Red Clover Extract (RCE) refers to any extract that is taken from the red clover plant, known botanically as trifolium pratense which is a good natural source of isoflavone molecules. There are a few brand name products of RCE (Promensil, Menoflavon, etc.) which isolate the isoflavones that are thought to be bioactive, and this mainly refers to two of the Soy Isoflavones which are also found in this plant (genistein and daidzein) and two structurally similar methylated isoflavones known as biochanin A and formononetin. Specifically, biochanin A is just methylated genistein (and can produce genistein in the body when it is ingested) whereas formononetin is methylated daidzein (can also produce daidzein in the body after ingestion). RCE, and its brand name products, are recommended for the treatment of menopause or asthmatic symptoms.
When looking at research on RCE and menopausal symptoms, there are indeed benefits in isolated studies relative to placebo but there are also many failures indicating that supplementation is pretty unreliable in benefitting symptoms; this may be in part due to differences in absorption or simply due to potential industry bias (since many studies using the brand name products are partially funded by the producers of the products, and the independent studies tend to be more likely to report no significant benefit). There may be a minor reduction in anxiety however, which would be a percievable benefit and needs to be further evaluated. It should also be noted that most studies do reported great benefit with supplementation, but the placebo effect per se is very prominent in studies on menopausal symptoms (case in point, studies on Black Cohosh where the placebo effect sometimes halves symptoms of menopause alone).
Beyond the above possible anxiolytic property of red clover that needs to be investigated further and a possibly benefit to asthma and cough (also needs to be investigated further), there does not appear to be any significant benefit associated with red clover extract.
Red Clover Extract (RCE) tends to refer to the plant known as trifolium pratense (of the fabaceaefamily) which is most well known for its content of Biochanin A, an estrogenic Bioflavonoids. It tends to be sold as a herbal tea (the dried floral blossoms being steeped as tea) or as a supplement for menopausal symptoms since dietary isoflavones in general (usually from soy) are correlated with reduced hot flash symptoms and biochanin A can convert into the soy isoflavones.
This plant is not known to have usage as a traditional medicine, although tea made from the aerial parts of this plant appears to be a remedy for cough and bronchitis.
Red Clover Extract tends to contain:
· Biochanin A (4′-O- methylated genistein)and two biochanin A glycosides with total biochanin A aglycones totalling 0.009-0.116% (flower), 0.022-0.095% (stem), 0.067-0.339% (root), and 0.077-0.133% (leaf)
· Formononetin (4′-O- methylated daidzein) and its glycoside (Ononin) as well as diglycosides with total formononetin aglycones totalling 0.018-0.038% (flower), 0.027-0.056% (stem), 0.023-0.151% (leaf), and 0.019-0.096% (root)
· All three Soy Isoflavones (daidzein, glycitein, and genistein) and their glycosides (daidzin, glycitin, genistin; respectively).Genistein (in total aglycones) at highest levels in the roots (0.1-0.58%) while not being very detectable elsewhere, daidzein being in relatively low concentrations (less than 0.1%) in all plant part, and glycitein also being high in the roots (0.319-0.863%) but also the leaves (0.430-0.820%) and stems (0.219-0.729%)
· Calycosin (also found in Astragalus membranaceus) and its glycoside with the aglycone of calycosin totalling 0.066-0.126% leaf dry weight, 0.054-0.084% of the stem, 0.06-0.184% of the root, and 0.021-0.039% flower
· Pratensein glycosides with total pratensein aglycones reaching 0.043-0.074% (leaf), 0.009-0.029% (stem), 0.034-0.062% (root), and 0.006-0.01% (flower)
· Prunetin and two glycosides with total prunetin aglcyones being detectable in the leaves (0.149-0.282%), stem (0.133-0.235%), roots (0.133-0.288%), and flowers (0.036-0.052%)[5]
· Pseudobaptigenin and two glycosides with total pseudobaptigenin aglycones totaling 0.029-0.372% (leaves), 0.069-0.585% (roots), 0.056-0.126% (stems), and 0.009-0.018% (flowers)
· Irilone (isoflavone with a catechol group on the C ring) and at least four glucosides with total aglycones totalling 0.121-0.167% (flowers), 0.038-0.169% (stems), 0.017-0.021% with an outlier at 0.907% (roots), and 0.532-0.737% with the same outlier at 0.02% (leaves)
Total isoflavones tend to range from 0.307-0.633% of the flower, 0.740-1.850% of the stem, 1.36-2.853% of the root, and 1.75-2.272% of the leaf.These numbers are much higher than other clover (trifolium) species such as white clover (trifolium repens) which has 0.0213-0.0354%, alsike clover (trifolium hybridum) which has 0.0070-0.0431%, and hop trefoils (trifolium campestre) at 0.00028-0.00061%.
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