Homoisoflavonoids (3-benzylidenechroman-4-ones) are a type of phenolic compounds occurring naturally in

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

s. 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 synthesized 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 a white solid that is soluble in many organic solvents. Dihydrochalcone per se is often minor s ...

s. Homoisoflavanones can be synthesized from 3,5-methoxy phenols via chroman-4-one in three steps or from

phloroglucinol Phloroglucinol is an organic compound with the formula C6H3(OH)3. It is a colorless solid. It is used in the organic synthesis, synthesis of pharmaceuticals and explosives. Phloroglucinol is one of three isomeric benzenetriols. The other two isom ...

. ;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 ''Portulaca oleracea'' (common purslane, also known as little hogweed, or pursley) is a succulent plant in the family Portulacaceae. Description The plant may reach in height. It has smooth, reddish, mostly prostrate stems, and the leaves, w ...

'' (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''. References

Homoisoflavonoids {{aromatic-stub ...

, 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

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 ''Hyacinth (plant), Hyacinthus ...

Sappanone A Sappanone A is a homoisoflavanone that can be found in '' Caesalpinia sappan''. References Homoisoflavonoids {{aromatic-stub ...

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 (from Vietnamese), laksa leaf (calque from Malay ''daun laksa''), Vietnamese cilantro, phak phai (from Thai: ผักแพว), praew leaf, hot mint, Cambodian mint and ...

''. 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 houseplant ''Chlorophytum comosum'' also referred to as a "spider plant". 3-(4'-Metho ...

'' (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 Weber agave () or tequila agave, is an agave plant that is an important economic product of Jalisco state of Mexico, due to its role as the base ingredient of tequila. The high production of agavins (bran ...

'' (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 a bulbous geophyte native to South Africa, Eswatini, and Lesotho. Uses A number of homoisoflavanones can be isolated from the bulbs of ''L. floribunda'' ...

'' (tribe Hyacintheae). Other compounds can be found in ''

Ledebouria revoluta ''Ledebouria revoluta'', the south Indian squill, is a flowering plant species in the genus ''Ledebouria'' found in Southern Africa and India. Description The leaves of ''Ledebouria revoluta'' are smooth and fleshy, and unlike those of some othe ...

'', 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'' (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 (biology), family Asparagaceae, subfamily Scilloideae, native plant, native to Southern Africa (the Cape Provinces, ...

'' (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'' (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 toxic metals, toxic chemicals, microbe neurotoxins, radiation particles and even specific neurotransmitters when the system is out of balance. Also some types of dr ...

activities towards four human cancer cell lines.

References