Luteolin lowers estradiol levels in animal study



Luteolin, a flavonoid institute in rosemary, thyme, parsley and citrus fruits, is one effective anti-oestrogen, according to some animal study published by researchers at Peking University Health Science Center in the Journal of Pharmacology and Experimental Therapeutics. Unlike pharmacological anti-oestrogens, luteolin too improves the cholesterol balance.

In 2013 this texture magazine already wrote about the anti-oestrogenic properties of luteolin. [Structural ~ry shown here.] Pharmacologists at the Chinese Chengdu Institute of Biology had screened completely 100 substances for their anti-oestrogenic qualities, and luteolin emerged in the same proportion that the most interesting. But that was in-vitro study. Now we have an animal study.

The researchers used offspring-bearing mice whose ovaries had been surgically separate for their experiment. A number of the animals were given androstenedione [AD] injections daily. The enzyme aromatase converts androstenedione effortlessly into estradiol.

Some animals were given luteolin [LUT] because well, administered orally. The doses used are shown in the figure underneath. The human equivalent of the doses varies from 45 – 450 mg luteolin by day. Some mice were also given injections of letrozole [LET], a over-powering pharmacological aromatase inhibitor.


After 12 weeks, the researchers limited the estradiol concentration in the mice’s kindred. The figure below shows that the anti-oestrogenic import of the highest dose of luteolin was the identical as that of letrozole.


The researchers had too injected the mice with estradiol-perceptive breast cancer cells. Both luteolin and letrozole inhibited the advance of the tumours, but letrozole performed slightingly better at this than luteolin.

Long-boundary use of pharmacological aromatase inhibitors leads to take ~s effects, one of which is that the cholesterol surplus becomes worse. The LDL concentration increases and that of HDL decreases. Luteolin in addition inhibits aromatase, but this flavone has the hostile effect on cholesterol balance. Luteolin lowers the LDL compression into a small compass and raises the HDL concentration.


The form above shows that luteolin can moreover cancel out the negative effect of letrozole put ~ cholesterol levels.

Luteolin had no fact on triglyceride levels.

“Although luteolin is widely distributed in furnish with ~s foods, the dosages used in the current study were too magnanimous for the normal levels that humans consume”, the researchers concluded. “Nevertheless, this study could prepare the scientific basis for nutraceutical or pharmacological unravelling of this flavone.”

“As a overbearing LDL/HDL ratio is usually associated by long-term use of aromatase inhibitors, the executive department of luteolin can be a potential compensation mechanism without compromising on aromatase.”

Coadministrating luteolin minimizes the indirect effects of the aromatase inhibitor letrozole.


Aromatase inhibitors (AIs) be obliged been used as adjuvant therapeutic agents against breast cancer. Their adverse side power on blood lipid is well documented. Some indigenous compounds have been shown to be potential AIs. In the present study, we compared the strength of the flavonoid luteolin to the clinically approved AI letrozole (Femara; Novartis Pharmaceuticals, East Hanover, NJ) in a organic unit and a mouse model. In the in vitro founded on fact results for aromatase inhibition, the Ki values of luteolin and letrozole were estimated to have ~ing 2.44 µM and 0.41 nM, respectively. Both letrozole and luteolin appeared to subsist competitive inhibitors. Subsequently, an animal design was used for the comparison. Aromatase-expressing MCF-7 cells were transplanted into ovariectomized athymic mice. Luteolin was given ~ the agency of mouth at 5, 20, and 50 mg/kg, considering that letrozole was administered by intravenous enema. Similar to letrozole, luteolin administration reduced plasma estrogen concentrations and suppressed the xenograft proliferation. The arrangement of cell cycle and apoptotic proteins-similar as a decrease in the statement of Bcl-xL, cyclin-A/D1/E, CDK2/4, and greaten in that of Bax-was nearly the same in both treatments. The most significant disparity was on blood lipids. In difference to letrozole, luteolin increased fasting plasma great-density lipoprotein concentrations and produced a eligible blood lipid profile. These results suggested that the flavonoid could be a coadjuvant therapeutic agent without impairing the deed of AIs.
Copyright © 2014 ~ the agency of The American Society for Pharmacology and Experimental Therapeutics.

PMID: 25138022 DOI: 10.1124/jpet.114.216754 [PubMed – indexed on this account that MEDLINE]


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