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).

Synthesis

Homoisoflavones can be synthetized from 2'-hydroxy

dihydrochalcone Dihydrochalcone (DHC) is the organic compound with the formula C6H5C(O)(CH2)2C6H5. It is the reduced derivative of chalcone (C6H5C(O)(CH)2C6H5). It is white solid that is soluble in many organic solvents. Dihydrochalcone per se is often minor si ...

s. Homoisoflavanones can be synthetized 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'' (common purslane, Caryophyllales, Portulacaceae). The 3,4-dihydroxyhomoisoflavans

sappanol Sappanol is a 3,4-dihydroxyhomoisoflavan, a type of homoisoflavonoid, that can be found in ''Caesalpinia sappan ''Biancaea sappan'' is a species of flowering tree in the legume family, Fabaceae, that is native to tropical Asia. Common names i ...

, 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 ''Barnardia japonica'', the Japanese jacinth, is a bulbous flowering plant in the family Asparagaceae, subfamily Scilloideae Scilloideae (named after the genus ''Scilla'', "squill") is a subfamily of bulbous plants within the family ''Asparagac ...

'').

Homoisoflavanones

Homoisoflavanones (3-Benzyl-4-chromanones) can be found in various plants, notably in Hyacinthaceae (

Scilloideae Scilloideae (named after the genus ''Scilla'', "squill") is a subfamily of bulbous plants within the family ''Asparagaceae''. Scilloideae is sometimes treated as a separate family Hyacinthaceae, named after the genus ''Hyacinthus''. Scilloideae or ...

Sappanone A Sappanone A is a homoisoflavanone that can be found in ''Caesalpinia sappan ''Biancaea sappan'' is a species of flowering tree in the legume family, Fabaceae, that is native to tropical Asia. Common names in English include sappanwood and Indi ...

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 ''Persicaria odorata'', with common names Vietnamese coriander, rau răm, laksa leaf, Vietnamese cilantro, phak phai, praew leaf, hot mint and Cambodian mint, is an herb with aromatic leaves, used in Southeast Asian and Northeast Indian cooking. ...

''. 5,7-Dihydroxy-3-(3-hydroxy-4-methoxybenzyl)-chroman-4-one, a homoisoflavanone extracted from ''

Cremastra appendiculata ''Cremastra appendiculata'' is an orchid species in the genus '' Cremastra''. It is the type species of its genus. There two subspecies: * ''Cremastra appendiculata ''var''. appendiculata'' - Taiwan, Tibet, Yunnan, Bhutan, Assam, Nepal, Japan, K ...

'' (Orchidaceae), has anti-angiogenic activities and inhibits UVB-induced skin inflammation through reduced cyclooxygenase-2 expression and NF-?B nuclear localization.

In Asparagaceae

3-(4'-Methoxybenzyl)-7,8-methylenedioxy-chroman-4-one, a homoisoflavanone with antimycobacterial activity, can be isolated from ''

Chlorophytum inornatum ''Chlorophytum inornatum'' is a flowering plant species in the genus ''Chlorophytum''. It is the type species of its genus. It is related to the commonly known plant Chlorophytum also referred to as a "spider plant". 3-(4'-Methoxybenzyl)-7,8-met ...

'' (Asparagaceae, Agavoideae). 5,7-Dihydroxy-3-(4-methoxybenzyl)-chroman-4-one, 7-hydroxy-3-(4-hydroxybenzyl)-chroman-4-one and 4’-demethyl-3,9-dihydro-punctatin can be isolated from ''

Agave tequilana ''Agave tequilana'', commonly called blue agave () or tequila agave, is an agave plant that is an important economic product of Jalisco, Mexico, due to its role as the base ingredient of tequila, a popular distilled beverage. The high production ...

'' (Asparagaceae, Agavoideae). ; in Scilloideae (Hyacinthaceae) 7-O-α-Rhamnopyranosyl-(1→6)-β-glucopiranosyl-5-hydroxy-3-(4-methoxybenzyl)-chroman-4-one, 7-O-α-rhamnopyranosyl-(1→6)-β-glucopiranosyl-5-hydroxy-3-(4′-hydroxybenzyl)-chroman-4-one, 5,7-dihydroxy-3-(4′-methoxybenzyl)-chroman-4-one ( 3,9-dihidroeucomin), 5,7-dihydroxy-6-methoxy-3-(4′-methoxybenzyl)-chroman-4-one, 5,7-dihydroxy 3-(4′-hydroxybenzyl)-chroman-4-one ( 4,4′-demethyl-3,9-dihydropuctatin), 5,7-dihydroxy-3-(4′-hydroxybenzyl)-6-methoxy-chroman-4-one ( 3,9-dihydroeucomnalin) and 7-hydroxy-3-(4′-hydroxybenzyl)-5-methoxy-chroman-4-one can be isolated from the bulbs of ''

Ledebouria floribunda ''Ledebouria floribunda'' is a species of flowering plant in the Asparagaceae family. It is found in Africa. Uses The homoisoflavanones 7-O-α-rhamnopyranosyl-(1→6)-β-glucopiranosyl-5-hydroxy-3-(4-methoxybenzyl)-chroman-4-one, 7-O-α-rhamno ...

'' (tribe Hyacintheae). 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'' (tribe Ornithogaloideae). Scillascillin-type homoisoflavanones (3-hydroxy-type homoisoflavonoids) can be isolated from ''

Drimiopsis maculata ''Drimiopsis maculata'', also known by the common names little white soldiers, African false hosta, leopards ears, African hosta, leopard plant, and Injoba is a flowering plant species in the genus ''Drimiopsis''. It is the type species of its ge ...

'' (tribe Hyacintheae, Massoniinae). Eucomin, eucomol, (E)-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 ''Eucomis bicolor'', the variegated pineapple lily or just pineapple lily, is a bulbous species of flowering plant in the family Asparagaceae, subfamily Scilloideae, native to Southern Africa (the Cape Provinces, Lesotho, KwaZulu-Natal, the ...

'' (tribe Hyacintheae, Massoniinae). 4′-o-Methyl-punctatin, autumnalin and 3,9-dihydro-autumnalin can be found in ''

Eucomis autumnalis ''Eucomis autumnalis'', the autumn pineapple flower, or autumn pineapple lily, is a species of flowering plant in the family (biology), family Asparagaceae, subfamily Scilloideae, native plant, native to Malawi, Zimbabwe and southern Africa. It i ...

''. Five homoisoflavanones, 3,5-dihydroxy-7,8-dimethoxy-3-(3',4'-dimethoxybenzyl)-4-chromanone, 3,5-dihydroxy-7-methoxy-3-(3',4'-dimethoxybenzyl)-4-chromanone, 3,5-dihydroxy-7,8-dimethoxy-3-(3'-hydroxy-4'-methoxybenzyl)-4-chromanone, 3,5,6-trihydroxy-7-methoxy-3-(3'-hydroxy-4'-methoxybenzyl)-4-chromanone and 3,5,7-trihydroxy-3-(3'-hydroxy-4'methoxybenzyl)-4-chromanone, can be isolated from the dichloromethane extract of the bulbs of '' Pseudoprospero firmifolium'' (tribe Hyacintheae, subtribe Pseudoprospero). A homoisoflavanone can also be found in '' Albuca fastigiata'' (tribe Ornithogaleae). The same molecule, 5,6-dimethoxy-7-hydroxy-3-(4′-hydroxybenzyl)-4-chromanone, can be found in the bulbs of '' Resnova humifusa'' and ''

Eucomis montana ''Eucomis montana'' is a plant species in the family Asparagaceae, subfamily Scilloideae, found in South Africa ( KwaZulu-Natal and the Northern Provinces) and Eswatini (Swaziland). When in flower in summer, the plant reaches a height of up to ...

'' (tribe Hyacintheae, subtribe Massoniinae).

Uses

The homoisoflavonoids portulacanones A, B, C and D show ''in vitro''

cytotoxic Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are an immune cell or some types of venom, e.g. from the puff adder (''Bitis arietans'') or brown recluse spider (''Loxosceles reclusa''). Cell physiology Treating cells ...

activities towards four human cancer cell lines.

References