Luteolin is a flavone which occurs in medicinal plants as well as in some 
vegetables and spices. It is a natural anti-oxidant with less pro-oxidant 
potential than the flavonol quercetin, the best studied flavonoid, but 
apparently with a better safety profile. It displays excellent radical 
scavenging and cytoprotective properties, especially when tested in complex 
biological systems where it can interact with other anti-oxidants like vitamins. 
Luteolin displays specific anti-inflammatory effects at micromolar 
concentrations which are only partly explained by its anti-oxidant capacities. 
The anti-inflammatory activity includes activation of anti-oxidative enzymes, 
suppression of the NFkappaB pathway and inhibition of pro-inflammatory 
substances. In vivo, luteolin reduced increased vascular permeability and was 
effective in animal models of inflammation after parenteral and oral 
application. Although luteolin is only a minor component in our nutrition (less 
than 1 mg/day) epidemiological studies indicate that it has the potential to 
protect from diseases associated with inflammatory processes such as 
cardiovascular disease. Luteolin often occurs in the form of glycosides in 
plants, but these are cleaved and the aglycones are conjugated and metabolized 
after nutritional uptake which has to be considered when evaluating in vitro 
studies. Some data for oral and topical bioavailability exist, but more 
quantitative research in this field is needed to evaluate the physiological and 
therapeutical potential of luteolin.