Preskimmianine: The Biogenetic Precursor of Skimmianine from Dictamnus albus L

Anticoccidial effects of the root bark of Dictamnus dasycarpus Turcz extract on experimental Eimeria tenella infection

Anticoccidial effects of the root bark of Dictamnus dasycarpus Turcz (Rutaceae) extract (DDE) were evaluated in chickens following oral infection with Eimeria (E.) tenella. Three-day-old chickens (n=30) were assigned to three groups (control, untreated, and DDE 0.1% treated). Chickens were fed a standard diet supplemented with or without DDE for 1 week prior to infection with E. tenella (10,000 sporulated oocysts per chicken). The effects of DDE on E. tenella infection were assessed by two parameters; fecal oocysts shedding and body weights gain. The DDE-fed chickens produced significantly reduced fecal oocysts (P<0.05) when compared to the E. tenella-infected group fed standard diet. Also, DDE-based diet, improved body weight loss caused by E. tenella infection. Our data demonstrated that DDE had remarkable anticoccidial activities against E. tenella. This finding might have implications for the development of anticoccidial drug. This study is the first to demonstrate anticoccidial effect of DDE on Eimeria parasites.

Neuroprotective effects of constituents of the root bark of Dictamnus dasycarpus in mouse hippocampal cells

Glutamate-induced oxidative injury causes neuronal degeneration related to many central nervous system diseases, such as Parkinson's disease, Alzheimer's disease, epilepsy and ischemia. The bioassay-guided fractionation of the EtOH extract of the root bark of Dictamnus dasycarpus Trucz. provided one neuroprotective limonoid, obacunone, together with a degraded limonoid, fraxinellone and two alkaloids, dictamine and haplopine. At concentrations of 100-150 microM, obacunone showed the potent neuroprotective effects on glutamateinduced neurotoxicity and induced the expression of heme oxygenase (HO)-1 in the mouse hippocampal HT22 cells. In addition, we found that obacunone increased p38 MAPK phosphorylation and induced HO-1 expression via p38 MAPK pathway. These results suggest that obacunone isolated from the root bark of D. dasycarpus increases cellular resistance to glutamate-induced oxidative injury in mouse hippocampal HT22 cells, presumably through the p38 MAPK pathway-dependent HO-1 expression. These results suggest that obacunone could be the effective candidates for the treatment of ROS-related neurological diseases.