Phytoalexins are antimicrobial substances, some of which are antioxidative as well. They are defined not by their having any particular chemical structure or character, but by the fact that they are defensively synthesized de novo by plants that produce the compounds rapidly at sites of pathogen infection. In general phytoalexins are broad spectrum inhibitors; they are chemically diverse, and different chemical classes of compounds are characteristic of particular plant taxa. Phytoalexins tend to fall into several chemical classes, including terpenoids, glycosteroids, and alkaloids; however, the term applies to any phytochemicals that are induced by microbial infection.
Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, seeds, and grains; capers, red onions, and kale are common foods containing appreciable amounts of it. It has a bitter flavor and is used as an ingredient in dietary supplements, beverages, and foods.
Naringenin is a flavanone from the flavonoid group of polyphenols. It is commonly found in citrus fruits, especially as the predominant flavonone in grapefruit.
Rutin is the glycoside combining the flavonol quercetin and the disaccharide rutinose. It is a flavonoid glycoside found in a wide variety of plants, including citrus.
Naringin is a flavanone-7-O-glycoside between the flavanone naringenin and the disaccharide neohesperidose. The flavonoid naringin occurs naturally in citrus fruits, especially in grapefruit, where naringin is responsible for the fruit's bitter taste. In commercial grapefruit juice production, the enzyme naringinase can be used to remove the bitterness (debittering) created by naringin. In humans naringin is metabolized to the aglycone naringenin by naringinase present in the gut.
Hesperidin is a flavanone glycoside found in citrus fruits. Its aglycone is hesperetin. Its name is derived from the word "hesperidium", for fruit produced by citrus trees.
Chalcone synthase or naringenin-chalcone synthase (CHS) is an enzyme ubiquitous to higher plants and belongs to a family of polyketide synthase enzymes (PKS) known as type III PKS. Type III PKSs are associated with the production of chalcones, a class of organic compounds found mainly in plants as natural defense mechanisms and as synthetic intermediates. CHS was the first type III PKS to be discovered. It is the first committed enzyme in flavonoid biosynthesis. The enzyme catalyzes the conversion of 4-coumaroyl-CoA and malonyl-CoA to naringenin chalcone.
In enzymology, an isoflavone 7-O-methyltransferase is an enzyme that catalyzes the chemical reaction
Flavonoids are synthesized by the phenylpropanoid metabolic pathway in which the amino acid phenylalanine is used to produce 4-coumaroyl-CoA. This can be combined with malonyl-CoA to yield the true backbone of flavonoids, a group of compounds called chalcones, which contain two phenyl rings. Conjugate ring-closure of chalcones results in the familiar form of flavonoids, the three-ringed structure of a flavone. The metabolic pathway continues through a series of enzymatic modifications to yield flavanones → dihydroflavonols → anthocyanins. Along this pathway, many products can be formed, including the flavonols, flavan-3-ols, proanthocyanidins (tannins) and a host of other various polyphenolics.
Tricin is a chemical compound. It is an O-methylated flavone, a type of flavonoid. It can be found in rice bran and sugarcane.
Isorhamnetin is an O-methylated flavon-ol from the class of flavonoids. A common food source of this 3'-methoxylated derivative of quercetin and its glucoside conjugates are pungent yellow or red onions, in which it is a minor pigment, quercetin-3,4'-diglucoside and quercetin-4'-glucoside and the aglycone quercetin being the major pigments. Pears, olive oil, wine and tomato sauce are rich in isorhamnetin. Almond skin is a rich source of isorhamnetin-3-O-rutinoside and isorhamnetin-3-O-glucoside, in some cultivars they comprise 75% of the polyphenol content, the total of which can exceed 10 mg/100 gram almond. Others sources include the spice, herbal medicinal and psychoactive Mexican tarragon (Tagetes lucida), which is described as accumulating isorhamnetin and its 7-O-glucoside derivate. Nopal is also a good source of isorhamnetin, which can be extracted by supercritical fluid extraction assisted by enzymes.
The O-methylated flavonoids or methoxyflavonoids are flavonoids with methylations on hydroxyl groups. O-methylation has an effect on the solubility of flavonoids.
Apiforol is a chemical compound belonging to the flavan-4ol class of flavonoids.
In biochemistry, naturally occurring phenols are natural products containing at least one phenol functional group. Phenolic compounds are produced by plants and microorganisms. Organisms sometimes synthesize phenolic compounds in response to ecological pressures such as pathogen and insect attack, UV radiation and wounding. As they are present in food consumed in human diets and in plants used in traditional medicine of several cultures, their role in human health and disease is a subject of research. Some phenols are germicidal and are used in formulating disinfectants.
Cunninghamella elegans is a species of fungus in the genus Cunninghamella found in soil.
Chalconoids, also known as chalcones, are natural phenols derived from chalcone. They form the central core for a variety of important biological compounds.
Momilactone-A synthase (EC 1.1.1.295, momilactone A synthase, OsMAS) is an enzyme with systematic name 3beta-hydroxy-9beta-pimara-7,15-diene-19,6beta-olide:NAD(P)+ oxidoreductase. This enzyme catalyses the following chemical reaction
Naringenin 7-O-methyltransferase is a methyltransferase isolated from rice, which catalyzes the biosynthesis of sakuranetin.
Pisatin (3-hydroxy-7-methoxy-4′,5′-methylenedioxy-chromanocoumarane) is the major phytoalexin made by the pea plant Pisum sativum. It was the first phytoalexin to be purified and chemically identified. The molecular formula is C17H14O6.
Cunninghamella echinulata is a fungal species in the genus Cunninghamella. It is an asexually reproducing fungus and a mesophile, preferring intermediate temperature ranges. C. echinulata is a common air contaminant, and is currently of interest to the biotechnology industry due to its ability to synthesize γ-linolenic acid as well as its capacity to bioconcentrate metals. This species is a soil saprotroph that forms rhizoids, preferring soils enriched in nitrogen, phosphorus and potassium. It has been reported occasionally an agent of mucormycosis following the inhalation of fungal spores. Czapek's agar is a suitable growth medium for the propagation of C. echinulata.
