What Does Apigenin Do In The Body?

What Is Apigenin 99?

Apigenin (AP) belongs to flavonoids and is widely found in fruits, vegetables, beans, and tea, among which celery has the highest content. The chemical structure of apigenin is 4', 5, 7-trihydroxyflavone, and the three hydroxyl groups and C2C3 double bonds at the 4', 5, and 7 positions determine its unique pharmacological effects and biological characteristics. In the prevention of high blood pressure, apigenin can inhibit the vasoconstriction caused by phenylephrine and high K+ ions, but has a weaker relaxing effect on vasoconstriction caused by phorbol. In addition, apigenin may not affect protein kinase C-mediated vasoconstriction. Instead, it induces the production of certain endothelial cell-derived stimulators, thereby producing endothelial cell-dependent vascular relaxation. Studies have found that apigenin also has antioxidant effects, estrogen-like effects, antibacterial effects, reduction of multidrug resistance of tumor cells, and anti-mutation effects. Therefore, the effect of apigenin on health has attracted widespread attention and has become a hot spot in nutrition and pharmacology research.

 

Apigenin In Chamomile Extract

Apigenin is extracted from the dried flowers of chamomile, which is a high-purity cosmetic-grade raw material. As a flavonoid compound, apigenin has various biological activities.

Chamomile (Matricaria recutita L.), also known as mother chrysanthemum, is an annual herb. Its wild plants were first found in Europe, North America and northern Africa. The place of origin is western Europe, and it is suitable for growing in milder sandy soil. Now there are a large number of artificial cultivation in Xinjiang, my country, and a small amount of distribution in Hunan, Sichuan and other places. Chamomile is rich in carbohydrates and proteins. Chamomile contains more than 120 kinds of secondary metabolites, including 36 kinds of flavonoids and 28 kinds of terpenoids. The content of flavonoids in chamomile is about 0.5. The main flavonoids are apigenin, luteolin, quercetin and so on. As a kind of herbal medicine, chamomile has good biological activity, and chamomile extract has great utilization value in the fields of medicine and cosmetics.

What Does Apigenin Extract Do In The Body?

Absorption and distribution of apigenin from chamomile in the body

Flavonoids combine with sugars in plants to form glycosides, and a small part exists in the form of aglycones. The absorption and bioavailability of flavonoids may be affected by the type of glycosides. Flavonoid glycosides (apigetrin) and aglycone (apigenin) have different degrees of absorption in the body. Yan Liu et al. found that apigenin glucoside seems to have low permeability in the study of rat intestinal gavage model, while apigenin was quickly absorbed. absorb. The reasons for the low absorption of apigenin glucoside are not fully understood, but possible mechanisms include:

(1) Very low passive diffusion;

(2) Low glucose carrier hydrolyzate;

(3) The efflux of intestinal efflux carriers such as P-glycoprotein (MDR1) is related to multidrug resistance-related proteins (MRPs).

Darina Romanová; etc., when measuring apigenin in rat plasma, injected apigenin intravenously at a dose of 25 mg/(kg bw), detected the concentration of apigenin at 10, 15, 30, 45, 60, and 90 min respectively, and injected apigenin After 30 minutes, the plasma apigenin content of male and female rats reached the highest concentration, which were (30.953±11.284), (26.218±19.366) µmol/L, and gradually decreased after 45 minutes. At 60 and 90 minutes, no celery was detected in the plasma. white. The experimental results showed that apigenin reached a relatively high level in rat plasma, which is very important for exerting its biological effects. Nielsen and Dragsted gave subjects oral celery supplement (MJ) containing 3.37~4.49mg/MJ apigenin), and detected the content of apigenin in the subjects' urine samples. During the celery intervention period, more apigenin was excreted in the test group than in the control group. After statistical testing, the difference between the two groups (20.7-5 723.3, 0-1 571.7 µg/24h) was statistically significant (P<0.05). Chen et al[11] conducted a flavonoid absorption test with a four-site perfusion mouse model, and concluded that the maximum amount of apigenin conjugates excreted in the intestine was 61nmol/L for 30min; the absorption rate of apigenin in the colon was the highest (40%), while in the ileum lowest (21%). Hellen Meyer et al. administered celery 2g/(kg bw) to the subjects [equivalent to (65.8±15.5) μmol apigenin, collected blood samples and 24h urine samples, and then detected the apigenin content in plasma, urine samples, and red blood cells. The results showed that apigenin was detected in plasma, urine samples and red blood cells, indicating that a small amount of apigenin supplied through food reached the human circulatory system.

Metabolism and excretion of apigenin in the body

The main organs for the body to metabolize flavonoids are the liver and the digestive tract. Most flavonoids taken orally are metabolized and absorbed in the gastrointestinal tract, and the components entering the body are their metabolites rather than their original components; for flavonoids injected intravenously, biotransformation reactions mainly occur in the liver . Nielsen et al. found that the metabolites of apigenin were glucuronidated and sulfated conjugates of apigenin, while apigenin was not detected in the human urine samples of the apigenin intervention study. The same result was also detected in mouse urine. Gritfth et al administered apigenin to rats to study the intestinal bacterial metabolites and metabolic pathways of apigenin. The results showed that p-hydroxyphenylpropionic acid, p-hydroxycinnamic acid and p-hydroxybenzoic acid were detected in urine. Augustin et al. studied the metabolism of apigenin in rats through the perfused rat liver model, and no phase I metabolites were detected. On the contrary, 2 monoglucuronide conjugates and a sulfated conjugate of apigenin were detected. In addition, Two new derivatives were also isolated and identified: diglucuronic acid conjugates and glucuronic acid sulfate conjugates. The results of this experiment have important reference value for the study of the metabolism of apigenin.

The main excretion routes of flavonoids including apigenin are renal excretion and bile excretion. After Nielsen gave the subjects oral celery supplements (containing 3.37~4.49mg/MJ apigenin), the content of apigenin in the subjects' urine samples was detected. The excretion rate in urine was estimated to be (0.58±0.16)% of the intake. Hellen Meyer et al. administered 2 g of celery (equivalent to 65.8±15.5 μmol apigenin) to the subjects, and collected 24-hour urine samples. The apigenin content detected in the urine samples was equivalent to (0.22±0.16)% of the intake dose. Chen et al. used a four-site perfusion mouse model to conduct an excretion test of apigenin II phase conjugates. The results showed that 33% of the conjugate was excreted from the intestine, and 7% of the conjugate was excreted from the bile.

Bioavailability of chamomile extract apigenin in human body

The chemical structure of flavonoids determines their rate of intestinal absorption and the identity of metabolites circulating in plasma. Studies on the bioavailability of flavonoids in humans have found that the main part (75%~99%) of ingested flavonoids cannot be detected in urine, which may mean that the substance is not absorbed through the intestinal barrier, or absorbed in the bile and excreted, or metabolized by gut microbes and tissues; and flavonoids detected in urine had been converted from one flavonoid to another. In general, only small amounts of flavonoids absorbed in the intestine are available in the human body. The same bioavailability studies have shown that if the amount of flavonoids ingested by the human body does not exceed the amount of daily diet, the concentration of the prototype flavonoids detected in human plasma rarely exceeds 1 μmol/L. The content of apigenin in the daily diet is very low. In 25 male subjects in Finland, it was estimated that the average daily intake of flavonoids was 10mg, and apigenin only accounted for 0.5%. Among the 725 investigators in Hungary (521 children; 204 adults), the average intake of apigenin in children and adults was estimated to be (0.57±0.71) and (0.85±0.87) mg/day, respectively. Hellen Meyer et al. conducted a study on the bioavailability of apigenin in celery in the human body. Eleven healthy volunteers (5 females and 6 males) took celery at 2g/(kg bw) [equivalent to containing (65.8± 15.5) µmol apigenin], blood samples were collected at 0, 4, 6, 7, 8, 9, 10, 11 and 28 hours after oral administration, and a 24-hour urine sample was collected. It was found that the concentration of apigenin in plasma was the highest after (7.2±1.3) hours of ingestion, and the average value was (127±81) nmol/L. For the subjects, the concentration of apigenin in plasma increased after ingesting celery, It fell below the detection limit of the method (2.3nmol/L) within 28h; the average content of apigenin in the 24h urine sample was (144±110)nmol/24h, and apigenin was also detected in red blood cells, but did not reflect the dose- Response relationship. Janssen K et al [18] administered 5 g of celery (containing 84 mg apigenin) to subjects orally for 7 days in a randomized crossover experiment, and no apigenin was detected in plasma. The researchers speculated that apigenin may not be absorbed in the intestine. Compared with the experimental results of Hellen Meyer et al., this speculation may not be true, because the detection limit of the assay method used is high (1.1 μmol/L), which may result in the detection of low levels of apigenin in plasma.

Polyphenols can directly bind to food components such as proteins and polysaccharides, and this binding can also affect their absorption; in addition, more dietary factors (pH, intestinal permeability, bile excretion, transit time, etc.) Can affect the absorption of polyphenols; enzymes and transporters involved in the absorption and metabolism of polyphenols can also be induced or inhibited by the presence of certain micronutrients or exogenous substances. The literature has reported the effect of food base components on the bioavailability of polyphenols. However, there are few reports on the effects of other nutrients on the bioavailability of apigenin.

Determination of the actual bioavailability of apigenin metabolites in tissues is more important than determination of their plasma concentrations, because some tissue-specific uptake and clearance of metabolites or tissue metabolism due to intracellular metabolic mechanisms The nature of the metabolites may differ from the metabolites in the blood. Whether plasma concentrations are accurate biomarkers of exposure remains to be studied.