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 rue[RUTACEAE](_blank)
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
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 ...
, although higher concentrations are present in the former.
See also
*
Tetranortriterpenoid The tetranortriterpenoid class of chemical compounds most noted for the chemical azadirachtin, extracted from the neem tree (''Azadirachta indica'') that displays insecticidal properties. Azadirachtin mimics insect hormones called ecdysones that reg ...
References
Terpenes and terpenoids
3-Furyl compounds
Lactones