Epstein-Barr virus-activating principle in the ether extracts of soils collected from under plants which contain active diterpene esters.

Soil samples were collected from the ground under the plants of Euphorbiaceae and Thymelaeaceae known to possess Epstein-Barr virus-activating diterpene esters. In a test system, the ether extracts of such soil samples at a concentration of 20 micrograms/ml induced Epstein-Barr virus early antigen in approximately 5-25% of the non-producer Raji cells. These findings suggest a possible interaction between plant-derived diterpene esters and the human system, and provide a new aspect in considering the cause of Epstein-Barr virus-associated diseases, particularly nasopharyngeal carcinoma.