title: Diuretic activity of some fractions of the epidermis of Poria cocos.
abstract: BACKGROUND
  Poria cocos Wolf (Polyporaceae) is a well-known medicinal fungus, the epidermis ("Fu-Ling-Pi" in Chinese) of the sclerotia is used as a diuretic for treating oedema and promoting the diuretic process. In this paper we report on the diuretic activity in rats of petroleum ether, ethyl acetate, n-butanol and the remaining fractions of the ethanol extract from the epidermis of Poria cocos.
  
  
  METHODS
  Petroleum ether, ethyl acetate, n-butanol and the remaining fractions of the ethanol extract of Fu-Ling-Pi were orally administered to rats. The urinary excretion rate and the pH and electrolyte excretion were measured in the urine of saline-loaded rats.
  
  
  RESULTS
  In this study, all the tested fractions of Fu-Ling-Pi increased the urinary excretion rate. The three doses of the ethyl acetate fraction all produced remarkable urinary output in 6h, and all produced a remarkable increase in Na(+) excretion and Cl(-) excretion. The Na(+)/K(+) value in the experimental group was significantly enhanced compared with that of the control group, but the three doses of the ethyl acetate fraction had no effect on the K(+) excretion. The 25-mg/kg and 50-mg/kg doses of the n-butanol fraction showed notable urinary output and produced a remarkable increase of Na(+) excretion and Cl(-) excretion, but the two doses did not produce a remarkable effect on the Na(+)/K(+) value. The petroleum ether and remaining fractions did not show remarkable diuretic activities compared with the control group.
  
  
  CONCLUSIONS
  This study confirmed that the ethyl acetate and n-butanol fractions present a remarkable diuretic effect, showing that they are the diuretic bioactive fractions of Fu-Ling-Pi. This finding appears to indicate at least two mechanisms for the observed diuretic activity, and the K(+)-saving diuretic effect may be related to the triterpenoid components of intermediate polarity contained in this fungus, particularly the lanostanes tetracyclic triterpenoids.
authors.affiliation: Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, the College of Life Sciences, Northwest University, No. 229 Taibai North Road, Xi'an, Shaanxi 710069, PR China.
authors.forename: Ya-Long
authors.initials: YL
authors.lastname: Feng
authors.forename: Ping
authors.initials: P
authors.lastname: Lei
authors.forename: Ting
authors.initials: T
authors.lastname: Tian
authors.forename: Lu
authors.initials: L
authors.lastname: Yin
authors.forename: Dan-Qian
authors.initials: DQ
authors.lastname: Chen
authors.forename: Hua
authors.initials: H
authors.lastname: Chen
authors.forename: Qibing
authors.initials: Q
authors.lastname: Mei
authors.forename: Ying-Yong
authors.initials: YY
authors.lastname: Zhao
authors.forename: Rui-Chao
authors.initials: RC
authors.lastname: Lin
mesh_terms: D000818:Animals; D004232:Diuretics / Q000494:pharmacology*; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D008297:Male; D055441:Poria; D011188:Potassium / Q000652:urine; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000652:urine; D000070660:Wolfiporia
chemical_list: D004232:Diuretics; D004365:Drugs, Chinese Herbal; D012964:Sodium; D011188:Potassium
keywords: Bioactive fractions; Diuretic activity; Electrolyte excretion; Poria cocos; Urinary excretion