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TABLE G Chaparral: Related Substances That Might Suggest Risk

Study Design


Results and Conclusions

Lignan: substituted guaiaretic acid derivative

Tetra-O-methylnordihydroguaiaretic acid, synthetic (Lambert et al., 2001)


No data suggestive of toxicity are available



Present in the roots of L. tridentate (Luo et al., 1988); not known to be present in the aerial parts of L. tridentata, but a possible component


In vitro study: weak cytotoxic activity

Potential hepatotoxin: in general, quinones are reactive species and readily form adducts with cellular macromolecules and thus can cause cellular damage; naphthoquinones are lipophilic and readily react with membrane-bound macromolecules (e.g., membrane bound enzymes such as the cytochrome P450s) as well as cytosolic molecules (e.g., glutathione)

Another mechanism by which quinones cause cellular damage is by increasing the oxidative stress of the cell as the quinone/semiquinone pair repeatedly cycle, generating oxygen radicals or other intracellular radicals with each cycle (Jaeschke et al., 2002)

NOTE: Only the substances considered to be relevant to the risk of chaparral as a dietary supplement are included in the table. “Functionally related” substances may exhibit an activity that chaparral exhibits, based on in vitro or other data; they are not listed here because they have a similar chemical composition.

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