Isoflavones

Isoflavones are produced by plants of the Fabaceae family, including red clover, soy bean, and also in green beans, chick pea, alfalfa, and peanuts.  Known to be estrogen forming, types of isoflavones include biochanin A, genistein, coumestrol, and equol.

Links to Plants Containing Isoflavones

RESEARCH

The listings of research below represents a compilation of scientific articles found on the topic, with a very brief overview description of each article/study.  This compilation of research articles does not necessarily imply that there are adequate results to demonstrate safe and/or effective human use of any herb listed.

ANTICANCER

• Isoflavone derivatives, biochanin A and genistein inhibited the cell growth of stomach cancer cell lines in vitro.  From:  Yanagihara, K., Ito, A., Toge, T., & Numoto, M. (1993). Antiproliferative effects of isoflavones on human cancer cell lines established from the gastrointestinal tract. Cancer Research, 53(23), 5815-5821.
• Red clover extract and its isoflavones showed powerful chemopreventive activity in vitro. From:  Krenn, L., & Paper, D. H. (2009). Inhibition of angiogenesis and inflammation by an extract of red clover (Trifolium pratense L.). Phytomedicine, 16(12), 1083-1088.  Link:  http://dx.doi.org/10.1016/j.phymed.2009.05.017
• Red clover isoflavones could protect against DNA damage.  From:  Chan, H. Y., Wang, H., & Leung, L. K. (2003). The red clover (Trifolium pratense) isoflavone biochanin A modulates the biotransformation pathways of 7, 12-dimethylbenz [a] anthracene. British journal of nutrition, 90(01), 87-92.
• Biochanin, an isoflavone isolated from red clover extract, inhibited breast cancer cell expression in vitro.  From:  Wang, Y., Gho, W. M., Chan, F. L., Chen, S., & Leung, L. K. (2008). The red clover (Trifolium pratense) isoflavone biochanin A inhibits aromatase activity and expression. British Journal of Nutrition, 99(02), 303-310.
• Dietary isoflavones reduced prostate cancer by inducing apoptosis in low to moderate-grade tumors.  From:  Jarred, R. A., Keikha, M., Dowling, C., McPherson, S. J., Clare, A. M., Husband, A. J., … & Risbridger, G. P. (2002). Induction of apoptosis in low to moderate-grade human prostate carcinoma by red clover-derived dietary isoflavones. Cancer Epidemiology and Prevention Biomarkers, 11(12), 1689-1696
• Coumestrol had a mutagenic, clastogenic effect on cultured human lymphoblastoid cells.  From:  Domon, O. E., McGarrity, L. J., Bishop, M., Yoshioka, M., Chen, J. J., & Morris, S. M. (2001). Evaluation of the genotoxicity of the phytoestrogen, coumestrol, in AHH-1 TK+/− human lymphoblastoid cells. Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 474(1), 129-137.  Link:  http://dx.doi.org/10.1016/S0027-5107(00)00170-6
• The chemo-preventative, anticancer activity of licochalcone, an estrogenic flavonoid from licorice was determined.  From:  Fu, Y., Hsieh, T. C., Guo, J., Kunicki, J., Lee, M. Y., Darzynkiewicz, Z., & Wu, J. M. (2004). Licochalcone-A, a novel flavonoid isolated from licorice root (Glycyrrhiza glabra), causes G2 and late-G1 arrests in androgen-independent PC-3 prostate cancer cells. Biochemical and biophysical research communications, 322(1), 263-270.

ANTIOXIDANT

• Isoflavones from licorice protected mitochondrial function against oxidative stress.  From:  HARAGUCHI, H., YOSHIDA, N., ISHIKAWA, H., TAMURA, Y., MIZUTANI, K., & KINOSHITA, T. (2000). Protection of mitochondrial functions against oxidative stresses by isoflavans from Glycyrrhiza glabra. Journal of pharmacy and pharmacology, 52(2), 219-223.

REDUCED BONE LOSS

• Isoflavones reduced lumbar spine bone loss in women.  From:  Atkinson, C., Compston, J. E., Day, N. E., Dowsett, M., & Bingham, S. A. (2004). The effects of phytoestrogen isoflavones on bone density in women: a double-blind, randomized, placebo-controlled trial1-3. The American Journal of clinical nutrition, 79(2), 326-333
• Red clover isoflavones were effective in reducing bone loss in rats. From:  Occhiuto, F., Pasquale, R. D., Guglielmo, G., Palumbo, D. R., Zangla, G., Samperi, S., … & Circosta, C. (2007). Effects of phytoestrogenic isoflavones from red clover (Trifolium pratense L.) on experimental osteoporosis. Phytotherapy Research, 21(2), 130-134.
• Bone density improved after women took extracts of isoflavones from red clover.  From:  Clifton-Bligh, P. B., Baber, R. J., Fulcher, G. R., Nery, M. L., & Moreton, T. (2001). The effect of isoflavones extracted from red clover (Rimostil) on lipid and bone metabolism. Menopause, 8(4), 259-265.

MEN’S HEALTH

• Red clover  isoflavones reduced non-malignant prostatic growth in mice by acting as anti-androgenic agents. From:  Jarred, R. A., McPherson, S. J., Jones, M. E., Simpson, E. R., & Risbridger, G. P. (2003). Anti‐androgenic action by red clover‐derived dietary isoflavones reduces non‐malignant prostate enlargement in aromatase knockout (arko) mice. The Prostate, 56(1), 54-64.

MENOPAUSE SYMPTOMS

• Hot flashes were reduced with a supplement of red clover isoflavones in menopausal women.  From:  van de Weijer, P. H., & Barentsen, R. (2002). Isoflavones from red clover (Promensil®) significantly reduce menopausal hot flush symptoms compared with placebo. Maturitas, 42(3), 187-193.  Link:  http://dx.doi.org/10.1016/S0378-5122(02)00080-4
• A review of 55 articles and 16 studies summarized that soy isoflavones show slight and slow effects on reducing menopause hot flashes.  From:  Li, L., Lv, Y., Xu, L., & Zheng, Q. (2015). Quantitative efficacy of soy isoflavones on menopausal hot flashes. British journal of clinical pharmacology, 79(4), 593-604.
• This double blind randomized placebo controled study of 51 women over twelve weeks showed 60 mg of isoflavones daily reduced hot flashes and night sweats by 57% and 43%, respectively.  From:  Cheng, G., Wilczek, B., Warner, M., Gustafsson, J. Å., & Landgren, B. M. (2007). Isoflavone treatment for acute menopausal symptoms. Menopause, 14(3), 468-473.
• A meta-analysis of all randomized, controlled trials concluded isoflavones reduced hot flushes in menopausal women.  From:  Howes, L. G., Howes, J. B., & Knight, D. C. (2006). Isoflavone therapy for menopausal flushes: a systematic review and meta-analysis. Maturitas, 55(3), 203-211.

SUNSCREEN

• The isoflavone: equol, from red clover showed potential as a sunscreen ingredient as tested on hairless rodents.  From:  Widyarini, S., Spinks, N., Husband, A. J., & Reeve, V. E. (2001). Isoflavonoid Compounds from Red Clover (Trifolium pratense) Protect from Inflammation and Immune Suppression Induced by UV Radiation¶. Photochemistry and Photobiology, 74(3), 465-470.  Link:  http://dx.doi.org/10.1562/0031-8655(2001)074%3C0465:ICFRCT%3E2.0.CO;2

ANTIMICROBIAL

• Constituents of licorice produced significant antimicrobial activity in vitro.  From:  Mitscher, L. A., Park, Y. H., Clark, D., & Beal, J. L. (1979). Antimicrobial agents from higher plants. Antimicrobial isoflavanoids and related substances from Glycyrrhiza glabra L. var. typica. Journal of natural products, 43(2), 259-269.
• Licorice produced antimycobacterial activity and its glabridin constituent was active against gram positive and gram negative bacteria and Mycobacterium tuberculosis.   Gupta, V. K., Fatima, A., Faridi, U., Negi, A. S., Shanker, K., Kumar, J. K., … & Darokar, M. P. (2008). Antimicrobial potential of Glycyrrhiza glabra roots. Journal of Ethnopharmacology, 116(2), 377-380
• Licoagrodione, a biflavonoid from licorice showed to have antimicrobial activity in vitro.  From:  Li, W., Asada, Y., & Yoshikawa, T. (1998). Antimicrobial flavonoids from Glycyrrhiza glabra hairy root cultures. Planta medica, 64(08), 746-747.

SKIN HEALING

• Based on research that estrogen improves skin thickness, collagen, and moisture, a study was conducted in which rats with low estrogen were fed red clover extract with 11% isoflavones and showed improved skin.  From:  Circosta, C., Pasquale, R. D., Palumbo, D. R., Samperi, S., & Occhiuto, F. (2006). Effects of isoflavones from red clover (Trifolium pratense) on skin changes induced by ovariectomy in rats. Phytotherapy research, 20(12), 1096-1099.

CHOLESTEROL LOWERING

• Postmenopausal women with a high BMI showed reduced cholesterol when taking supplement of isoflavones from red clover.  Chedraui, P., San Miguel, G., Hidalgo, L., Morocho, N., & Ross, S. (2008). Effect of Trifolium pratense-derived isoflavones on the lipid profile of postmenopausal women with increased body mass index. Gynecological Endocrinology, 24(11), 620-624.
• Isoflavones reduced triglyceride levels in menopausal women.  From:  Schult, T. M. K., Ensrud, K. E., Blackwell, T., Ettinger, B., Wallace, R., & Tice, J. A. (2004). Effect of isoflavones on lipids and bone turnover markers in menopausal women. Maturitas, 48(3), 209-218.  Link:  http://dx.doi.org/10.1016/j.maturitas.2003.09.027
• Red clover phytoestrogens reduced serum lipid levels in postmenopausal women.  From:  Terzic, M. M., Dotlic, J., Maricic, S., Mihailovic, T., & Tosic‐Race, B. (2009). Influence of red clover‐derived isoflavones on serum lipid profile in postmenopausal women. Journal of Obstetrics and Gynaecology Research, 35(6), 1091-1095.

ANALGESIC

• Women showed reduced mastalgia with isoflavone supplements.   From:  Ingram, D. M., Hickling, C., West, L., Mahe, L. J., & Dunbar, P. M. (2002). A double-blind randomized controlled trial of isoflavones in the treatment of cyclical mastalgia. The Breast, 11(2), 170-174.

IMPROVED KIDNEY FUNCTION

• Glabridin, a pyranoisoflavan constituents from licorice reduced protein excretion found in the urine.  From:  Fukai, T., Satoh, K., Nomura, T., & Sakagami, H. (2003). Preliminary evaluation of antinephritis and radical scavenging activities of glabridin from Glycyrrhiza glabra. Fitoterapia, 74(7), 624-629.

By: Kathy Sadowski

Updated: 1/11/19