Dermaseptin S4 derivative K4K20S4: a potential candidate for development of a new microbicide contraceptive agent--an...

Sexually transmitted infections (STIs) and unplanned pregnancies have serious effects on the reproductive health of women. The present study was undertaken with a view to develop an effective means of prevention. The microbicidal and contraceptive potential of cationic peptides from frog's skin, namely, dermaseptin S4 and its derivatives were investigated in vitro.: STUDY DESIGN Different bacterial and fungal strains were resorted to for determining the antimicrobial activity of the new compounds. The spermicidal activities of the latter were assessed using normal human semen samples, and their toxic effects were identified in a HeLa culture.

All S4 derivatives elicited concentration-dependent spermicidal and antimicrobial activities at microgram concentrations. The highest levels recorded for both types of activity were displayed by K4K20S4, and the lowest levels were exhibited by D4D20S4 and S4(5-28). Cytotoxicity assays revealed that some of these compounds were significantly safer than nonoxynol-9 (N-9).

The ability of these peptides to instantaneously kill human sperm and STI pathogens at low concentrations indicates that their application as active ingredients in vaginal contraceptive preparations could induce considerably better effects than N-9.