Homoisoflavonoid
Homoisoflavonoids are a type of phenolic compounds occurring naturally in plants.
Chemically, they have the general structure of a 16-carbon skeleton, which consists of two phenyl rings and heterocyclic ring.
Synthesis
Homoisoflavones can be synthesized from 2'-hydroxydihydrochalcones.Homoisoflavanones can be synthesized from 3,5-methoxy phenols via chroman-4-one in three steps or from phloroglucinol.
;Conversion
Homoisoflavanes can be obtained from the conversion of homoisoflavonoids.
Natural occurrences
The homoisoflavonoids portulacanones A, B, C and D can be found in Portulaca oleracea.The 3,4-dihydroxyhomoisoflavans sappanol, episappanol, 3'-deoxysappanol, 3'-O-methylsappanol and 3'-O-methylepisappanol can be found in Caesalpinia sappan.
The homoisoflavones scillavones A and B can be isolated from the bulbs of Scilla scilloides.
Homoisoflavanones
Homoisoflavanones can be found in various plants, notably in Hyacinthaceae.Sappanone A can be found in Caesalpinia sappan.
C-Methylated homoisoflavanones -5,7-dihydroxy-6-methyl-8-methoxy-chroman-4-one, 3--5,7-dihydroxy-6,8-dimethyl-chroman-4-one, 3--5,7-dihydroxy-6,8-dimethyl-chroman-4-one, 3--5,7-dihydroxy-6-methyl-8-methoxy-chroman-4-one and 3- can be found in the rhizomes of Polygonum odoratum.
5,7-Dihydroxy-3--chroman-4-one, a homoisoflavanone extracted from Cremastra appendiculata, has anti-angiogenic activities and inhibits UVB-induced skin inflammation through reduced cyclooxygenase-2 expression and NF-?B nuclear localization.
In Asparagaceae
, a homoisoflavanone with antimycobacterial activity, can be isolated from Chlorophytum inornatum.5,7-Dihydroxy-3--chroman-4-one, 7-hydroxy-3--chroman-4-one and 4'-demethyl-3,9-dihydro-punctatin can be isolated from Agave tequilana.
; in Scilloideae
7-O-α-Rhamnopyranosyl--β-glucopiranosyl-5-hydroxy-3--chroman-4-one, 7-O-α-rhamnopyranosyl--β-glucopiranosyl-5-hydroxy-3--chroman-4-one, 5,7-dihydroxy-3--chroman-4-one, 5,7-dihydroxy-6-methoxy-3--chroman-4-one, 5,7-dihydroxy 3--chroman-4-one, 5,7-dihydroxy-3--6-methoxy-chroman-4-one and 7-hydroxy-3--5-methoxy-chroman-4-one can be isolated from the bulbs of Ledebouria floribunda. Other compounds can be found in Ledebouria revoluta, a plant widely used as an ethnomedicinal in southern Africa.
The homoisoflavanone glycosides -7-O-methyleucomol 5-O-beta-D-glucopyranoside, -7-O-methyleucomol 5-O-beta-rutinoside and -7-O-methyleucomol 5-O-beta-neohesperidoside can be isolated from the bulbs of Ornithogalum caudatum.
Scillascillin-type homoisoflavanones can be isolated from Drimiopsis maculata.
Eucomin, eucomol, -7-O-methyl-eucomin, -7-O-methyleucomol, -3,9-dihydro-eucomin and 7-O-methyl-3,9-dihydro-eucomin can be isolated from the bulbs of Eucomis bicolor. 4'-o-Methyl-punctatin, autumnalin and 3,9-dihydro-autumnalin can be found in Eucomis autumnalis.
Five homoisoflavanones, 3,5-dihydroxy-7,8-dimethoxy-3--4-chromanone, 3,5-dihydroxy-7-methoxy-3--4-chromanone, 3,5-dihydroxy-7,8-dimethoxy-3--4-chromanone, 3,5,6-trihydroxy-7-methoxy-3--4-chromanone and 3,5,7-trihydroxy-3--4-chromanone, can be isolated from the dichloromethane extract of the bulbs of Pseudoprospero firmifolium.
A homoisoflavanone can also be found in Albuca fastigiata.
The same molecule, 5,6-dimethoxy-7-hydroxy-3--4-chromanone, can be found in the bulbs of Resnova humifusa and Eucomis montana.