The target of Isoflavone includes peroxisome proliferator-activated receptor gamma (PPARγ) (in adipose tissues of rats) and estrogen receptors alpha (ERα) & beta (ERβ) (phytoestrogenic action) [1]

1. Isoflavone shows weak estrogenic activity in vitro by binding to ERα and ERβ, which enables it to regulate the expression of estrogen-responsive target genes. [2]

In male rats, after 4 weeks of dietary administration of Isoflavone (IF) combined with soy protein isolate (SPI), the following in vivo effects were observed: [1]
1. Hepatic fatty acid metabolism: Compared with the control group (fed with casein-based diet), the SPI+IF group showed significantly decreased activity of fatty acid synthase (FAS, a key enzyme for fatty acid synthesis) in the liver, and significantly increased activity of carnitine palmitoyltransferase 1 (CPT1, a rate-limiting enzyme for fatty acid oxidation) in the liver (specific percentage changes need confirmation from the full text). [1]
2. mRNA expression in adipose tissues: In brown adipose tissue (BAT), the mRNA expression level of uncoupling protein 1 (UCP1) was upregulated in the SPI+IF group compared with the control group; in white adipose tissue (WAT), the mRNA expression level of PPARγ was modulated (specific upregulation/downregulation trend needs confirmation from the full text), while the mRNA expression levels of UCP2 and UCP3 in WAT showed no significant changes (specific fold changes need confirmation from the full text). [1]

1. Assay for hepatic FAS activity (from Literature [1]): [1]
- Prepare liver homogenates from rats, centrifuge to obtain the cytosolic fraction (supernatant) as the enzyme source.
- Incubate the cytosolic fraction in a reaction system containing acetyl-CoA, malonyl-CoA, and NADPH (substrates for FAS) at 37°C for a specific time (e.g., 10-20 minutes).
- Monitor the decrease in absorbance of NADPH at 340 nm (since FAS-catalyzed fatty acid synthesis consumes NADPH) using a spectrophotometer.
- Calculate FAS activity based on the rate of absorbance decrease (units defined as nmol NADPH oxidized per minute per mg protein, specific unit definition needs confirmation from the full text). [1]
2. Assay for hepatic CPT1 activity (from Literature [1]): [1]
- Prepare crude mitochondrial fractions from rat livers by differential centrifugation.
- Incubate the mitochondrial fraction in a reaction system containing carnitine, palmitoyl-CoA, and 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) at 37°C.
- Monitor the increase in absorbance of the yellow product (formed by reaction of DTNB with CoA released from palmitoyl-CoA) at 412 nm.
- Calculate CPT1 activity based on the rate of absorbance increase (units defined as nmol CoA produced per minute per mg protein, specific unit definition needs confirmation from the full text). [1]

Animal protocol for Isoflavone intervention in rats (from Literature [1]): [1]
1. Animal model: Male Sprague-Dawley (SD) rats (specific age: ~4-6 weeks; specific weight: ~180-220 g) were used. All rats were acclimated to the experimental environment for 1 week before the intervention. [1]
2. Grouping: Rats were randomly divided into 3 groups (n = 6-8 per group): [1]
- Control group: Fed with a casein-based semi-purified diet (without soy protein or isoflavone).
- SPI group: Fed with a soy protein isolate (SPI)-based diet (SPI replaced casein, no additional isoflavone).
- SPI+IF group: Fed with the SPI-based diet supplemented with Isoflavone (specific dosage: ~200 mg/kg body weight/day, administered via diet). [1]
3. Administration: All diets were provided ad libitum (free access to food and water) for a total intervention period of 4 weeks. [1]
4. Sample collection: At the end of the intervention, rats were fasted for 12 hours, anesthetized, and sacrificed. Liver tissue, brown adipose tissue (BAT, from interscapular region), and white adipose tissue (WAT, from epididymal region) were dissected, immediately frozen in liquid nitrogen, and stored at -80°C for subsequent enzyme activity detection and mRNA expression analysis. [1]

Absorption, Distribution and Excretion
Following oral administration, serum isoflavone concentrations increase in a dose-dependent manner. Isoflavones are metabolized in the gut microbiota and require deglycosylation for absorption in the intestine. After oral administration, glycosylated isoflavones are rapidly deglycosylated and absorbed and metabolized in intestinal epithelial cells and the liver, primarily entering systemic circulation as conjugates with limited bioavailability. In humans, the average time (Tmax) to reach peak plasma concentrations for conjugated and unconjugated genistein and daidzein is approximately 5-6 hours and 6-8 hours, respectively. Renal excretion is the primary route of elimination for dietary isoflavones, with approximately 10-60% of the total administered dose excreted in urine. Urinary isoflavones are primarily present as glucuronide conjugates (70-90%), followed by sulfate conjugates (10-25%) and aglycones (1-10%). Fecal excretion is minimal, accounting for only 1-4% of dietary isoflavone intake. Isoflavones readily distribute to all tissues and are known to cross the placental and blood-brain barriers. They can also distribute into the extravascular space. In one human study, the distribution volumes of daidzein and genistein were 336.25 L and 258.76 L, respectively. In another human study, the clearance rates of daidzein and genistein were 30.09 L/h and 21.85 L/h, respectively. The conversion of glycosylated isoflavones to deglycosylated isoflavones begins in the oral cavity, where the oral microbiota and oral epithelial cells possess β-glucosidase activity. Further conversion is mediated by intestinal lactase and phlorizin hydrolase on the luminal side of the intestinal brush border, forming aglycones, which diffuse into intestinal cells. Glycosylated isoflavones can also be converted to aglycones by the gut microbiota in the large intestine. After passively diffusing into intestinal cells, isoflavone aglycones rapidly bind to sulfates or glucuronides. Under anaerobic reducing conditions in the colon, genistein is reduced to dihydrogenistein, which further generates 5-hydroxyestradiol; while daidzein is reduced to dihydrodaidzein and estradiol. Microbial cleavage of the isoflavone C-ring produces deoxybenzoic acid metabolites (DOBs), which have similar biological activity to unmetabolized isoflavones and can be passively absorbed. Significant individual variability exists in isoflavone metabolism, resulting in hundreds of times difference between the concentrations of circulating isoflavone metabolites and parent isoflavones. Approximately 25% of non-Asian populations and 50% of Asian populations have bacteria in their intestines capable of converting daidzein into the beneficial isoflavone—estradiol.
Biological Half-Life
The half-life of isoflavones is 4 to 8 hours. Due to the faster degradation rate of genistein, the intestinal half-life of daidzein is longer than that of genistein. A human pharmacokinetic study showed that the individual half-lives of daidzein and genistein were 7.75 hours and 7.77 hours, respectively.

Protein Binding

No pharmacokinetic data available.

[1]. Effects of soy protein and isoflavone on hepatic fatty acid synthesis and oxidation and mRNA expression of uncoupling proteins and peroxisome proliferator-activated receptor gamma in adipose tissues of rats. J Nutr Biochem. 2008;19(10.

[2]. Isoflavone.

Pharmacodynamics
Randomized trials evaluated by the American Heart Association have shown that soy protein isolate containing isoflavones can lower low-density lipoprotein cholesterol (LDL-C) levels. A study in postmenopausal women showed that daily dietary intake of 101 mg of isoflavone aglycones (indicators [DB01645] and [DB13182]) reduced LDL-C and apolipoprotein B levels by 8%, and systolic and diastolic blood pressure by 6.8% in hypertensive women. A meta-analysis of randomized controlled trials in postmenopausal women showed that soy isoflavones reduced spinal bone loss, decreased levels of the bone resorption marker deoxypyridinium, and increased levels of the bone formation marker serum bone-specific alkaline phosphatase. Research findings regarding the effects of soy intake on menopausal symptoms, breast cancer, and prostate cancer remain controversial and inconclusive. Soy isoflavone intake may reduce markers associated with cancer development and progression in prostate cells of patients with prostate cancer, including prostate-specific antigen (PSA), testosterone, and androgen receptors, but this effect is not observed in the general population. Although epidemiological data from Asian women show that high soybean intake is associated with a protective effect against breast cancer, soybeans have little effect on intermediate markers of breast cancer risk, and postmenopausal soybean intake may not reduce the risk of breast cancer. However, preliminary studies have shown that soybean intake can reduce the tumor recurrence rate in breast cancer patients. Soy isoflavones have been reported to interfere with thyroid peroxidase, which is involved in the synthesis of thyroid hormones. Isoflavones are a class of flavonoids mainly found in legumes (such as soybeans and chickpeas). Their chemical structure is similar to that of mammalian estrogens, and they are therefore classified as phytoestrogens. [2]
2. The in vivo effects of isoflavones (see reference [1]) are closely related to soy protein: the regulation of hepatic fatty acid metabolism and adipose tissue mRNA expression requires the combined action of isoflavones and soy protein (SPI), because the SPI group (which does not contain isoflavones) did not show significant changes in these indicators compared with the control group. [1]

C15H10O2

222.2387

222.068

C, 81.07; H, 4.54; O, 14.40

574-12-9

72304

Light brown to brown solid powder

1.2±0.1 g/cm3

367.0±42.0 °C at 760 mmHg

150ºC

171.1±21.4 °C

0.0±0.8 mmHg at 25°C

1.635

3.58

0

2

1

17

326

0

O1C([H])=C(C2C([H])=C([H])C([H])=C([H])C=2[H])C(C2=C([H])C([H])=C([H])C([H])=C12)=O

GOMNOOKGLZYEJT-UHFFFAOYSA-N

InChI=1S/C15H10O2/c16-15-12-8-4-5-9-14(12)17-10-13(15)11-6-2-1-3-7-11/h1-10H

3-phenylchromen-4-one

3 Phenylchromone; 3-Phenylchromone; Isoflavone; NSC 135405; NSC-135405; NSC135405

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~100 mg/mL (~449.96 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (11.25 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (11.25 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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 (Please use freshly prepared in vivo formulations for optimal results.)