title: Effect of Polygala tenuifolia root extract on scopolamine-induced impairment of rat spatial cognition in an eight-arm radial maze task.
abstract: The effects of Polygala tenuifolia root fractions and the acyl groups of its constituents on the retrieval process of spatial cognition in rats were studied using an eight-arm radial maze task. Oral administration of a precipitate fraction (PTB) obtained by concentration of the n-BuOH-soluble portion from the extract of the roots significantly decreased the number of total errors (TEs) and that of working memory errors (WMEs) at doses of 100 mg/kg and 200 mg/kg. However, it caused no significant decrease in the number of reference memory errors (RMEs). In addition, the saponin-rich fraction (PTBM) obtained by purification of PTB also showed significant decreases in TEs and WMEs at a dose of 100 mg/kg. Among the cinnamic acid derivatives present as the acyl groups in the P. tenuifolia constituents, sinapic acid (SNPA) significantly decreased TEs and WMEs at doses of 10 to 100 mg/kg. These results indicated that P. tenuifolia extracts, PTB and PTBM, and SNPA had a beneficial effect on the memory impairment induced by dysfunction of the cholinergic system in the brain. The memory improvement in the scopolamine-induced memory impairment seen in the radial maze performance was due to improvement in the short-term memory. A contribution of some constituents other than SNPA to the memory improvement was also suggested.
authors.affiliation: Department of Pharmacognosy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Tsushima, Okayama 700-8530, Japan.
authors.forename: Xiu-Lan
authors.initials: XL
authors.lastname: Sun
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ito
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Masuoka
authors.forename: Chiaki
authors.initials: C
authors.lastname: Kamei
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hatano
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003373:Coumaric Acids / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008568:Memory / Q000187:drug effects; D008570:Memory, Short-Term / Q000187:drug effects; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D010275:Parasympathetic Nervous System / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology; D018517:Plant Roots / Q000737:chemistry; D031801:Polygala / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D012503:Saponins / Q000494:pharmacology; D012601:Scopolamine / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D013028:Space Perception / Q000187:drug effects*