Blood pressure lowering activity of a flavonoid and phytosterol rich extract of the sclerotia of Pleurotus tuberregium (Fr) Sing in salt-loaded rats

The sclerotia of Pleurotus tuberregium are eaten as food, and used in traditional health care, for the management of hypertension, yet there is scarcity of information in the literature regarding the nature of its effect on blood pressure indices. Thus, in this study, the ability of an aqueous extract of the sclerotia to moderate blood pressure indices and pulse rates were investigated in normal and sub-chronic salt-loaded rats. The normal and treatment control groups received a diet consisting 100% of commercial feed, while the test control, reference and test treatment groups received an 8% salt-loaded diet. The extract (at 100 and 200 mg/kg body weight) and moduretics (at 1 mg/kg body weight) were orally administered daily. The normal and test control groups orally received appropriate volumes of water. The extract was screened for bioactive components using gas chromatography coupled with flame ionization detector. The flavonoids were the major components (52.82 mg/kg), and consisted of thirty-eight known flavonoids (mainly 29.03% kaempferol and 20.84% quercetin). The most abundant of the seven phytosterols and the twelve glycosides detected were sitosterol (98.16%) and amygdalin (37.56%), respectively. Compared to test control and corresponding values on day 0, the extract dose-dependently lowered the systolic, diastolic, pulse and mean arterial pressures of the salt-loaded rats; while producing a mixed effect on the pulse rates. This result suggests that the sclerotia can moderate all the blood pressure indices, and supports the use of the sclerotia in traditional health care, for the management of hypertension.