Effects of Curcuma Comosa extracts on choline acetyltransferase and acetylcholinesterase in rat brain

Abstract

Curcuma comosa Roxb., a plant in family Zingiberazeae, is one of the well-known medicinal plants in Thailand. Rhizome of this plant has been traditionally used for the treatment of various abnormal symptoms of uterus. Those medicinal purposes of C. comosa may be associated with its estrogenic-like effects reported by many studies. The objective of this study was to investigate effects of C. comosa hexane and ethanolic extracts on the activities of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) in rat brain. Forty five rats were randomly divided into 6 treatment groups. Rats were administered orally with 1 ml/kg/day of corn oil (control group); 250 and 500 mg/kg/day of C. comosa hexane extract (group 2, 3); 250 and 500 mg/kg/day of C. comosa ethanolic extract (group 4, 5) for 30 days. Each group comprised 8 rats. Estradiol valerate was given intramuscularly to 5 rats at a dose of 10 μg/kg/day for 7 days, serving as an estrogen reference group. At the end of the treatment, rats were anesthesized then cervical dislocated. Serum samples were determined for estradiol concentration. Brain was collected and dissected for cerebral cortex, basal forebrain and hippocampus. Each brain region homogenates was prepared for enzyme activity assay. The results showed that both dosages of C. comosa ethanolic extract caused an increase of ChAT activity in cerebral cortex and hippocampus but not in basal forebrain. C. comosa hexane and ethanolic extracts did not affect AChE activities in all three brain regions. Estradiol given at the dosage regimen in this study did not affect both ChAT and AChE activities. Even though an increase of serum estradiol level from C. comosa extracts was less than the estradiol group, both extracts caused a significant increase of serum estradiol level as compared to the control group. These findings demonstrated that C. comosa ethanolic extract potentially possessed a beneficial effect on cholinergic nervous system showing by an enhancement effect on the activity of ChAT, an enzyme responsible for brain acetylcholine synthesis.