Соя изофлавонолы: Эқуол метаболизмі және қасиеттері

Isoflavandiol estrogen metabolized from daidzein

Equol (4',7 isoflavandiol) is an isoflavandiol estrogen metabolized from daidzein, a type of isoflavone found in soybeans and other plant sources, by bacterial flora in the intestines. While endogenous estrogenic hormones such as estradiol are steroids, equol is a nonsteroidal estrogen. Only about 30–50% of people have intestinal bacteria that make equol.

(S) Equol was first isolated from horse urine in 1932, and the name was suggested by this equine connection. Since then, equol has been found in the urine or plasma of many other animal species, although these animals have significant differences in their ability to metabolize daidzein into equol. The ability of (S) equol to play a role in the treatment of estrogen or androgen mediated diseases or disorders was first proposed in 1984.

Equol is a compound that can exist in two mirror image forms known as enantiomers: (S) equol and (R) equol. (S) equol is produced in humans and animals with the ability to metabolize the soy isoflavone daidzein, while (R) equol can be chemically synthesized. The molecular and physical structure of (S) equol is similar to that of the hormone estradiol. (S) Equol preferentially binds estrogen receptor beta.

(S) equol is a nonsteroidal, selective agonist of ERβ (Ki = 16 nM) with 13 fold selectivity for ERβ over ERα. Equol has been found to act as an agonist of the GPER (GPR30).

(S) Equol is a very stable molecule that essentially remains unchanged when digested, and this lack of further metabolism explains its very quick absorption and high bioavailability. When (S) equol is consumed, it is rapidly absorbed and achieves a Tmax (rate of peak plasma concentration) in two to three hours. In comparison, the Tmax of daidzein is 4 to 10 hours because daidzein exists in glycoside (with a glucose side chain) form. The body must convert daidzein to its aglycone form (without the glucose side chain) via removal of the sugar side chain during digestion before it can use daidzein. If consumed directly in aglycone form, daidzein has a Tmax of one to three hours. The percent fractional elimination of (S) equol in urine after oral administration is high and in some adults can reach close to 100 percent. The percent fractional elimination of daidzein is much lower at 30 to 40 percent.

To produce (S) equol after soy consumption, humans must have certain strains of bacteria living within their intestines. while 50 to 60 percent of adults from Japan, Korea, and China are equol producers. Vegetarians have also been reported to be more capable of transforming daidzein into (S) equol. Seaweed and dairy consumption can enhance the production of equol. The ability of a person to produce (S) equol is determined by testing people who have not taken any antibiotics for at least a month. For this standardized test, the individual drinks two 240 milliliter glasses of soy milk or eats a soy food equivalent for three days. The (S) equol concentration in each test subject's urine is determined on day four.

The topical effects of equol as an anti aging substance have been shown in different studies. The effects result from both molecular and structural changes to the skin. Equol can, for instance, lead to an increase in telomere length. As an antioxidant, equol can decrease the aging process by reducing damage caused by reactive oxygen species (ROS). It may also act as a protective anti photoaging substance by inhibiting acute UVA induced lipid peroxidation. In addition, equol may have a positive impact on epigenetic regulation. Equol's phytoestrogenic properties may also affect skin health. Reduction of dark circles and eye wrinkles after treatment with equol has been reported. Equol may also protect skin from damage by pollution due to its anti oxidative and anti inflammatory properties. Each of the enantiomers and the racemic mixture of both enantiomers have different characteristics, bioavailabilities and molecular effects. According to one study, (RS) equol provided the greatest overall improvement in skin health, especially when applied topically. (RS) equol was also reported to reduce symptoms associated with menopausal vaginal atrophy, such as vaginal itching, vaginal dryness and pain with intercourse and cause positive shifts in the vaginal bacterial population, cell composition, and pH. According to animal studies, it has anti androgenic effects and may lead to inhibited 5 alpha reductase as well as lowered dihydrotestosterone (DHT) levels.