Parsley, Petroselinum crispum is an herb used for a large myriad of medical conditions such as urinary tract infections, kidney stones, gastrointestinal disorders, constipations, jaundice, flatulence, indigestion, colic, diabetes, bronchitic cough, asthma, oedema, osteoarthritis, anemia, hypertension prostate and spleen conditions (1, 2). Parsley contains volatile oils, carotenoids, vitamins B1, B2, C and K (1, 2). The volatile oil component could be further broken down into apiole, myristicin, furanocaumarins, phenyl propanoids, phanthalides, tocopherol, ascorbic acid and various terpenoic compounds (1, 3-5). The volatile oil compounds allow parsley to induce a range of medical effects such as antimicrobial, antirheumatic, appetite stimulation, antispasmodic, digestive, laxative, antihypertensive, diuretic effects, hypouricemic, anti-oxidative, and estrogenic activities (1-3, 5, 6).
Parsley has long been traditionally used as a diuretic in folk medicine (1, 7). Despite its use and widespread reputation as a diuretic agent, scientific proof of its function was not available until it was demonstrated in the works of Kreydiyyeh et al. in 2002 (7). The demonstration involved the application of rat models that were offered an aqueous parsley seed extract and drinking water. Ending with results of significantly increased urine flow rates for rats that had taken the parsley seed extract over drinking water in a time frame of 24 hours, parsley as a diuretic agent was recognized scientifically (7).
Parsley used as a diuretic is better described by its aquaretic effect in which urine volume is increased but sodium excretion remains unchanged (1, 2). Apiole and myristicin are the two main components responsible for the aquaresis activity of parsley (1, 2). Apiole and myristicin promotes aquaresis by renal glomeruli vasodilation, increasing smooth muscle contractibility in the bladder, and the inhibition of the Na+-K+ transporter pump (1, 2, 5, 8).
Inhibition of the Na+-K+ transporter pump in the kidney is the primary aquaretic effect that is associated with parsley. The mechanism of action of parsleys is mediated by the inhibition of the Na+-K+ transporter pump causes a decrease in potassium ion secretion as well as reducing sodium and potassium ions reabsorption (6, 7). Since more sodium and potassium ions are retained within the lumen of the kidney tubules over time with Na+-K+ transporter pump inhibition (7). Since sodium and potassium ions reabsorption is reduced, osmotic water flow into the lumen increases which eventually leads to the observed diuretic effect (7). This mechanism of action is further supported by a follow up experiment with amiloride, furosemide, and absence of sodium or potassium ions in testing buffers correspondingly. The supporting experiment suggested that the diuretic effect is mediated by potassium ions retention but not sodium ions, as the absence of sodium ions did not prevent the diuretic effect of parsley...