Formononetin

• Anticancer potential
• Cardiovascular protection
• Antioxidant
• Anti-inflammatory

• Neuroprotection
• Bone health
• Menopausal symptom relief
• Immunomodulation
• Antimicrobial

Formononetin (7-hydroxy-4′-methoxyisoflavone) exerts its diverse biological effects through multiple molecular pathways. As a methoxylated isoflavone, formononetin possesses a unique structural feature with a methoxy group at the C-4′ position, distinguishing it from other isoflavones like daidzein. This structural characteristic influences its pharmacokinetics, metabolism, and biological activities. As a phytoestrogen, formononetin demonstrates weak estrogenic activity due to its structural similarity to 17β-estradiol.

It binds to estrogen receptors (ERs), with a higher affinity for ER-β compared to ER-α. This selective ER modulation contributes to formononetin’s potential benefits for hormone-dependent conditions while potentially reducing risks associated with ER-α activation. The estrogenic effects of formononetin are context-dependent, showing estrogen-like effects in low-estrogen environments (such as postmenopausal women) and potentially anti-estrogenic effects in high-estrogen environments through competitive binding to ERs. In the body, formononetin can be demethylated to form daidzein, which can be further metabolized by gut microbiota to produce equol in some individuals.

This metabolic conversion is significant because equol has potent estrogenic and antioxidant activities. However, the ability to produce equol varies among individuals based on their gut microbiome composition, with approximately 30-50% of adults being equol producers. One of formononetin’s most significant mechanisms is its anticancer activity, which operates through multiple pathways. It inhibits cell proliferation by inducing cell cycle arrest, primarily at the G0/G1 or G2/M phases, through modulation of cyclins, cyclin-dependent kinases (CDKs), and CDK inhibitors.

Formononetin induces apoptosis (programmed cell death) in various cancer cell lines through both intrinsic (mitochondrial) and extrinsic (death receptor) pathways. It upregulates pro-apoptotic proteins (Bax, Bad) and downregulates anti-apoptotic proteins (Bcl-2, Bcl-xL), leading to mitochondrial membrane permeabilization, cytochrome c release, and caspase activation. Formononetin also inhibits angiogenesis (formation of new blood vessels) by downregulating vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α), thereby limiting tumor growth and metastasis. Additionally, it suppresses cancer cell migration and invasion by inhibiting matrix metalloproteinases (MMPs) and modulating epithelial-mesenchymal transition (EMT) markers.

Formononetin demonstrates potent anti-inflammatory effects through inhibition of the nuclear factor-kappa B (NF-κB) signaling pathway. It prevents IκB kinase (IKK) activation and subsequent nuclear translocation of NF-κB, thereby reducing the expression of pro-inflammatory genes. It suppresses the production of inflammatory cytokines including tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), while inhibiting cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression. Formononetin also modulates the mitogen-activated protein kinase (MAPK) signaling pathways, including p38 MAPK, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK), further contributing to its anti-inflammatory properties.

As an antioxidant, formononetin scavenges reactive oxygen species (ROS) and free radicals through its hydroxyl group. It also enhances endogenous antioxidant defenses by activating nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that regulates the expression of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and heme oxygenase-1 (HO-1). In cardiovascular health, formononetin improves endothelial function by increasing nitric oxide (NO) production through activation of endothelial nitric oxide synthase (eNOS). It also demonstrates vasodilatory effects by activating large-conductance calcium-activated potassium (BKCa) channels in vascular smooth muscle cells.

Formononetin inhibits platelet aggregation and thrombus formation, potentially reducing the risk of thrombotic events. Additionally, it improves lipid profiles by reducing total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides while increasing high-density lipoprotein (HDL) cholesterol. For bone health, formononetin inhibits osteoclast differentiation and activity while promoting osteoblast proliferation and differentiation, potentially leading to increased bone formation and reduced bone resorption. These effects are mediated through both ER-dependent and ER-independent pathways, including modulation of the receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) system.

In the central nervous system, formononetin exhibits neuroprotective effects through multiple mechanisms. It reduces oxidative stress and neuroinflammation, protects against excitotoxicity, and promotes neuronal survival. Formononetin also enhances the expression of neurotrophic factors, including brain-derived neurotrophic factor (BDNF), and activates the PI3K/Akt/glycogen synthase kinase-3β (GSK-3β) pathway, promoting neuronal survival and synaptic plasticity. Formononetin demonstrates immunomodulatory effects by regulating the balance between pro-inflammatory and anti-inflammatory cytokines, modulating T cell differentiation, and enhancing natural killer (NK) cell activity.

It also exhibits antimicrobial properties against various bacteria and fungi, potentially through disruption of cell membranes and inhibition of essential microbial enzymes. The methoxy group at the C-4′ position of formononetin influences its pharmacokinetics and metabolism compared to other isoflavones. This structural feature affects its lipophilicity, membrane permeability, and interaction with metabolic enzymes, potentially leading to different biological activities and therapeutic applications compared to non-methoxylated isoflavones like daidzein.

Optimal dosage ranges for formononetin are not well-established due to limited clinical studies specifically evaluating formononetin as a standalone supplement. Most research has been conducted on plant extracts containing formononetin along with other bioactive compounds. Based on the available research and traditional use, the following dosage ranges can be considered: For standardized red clover extract (typically containing 1-5% formononetin), the common dosage range is 40-160 mg daily, corresponding to approximately 0.4-8 mg of formononetin. For standardized Astragalus extract (typically containing 0.5-2% formononetin), typical dosages range from 500-1000 mg daily, corresponding to approximately 2.5-20 mg of formononetin.

Isolated formononetin supplements are rare, but when available, typical dosages would range from 5-30 mg daily, based on preclinical studies and its proportional content in effective herbal extracts. It’s important to note that formononetin’s bioavailability and metabolism can vary significantly between individuals based on gut microbiome composition, particularly regarding its conversion to daidzein and potentially to equol. For most health applications, starting with a lower dose and gradually increasing as needed and tolerated is recommended. Divided doses (2-3 times daily) may be preferred due to formononetin’s relatively short half-life, though specific pharmacokinetic data in humans is limited.

Formononetin has relatively low oral bioavailability, estimated at approximately 10-20% in animal studies, though comprehensive human pharmacokinetic data is limited. As a methoxylated isoflavone, formononetin has greater lipophilicity compared to non-methoxylated isoflavones like daidzein, which may enhance its passive diffusion across cell membranes. However, its overall bioavailability is still limited by several factors. Upon oral administration, formononetin undergoes significant first-pass metabolism in the intestine and liver.

In the intestine, formononetin can be demethylated by cytochrome P450 enzymes to form daidzein, which can be further metabolized by gut microbiota to produce equol in some individuals. This metabolic conversion is significant because equol has potent estrogenic and antioxidant activities. However, the ability to produce equol varies among individuals based on their gut microbiome composition, with approximately 30-50% of adults being equol producers. In the liver, formononetin undergoes phase II metabolism, primarily through glucuronidation and sulfation, forming conjugates that are more water-soluble and readily excreted.

These conjugates may be less biologically active than free formononetin, though some evidence suggests they can be deconjugated in target tissues, releasing the active compound. The plasma half-life of formononetin is relatively short, estimated at approximately 4-8 hours based on animal studies, necessitating multiple daily doses for sustained therapeutic effects. Formononetin demonstrates moderate distribution to various tissues, with some evidence suggesting preferential accumulation in hormone-responsive tissues such as breast, uterus, and prostate, likely due to its interaction with estrogen receptors in these tissues. The methoxy group at the C-4′ position of formononetin influences its pharmacokinetics and metabolism compared to other isoflavones.

This structural feature increases its lipophilicity and may enhance its membrane permeability, potentially leading to different tissue distribution patterns compared to non-methoxylated isoflavones.

Liposomal formulations – can increase bioavailability by 2-4 fold by enhancing cellular uptake and protecting formononetin from degradation, Nanoemulsion formulations – can increase bioavailability by 3-5 fold by improving solubility and enhancing intestinal permeability, Self-emulsifying drug delivery systems (SEDDS) – improve dissolution and absorption in the gastrointestinal tract, Phospholipid complexes – enhance lipid solubility and membrane permeability, Cyclodextrin inclusion complexes – improve aqueous solubility while maintaining stability, Solid dispersion techniques – enhance dissolution rate and solubility, Combination with piperine – inhibits P-glycoprotein efflux and intestinal metabolism, potentially increasing bioavailability by 30-60%, Microemulsions – provide a stable delivery system with enhanced solubility, Co-administration with fatty meals – can increase absorption by stimulating bile secretion and enhancing lymphatic transport, Combination with probiotics – certain probiotic strains may enhance the conversion of formononetin to daidzein and potentially to equol, increasing its biological activity in equol producers

Formononetin is best absorbed when taken with meals containing some fat, which can enhance solubility and stimulate bile secretion, improving dissolution and absorption. The presence of dietary fiber may reduce absorption, so supplements may be more effective than whole food sources for achieving specific therapeutic effects. Due to the relatively short half-life of formononetin (estimated at 4-8 hours based on animal studies), divided doses (2-3 times daily) may be beneficial for maintaining consistent blood levels throughout the day, though specific human pharmacokinetic data is limited. For anticancer support, consistent daily dosing is important to maintain therapeutic levels in target tissues.

Some research suggests that timing may influence efficacy, with potential benefits to taking formononetin during specific phases of cancer treatment, though this requires medical supervision. For cardiovascular support, consistent daily dosing is recommended, with some evidence suggesting that morning dosing may be particularly beneficial for blood pressure regulation, though more research is needed. For menopausal symptom relief, consistent daily dosing is recommended, with some women reporting better results when taking isoflavones in the morning for hot flashes that occur during the day, or in the evening for night sweats. For bone health, consistent daily dosing is important, as these effects develop gradually over time with regular use.

Enhanced delivery formulations like liposomes or nanoemulsions may have different optimal timing recommendations based on their specific pharmacokinetic profiles, but generally follow the same principles of taking with food for optimal absorption. The timing of formononetin supplementation relative to other medications should be considered, as it may interact with certain drugs, particularly those affecting hormone levels or those metabolized by the same enzymes. In general, separating formononetin supplementation from other medications by at least 2 hours is recommended to minimize potential interactions.

• Gastrointestinal discomfort (mild to moderate, common)
• Nausea (uncommon)
• Headache (uncommon)
• Menstrual changes in women (uncommon, due to phytoestrogenic effects)
• Breast tenderness (rare, due to phytoestrogenic effects)
• Allergic reactions (rare, particularly in individuals with legume allergies)
• Mild dizziness (rare)
• Skin rash (rare)
• Mild insomnia (rare)
• Constipation or diarrhea (uncommon)

• Pregnancy and breastfeeding (due to phytoestrogenic effects and insufficient safety data)
• Hormone-sensitive conditions including hormone-dependent cancers (breast, uterine, ovarian) due to phytoestrogenic effects
• Individuals with legume allergies (particularly for red clover or Astragalus-derived formononetin)
• Individuals with severe liver disease (due to potential effects on liver enzymes)
• Individuals scheduled for surgery (discontinue 2 weeks before due to potential effects on blood clotting)
• Children and adolescents (due to potential hormonal effects during development)
• Individuals with thyroid disorders (isoflavones may affect thyroid function in susceptible individuals)
• Individuals with estrogen receptor-positive breast cancer or a history of such cancer (due to potential estrogenic effects)
• Individuals with endometriosis or uterine fibroids (conditions that may be estrogen-sensitive)

• Hormone replacement therapy and hormonal contraceptives (may interfere with or enhance effects due to phytoestrogenic activity)
• Tamoxifen and other selective estrogen receptor modulators (SERMs) (potential competitive binding to estrogen receptors)
• Anticoagulant and antiplatelet medications (may enhance antiplatelet effects, potentially increasing bleeding risk)
• Cytochrome P450 substrates (may affect the metabolism of drugs that are substrates for CYP1A2, CYP2C9, and CYP3A4)
• Thyroid medications (isoflavones may affect thyroid function in susceptible individuals)
• Antidiabetic medications (may enhance blood glucose-lowering effects)
• Drugs metabolized by UDP-glucuronosyltransferases (UGTs) (potential competition for these enzymes)
• Drugs with narrow therapeutic indices (warfarin, digoxin, etc.) require careful monitoring due to potential interactions
• Aromatase inhibitors (may counteract the effects of these drugs used in breast cancer treatment)
• Immunosuppressants (potential interaction due to immunomodulatory effects)

Based on preclinical studies and limited clinical data, the upper limit for formononetin supplementation is generally considered to be 30-50 mg daily for most adults. For red clover extracts (typically containing 1-5% formononetin), upper limits of 160-200 mg daily have been used in clinical studies without significant adverse effects. For Astragalus extracts (typically containing 0.5-2% formononetin), upper limits of 1000-1500 mg daily are generally considered safe. Higher doses may increase the risk of hormonal effects and drug interactions, particularly in sensitive individuals.

For general supplementation, doses exceeding these levels are not recommended without medical supervision. The safety profile of formononetin is generally favorable at recommended doses, with most side effects being mild and transient. However, the phytoestrogenic properties and potential for drug interactions necessitate caution, particularly with long-term use or in vulnerable populations. Individuals with hormone-sensitive conditions, thyroid disorders, or those taking medications with potential interactions should consult healthcare providers before use.

The long-term safety of high-dose formononetin supplementation has not been fully established, particularly regarding effects on hormone-sensitive tissues. Some regulatory authorities have expressed caution about long-term, high-dose isoflavone supplementation in certain populations, such as women with a history or family history of breast cancer. The potential for formononetin to act as both an estrogen agonist and antagonist, depending on the tissue, estrogen environment, and dose, adds complexity to safety considerations. This dual activity may be beneficial in some contexts (such as bone health in postmenopausal women) but potentially harmful in others (such as in estrogen-sensitive cancers).

It’s worth noting that most safety data for formononetin comes from studies on plant extracts containing formononetin along with other bioactive compounds, rather than isolated formononetin. Therefore, the specific safety profile of isolated formononetin may differ from that of the plant extracts.

In the United States, formononetin is not approved by the FDA as a drug. Red clover and Astragalus extracts containing formononetin are regulated as dietary supplements under the Dietary Supplement Health and Education Act (DSHEA) of 1994. Manufacturers cannot make specific disease treatment claims but may make general structure/function claims with appropriate disclaimers. The FDA has not evaluated the safety or efficacy of formononetin specifically.

Red clover and Astragalus are generally recognized as safe (GRAS) when used in traditional amounts as herbs or supplements.

Eu: In the European Union, formononetin is not approved as a medicinal product. Red clover and Astragalus extracts are primarily regulated as food supplements under the Food Supplements Directive (2002/46/EC). The European Food Safety Authority (EFSA) has evaluated several health claims related to isoflavones and has generally not found sufficient evidence to approve specific claims, particularly for menopausal symptoms and bone health. EFSA has expressed some caution regarding long-term, high-dose isoflavone supplementation in certain populations, such as women with a history or family history of breast cancer.

Uk: In the United Kingdom, red clover and Astragalus extracts are regulated as food supplements. They are not licensed as medicines and cannot be marketed with medicinal claims. The Medicines and Healthcare products Regulatory Agency (MHRA) has not issued specific guidance on formononetin or isoflavones.

Canada: Health Canada regulates red clover and Astragalus extracts as Natural Health Products (NHPs). Several products containing these extracts have been issued Natural Product Numbers (NPNs), allowing them to be sold with specific health claims, primarily related to traditional use in herbal medicine. Isolated formononetin is not specifically approved as a standalone ingredient.

Australia: The Therapeutic Goods Administration (TGA) regulates red clover and Astragalus extracts as complementary medicines. Several products containing these extracts are listed on the Australian Register of Therapeutic Goods (ARTG). Traditional use claims are permitted with appropriate evidence of traditional use. Formononetin as an isolated compound is not specifically regulated.

China: In China, Astragalus (Huangqi) is officially listed in the Chinese Pharmacopoeia as a traditional Chinese medicine and is approved for various indications including strengthening immunity, promoting tissue regeneration, and increasing vitality. Red clover is not as commonly used in traditional Chinese medicine but may be included in some formulations. Formononetin as an isolated compound is primarily used in research rather than as an approved therapeutic agent.

Japan: In Japan, Astragalus is recognized as a traditional herbal medicine ingredient and is included in several approved Kampo formulations. Red clover extracts are available as dietary supplements but are not as commonly used as in Western countries. Isolated formononetin is not specifically approved as a pharmaceutical but is available as a component of various dietary supplements.

Korea: In South Korea, Astragalus is recognized as a traditional herbal medicine and is included in the Korean Pharmacopoeia. Red clover extracts are available as dietary supplements. Formononetin as an isolated compound is primarily used in research rather than as an approved therapeutic agent.

Medium

Isolated formononetin supplements are rare and typically expensive

when available, costing $1.50-$3.50 per day for effective doses (5-30 mg daily). Standardized red clover extracts (containing formononetin along with other isoflavones) typically cost $0.30-$1.00 per day for basic extracts (40-160 mg daily, corresponding to approximately 0.4-8 mg of formononetin) and $1.00-$2.00 per day for premium, highly standardized formulations. Standardized Astragalus extracts (containing formononetin along with other bioactive compounds) typically cost $0.50-$1.50 per day for basic extracts (500-1000 mg daily, corresponding to approximately 2.5-20 mg of formononetin) and $1.50-$3.00 per day for premium formulations. Enhanced delivery formulations such as liposomes or nanoemulsions typically cost $2.00-$5.00 per day, though

they may offer better bioavailability and potentially superior therapeutic outcomes.

For anticancer support as a complementary approach, formononetin offers moderate value. Preclinical studies have demonstrated significant anticancer effects through multiple mechanisms, including cell cycle arrest, induction of apoptosis, inhibition of angiogenesis, and suppression of metastasis. However, clinical evidence in humans is lacking, and formononetin should only be considered as a complementary approach alongside conventional cancer treatments, not as a standalone treatment. When compared to other natural compounds with anticancer potential, formononetin is moderately priced and offers a unique mechanism of action through its methoxylated isoflavone structure.

For cardiovascular support, formononetin offers good value. Preclinical studies have demonstrated significant cardiovascular benefits, including improved endothelial function, vasodilation, and lipid profile improvements. While clinical evidence in humans is limited, the mechanisms of action are well-established, and the potential benefits align with traditional uses of plants containing formononetin, particularly Astragalus. When compared to other cardiovascular supplements, formononetin (particularly as part of Astragalus extracts) is moderately priced and offers a comprehensive approach to cardiovascular health.

For menopausal symptom relief, formononetin (as part of red clover extracts) offers moderate value. Clinical studies on red clover extracts have shown modest benefits for vasomotor symptoms, though results have been inconsistent. The phytoestrogenic effects of formononetin may contribute to these benefits, though other isoflavones in red clover likely play a significant role as well. When compared to other natural approaches for menopausal symptoms, red clover extracts are moderately priced and offer a reasonable option for women with mild to moderate symptoms.

For bone health, formononetin offers moderate value. Preclinical studies have demonstrated bone-protective effects through modulation of osteoblast and osteoclast activity. While clinical evidence in humans is limited, the mechanisms of action are well-established, and the potential benefits align with the known effects of phytoestrogens on bone metabolism. When compared to other bone health supplements, formononetin is moderately priced and offers a complementary approach that may be particularly beneficial when combined with calcium and vitamin D.

For anti-inflammatory support, formononetin offers good value. Preclinical studies have demonstrated significant anti-inflammatory effects through inhibition of the NF-κB pathway and modulation of inflammatory cytokines. While clinical evidence in humans is limited, the mechanisms of action are well-established, and the potential benefits align with traditional uses of plants containing formononetin. When compared to other anti-inflammatory supplements, formononetin (particularly as part of Astragalus extracts) is moderately priced and offers a comprehensive approach to inflammation.

When comparing the cost-effectiveness of different sources of formononetin: Red clover extracts offer a good balance of cost and standardized dosing for most health applications, particularly menopausal symptom relief and bone health. They typically contain formononetin alongside other isoflavones like biochanin A, providing a comprehensive isoflavone profile. Astragalus extracts are more expensive than red clover extracts but provide formononetin alongside other bioactive compounds like astragalosides, which may offer synergistic effects for certain applications, particularly cardiovascular and immune support. Enhanced delivery formulations such as liposomes or nanoemulsions offer better bioavailability and potentially superior therapeutic outcomes, which may justify their higher cost for specific health conditions.

However, for general health maintenance, standard formulations are likely more cost-effective. Individual variation in formononetin metabolism significantly affects the value proposition of formononetin supplementation. Factors such as gut microbiome composition, diet, and genetic factors can influence the conversion of formononetin to daidzein and potentially to equol, leading to variable responses among individuals.

Pure formononetin has moderate stability, with a typical shelf life of 1-2 years when properly stored. The methoxy group at the C-4′ position may provide some additional stability compared to non-methoxylated isoflavones like daidzein, though specific comparative stability studies are limited. Standardized plant extracts containing formononetin (such as red clover or Astragalus extracts) typically have a shelf life of 1-2 years from the date of manufacture when properly stored. Dried plant material (red clover flowers, Astragalus root) properly stored can maintain acceptable formononetin content for 1-2 years.

Traditional decoctions and liquid extracts have a much shorter shelf life, with optimal potency maintained for only a few days under refrigeration. Enhanced delivery formulations such as liposomes or nanoemulsions generally have shorter shelf lives of 1-2 years, depending on the specific formulation and preservative system.

Store in a cool, dry place away from direct sunlight in airtight, opaque containers. Refrigeration is recommended for liquid formulations and can extend shelf life of extracts containing formononetin. Protect from moisture, heat, oxygen, and light exposure, which can accelerate degradation. For research-grade pure formononetin, storage under inert gas (nitrogen or argon) at -20°C is recommended for maximum stability.

For dried plant material (red clover flowers, Astragalus root), store in airtight containers away from light and moisture to preserve the formononetin content. The addition of antioxidants such as vitamin E or ascorbic acid to formulations can help prevent oxidation and extend shelf life. Enhanced delivery formulations may have specific storage requirements provided by the manufacturer, which should be followed carefully to maintain stability and potency. Avoid repeated freeze-thaw cycles, particularly for liquid formulations, as this can destabilize the product.

For traditional decoctions, prepare fresh and consume within 24-48 hours, storing any remainder in the refrigerator.

Exposure to UV light and sunlight – causes photodegradation of the isoflavone structure, High temperatures (above 30°C) – accelerates decomposition and oxidation, Moisture – promotes hydrolysis and microbial growth, particularly in liquid formulations, Oxygen exposure – leads to oxidation, particularly affecting the hydroxyl group at the C-7 position, pH extremes – formononetin is most stable at slightly acidic to neutral pH (5-7), with increased degradation in strongly acidic or alkaline conditions, Metal ions (particularly iron and copper) – can catalyze oxidation reactions, Enzymatic activity – certain enzymes, particularly those involved in demethylation, can convert formononetin to daidzein, Microbial contamination – particularly relevant for liquid formulations, can lead to degradation of active compounds, Incompatible excipients in formulations – certain preservatives or other ingredients may interact negatively with formononetin, Repeated freeze-thaw cycles – can destabilize enhanced delivery formulations such as liposomes or nanoemulsions

Synthesis Methods

Natural Sources

Quality Considerations

Formononetin itself was not identified or isolated until the modern era, but it is a bioactive constituent of several plants that have been used in traditional medicine systems for thousands of years. While the specific contribution of formononetin to the traditional uses of these plants was unknown to ancient practitioners, it is now recognized as one of the compounds responsible for many of their medicinal properties. Red clover (Trifolium pratense) has a rich history of use in European folk medicine dating back centuries. Traditional herbalists used red clover for various conditions, including respiratory ailments (such as whooping cough, bronchitis, and asthma), skin disorders (including eczema and psoriasis), and as a blood purifier.

It was also traditionally used for women’s health issues, though not specifically for menopausal symptoms as it is often used today. In the 19th century, red clover became part of various herbal formulations for treating cancer and other chronic diseases, most notably as an ingredient in the Hoxsey formula, a controversial alternative cancer treatment. Native American tribes, including the Cherokee, Iroquois, and Ojibwa, also used red clover for respiratory conditions, fever, and as a blood cleanser. Astragalus membranaceus (Huangqi) has an even longer documented history in traditional Chinese medicine (TCM), dating back over 2,000 years.

It was first described in the ‘Shennong Bencao Jing’ (Divine Farmer’s Classic of Materia Medica), compiled around 200-300 CE, where it was classified as a superior herb, indicating its high value and relative safety. In TCM, Astragalus root was traditionally used to strengthen the ‘Qi’ (vital energy), particularly of the spleen and lungs, to strengthen resistance to disease, promote tissue regeneration, and increase vitality. It was commonly used for fatigue, weakness, frequent colds, shortness of breath, and poor appetite. Astragalus was also traditionally used for chronic ulcers, wounds that wouldn’t heal, and chronic infections, applications that align with modern research on formononetin’s wound healing and antimicrobial properties.

The ‘Compendium of Materia Medica’ (Bencao Gangmu), compiled by Li Shizhen in the 16th century during the Ming Dynasty, expanded on the medicinal uses of Astragalus, noting its benefits for the heart, liver, and kidneys. This comprehensive pharmacopeia described various Astragalus preparations and their specific applications in traditional medicine. Ononis spinosa (Spiny restharrow), another plant containing formononetin, has been used in European traditional medicine since ancient times. It was mentioned by Dioscorides in his ‘De Materia Medica’ in the 1st century CE.

Traditionally, it was used primarily as a diuretic and for urinary tract conditions, including kidney stones and urinary tract infections. It was also used for skin conditions, rheumatic complaints, and as a mild laxative. The modern scientific study of formononetin began in the mid-20th century, with its isolation and characterization from various plant sources. The structure of formononetin was elucidated as 7-hydroxy-4′-methoxyisoflavone, distinguishing it from other isoflavones by the methoxy group at the C-4′ position.

Research on formononetin’s biological activities expanded significantly in the 1990s and early 2000s, with studies investigating its phytoestrogenic, anticancer, cardiovascular, and anti-inflammatory properties. The interest in red clover as a source of isoflavones, including formononetin, for menopausal symptom relief grew during this period, leading to the development of various standardized red clover extracts for this purpose. In recent decades, research on formononetin has expanded to include its potential applications in cancer prevention and treatment, cardiovascular health, bone health, neuroprotection, and immunomodulation. The unique structure of formononetin, with its methoxy group at the C-4′ position, continues to be investigated for its distinct biological activities and potential therapeutic applications.

Today, formononetin is recognized as one of the key bioactive compounds in red clover, Astragalus, and other medicinal plants, providing a scientific basis for many of their traditional uses while also revealing new potential therapeutic applications based on its unique pharmacological properties.

Preclinical investigations into formononetin’s anticancer effects, particularly for hormone-dependent cancers such as breast, prostate, and ovarian cancer, Studies on formononetin’s neuroprotective effects in models of neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease, Investigations into formononetin’s cardiovascular benefits, particularly its effects on endothelial function, blood pressure, and lipid metabolism, Research on formononetin’s bone-protective effects, especially for postmenopausal osteoporosis, Studies on formononetin’s anti-inflammatory and immunomodulatory properties for various inflammatory conditions, Investigations into novel delivery systems to enhance formononetin’s bioavailability and targeted delivery, Limited clinical trials evaluating red clover extracts (containing formononetin) for menopausal symptoms and cardiovascular health