Plant Profiler

Gumweed (Grindelia squarrosa)

Gumweed (Grindelia squarrosa) Image
Synonyms / Common Names / Related Terms
Asteraceae (family), August flower, California gumplant, grindelia, Grindelia camporum, Grindelia robusta, Grindeliae herba, Grindelie, gum plant, gumplant, gum weed, hardy grindelia, rosin weed, scaly grindelia, tar weed, tarweed.

Mechanism of Action


  • Constituents: Grindelia species contain many diterpenoids.1,2 Plants in this genus also contain flavonoids, sterols, and sapogenins.3,4,5 Little is known about the mechanisms of action or potential drug interactions of these compounds.
  • Grindelane diterpenoids make up most of the resin of gumweed (Grindelia camporum). The resin can be 10% of the plant weight or 20% of the dry weight. Grindelic acid, camporic acid, 17-carboxygrindelic acid, chrysolic acid, strictanonic acid6and many other diterpenoids have been identified in gumweed7,8. The diterpenoids in gumweed appear to have antibiotic activity.5
  • Flavonoids such as acacetin, kumatakenin and quercitin are found in gumweed.7 Acacetin is being investigated for anticancer activity and is a vasorelaxant.9 Kumatakenin has antiplatelet and other activities.10 Quercitin has hypolipidemic, antiatherogenic and other activities.11


  • There is insufficient available evidence regarding the pharmacodynamics or pharmacokinetics of the diterpenoids of gumweed.
  • Of the flavonoids present in gumweed, only quercitin has been investigated.12 Quercitin aglycone is 36-53% absorbed across the gastrointestinal tract after oral administration. Of course, the plant flavonoid is not present as an aglycone, but is conjugated to various sugars. The plasma levels peak at about two hours. The half-life of quercitin is 20-72 hours. The clearance of quercitin has not been adequately investigated, but may involve glucuronide conjugation and elimination in the urine and feces.


  1. Bohlman, F., Ahmed, M., Borthakur, N., Wallmeyer, M., Jakupovic, J., King, R. M., and Robinson, H. Diterpenes related to grindelic acid and further constituents from Grindelia species. Phytochem 1982;21:167-172.
  2. Timmermann, B. N., McLaughlin, S. P., and Hoffmann, J. J. Quantitative variation of grindelane diterpene acids in 20 species of North American Grindelia. Biochem Systemat Ecol 1987;15:401-410.
  3. Zhou, L., Fuentes, E. R., Hoffmann, J. J., and Timmermann, B. N. Diterpenoids from Grindelia tarapacana. Phytochem 1995;40:1201-1207.
  4. Timmermann, B. N., Hoffmann, J. J., Jolad, S. D., Bates, R. B., and Siahann, T. J. Diterpenoids and flavonoids from Grindelia discoidea. Phytochem 1986;25:723-727.
  5. Kreutzer, S., Schimmer, O., and Waibel, R. [Triterpenoid sapogenins in the genus Grindelia]. Planta Med 1990;56(4):392-394. 2236296
  6. Hoffmann, J. J., Jolad, S. D., Timmermann, B. N., Bates, R. B., and Camou, F. A. Two grindelane diterpenoids from Grindelia camporum. Phytochem 1988;27:493-496.
  7. Timmermann, B. N., Hoffmann, J. J., Jolad, S. D., and Schram, K. H. Grindelane diterpenoids from Grindelia squarrosa and G camporum. Phytochem 1985;24:1031-1034.
  8. Timmermann, B. N., Luzbetak, B. J., Hoffmann, J. J., Jolad, S. D., Schram, K. H., Bates, R. B., and Klenck, R. E. Grindelane diterpenoids from Grindelia camporum and Chrysothamnus paniculatus. Phytochem 1983;22:523-525.
  9. Calderone, V., Chericoni, S., Martinelli, C., Testai, L., Nardi, A., Morelli, I., Breschi, M. C., and Martinotti, E. Vasorelaxing effects of flavonoids: investigation on the possible involvement of potassium channels. Naunyn Schmiedebergs Arch Pharmacol 2004;370:290-298.
  10. Afifi, U. and Aburjai, T. Antiplatelet activity of Varthemia iphionoides. Fitoterapia 2004;75:629-633.
  11. Juzwiak, S., Wojcicki, J., Mokrzycki, K., Marchlewicz, M., Bialecka, M., Wenda-Rozewicka, L., Gawronska-Szklarz, B., and Drozdzik, M. Effect of quercetin on experimental hyperlipidemia and atherosclerosis in rabbits. Pharmacol Rep 2005;57(5):604-609. 16227643
  12. Heim, K. E., Tagliaferro, A. R., and Bobilya, D. J. Flavonoid antioxidants: chemistry, metabolism and structure-activity relationships. J Nutr Biochem 2002;13(10):572-584. 12550068

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