Diosgenin, a steroid sapogenin, is the product of hydrolysis by acids, strong bases, or enzymes of saponins, extracted from the tubers of Dioscorea

Dioscorea

Dioscorea is a genus of over 600 species of flowering plants in the family Dioscoreaceae, native throughout the tropical and warm temperate regions of the world. The vast majority of the species are tropical, with only a few species extending into temperate climates...

 wild yam

Wild yam

Dioscorea villosa is a species of a twining tuberous vine that is native to and found growing wild in North America. Its fame is based on its steroid-like saponins which can be chemically converted to progesterone ; and cortisone....

, such as the Kokoro

Kokoro (vegetable)

Kokoro is a variety of Dioscorea rotundata yam that are abundant in Western Nigeria, Benin and Togo. Their common use by ethnic groups such as the Yoruba that put heavy pressure on the cultivated land suggest that they have been cultivated since ancient times, since they are the only type of yam...

. The sugar-free (aglycone

Aglycone

An aglycone is the non-sugar compound remaining after replacement of the glycosyl group from a glycoside by a hydrogen atom. The spelling aglycon is sometimes encountered .Classes of phytochemicals found in the aglycone and glycosides forms :...

), diosgenin is used for the commercial synthesis of cortisone

Cortisone

Cortisone is a steroid hormone. It is one of the main hormones released by the adrenal gland in response to stress. In chemical structure, it is a corticosteroid closely related to corticosterone. It is used to treat a variety of ailments and can be administered intravenously, orally,...

, pregnenolone

Pregnenolone

Pregnenolone is a steroid hormone involved in the steroidogenesis of progesterone, mineralocorticoids, glucocorticoids, androgens, and estrogens. As such it is a prohormone. Pregnenolone sulfate is a GABAA antagonist and increases neurogenesis in the hippocampus.-Chemistry:Like other steroids,...

, progesterone

Progesterone

Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...

, and other steroid products.

Sources

It is present in Costus speciosus

Costus speciosus

Costus speciosus or Cheilocostus speciosus or crape ginger is possibly the best known cultivated species of the genus Costus. This plant is native to southeast Asia, especially on the Greater Sunda Islands in Indonesia...

, Smilax menispermoidea, species of Paris, Trigonella

Trigonella

Trigonella is a genus from the family Fabaceae. The best known member is the herb Fenugreek.-Species:The genus Trigonella currently has 37 recognized species:* Trigonella anguina Delile* Trigonella arabica Delile...

, and Trillium

Trillium

Trillium is a genus of about 40–50 species of spring ephemeral perennials, native to temperate regions of North America and Asia....

, and many species of Dioscorea

Dioscorea

Dioscorea is a genus of over 600 species of flowering plants in the family Dioscoreaceae, native throughout the tropical and warm temperate regions of the world. The vast majority of the species are tropical, with only a few species extending into temperate climates...

 - D. althaeoides, colletti, futschauensis, gracillima, hispida, hypoglauca, mexicana

Dioscorea mexicana

Mexican yam or barbasco de placa is a species of yam in the genus Dioscorea. It ranges from the state of Veracruz in Mexico south to Panama. It is notable for its production of diosgenin, which is a precursor for the synthesis of hormones such as progesterone. Russell Marker developed the...

' nipponica, panthaica, parviflora, septemloba, and zingiberensis.

Clinical uses

Diosgenin is the precursor for the semisynthesis of progesterone which in turn was used in early combined oral contraceptive pills. The unmodified steroid has estrogenic activity and can reduce the level of serum

Blood serum

In blood, the serum is the component that is neither a blood cell nor a clotting factor; it is the blood plasma with the fibrinogens removed...

 cholesterol

Cholesterol

Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

.

Chemistry

The glycoside

Glycoside

In chemistry, a glycoside is a molecule in which a sugar is bound to a non-carbohydrate moiety, usually a small organic molecule. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. These can be activated by enzyme...

 dioscin from the Mexican wild yam root, Dioscorea

Dioscorea

Dioscorea is a genus of over 600 species of flowering plants in the family Dioscoreaceae, native throughout the tropical and warm temperate regions of the world. The vast majority of the species are tropical, with only a few species extending into temperate climates...

, constituted the first plant source for steroid drugs.

Hydrolysis of this saponin

Saponin

Saponins are a class of chemical compounds, one of many secondary metabolites found in natural sources, with saponins found in particular abundance in various plant species...

 leads to scission of the trisaccharide at the 3-position and the formation of the aglycone

Aglycone

An aglycone is the non-sugar compound remaining after replacement of the glycosyl group from a glycoside by a hydrogen atom. The spelling aglycon is sometimes encountered .Classes of phytochemicals found in the aglycone and glycosides forms :...

, diosgenin. Treatment of this acetal

Acetal

An acetal is a molecule with two single-bonded oxygen atoms attached to the same carbon atom.Traditional usages distinguish ketals from acetals...

 with hot acetic anhydride

Acetic anhydride

Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula 2O. Commonly abbreviated Ac2O, it is the simplest isolatable acid anhydride and is a widely used reagent in organic synthesis...

 in the presence of toluenesulfonic acid leads initially to protonation of one of the acetal oxygens followed by elimination

Elimination reaction

An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one or two-step mechanism...

 to form an enol ether

Enol ether

An enol ether is an alkene with an alkoxy substituent. The general structure is R_1R_2C=CR_3-O-R_4 with R an alkyl or an aryl group. Enol ethers and enamines are so-called activated alkenes or electron rich alkenes because the oxygen atom donates electrons to the double bond by forming a resonance...

. Oxidation by means of chromium trioxide

Chromium trioxide

Chromium trioxide is the inorganic compound with the formula CrO3. It is the acidic anhydride of chromic acid, and is sometimes marketed under the same name.This compound is a dark-red/orange brown solid, which dissolves in water concomitant with hydrolysis...

 leads to preferential attack at the electron-rich enol ether double bond. In effect, this transformation converts the side chain at C-17 in diosgenin to the acetyl group required for many steroid drugs. Heating that intermediate in with alcoholic sodium hydroxide leads to the elimination of the ester grouping beta to the ketone; there is thus obtained 16-dehydropregnenolone acetate. The presence of the olefin at C-17 allows ready entry to C-19 androstane

Androstane

Androstane is a steroid nucleus. Androstane can exist as either of two isomers, known as 5α-androstane and 5β-androstane....

s and provides the necessary function for the synthesis of potent C-16- and C-16,17-substituted corticosteroid

Corticosteroid

Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...

s.