Abstract
We previously reported that Wen-Qing-Yin (Unsei-in), a traditional Chinese blended
medicine, inhibited the induction phase of various kinds of delayed type hypersensitivity
(DTH) and local graft-versus-host (GvH) reactions, but did not affect humoral immune
responses or the effector phase of DTH in experimental animals. In another report,
we demonstrated that Phellodendri Cortex (bark of Phellodendron amurense Rupr. Rutaceae) was a component having the most potent suppressive effect on the
cellular immune response among the 8 medical plants composing Unsei-in. In the present
study, we isolated OB-1 and OB-5 from Phellodendri Cortex as the biologically active
principles to suppress local GvH reactions in mice. OB-1 and OB-5 are quaternary base
alkaloids known as magnoflorine and phellodendrine, respectively. They suppressed
the local GvH reaction, when given i.p. to the host mice at 5-20 mg/kg for 8 consecutive days from the day of spleen cell
transfer to cause the reaction. Both OB-1 and OB-5 suppressed picryl chloride-induced
delayed type hypersensitivity (PC-DTH) when given i.p. to mice at 10 and 20 mg/kg for 5 consecutive days from the day of the sensitization,
but did not suppress it when given at the time of the challenge. These results suggest
that OB-1 and OB-5 suppress the induction phase but not the effector phase of the
cellular immune response. They are expected to have a value as a new type of immunosuppressor.
Key words
Phellodendron amurense Rupr. - Rutaceae - magnoflorine - phellodendrine - graft-versus-host reaction - delayed-type
hypersensitivity - immunosuppression
