Screening of Phagocyte Activators in Plants : Enhancement of TNF Production by Flavonoids

The tumor necrosis factor (TNF) was first discovered as a substance that induced necrosis of transplanted tumors. Recently, TNF has been recognized as an important and endogenous mediator in host defense mechanisms. To prove the fact that plant foods contain substances which activate the host defense mechanisms, we first examined if the administration of flavonoids could induce TNF production in mice. Some selected flavonoids such as naringin, apiin, poncirin and rutin were shown to amplify TNF release from murine macrophages in vivo in response to OK-432 as a second stimulus. However, their aglycone forms were not effective. The differences in the saccharide-chain of flavonoids induced the variety of TNF production.