Current research on the environmental impact of Lycopus europaeus in the Great Lakes is inadequate to support proper assessment.
Realized:
Lycopus europaeus invades numerous wetland ecosystems and is capable of displacing natives, including L. americanus Muhl. ex W. Bartram, L. amplectens Raf., L. rubellus Moench, L. uniflorus Michx., and L. virginicus L. (USDA NRCS 2012).
Potential:
Hybridization between L. europaeus and L. americanus can occur when both species are living in close proximity. Hybrids have been found in North America; however, there are no records of hybrids in the Great Lakes (Reznicek et al. 2011).
In its native range, European water horehound is a common, widespread species that can dominate some ecosystems (Lucassen et al. 2006, van der Valk and Verhoeven 1988). A majority of seeds collected during a survey of moving bodies of water in the Netherlands were from L. europaeus. This species also had the highest germination rate of all the seeds collected (Boedeltje et al. 2003).
Stammel et al. (2003) report that L. europaeus possess a chemical compound that may be effective against herbivores in the Great Lakes.
There is little or no evidence to support that Lycopus europaeus has significant socio-economic impacts in the Great Lakes.
Potential:
Lycopus europaeus can be found in brick and concrete wall structures in urban environments (Francis and Hoggart 2011). Over time these structures could weaken.
There is little or no evidence to support that Lycopus europaeus has significant beneficial effects in the Great Lakes.
Realized:
Historically, L. europaeus has been used as an astringent, cosmetic, douche, narcotic, refrigerant, and to treat fever, sores, and wounds.
Potential:
Six isopimarane diterpeniods, which are compounds frequently used in pharmaceuticals, have been isolated from L. europaeus (Hussein et al. 1999). A diterpenoid isolated from L. europaeus, euroabienol, showed activity against 15 strains of bacteria and 6 fungal strains. Euroabienol has great potential to be used as a broad spectrum antibiotic and/or antifungal (Radulovic et al. 2010). Gibbons et al. (2003) found that diterpenes from L. europaeus, when combined with other compounds, have potential at regulating bacteria that have resistance to multiple drugs.
Polar extracts from L. europaeus contain flavonoids and phenolic acids; both of which are antioxidants (López et al. 2007). Another polyphenolic compound extracted exhibits the potential to influence the thyroid glands and gonads (Fecka and Cisowski 1999). Mild forms hyperthyroidism can be improved by taking extracts from L. europaeus (Beer et al. 2008, Wojciechowski et al. 2003). Patients who were given low doses of L. europaeus experienced reduced levels of thyroid hormone and reduced cardiac symptoms (Vonhoff et al. 2006).