Context: 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, acetal, hemiacetal, tetra-substituted epoxide and a variety of carboxylic esters., Citrus is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops like oranges, lemons, grapefruit, pomelo and limes., In botany, a fruit is the seed-bearing structure in flowering plants (also known as angiosperms) formed from the ovary after flowering., Meliaceae, or the Mahogany family, is a flowering plant family of mostly trees and shrubs (and a few herbaceous plants, mangroves) in the order Sapindales., In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a woody trunk and branches as a way to tower above other plants to compete for sunlight. In looser senses, the taller palms, the tree ferns, bananas and bamboos are also trees. Trees tend to be long-lived, some reaching several thousand years old. The tallest known tree, a coast redwood named Hyperion, stands high. Trees have been in existence for 370 million years. It is estimated that there are just over 3 trillion mature trees in the world., A furanolactone is a heterocyclic chemical compound that contains both a lactone and a furan ring structure., Limonoids are phytochemicals, abundant in citrus fruit and other plants of the families Rutaceae and Meliaceae. Currently, limonoids are under investigation for possible effects in humans, although no proof of effect exists to date. Certain limonoids are insecticides such as azadirachtin from the neem tree., An insecticide is a substance used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to be a major factor behind the increase in agricultural 20th century's productivity. Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans; some concentrate along the food chain., A genus ( genera) is a taxonomic rank used in the biological classification of living and fossil organisms in biology. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus., Citrus maxima (or "Citrus grandis"), (Common names: pomelo, pomello, pummelo, pommelo, pamplemousse, jabong (Hawaii), shaddick, or shaddock) is a natural (non-hybrid) citrus fruit, similar in appearance to a large grapefruit, native to South and Southeast Asia., The Rutaceae are a family, commonly known as the rue or citrus family, of flowering plants, usually placed in the order Sapindales., The lemon ("Citrus" × "limon") is a species of small evergreen tree native to Asia., A flower, sometimes known as a bloom or blossom, is the reproductive structure found in plants that are floral (plants of the division Magnoliophyta, also called angiosperms). The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs. Flowers may facilitate outcrossing (fusion of sperm and eggs from different individuals in a population) or allow selfing (fusion of sperm and egg from the same flower). Some flowers produce diaspores without fertilization (parthenocarpy). Flowers contain sporangia and are the site where gametophytes develop. Many flowers have evolved to be attractive to animals, so as to cause them to be vectors for the transfer of pollen. After fertilization, the ovary of the flower develops into fruit containing seeds., 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 furanolactones ., The grapefruit ("Citrus" × "paradisi") is a subtropical citrus tree known for its sour to semi-sweet fruit. Grapefruit is a hybrid originating in Barbados as an accidental cross between two introduced species, sweet orange ("C. sinensis") and pomelo or shaddock ("C. maxima"), both of which were introduced from Asia in the seventeenth century. When found, it was named the forbidden fruit; and it has also been misidentified with the pomelo., A shrub or bush is a small to medium-sized woody plant. It is distinguished from a tree by its multiple stems and shorter height, usually under 6 m (20 ft) tall. Plants of many species may grow either into shrubs or trees, depending on their growing conditions. Small, low shrubs, generally less than 2 m (6.6 ft) tall, such as lavender, periwinkle and most small garden varieties of roses, are often termed subshrubs., A crop is any cultivated plant, fungus, or alga that is harvested for food, clothing, livestock, fodder, biofuel, medicine, or other uses. In contrast, animals that are raised by humans are called livestock, except those that are kept as pets. Microbes, such as bacteria or viruses, are referred to as cultures. Microbes are not typically grown for food, but are rather used to alter food. For example, bacteria are used to ferment milk to produce yogurt., Subject: limonin, Relation: instance_of, Options: (A) accidental (B) agriculture (C) biological classification (D) biology (E) botany (F) chain (G) chemical compound (H) citrus (I) classification (J) cultivated plant (K) division (L) family (M) flower (N) fodder (O) food (P) fossil (Q) fruit (R) genus (S) grapefruit (T) group (U) humans (V) hybrid (W) insecticide (X) may (Y) medicine (Z) order ([) part (\) plant (]) rank (^) seed (_) shrub (`) species (a) structure (b) tower (c) tree (d) two
Output: chemical compound