184Vegetables, Fruits, and Herbs in Health Promotion12.3 HERBS FOR THE UROGENITAL SYSTEM 12.3.1 ASSISTANCEFOR THEKIDNEYSHerbal diuretics function by promoting blood w in the kidneys and hence increase the volume of urine produced. These herbs may also be useful for the treatment of kidney infections and inmmation of the urinary tract, or for the prevention of kidney stones.4 A number of herbal preparations have also been widely used as diuretics to treat premenstrual syndrome and other conditions. Extracts of goldenrod, buchu, juniper, parsley, bearberry, and stinging nettle appear to be modestly effective diuretics that may be used safely in moderation.11 The most effective herbal product that safely acts as a diuretic is goldenrod (Solidago sp.). It is widely used in Europe to treat inmmations of the urinary tract. In addition, goldenrod also has anti-inmmatory and antibacterial activity. While there are over 130 species of goldenrod, most of them have similar diuretic activities. The active constituents of goldenrod include vonoids, tannins, and saponins.4 Buchu (Barosma betulina), a small shrub indigenous to South Africa, is useful for its diuretic properties. Its leaves, which have a peppermint odor, are rich in vonoids and contain an aromatic oil rich in terpenoids such as diosphenol, limonene, and menthone. Buchu leaf is used to treat inmmations and infections of the kidney, bladder, and urinary tract.2 The dried ripe berries of the juniper tree (Juniperus communis) have a useful diuretic function. Juniper is also useful for urinary tract infections and inmmations, kidney and bladder stones, and digestive disorders such as heartburn and bloating.2 The diuretic effect of juniper results from its content of terpinen-4-ol and other monoterpenes in the essential oil of the berries. These compounds seem to increase the glomerular tration rate in the kidney. Juniper berries are potentially the most toxic of the diuretic herbs. Long-term use or an overdosage may cause kidney damage characterized by albuminuria or renal hematuria.4 Parsley (Petroselinum crispum) is widely used as a garnish. The leaves and roots of parsley are useful for the treatment of infections of the urinary tract, and for kidney and bladder stones. Parsley contains substantial levels of a variety of phytochemicals �furocoumarins, terpenoids, vonoids, and phthalides. The active constituents in the essential oil of parsley seeds include apiol and myristicin.4 A tea made from the dried leaves of bearberry or uva ursi (Arctostaphylos uvaursi) has diuretic and strong astringent qualities. Bearberry is also very effective against urinary tract infections. Antibacterial action results from the presence of two phenolic glycosides, hydroquinone glucuronides and hydroquinone sulfate esters, formed in the body from arbutin, a natural constituent of bearberry. One drawback of uva ursi is that it is effective only if the urine is alkaline.4 Prolonged use of uva ursi is not recommended since large and frequent doses can cause vomiting, convulsions, and other side effects.4,7 The ovate leaves and rous stems of stinging nettle (Urtica dioica) are covered with tiny, hollow, silica-tipped hairs which release the irritant formic acid and histamine when touched. However, the stinging irritant can be tamed by cooking or drying. Nettle juice or the dried leaves of U. dioica possess diuretic activity, possibly
