Synthesis of Constrained Tetracyclic Peptides by Consecutive CEPS, CLIPS, and Oxime Ligation

In Nature, multicyclic peptides constitute a versatile molecule class with various biological functions. For their pharmaceutical exploitation, chemical methodologies that enable selective consecutive macrocyclizations are required. We disclose a combination of enzymatic macrocyclization, CLIPS alkylation, and oxime ligation to prepare tetracyclic peptides. Five new small molecular scaffolds and differently sized model peptides featuring noncanonical amino acids were synthesized. Enzymatic macrocyclization, followed by one-pot scaffold-assisted cyclizations, yielded 21 tetracyclic peptides in a facile and robust manner

Sub-chronic (13-week) oral toxicity study in rats with recombinant human lactoferrin produced in the milk of transgenic cows

The oral toxicity of recombinant human lactoferrin (rhLF) produced in the milk of transgenic cows was investigated in Wistar rats by daily administration via oral gavage for 13 consecutive weeks, 7 days per week. The study used four groups of 20 rats/sex/dose. The control group received physiological saline and the three test groups received daily doses of 200, 600 and 2000 mg of rhLF per kg body weight. Clinical observations, growth, food consumption, food conversion efficiency, water consumption, neurobehavioural testing, ophthalmoscopy, haematology, clinical chemistry, renal concentration test, urinalysis, organ weights and gross examination at necropsy and microscopic examination of various organs and tissues were used as criteria for detecting the effects of treatment. Overall, no treatment-related, toxicologically significant changes were observed. The few findings that may be related to the treatment (lower cholesterol in high-dose females, lower urinary pH in high-dose males and females and very slightly higher kidney weight in high-dose females) were considered of no toxicological significance. Based on the absence of treatment-related, toxicologically relevant changes, the no-observed-adverse-effect level (NOAEL) was considered to be at least 2000 mg/kg body weight/day. © 2005 Elsevier Ltd. All rights reserved