Table of Contents > Interactions & Depletions > Japanese knotweed (Polygonum cuspidatum, Reynoutria japonica, Fallopia japonica) Print

Japanese knotweed (Polygonum cuspidatum, Reynoutria japonica, Fallopia japonica)



Interactions

Japanese knotweed/Drug Interactions:
  • AntibioticsAntibiotics: Based on in vitro research, a methanol extract inhibited growth of Streptococcus mutans and Streptococcus sobrinus at micromolar ranges but augmented growth at submicromolar doses (4). Theoretically, concurrent use of Japanese knotweed with certain antibiotics may have additive effects.
  • Anticoagulants and antiplateletsAnticoagulants and antiplatelets: In an in vitro assay, resveratrol from Polygonum cuspidatum reduced adenosine diphosphate aggregation and decreased the number of platelets expressing surface P-selectin in a dose-dependent manner (26). Theoretically, concurrent use of Japanese knotweed with anticoagulants or antiplatelets may increase the risk of bleeding.
  • Anti-inflammatory agents, Anti-inflammatory agents: In in vitro enzymatic assays, Polygonum cuspidatum inhibited the activity of several inflammatory enzymes (7). Theoretically, concurrent use of Japanese knotweed with anti-inflammatory agents may have additive effects.
  • Antilipemic agentsAntilipemic agents: In a nonalcohol fatty liver disease rat model, root extracts of Japanese knotweed significantly reduced total cholesterol, triglyceride, and glucose in liver tissue (25). Theoretically, concurrent use of Japanese knotweed with antilipemic agents may have additive effects.
  • Antineoplastic agentsAntineoplastic agents: Based on in vitro studies with human cancer cell lines, a root extract which contained trans- and cis-resveratrol inhibited proliferation, without inhibiting growth of normal human liver cells (12). Theoretically, concurrent use of Japanese knotweed with antineoplastic agents may have additive effects.
  • Antiviral agentsAntiviral agents: Based on in vitro studies, extracts modulated the replication of duck hepatitis B virus (DHBV) and human hepatitis B virus (HBV) (18). In in vitro assays, the ethanol extract of Polygonum cuspidatum (10mcg/mL) inhibited the production of human hepatitis B virus but increased the expression of the noninfectious surface antigen of hepatitis B virus (HBsAg) (27). Theoretically, concurrent use of Japanese knotweed with antiviral agents may have additive effects.
  • Cardiovascular drugsCardiovascular drugs: Based on in vitro studies, polydatin, a constituent of Japanese knotweed, may interact with cardioactive agents by improving heart function and microcirculatory perfusion (15).
  • Drugs used for osteoporosisDrugs used for osteoporosis: In an ovariectomized rat model of bone loss, rats fed oral resveratrol (0.7mg/kg of body weight) from Polygonum cuspidatum had significantly higher bone mineral density and bone calcium content than ovariectomized rats, similar to alendronate sodium treatment (24). Theoretically, concurrent use of Japanese knotweed with drugs used for osteoporosis may have additive effects.
  • EstrogensEstrogens: Based on in vitro studies of the relative estrogenic activity and binding to estrogen receptors (1; 23; 28), Polygonum cuspidatum may augment the effects of hormone replacement therapy. Theoretically, Japanese knotweed constituents may compete for binding to the estrogen receptor with a labeled estrogen and raise the resulting "estrogen" level in assays based on binding to human estrogen receptor.
  • Lipoxygenase inhibitorsLipoxygenase inhibitors: Based on in vitro studies of stimulated human polymorphonuclear leukocytes, resveratrol from Polygonum cuspidatum inhibited 5-lipoxygenase products and lysosomal activity (7). Theoretically, concurrent use of Japanese knotweed with lipoxygenase inhibitors may have additive effects.
  • Photosensitizing agentsPhotosensitizing agents: According to secondary sources, sunlight exposure induced a rash on some people who were taking Japanese knotweed.

Japanese knotweed/Herb/Supplement Interactions:
  • AntibacterialsAntibacterials: Based on in vitro research, a methanol extract inhibited growth of Streptococcus mutans and Streptococcus sobrinus at micromolar ranges but augmented growth at submicromolar doses (4). Theoretically, concurrent use of Japanese knotweed with antibacterial agents may have additive effects.
  • Anticoagulants and antiplateletsAnticoagulants and antiplatelets: In an in vitro assay, resveratrol from Polygonum cuspidatum reduced adenosine diphosphate aggregation and decreased the number of platelets expressing surface P-selectin in a dose-dependent manner (26). Theoretically, concurrent use of Japanese knotweed with anticoagulants or antiplatelets may increase the risk of bleeding.
  • Anti-inflammatory herbs, Anti-inflammatory herbs: In in vitro enzymatic assays, Polygonum cuspidatum inhibited the activity of several inflammatory enzymes (7). Theoretically, concurrent use of Japanese knotweed with anti-inflammatory agents may have additive effects.
  • AntilipemicsAntilipemics: In a nonalcohol fatty liver disease rat model, root extracts of Japanese knotweed significantly reduced total cholesterol, triglyceride, and glucose in liver tissue (25). Theoretically, concurrent use of Japanese knotweed with antilipemic agents may have additive effects.
  • AntineoplasticsAntineoplastics: Based on in vitro studies with human cancer cell lines, a root extract which contained trans- and cis-resveratrol inhibited proliferation, without inhibiting growth of normal human liver cells (12). Theoretically, concurrent use of Japanese knotweed with antineoplastic agents may have additive effects.
  • AntioxidantsAntioxidants: In rodent studies, Protykin®, the standardized Polygonum cuspidatum extract, at 50mg/kg or 100mg/kg daily for three weeks, significantly reduced reactive oxygen species (1). Theoretically, concurrent use of Japanese knotweed with antioxidants agents may have additive effects.
  • Antiviral agentsAntiviral agents: Based on in vitro studies, extracts modulated the replication of duck hepatitis B virus (DHBV) and human hepatitis B virus (HBV) (18). In in vitro assays, the ethanol extract of Polygonum cuspidatum (10mcg/mL) inhibited the production of human hepatitis B virus but increased the expression of the noninfectious surface antigen of hepatitis B virus (HBsAg) (27). Theoretically, concurrent use of Japanese knotweed with antiviral agents may have additive effects.
  • Cardiovascular herbs and supplementsCardiovascular herbs and supplements: Based on in vitro studies, polydatin, a constituent of Japanese knotweed, may interact with cardioactive agents by improving heart function and microcirculatory perfusion (15).
  • Osteoporosis herbs/supplementsOsteoporosis herbs/supplements: In an ovariectomized rat model of bone loss, rats fed oral resveratrol (0.7mg/kg of body weight) from Polygonum cuspidatum had significantly higher bone mineral density and bone calcium content than ovariectomized rats, similar to alendronate sodium treatment (24). Theoretically, concurrent use of Japanese knotweed with agents used for osteoporosis may have additive effects.
  • PhotosensitizersPhotosensitizers: According to secondary sources, sunlight exposure induced a rash on some people who were taking Japanese knotweed.
  • PhytoestrogensPhytoestrogens: Based on in vitro studies of the relative estrogenic activity and binding to estrogen receptors (1; 23; 28), Polygonum cuspidatum may augment the effects of hormone replacement therapy. Theoretically, Japanese knotweed constituents may compete for binding to the estrogen receptor with a labeled estrogen and raise the resulting "estrogen" level in assays based on binding to human estrogen receptor.
  • ResveratrolResveratrol: Based on in vitro constituent studies, Polygonum cuspidatum contains resveratrol and trans-resveratrol (11; 1). Theoretically, concurrent use of Japanese knotweed with resveratrol may have additive effects.

Japanese knotweed/Food Interactions:
  • Insufficient available evidence.

Japanese knotweed/Lab Interactions:
  • Antioxidant levelsAntioxidant levels: Based on rodent and in vitro studies, resveratrol and trans-resveratrol exhibited antioxidant activity (1).
  • Bone mineral densityBone mineral density: In an ovariectomized rat model of bone loss, rats fed oral resveratrol (0.7mg/kg of body weight) from Polygonum cuspidatum had significantly higher bone mineral density and bone calcium content than ovariectomized rats, similar to alendronate sodium treatment (24).
  • Coagulation panelCoagulation panel: In an in vitro assay, resveratrol from Polygonum cuspidatum reduced adenosine diphosphate aggregation and decreased the number of platelets expressing surface P-selectin in a dose-dependent manner (26).
  • EstrogenEstrogen: Based on in vitro assays, extracts of Polygonum cuspidatum, including resveratrol and trans-resveratrol, bound to human estrogen receptor (23; 1). Theoretically, Japanese knotweed constituents may compete for binding to the estrogen receptor with a labeled estrogen and raise the resulting "estrogen" level in assays based on binding to human estrogen receptor.
  • Lipid profileLipid profile: In a nonalcohol fatty liver disease rat model, root extracts of Japanese knotweed significantly reduced total cholesterol, triglyceride, and glucose in liver tissue (25).

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The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.