Bioactivity-directed isolation, identification of diuretic compounds from Polyporus umbellatus.
OBJECTIVE
Polyporus umbellatus is a fungus used as a diuretic medicine. The objective of this study was to isolate and elucidate the diuretic constituents of n-hexane, ethyl acetate, n-butanol and water extracts of Polyporus umbellatus and to evaluate their diuretic activity.


METHODS
The n-hexane, ethyl acetate, n-butanol and water extracts of Polyporus umbellatus were tested by diuretic experiment of normal rats in metabolic cage. The n-hexane extract and n-butanol extract were prepared separately by the bioassay-guided approach. Three isolated compounds doses (5, 10 and 20 mg/kg BW) were orally administered to normal rats. Water excretion rate, pH and content of Na(+), K(+) and Cl(-) were measured in the urine of saline-loaded rats.


RESULTS
n-Hexane extract (P<0.05), n-butanol extract (P<0.05) and three isolated compounds (ergosta-4,6,8(14),22-tetraen-3-one, ergosterol and d-mannitol) displayed diuretic activity.


CONCLUSIONS
The ergosta-4,6,8(14),22-tetraen-3-one was the strongest diuretic constituent in the three compounds. Ergosterol and D-mannitol were found to be also responsible for duiretic effects in Polyporus umbellatus for the first time. Data show that 20 mg/kg dose of the ergosterol for urine out put became significantly higher than in the control rats, but the ratio of Na(+)/K(+) almost unaltered in the three doses. The highest dose of the D-mannitol was significant and increased the cumulative urine output. Regarding the electrolyte excretion, data show that the doses 10 and 20 mg/kg produce significant increase for excretion of Na(+) and Cl(-). The present results provide a quantitative basis explaining application of Polyporus umbellatus as a diuretic medicine. The result proved that its diuretic effects were also due to the contribution of multi-components in clinical application.
Zhao
Ying-Yong
YY
Biomedicine Key Laboratory of Shaanxi Province, Northwest University, Xi'an, Shaanxi, China.
Xie
Ren-Ming
RM
Chao
Xu
X
Zhang
Yongmin
Y
Lin
Rui-Chao
RC
Sun
Wen-Ji
WJ
D000818:Animals; D001681:Biological Assay / Q000379:methods*; D002783:Cholestenones; D045424:Complex Mixtures / Q000737:chemistry / Q000494:pharmacology*; D004231:Diuresis / Q000187:drug effects*; D004232:Diuretics / Q000737:chemistry* / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004875:Ergosterol / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000494:pharmacology; D008297:Male; D008353:Mannitol / Q000494:pharmacology; D008516:Medicine, Chinese Traditional; D055492:Polyporus / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley
D002783:Cholestenones; D045424:Complex Mixtures; D004232:Diuretics; D008353:Mannitol; C015860:ergosta-4,6,8(14),22-tetraen-3-one; D004875:Ergosterol