1988 Volume 36 Issue 3 Pages 1000-1006
The fruit body of Grifola frondosa (maitake), Basidiomycetes, was confirmed to contain a substance with blood pressure-lowering activity. When powdered fruit body of maitake was given orally to spontaneously hypertensive rats (SHR), blood pressure reduction was observed, in contrast to the control group in which the blood pressure increased with ageing. Ether-soluble (ES) and hot water-soluble (WS) fractions were prepared from the fruit body and their hypertensive action was examined. Blood pressure-lowering activity was found when the dried ES fraction was administered orally at 30mg/kg, but the WS fraction was inactive. Thus, the ES fraction was further separated into setone-soluble (ES-AS) and insoluble (ES-AP) fractions. Administration of 20mg/kg dried material caused a blood pressure reduction of about 45mmHg in the former case and 65mmHg in the latter as compared with the control (about 220mmHg). When the EA-AP fraction was separated to 5 subfractions by thin layer chromatographic analysis, the most potent activity was observed in the subfraction which was detected on the spot of Rf=55.3. When authentic antihypertensive agents were examined in combination with maitake, a hypotensive effect was observed on administration of reserpine. This suggests that the blood pressure-lowering effect of maitake was brought about by a mechanism other than sympatholytic action.