Catalpol
Encyclopedia
Catalpol is an iridoid
glucoside
that is found in plants belonging to several families, including, but not limited to, Scrophulariaceae
, Lamiaceae
, and Bignoniaceae
. This natural product falls in the class of iridoid glycosides, which are simply monoterpene
s with a glucose
molecule attached. First isolated in 1962, catalpol was named for plants in the genus Catalpa
in which it was discovered. Later in 1969, catalpol was found to be present in larger quantities in several plants in genus Rehmannia
. Although the pharmacological
action of catalpol as well as many other iridoids has not been fully established, there is evidence that their primary function is to stimulate the production of adrenal cortical
hormone
s, which increases the production of sex hormones. Catalpol also exhibits anti-inflammatory
activity and has shown to increase the production of androgen
s yielded by the adrenal gland, which can lead to increases in muscle mass.
origin, epi-iridotrial's precursor, epi-iridodial, is derived from geraniol
. Addition of a glucose at carbon 1 (C1) of the iridoid backbone and oxidation of the aldehyde at C4 of epi-iridotrial produced 8-epiloganic acid. A subsequent hydrolysis at C8 yielded mussaenosidic acid, followed by a dehydration to yield deoxyngeniposidic acid. The next precursor, geniposidic acid
, was furnished via hydrolysis of C10, and then a decarboxylation to remove the carboxylic acid at C4 provided bartsioside. The very widely known and accepted precursor to catalpol, aucubin, was then furnished via hydroxylation at C6. Finally an epoxidation with the alcohol at C10 yielded the natural product, catalpol.
Iridoid
Iridoids are a class of secondary metabolites found in a wide variety of plants and in some animals. They are monoterpenes biosynthesized from isoprene and they are often intermediates in the biosynthesis of alkaloids. Chemically, the iridoids usually consist of a cyclopentane ring fused to a...
glucoside
Glucoside
A glucoside is a glycoside that is derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes....
that is found in plants belonging to several families, including, but not limited to, Scrophulariaceae
Scrophulariaceae
Scrophulariaceae, the figwort family, are a family of flowering plants. The plants are annual or perennial herbs with flowers with bilateral or rarely radial symmetry. Members of the Scrophulariaceae have a cosmopolitan distribution, with the majority found in temperate areas, including...
, Lamiaceae
Lamiaceae
The mints, taxonomically known as Lamiaceae or Labiatae, are a family of flowering plants. They have traditionally been considered closely related to Verbenaceae, but in the 1990s, phylogenetic studies suggested that many genera classified in Verbenaceae belong instead in Lamiaceae...
, and Bignoniaceae
Bignoniaceae
The Bignoniaceae, or Trumpet Creeper Family, is a family of flowering plants comprising about 650-750 species in 116-120 genera. Members of the family are mostly trees and lianas , shrubs and more rarely herbaceous plants. As climber plants, they are twine climbers or tendril climbers, and rarely...
. This natural product falls in the class of iridoid glycosides, which are simply monoterpene
Monoterpene
Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear or contain rings...
s with a glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
molecule attached. First isolated in 1962, catalpol was named for plants in the genus Catalpa
Catalpa
Catalpa, commonly called catalpa or catawba, is a genus of flowering plants in the trumpet vine family, Bignoniaceae, native to warm temperate regions of North America, the Caribbean, and East Asia....
in which it was discovered. Later in 1969, catalpol was found to be present in larger quantities in several plants in genus Rehmannia
Rehmannia
Rehmannia is a genus of six species of flowering plants in the order Lamiales, endemic to China.The genus was included in the family Scrophulariaceae or Gesneriaceae in some older classifications. The current placement of the genus is in neither Scrophulariaceae s.s. nor Plantaginaceae s.l....
. Although the pharmacological
Pharmacology
Pharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...
action of catalpol as well as many other iridoids has not been fully established, there is evidence that their primary function is to stimulate the production of adrenal cortical
Adrenal cortex
Situated along the perimeter of the adrenal gland, the adrenal cortex mediates the stress response through the production of mineralocorticoids and glucocorticoids, including aldosterone and cortisol respectively. It is also a secondary site of androgen synthesis.-Layers:Notably, the reticularis in...
hormone
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
s, which increases the production of sex hormones. Catalpol also exhibits anti-inflammatory
Anti-inflammatory
Anti-inflammatory refers to the property of a substance or treatment that reduces inflammation. Anti-inflammatory drugs make up about half of analgesics, remedying pain by reducing inflammation as opposed to opioids, which affect the central nervous system....
activity and has shown to increase the production of androgen
Androgen
Androgen, also called androgenic hormone or testoid, is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors...
s yielded by the adrenal gland, which can lead to increases in muscle mass.
Biosynthetic pathway
Though first isolated in the 1960s, there has been very little investigation of the biosynthetic pathway of catalpol. S. R. Jensen has described a possible biosynthetic pathway for catalpol. With iridoids stemming from a terpenoidTerpenoid
The terpenoids , sometimes called isoprenoids, are a large and diverse class of naturally occurring organic chemicals similar to terpenes, derived from five-carbon isoprene units assembled and modified in thousands of ways. Most are multicyclic structures that differ from one another not only in...
origin, epi-iridotrial's precursor, epi-iridodial, is derived from geraniol
Geraniol
Geraniol is a monoterpenoid and an alcohol. It is the primary part of rose oil, palmarosa oil, and citronella oil . It also occurs in small quantities in geranium, lemon, and many other essential oils. It appears as a clear to pale-yellow oil that is insoluble in water, but soluble in most common...
. Addition of a glucose at carbon 1 (C1) of the iridoid backbone and oxidation of the aldehyde at C4 of epi-iridotrial produced 8-epiloganic acid. A subsequent hydrolysis at C8 yielded mussaenosidic acid, followed by a dehydration to yield deoxyngeniposidic acid. The next precursor, geniposidic acid
Geniposidic acid
Geniposidic acid is a natural chemical compound, classified as an iridoid glucoside, found in a variety of plants including Eucommia ulmoides and Gardenia jasminoides....
, was furnished via hydrolysis of C10, and then a decarboxylation to remove the carboxylic acid at C4 provided bartsioside. The very widely known and accepted precursor to catalpol, aucubin, was then furnished via hydroxylation at C6. Finally an epoxidation with the alcohol at C10 yielded the natural product, catalpol.