10. Steroids

Question 1

What are steroids?

Answer 1

Steroids are the large class of organic compounds with a characteristic molecular structure containing three six membered and one five membered ring (cyclo-pentano-perhydrophenanthrene ring system).

Question 2

What are some steroids distributed throughout nature?

Answer 2

Steroids are widely distributed throughout the nature . They are involved in :
1. Control development of reproductive tracts in humans (estradiols, progesterone, testosterone)
2. Molting in insects (ecdysone).
3. Induction of sexual reproduction in aquatic fungi (antheridiol)
4. Vitamin D precursor (ergosterol)
5. Anti-inflammatory agents (corticosteroids)
6. Anabolic agents (androgens)

Question 3

What is the general reaction for steroid synthesis?

Answer 3

Isopentenyl pyrophosphate —-> Tri-terpenoid squalene (intermediate) —-> Steroid

Question 4

What is the biosynthesis of steroids?

Answer 4

From register

Question 5

What were the first isolated steroids?

Answer 5

The first steroids isolated from nature were a series of C27-C29 alcohols that were found in the lipid fractions of many tissues. These compounds were solids and therefore named sterols from the Greek stereos, meaning solid.

Question 6

What is the most common steroids?

Answer 6

The most widely occurring sterol is cholesterol, It was first isolated from human gallstones and, because it is a constituent of animal cell membranes, it has been found in all animal tissue.

Question 7

Where is cholesterol found?

Answer 7

It is one of the chief constituents of lanolin and therefore is found in many drug products. Until recently, cholesterol was thought to be restricted to the animal kingdom; however, it has now been identified in algae, fungi, ferns and higher plants.

Question 8

What is the health concern associated with cholesterol?

Answer 8

Strongly connected with human health mainly found in atherosclerosis

Question 9

What is ergosterol?

Answer 9

The principle sterol in fungi is ergosterol ,a C28 compound also known as provitamin D2 found in human skin where irradiation from sun catalyzes the formation of vitamin D3.

Question 10

What is beta-sitosterol?

Answer 10

The most common sterol in plants is beta-sitosterol a C29 compound. in general, sitosterols are widely distributed throughout the plant kingdom and may be obtained from wheat germ oil, rye germ oil, corn oil, cottonseed oil, and other seed oils.

Question 11

What is stigmasterol?

Answer 11

Closely related to beta-sitosterol is the stigmasterol, which was first isolated from calabar beans but is also found in soybean oil.

Question 12

What are bile acids?

Answer 12

In liver of human and other animals the side chain of cholesterol is degraded to C24 steroids, These steroids are collected in the bile; therefore, they are referred to as the bile acids.

Question 13

What are the primary bile acids?

Answer 13

The primary bile acids formed in the human liver are cholic acid and chenodesoxycholic acid.

Question 14

What are the secondary bile acids?

Answer 14

Desoxycholic acid and lithocholic acid ( secondary bile acids ) are also found in substantial amounts in mammalian bile; however, they are not formed in the liver.

Question 15

How are bile acids produced and occur?

Answer 15

They are produced in the intestinal tract by the action of microorganisms on cholic acid to form desoxycholic acid and on cheno-desoxycholic acid to form lithocholic acid .
Generally the bile acids are not occur in free state but are conjugated through a peptide to either glycine or taurine. The conjugated bile acids are discharged into duodenum where they acts as emulsifying agent to aid in the intestinal absorption of fats.

Question 16

What are bile salts?

Answer 16

Bile salts are the sodium salts of conjugated acids and are the principle constituents of ox bile extracts.

Question 17

What is ox bile extract?

Answer 17

Ox bile extract is prepared by partial evaporation of fresh ox bile, precipitation of the mucus and albuminous matter with alcohol, filtering, washing, and evaporating the combined filtrates to dryness at a temperature not exceeding 80° C. It contains an amount of the sodium salts of glycocholic acid and taurocholic acid equivalent to not less than 45% of cholic acid.

Question 18

What is chenodiol, it’s use and adverse effect?

Answer 18

Chenodiol example of bile acid suppresses hepatic synthesis of both cholesterol and cholic acid this contributes to biliary cholesterol desaturation and dissolution of cholesterol gallstones. The recommended dosage of chenodiol is 13-16mg/kg/day. the duration of treatment may be 2 years and the stones may recur when therapy is discontinued.
The most common adverse effects associated with the chenodiol are elevated liver enzyme levels and diarrhea.

Question 19

How is chenodiol extracted?

Answer 19

The chenodiol is extracted mainly by carbon dioxide supercritical extraction method first of all saponifying the bile adjust the pH value to 3-4 by using dil. HCl filtering the paste drying the filtrate to obtain the bile acid crude product.
Crushing the product in carbon dioxide supercritical extraction kettle including carbon dioxide gas in acetone heat at temperature of 58-62 degree Celsius then cooling the product , and extracting the product for 1 hour , collecting the precipitates and then crystallizing the product by using chloroform and finally refine it

Question 20

What are the classes of steroid hormones?

Answer 20

The steroid hormones can be divided into 2 classes, the sex hormones and the adrenocortical hormones

Question 21

What are sex hormones?

Answer 21

The former are produced primarily, in the gonads and mediate the growth, development, maintenance, and function of the reproductive tract and the accessory sex organs. These hormones fall into 3 chemically and physiologically distinct categories: the estrogens and progestins, which regulate various functions of the female reproductive tract, and the androgens, which stimulate the development of the male reproductive organs.

Question 22

What are the two classes of adrenocortical hormones?

Answer 22

The adrenocortical hormones are produced by the outer cortical portion of the adrenal glands, and they are divided into 2 classes, depending on their biologic activity. The hormones that principally affect the excretion of fluid and electrolytes, with a subsequent sodium retention, are called mineralocorticoids those that affect intermediary metabolism are called glucocorticoids.

Question 23

How are steroid hormones produced?

Answer 23

The production of steroid hormones in the body is initiated by the releasing factors of the hypothalamus, which travel to the anterior lobe of the pituitary gland where they induce the release of tropic hormones into the blood When stimulated by the appropriate tropic hormone, steroids are synthesized at the target Site, either the adrenal cortex or the gonads

Question 24

How are steroid hormones regulated?

Answer 24

Steroid level in the blood is held in balance by a mechanism of feedback regulation that is mediated through the hypothalamus. When excess active steroid is in the blood that reaches the hypothalamus, the production of the hypothalamic releasing factors is stopped .

Question 25

What is the mechanism of action of steroid hormones?

Answer 25

The steroid hormones do not act through an increase in cyclic AMP but rather through a stimulation of protein synthesis. A possible explanation of this mechanism is that the steroid binds with the specific receptor protein in the cytoplasm of the target cell. This complex enters the nucleus, where it is bound to the chromosome through a specific acceptor protein associated with chromatin. The interaction of steroid, of cytoplasm receptor protein, and of the chromosomal receptor protein may lead to a depression ( decrease or inhibit the expression of gene ) of a segment of chromosome, which would result in the increased production of a particular enzyme protein.

Question 26

Which are the gluco-corticoids?

Answer 26

Cortisone and hydrocortisone or cortisol constitute the majority of the hormones that regulate protein and carbohydrate metabolism, they have been referred to as glucocorticoids.

Question 27

What is the use of glucocorticoids?

Answer 27

Cortisone is used to treat rheumatoid arhthritis, addison’s disease the usual dose given orally is 25-300mg and intramuscularly is 20-300mg a day.
The usual oral dose of cortisol is 20-240 mg.

Question 28

What are mineralocorticoids?

Answer 28

Aldosterones and desoxycorticosterone are known as mineralocorticoids. Aldosterone is the principal adrenal steroid that regulates sodium, potassium and water balance in the organism

Question 29

What is dexcorticosterone?

Answer 29

A steroid hormone It was synthesized from stigmasterol
A mineralocorticoid restores a balance of sodium and potassium in body fluids and to restore kidney function in cortical deficiency.
The hydroxyl function group at C-21 is esterified with acetic acid

Question 30

Which dose of dexcorticosterone is used?

Answer 30

effective when given orally or I/M.
The usual dose is 1-5 mg daily administered intramuscularly or subcutaneously.

Question 31

What is testosterone?

Answer 31

Testosterone is the primary male sex hormone and an anabolic steroid

Question 32

What is the role of testosterone in males?

Answer 32

In male humans, testosterone plays a key role in the development of male reproductive tissues such as the testis and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair.

Question 33

What is the role of testosterone in females?

Answer 33

Small amounts of testosterone are also produced in a woman’s ovaries and adrenal system

Question 34

What is the use and dosage of testosterone?

Answer 34

Testosterone injection is used in men and boys to treat conditions caused by a lack of this hormone, such as delayed puberty, impotence, or other hormonal imbalances the usual dose given intramuscularly is 25mg.

Question 35

What is the role of estrogen?

Answer 35

Develop and maintain secondary female sex characters
Develop and maintain uterus and vagina

Question 36

What is the use of estrogen and its dose?

Answer 36

Act as growth hormone for uterine smooth muscle cells during pregnancy the usual dose for menopausal symptoms orally is 625ug - 1.25mg orally.

Question 37

What is the use of progesterone?

Answer 37

This hormone is used in treatment of amenorrhea, dysmenorrhea, functional uterine bleeding, habitual abortion.
suppresses ovulation during pregnancy.

Question 38

What is ecdysone?

Answer 38

Ecdysone is a steroid hormone that controls molting in insects and other arhropods. It also regulated metamorphosis and reproduction.

Question 39

What is the site of ecdysone synthesis?

Answer 39

The site of ecdysone synthesis in insects nymph or larvae is the prothoracic gland in response to PTTH signaling ( prothoracicotropic hormone ) a neuropeptide from brain stimulate the secretion of ecdysone, while in adults the majority of ecdysone is synthesized in the follicle cell of ovaries. Ecdysone is secreted into the hemolymph and absorbed by fat body cells where it is converted into 20E (20-hydroxyecdysone) by enzyme ecdysone mono-oxygenase,. The 20E product is then released into hemolymph where it travels to targeted tissues

Question 40

What is the use of ecdysone?

Answer 40

It controls molting other physiological process including wandering behavior of larvae ,development of complex neuronal networks and oocyte maturation in adult female insects.
In adult female mosquito 20E is required for the completion of gonotrophic cycle and production of viable eggs

Question 41

What are withanolides?

Answer 41

Withanolides are a group of at least 300 naturally occurring steroids built on an ergostane skeleton. They occur as secondary metabolites primarily in genera of the Nightshade family.

Question 42

What is the structure of withanolides?

Answer 42

Structurally, withanolides consist of a steroid backbone bound to a lactone or one of its derivatives; they are produced via oxidation of steroids. they may act as a deterrent for feeding insect larvae and other herbivores.

Question 43

Which was the first withanolide to be isolated?

Answer 43

Withaferin A the first withanolide to be isolated, was found in winter cherry, In the withania somnifera ( Ashwagandha ) plant, the withanolide, Withaferin A, is present in the leaves, roots

Question 44

How are withanolides extracted?

Answer 44

Take roots because they contain high concentration of withanolides dry to remove moisture roots are grounded and extraction is carried out by using solvent mixture ( 60% alcohol ,40%water ) then filter the solvent extract to separate the liquid containing withanolides from solid plant material concentrate the filtrate and obtain the withanolides by precipitation or crystallization after it dry and purify.

Question 45

What are the medicinal uses of this plant?

Answer 45

This medicinal plant has been found to have anti-epileptic, anti-inflammatory, anti-arthritic, anti-depressant, anti-coagulant, anti-oxidant, anti-diabetic, anti-pyretic effects.

Question 46

What are steroidal sapogenins?

Answer 46

Sapogenins are aglycones part of saponins, a large family of natural products. Sapogenins contain steroid or other triterpene frameworks as their key organic feature.

Question 47

Where are steroidal sapogenins found?

Answer 47

Steroidal sapogenins are commonly found in plants, especially in the family Solanaceae (nightshade family), Dioscoreaceae (yam family), and Agavaceae (agave family).Some well-known sources of steroidal sapogenins include wild yam (Dioscorea species), tribulus terrestris, fenugreek, and certain species of Solanum

Question 48

What are the uses of steroidal sapogenins?

Answer 48

biological activities, including anti-inflammatory, antioxidant, and immune-modulating properties. Some steroidal sapogenins may also have potential cytotoxic effects on certain cancer cells, making them of interest in cancer research.
Extracts from plants containing steroidal sapogenins have been traditionally used in herbal medicine for various purposes, including hormonal balance, joint health, and as an aphrodisiac.

Question 49

How is extraction of steroidal sapogenins done?

Answer 49

Extraction is done by soaking the plant material in 95% ethanol overnight then filter the solvent extract to separate the liquid containing withanolides from solid plant material concentrate the filtrate and obtain the withanolides by precipitation or crystallization after it dry and purify.

Question 50

What is disogenin?

Answer 50

Diosgenin, a common steroidal sapogenin found in wild yam, has been used as a starting material for the synthesis of steroids, including progesterone and cortisone.