Urinary output of urodiolenone in essential hypertension

Increased amounts of urodiolenone, an isomer of a phytoalexin, were found in the urine of 34% of patients with essential hypertension. Urodiolenone was also excreted in 70% of patients with neurocirculatory asthenia (hyperkinetic syndrome) and labile hypertension; very small quantities were found in normal subjects. When grapefruit juice, which is rich in urodiolenone, was offered to hypertensive subjects, urodiolenone excretion was much higher than the amount ingested, indicating that output was not due to precursors present in the diet.