Abstract: The present invention relates to use of rosmarinic acid and/or derivatives thereof as immunosuppressive agents and/or as inhibitor of SH2 domain function. Disclosed in the present invention is that rosmarinic acid and derivatives thereof specifically inhibit the binding of ligand peptides to Lck SH2 domain, disturb the Lck-mediated signal transduction in T cells, also inhibit cytoline gene expression, and suppress immune responses in the transplanted tissue. These activities of rosmarinic acid and derivatives thereof support their applicability to treatment, prevention and/or diagnosis of graft rejection, GVHD, autoimmune diseases, inflammatory diseases, etc.

Abstract: The present invention relates to novel antibiotic peptides which possess antibacterial and/or antifungal activities causing no cytotoxicity, and to antibacterial and/or antifungal agents containing said peptides as active ingredients. In accordance with the present invention, it has been discovered that a number of chemically-synthesized peptides which are derived from Tenecin, show superior antibacterial and/or antifungal activities, while causing no untoward effects, and they can be applied for the development of antibacterial and/or antifungal agents.