Melanogenesis inhibitors from Rabdosia japonica

Hiroki Satooka, Takahiko Isobe, Teruhiko Nitoda, Isao Kubo

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


The effects of the four major ent-kaurene diterpenoids isolated from the aerial part of Rabdosia japonica (Labiatae) on murine B16-F10 melanoma cells were investigated. Among the compounds tested, oridonin and nodosin most significantly suppressed cellular melanin production when the cells were cultured with these diterpenoids. However, oridonin and nodosin exhibited cytotoxicity against the same melanoma cells with an IC50 of 1.1 μM (0.40 μg/ml) and of 1.3 μM (0.47 μg/ml) and almost complete lethality was observed at 4.0 μM and at 8.0 μM, respectively, and therefore observed melanogenesis inhibition is mainly due to its melanocytotoxic effect. Morphological observation showed that oridonin or nodosin treated B16-F10 melanoma cells induced dendrite structure. Diterpenoids quickly formed adducts partly in Dulbecco's Modified Eagle's Medium (DMEM) containing 10% of fetal bovine serum (10% FBS-DMEM) before their application to the cells. Approximately 20% of oridonin formed adducts within the first 15 min. Notably, dihydronodosin exhibited inferior cytotoxicity (>85% cell viability at 100 μM) but still significantly suppressed melanogenesis (>55%) when murine B16-F10 melanoma cells were cultured with this diterpenoid derivatives. Hence, dihydronodosin can be a potential melanogenesis inhibitor.

Original languageEnglish
Pages (from-to)1016-1023
Number of pages8
Issue number11
Publication statusPublished - Aug 15 2012
Externally publishedYes


  • Diterpenes
  • Melanin production inhibitor
  • Rabdosia japonica

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Drug Discovery
  • Complementary and alternative medicine


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