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Substance
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Structure
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Safety Issues
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Lignans, nordihydroguaiaretic acid (NDGA), and other substituted guaiaretic acid derivatives
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NDGA (Duisberg et al., 1949; Waller and Gisvold, 1945)
Present in all parts of Larrea tridentata, including leaves, stems and twigs at 5–15% of the dry leaf weight (Mabry et al., 1977)
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Animal studies: see Table E for safety issues from animal studies with NDGA
In vitro study: see Table F-2 for safety issues from in vitro studies with NDGA
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Dihydroguaiaretic acid (Obermeyer et al., 1995)
Partially demethylated dihydroguaiaretic acid is also present (Gisvold and Thaker, 1974)
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In vitro study: weak cytotoxic activity (IC50 1–3 μg/mL) (Njoku et al., 1997)
In vitro study: weak cytotoxic activity (10 μg/mL) and (Gisvold and Thaker, 1974)
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Guaiaretic acid (Obermeyer et al., 1995)
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No data suggestive of toxicity are available
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Secoisolariciresinol (Obermeyer et al., 1995)
Present in the stems of L. tridentata (Konno et al., 1990)
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In vitro study: weak cytotoxic activity (IC50 0.6–8.3 μg/mL) (Shen et al., 1997); see Table F-2
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Lignans, furanoid
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Larreatricin (Konno et al., 1987)
Present in the stems of L. tridentata (Konno et al., 1990) in trace amounts (0.001% of dry leaf weight)
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No data suggestive of toxicity are available
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4-epi-Larreatricin (Konno et al., 1987)
Present in the leaves, twigs and stems of L. tridentata (Konno et al., 1990) in trace amounts (up to 0.0003% of dry leaf weight)
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No data suggestive of toxicity are available
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