User:TigerERTH4303/Carminic acid

Carminic acid (C22H20O13) is a red glucosidal hydroxyanthrapurin that occurs naturally in some scale insects, such as the cochineal, Armenian cochineal, and Polish cochineal. The insects produce the acid as a deterrent to predators. An aluminum salt of carminic acid is the coloring agent in carmine, a pigment. Natives of Peru had been producing cochineal dyes for textiles since at least 700 CE. Synonyms are C.I. 75470 and C.I. Natural Red 4.

The chemical structure of carminic acid consists of a core anthraquinone structure linked to a glucose sugar unit. Carminic acid was first synthesized in the laboratory by organic chemists in 1991.

It was previously thought that it contains α- D -glucopyranosyl residue, which was later redetermined to be the β- D -glucopyranosyl anomer.

Harvesting from Cochineals
Carminic acid is commonly harvested from an American species scaled insects called Dactylopius coccus (or cochineals). Cochineals are parasitic scaled insects which are abundantly found on their host plants, the prickly pear cactus native to Mexico and South America. The insects are either cultivated or harvested from wild populations, mainly for the wingless females of the species which attach themselves to the cactus and outnumber the winged males of the species two hundred to one. Classically, cultivated species were grown from eggs placed by workers onto the cactus leaves and left to grow. There the female cochineals would remain immobile for about 3 months until being brushed off, collected, and dried for shipping. Females possess concentrations of about 1.5% bodyweight of carminic acid and newborns about 3.0%. The carminic acid is then extracted by soaking the dried cochineals in water, and additives are then added to alter dye colour and enable they dye to adhere to objects.

Use as a Deterrent
For many scaled insects of the genus Dactylopius, carminic acid, thoroughly documented by Thomas Eisner, has been shown to be a highly potent feeding deterrent against ants. In Eisner's 1980 paper, he notes that the red colour of the carminic acid released when the cochineals are crushed could also be a visual aposematic deterrent for predators as well. However, he notes that tests have not been done on vertebrates to provide any support to that theory. In the same paper however, Eisner mentions that cochineals were bitter when tasted by humans.

Like other compounds housed in various plants, predators which are able to overcome the deterrent are able to sequester carminic acid in their flesh and utilize the deterrent for their own defense. The pyralid moth (Laetilia coccidivora) is one such predator which feeds on cochineals, sequestering their prey's carminic acid in their own body for defense against predators. The ability to sequester carminic acid has also been seen in several other larval bearing species (Hyperaspis, Leucopis, etc). Eisner remarks that the ability to sequester the compound likely arose due to ants being a common predator amongst larvae