RÉSUMÉ
As a part of novel drug delivery carriers, peptides have diverse biological activities, low immunogenicity and good biocompatibility. In recent years, studies on the delivery carriers modified by peptides have attracted much attention. Among them, the peptides with acid sensitivity can change their secondary structures under slightly acidic microenvironment of the tumor or in lysosome. Therefore, the carriers made or modified by acid-sensitive peptides can specifically release the loaded drug in the tumor tissue, enhance the cell internalization of drugs and improve its therapeutic effects. In accordance with acid-sensitive peptides studied, the side chains, number of polar residues, sequence and secondary structure of the peptides might be involved in the acid sensitivity. In this review, we summarize the acid-sensitive peptides from recent literatures, analyze the connection between the structure and the acid sensitivity, and focus on the mechanism and application of acid-sensitive peptides in drug delivery. This provides the basis for further development and utilization for acid-sensitive peptides for efficient drug delivery.
RÉSUMÉ
For thousands of years, scorpions and their venoms have been applied in traditional medicine in China to treat a variety of difficult miscellaneous diseases. The venom is a complex mixture of bioactive molecules, such as peptides and proteins (e.g. neurotoxins). Among them, neurotoxins (named scorpion toxins) are the most important bioactive components. Up to now, more and more characterized venom components have been isolated from different scorpions, providing numerous candidate molecules for drug design and development. Many investigations have shown the potent effects of venom or its components against the nervous, immune, infection, cardiovascular and neoplastic diseases. Moreover, the scorpion toxins could be used as molecular backbone to develop new specific drugs based on their unique structures and functions. In this review, we focus on the medicinal values and the possible mechanisms of scorpion toxins with promising medicinal prospect against the relative diseases, providing the data basis for further development of relative drugs.