Homoisoflavonoids (3-benzylidenechroman-4-ones) 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 (A and B) and heterocyclic ring (C).
Homoisoflavones can be synthetized from 2'-hydroxydihydrochalcones.
Homoisoflavanones can be synthetized from 3,5-methoxy phenols via chroman-4-one in three steps or from phloroglucinol.
Homoisoflavanes can be obtained from the conversion of homoisoflavonoids.
The homoisoflavonoids portulacanones A, B, C and D can be found in Portulaca oleracea (common purslane, Caryophyllales, Portulacaceae).
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 (Barnardia japonica).
Homoisoflavanones (3-Benzyl-4-chromanones) can be found in various plants, notably in Hyacinthaceae (Scilloideae).
Sappanone A can be found in Caesalpinia sappan.
C-Methylated homoisoflavanones (3-(4'-methoxy-benzyl)-5,7-dihydroxy-6-methyl-8-methoxy-chroman-4-one, 3-(4'-methoxy-benzyl)-5,7-dihydroxy-6,8-dimethyl-chroman-4-one, 3-(4'-hydroxy-benzyl)-5,7-dihydroxy-6,8-dimethyl-chroman-4-one, 3-(4'-hydroxy-benzyl)-5,7-dihydroxy-6-methyl-8-methoxy-chroman-4-one and 3-(4'-hydroxy-benzyl)-5,7-dihydroxy-6-methyl-chroman-4-one) can be found in the rhizomes of Polygonum odoratum.
5,7-Dihydroxy-3-(3-hydroxy-4-methoxybenzyl)-chroman-4-one, a homoisoflavanone extracted from Cremastra appendiculata (Orchidaceae), has anti-angiogenic activities and inhibits UVB-induced skin inflammation through reduced cyclooxygenase-2 expression and NF-?B nuclear localization.