Calphostins (UCN-1028), novel and specific inhibitors of protein kinase C. I. Fermentation, isolation, physico-chemical properties and biological activities

J Antibiot (Tokyo). 1989 Oct;42(10):1470-4. doi: 10.7164/antibiotics.42.1470.


A novel complex of calphostin (UCN-1028), which specifically inhibits protein kinase C (PKC) has been isolated from the culture broth of a fungi Cladosporium cladosporioides. Purification of individual components was carried out by silica gel, non-porus resin Diaion HP-20SS and Sephadex LH-20 chromatography, leading to isolation of five closely related components. A, B, C, D and I. Calphostins showed cytotoxic activities against various tumor cells, and these cytotoxicities were proportional to their inhibitory activities against PKC.

MeSH terms

  • Antibiotics, Antineoplastic / analysis
  • Antibiotics, Antineoplastic / isolation & purification*
  • Antibiotics, Antineoplastic / pharmacology
  • Chemical Phenomena
  • Chemistry, Physical
  • Chromatography, High Pressure Liquid
  • Cladosporium / metabolism
  • Fermentation
  • HeLa Cells / drug effects
  • Naphthalenes*
  • Polycyclic Compounds / analysis*
  • Polycyclic Compounds / isolation & purification*
  • Polycyclic Compounds / pharmacology
  • Protein Kinase C / antagonists & inhibitors*


  • Antibiotics, Antineoplastic
  • Naphthalenes
  • Polycyclic Compounds
  • calphostin complex
  • calphostin A
  • calphostin B
  • calphostin I
  • Protein Kinase C
  • calphostin D
  • calphostin C