Limonoids are

phytochemicals Phytochemicals are chemical compounds produced by plants, generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals. The name comes . Some phytochemicals have been used as poison ...

of the

triterpenoid Triterpenes are a class of chemical compounds composed of three terpene units with the molecular formula C30H48; they may also be thought of as consisting of six isoprene units. Animals, plants and fungi all produce triterpenes, including squal ...

class which are abundant in sweet or sour-scented

citrus ''Citrus'' is a genus of flowering plant, flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as Orange (fruit), oranges, Lemon, lemons, grapefruits, pomelos, and lim ...

fruit and other plants of the families

Cucurbitaceae The Cucurbitaceae, also called cucurbits or the gourd family, are a plant family consisting of about 965 species in around 95 genera, of which the most important to humans are: *''Cucurbita'' – squash, pumpkin, zucchini, some gourds *''Lagena ...

Rutaceae The Rutaceae is a family, commonly known as the rueRUTACEAE
in BoDD – Botanical Derm ...

, and

Meliaceae Meliaceae, the mahogany family, is a flowering plant family of mostly trees and shrubs (and a few herbaceous plants, mangroves) in the order Sapindales. They are characterised by alternate, usually pinnate leaves without stipules, and by syncarp ...

. Certain limonoids are

antifeedant Antifeedants are organic compounds produced by plants to inhibit attack by insects and grazing animals. These chemical compounds are typically classified as secondary metabolites in that they are not essential for the metabolism of the plant, but i ...

s such as

azadirachtin Azadirachtin, a chemical compound belonging to the limonoid group, is a secondary metabolite present in neem seeds. It is a highly oxidized tetranortriterpenoid which boasts a plethora of oxygen-bearing functional groups, including an enol ether, a ...

from the

neem ''Azadirachta indica'', commonly known as neem, nimtree or Indian lilac, is a tree in the mahogany family Meliaceae. It is one of two species in the genus ''Azadirachta'', and is native to the Indian subcontinent and most of the countries in Afr ...

tree.{{cite journal, title=Biological activity of limonoids from the rutales, journal=Phytochemistry, volume=31, pages=377–394, authors=Donald E.Champagne, Opender Koul, Murray B. Isman, Geoffrey G. E.Scudder, G. H. Neil Towers, year=1992, issue=2, doi=10.1016/0031-9422(92)90003-9 Chemically, the limonoids consist of variations of the

furanolactone A furanolactone is a heterocyclic chemical compound that contains both a lactone and a furan ring structure. Examples include: * The salvinorins, including the hallucinogenic compound salvinorin A * Columbin, a bitter diterpenoid from '' Calumb ...

core structure. The prototypical structure consists of four six-membered rings and a

furan Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen atom. Chemical compounds containing such rings are also referred to as furans. Furan is a colorless, flammable, highly ...

ring. Limonoids are classed as tetranortriterpenes. Citrus fruits contain the limonoids

limonin Limonin is a limonoid, and a bitter, white, crystalline substance found in citrus and other plants. It is also known as limonoate D-ring-lactone and limonoic acid di-delta-lactone. Chemically, it is a member of the class of compounds known as fu ...

, nomilin and nomilinic acid, while both neem seeds and leaves contain the limonoid

, although higher concentrations are present in the former.

References

Terpenes and terpenoids 3-Furyl compounds Lactones

See also

References