN 64745 (2), were isolated from an Aspergillus culture originally isolated from soil and their structures established on the basis of chemical and spectroscopic evidence. The dimer la has Cl symmetry with each of two equivalent

In order to identify novel chemical classes of factor Xa inhibitors, five scoring functions (FlexX, DOCK, GOLD, ChemScore and PMF) were engaged to evaluate the multiple docking poses generated by FlexX. The compound collection was composed of confirmed potent factor Xa inhibitors and a subset of the LeadQuest screening compound library. Except for PMF the other four scoring functions succeeded in reproducing the crystal complex (PDB code: 1FAX). During virtual screening the highest hit rate (80%) was demonstrated by FlexX at an energy cutoff of -40 kJ/mol, which is about 40-fold over random screening (2.06%). Limited results suggest that presenting more poses of a single molecule to the scoring functions could deteriorate their enrichment factors. A series of promising scaffolds with favorable binding scores was retrieved from LeadQuest. Consensus scoring by pair-wise intersection failed to enrich the hit rate yielded by single scorings (i.e. FlexX). We note that reported successes of consensus scoring in hit rate enrichment could be artificial because their comparisons were based on a selected subset of single scoring and a markedly reduced subset of double or triple scoring. The findings presented in this report are based upon a single biological system and support further studies.

The potential of octenidine hydrochloride (WIN 41464-2) as a topical microbicide was measured both by in vitro death kinetics and reductions in numbers of bacteria on the skin of cynomolgus monkeys. Semilogarithmic survial curves were plotted to measure the microbicidal activity of various concentrations of octenidine against Staphylococcus aureus. The microbicidal activity of octenidine was also determined for Staphylococcus epidermidis, Proteus mirabilis, Streptococcus pyogenes, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, and Candida albicans. Death rates for the same microbial strains were compared with those obtained by using chlorhexidine gluconate. Octenidine concentrations of <1.5 ,LM (0.94 ,ug/ml) caused a greater than 99% reduction of each microbial population within 15 min. Staphylococcus epidermidis was the most susceptible of the test organisms, and E. coli and C. albicans were the least susceptible. Octenidine was more active than chlorhexidine against each test strain. Skin-degerming activities of aqueous and formulated octenidine and formulated chlorhexidine were compared in single and multiple applications of these agents to the hand and foot surfaces of monkeys by using a glove-juice extraction procedure to measure the skin microflora. Aqueous octenidine, at a concentration of 0.2 to 1.6% reduced resident microflora populations from 90 to 99.98%, depending on the concentration and number of applications. Octenidine formulated at 2% in a surfactant-based vehicle exhibited significantly better skin-degerming activity than did either a nonmedicated vehicle or the Hibiclens brand of 4% chlorhexidine gluconate.

A new diketopiperazine dimer, 1'-(2-phenyl-ethylene)-ditryptophenaline [1], was isolated together with ditryptophenaline [2] from the fungus Aspergillus flavus. The structure of 1 was determined by analysis of spectroscopic data. In contrast to the structurally related substance-P antagonist WIN 64821 [3], both 1 and 2 are weak substance-P inhibitors, indicating that stereochemistry at the position of dimerization is an important determinant of biological potency for these molecules.

Methylpendolmycin, a new indole alkaloid with an N-methylisoleucine moiety incorporated in the nine-membered indolactam ring, has been isolated from an actinomycete culture of Nocardiopsis. Methylpendolmycin exhibited inhibition of phorbol ester binding to protein kinase C. Its structure was assigned on the basis of spectroscopic data.