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Dietary Supplements: A Framework for Evaluating Safety
ter-soluble glycosides, and as sulfated flavonoids (Mabry et al., 1977). Chaparral also contains triterpenes, including sapogenins (Mabry et al., 1977). The aglycone forms of the flavonoids and triterpenes are listed in Table A. Chaparral contains volatile oils, wax esters, sterols, and other hydrocarbons (Mabry et al., 1977; Waller and Gisvold, 1945).
Although a number of the known components of chaparral exhibit cytotoxic activity under various conditions, these effects are judged to be weak and require high concentrations of the substance, and thus would extrapolate to the ingestion of large amounts of chaparral in order to exhibit potential toxic activity in humans. Additionally, many of these components are present in the diet from other sources.
C.Description of Dietary Supplement Preparations and Amounts Ingested in Ordinary Use
Chaparral is sold in several forms, one of which is the dried, broken leaves, green stems, and fine twig tips that can be brewed as a tea (i.e., an aqueous extract). An example of the modern preparation of chaparral tea would be to steep 7 to 8 g of crumbled dried leaves, stems, and twigs in one quart of hot water. In ordinary use as a water extract, chaparral might be consumed in the amount of 1 to 3 cups of chaparral tea per day for a period of 2 to 3 weeks (Micromedex, 2002).
Another form of chaparral is a tincture or aqueous alcohol extract. The ordinary use of such an extract might be 20 to 30 drops per day for a period of 2 to 3 weeks (Micromedex, 2002).
Chaparral is also available as a dried leaf powder (frequently sold in capsule or tablet form). Typical suggested uses of such capsules or tablets would be one to two 500-mg capsules or tablets per day for 2 to 3 weeks.
Chaparral is also available as a component of various botanical mixtures sold as tinctures and as loose leaves, stems, and twigs for teas. Chaparral dried leaf capsules are also available in combination with silymarin (a flavanolignan complex from milk thistle), vitamin C, or other antioxidants.
II.INFORMATION RELEVANT TO LIVER CONCERNS
A.Human Use Information and Safety Data
Chaparral has been used for many centuries for a variety of medicinal purposes (Heron and Yarnell, 2001). Native populations in the southwestern United States have used chaparral tea for decades without published evidence of toxicity. Most processing of chaparral used in American Indian