Anti-Oxidant, Anti-Inflammatory and Anti-Allergic Activities of Luteolin

Abstract

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.

Luteolin potentiates the effects of aminoglycoside and β-lactam antibiotics against methicillin-resistant Staphylococcus aureus in vitro

“…The use of three different antibiotics, namely AM, OX and GT, in combination with LUT clearly suppressed MRSA growth, enabling the dose of the antibiotics to be reduced. The time-kill curves confirmed the ability of LUT to increase the antibacterial effects of the antibiotics, synergistically reducing the bacterial counts below the lowest detectable limit after [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] h. The present study demonstrated the potential of LUT as an effective therapeutic agent against MRSA, reinforcing the possibility of substantially reducing the use of existing antibiotics. The results obtained for the combinations tested in the current study suggest that LUT can increase susceptibility to antibacterial action, as well as reduce the inducible antibiotic resistance of bacteria.…”

“…Dietary sources of LUT include carrots, peppers, celery, olive oil, peppermint, thyme, rosemary and oregano. LUT is considered to have diverse biological benefits, including cardioprotective, antioxidant, anti-inflammatory and anticancer activities (11)(12)(13)(14). In addition, LUT has exhibited a strong antiproliferative activity against various human cancer cell lines, such as lung cancer cell lines, and is a widely used ingredient in nutritional supplements (13,14).…”

CoCl₂ Decreases EC-SOD Expression through Histone Deacetylation in COS7 Cells

“…[22][23][24] We previously reported that luteolin significantly suppressed phorbol ester (TPA)-induced human monocytic differentiation into macrophages, and these events were closely associated with the inhibition of intracellular ROS signaling. 25) Accordingly, some flavonoids may be seed compounds that maintain redox homeostasis.…”

Whitening Agents from Reseda luteola L. and Their Chemical Characterization Using Combination of CPC, UPLC-HRMS and NMR

“…R. luteola extracted with ethyl acetate exhibiting interesting whitening (42%), anti-inflammatory (54%), and anti-oxidant (67%) activities appeared to be particularly compelling for further investigation. If the R. luteola anti-inflammatory and anti-oxidant activities, mainly credited to its luteolin content, have already been discussed [20], to our knowledge, the literature only alludes to its skin whitening briefly. In fact, R. luteola, like other species from the order Brassicales, contains glucosinolates (sulfur-and nitrogen-containing secondary metabolites) and notably glucobarbarin, the hydrolysis of which leads to barbarin (= (R)-5-phenyl-2-oxazolidinethione), which is identified as a potent inhibitor of mushroom and murine tyrosinases [21,22].…”

“…Luteolin's anti-allergic, anti-oxidant, anti-carcinogenic, anti-inflammatory, and notably whitening properties have already been largely documented [20,[37][38][39][40]. Apigenin, particularly promising for cancer prevention [41], also displays a variety of engaging activities and notably anti-inflammatory and anti-oxidant properties [39,42].…”