Isoflavones in red clover

Wu, Q., Wang, M. Simon, J.E. (2003). Determination of isoflavones in red clover and related species by high-performance hquid chromatography combined with ultraviolet and mass spectrometric detection. Journal of Chromatography A, 916, 195-209. 

Peng, Y.Y. and Ye, J.N., Determination of isoflavones in red clover by capillary electrophoresis with electrochemical detection, Fitoterapia, 77, 171 178, 2006. 

Klejdus B, Vitamvasova D and Kuban V. 2001. Identification of isoflavone conjugates in red clover (Trifolium pratense) by liquid chromatography-mass spectrometry after two-dimensional solid-phase extraction. Anal Chim Acta 450 81-97. 

Nestel, P.J., Pomeroy, S., Kay, S., Komesaroff, P., Behrsing, J., Cameron, J.D. and West, L. (1999). Isoflavones from red clover improve systemic arterial compliance but not plasma lipids in menopausal women, J. Clin. Endocrinol. Metab., 84, 895-898. 

Black cohosh may cause nausea, vomiting, hypotension, and even miscarriage. It is absolutely contraindicated in pregnancy. Red clover contains coumarins and should therefore be avoided with anticoagulants. Diets high in red clover isoflavones have reduced livestock fertility and theoretically could do the same in humans. Flaxseed may cause nausea, diarrhea, and flatulence. Cyanogenic nitrates in flax (especially in immature seed pods) have produced toxic reactions. 

Tamura, S., Chang, C., Suzuki, A., Kymai, S. Isolation and structure of a novel isoflavone derivative in red clover. Agri Biol Chem 1967 31 1108-1109. 

One trial using 80 mg daily of isoflavones from red clover reported a 44 /o reduction in hot flushes, while another study reported no clinically important effects on either hot flushes or other menopause symptoms. ... 

B. Klejdus, D. Vitamvasova-Steerbova, V. Kuban, Identification of isoflavone conjugates in red clover (T. pratense) by LC-MS after two-dimensional SPE, Anal. Chirn. Acta, 450 (2001) 81. 

Documented effects A tincture of the plant is used to treat arteriosclerosis in patients with normal blood pressure (Nuraliev 1989). In modem medicine this species is used as an expectorant, diuretic, and antiseptic (Khodzhimatov 1989). Metabolites of isoflavones found in the plant were found to protect against UV radiation-induced inflammation and immunosuppression (Widyarini et al. 2001). Isoflavones found in red clover inhibited COX enzyme activity in certain cancer cell types (Lam et al. 2004). Extracts of red clover and individual flavonoid constituents exhibited estrogenic activity in a variety of in vitro assays (Overk et al. 2005). 

Fig. 9.1 Isoflavones present in red clover (1) formononetin, (2) biochanin A, (3) genistein, (4) daidzein, (5) isoformononetin, (6) pseudobaptigen, (7) glycitein, (8) pratensein, (9) calycosin, (10) orobol, (11) irilone, and (12) prunetin. (13-16) Examples of isoflavone glucosides present in red clover.

All red clover varieties studied contain isoflavones. The isoflavone content in red clover is typically 0.5-2.5% of dry matter (Pettersson et al, 1984 Saloniemi et al, 1995). By contrast, the isoflavone content of green subterranean clover has been reported to be as high as 5% of dry matter (Adams, 1998). Leaves are found to have the highest isoflavone concentration followed by stems and inflorescences (Sivesind Seguin, 2005 ... 

Beekman, M.C., Lingeman, H., Brinkman, U.A.Th., and Gooijer, C., Determination of the isoflavone formononetin in red clover (Trifolium pratense L.) by micellar electrokinetic chromatography combined with deep-UV laser-induced wavelength-resolved fluorescence detection, J. Microcolumn Sep., 11, 347-350, 1999. 

TSUNODA N, POMEROY s, NESTED p (2002) Absorption in hiunans of isoflavones from soy and red clover is similar. JNutr 132, 2199-2201. 

Several studies have evaluated dietary supplements such as isoflavones, which are found in soy products and red clover. A well-controlled trial in more than 400 postmenopausal women evaluating a specific isoflavone, ipriflavone, found no benefits on bone mineral density or fracture rates after 3 years.47 Nevertheless, because these therapies are available without prescription and are not regulated by the FDA, patients may choose to self-medicate with isoflavones. Lymphocytopenia appeared in several patients treated with ipriflavone in clinical trials. Additionally, ipriflavone should be used with caution in immunocompromised patients or those with renal disease. It may inhibit CYP1A2 and CYP2C9 and may interact with drugs metabolized by those pathways, such as warfarin. 

Phytoestrogens are a diverse group of polyphenolic non-steroidal plant compounds that bind to human estrogen receptors (Cos et al., 2003). The best studied of these compounds are the isoflavones, the phytoestrogens present in soy and red clover. 

Red clover is a plant that contains isoflavones in a slightly different composition compared with soy. Red clover contains formononetin and biochanin A, which are not present in soy and may thus have additional biological activity. So far, four studies (Barber et ah, 1999 Knight et ah, 1999 van de Weijer, 2002 Tice et ah, 2003) have been performed using isoflavones derived from red clover (Table 4.3). These have used doses of isoflavones ranging from 40 to 160 mg. Three out of four of these studies did not show any effects, even in spite of a very large sample size (Tice et ah, 2003). Only one study showed a reduction in the number of hot flushes. The reduction, however, was small (van de Weijer and Barentsen, 2002). Red clover therefore does not appear to have much of an effect on the reduction of hot flushes. 

Isoflavones, chiefly found in the Leguininosae (such as soy, Medicago sativa, and red clover. Trifolium pratense) in the plant kingdom, are also successfully analyzed by HPLC on Ci8 columns. ... 

Atkinson C, Oosthuizen W, Scollen et al. Modest protective effects of isoflavones from a red clover-derived dietary supplement on cardiovascular disease risk factors in perimenopausal women, and evidence of an interaction with ApoE genotype in 49-65 year-old women. J. Nutr. 134, 1759-1764, 2004. 

Delmonte P, Perry J, Rader JI. 2006. Determination of isoflavones in dietary supplements containing soy, red clover and kudzu Extraction followed by basic or acid hydrolysis. J Chromatography A 1107 59-69. 

Rijke E, Zafra-Gomez A, Ariese F, Brinkman UAT and Gooijer C, Determination of isoflavone glucoside malonates in Trifolium pretense L. (red clover) extracts Quantification and stability studies. J Chromatogr A 932 55-64 (2001). 

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