The precise mechanism of injury is not known in most cases. Because adverse event

reporting is voluntary, toxicity has been documented mostly in case reports. Considering the paucity of such reports in the face of widespread use of herbal substances, it may be assumed that BI 2536 price most of the commonly used herbs are not nephrotoxic. Acute kidney injury caused by herbal compounds2 will not be discussed further in this review. Chronic kidney injury has been described in association with ingestion of several botanicals (Table 1). Some examples are described below. The leaves of the creosate bush (Larrea tridentata), a Native American shrub, are commonly used to make tea in the south-western states of North America. Its roots and leaves are also dispensed in capsule or tablet form as a drug called chaparral. The active substance,

nordihydroguaiaretic acid, is an antioxidant and blocks cell division.20 It was thought to have anticancer properties, but hepatotoxicity precluded further testing. This compound is also used experimentally to induce cystic renal disease in rats. Renal cysts and renal cell carcinoma have been reported following long-term consumption of chaparral tea.21 Liquorice (Glycyrrhiza glabra) has diuretic properties and causes hypokalaemia. Severe hypokalaemia can lead selleckchem Suplatast tosilate to rhabdomyolysis and acute kidney injury. Chronic hypokalaemic nephropathy secondary to long-term consumption of liquorice has been reported.22 Yohimbine, present in the plant yohimbe (Pausinystalia yohimbe), is known to cause systemic lupus erythematosus (SLE). A case report described SLE-like syndrome with proteinuria and renal failure following ingestion of this compound that responded

to steroids.23 Willow bark (Salix daphnoides) has been implicated in the causation of renal papillary necrosis on the basis of a review of the autopsy of Ludwig van Beethoven.24 The bark contains salicin, which is metabolized in the body to the well-known prostaglandin inhibitor, salicylate.25 Obstructive uropathy has been reported following ingestion of fruits of djenkol (jering) trees (Pithecolobium lobatum and P. jiringa),26 Ma-Huang (ephedra, Ephedra sinica),27,28 star fruit (A. carambola),29 and cranberry (Vaccinium macrocarpon) concentrate.30 The toxic compounds can precipitate in the tubular lumina acutely leading to acute kidney injury, especially if consumed in large quantities with little water. Repeated ingestion may cause nephrolithiasis and chronic interstitial nephritis. Chronic interstitial nephritis has been described anecdotally following chronic ingestion of several botanicals.31–33 Bladder-wrack (Fucus vesiculosus), a large brown alga, is a common food in Japan.