Sorgoleone
Sorgoleone
Sorgoleone is a compound belonging to the p-benzoquinone class, whose IUPAC name is: 2-hydroxy-5-methoxy-3-[(8Z,11Z)-pentadeca-8,11,14-trienyl]cyclohexa-2,5-diene-1,4-dione.
Sorgoleone has the molecular formula CāāHāāOā.
Its molecular weight is approximately 358.5 g/mol; monoisotopic mass: ~358.2144 g/mol.
It is a compound with a benzoquinone ring with a long aliphatic chain (pentadecatrienyl) containing double bonds in the 8Z,11Z,14Z configuration.
– Physicochemical Properties
Sorgoleone has high hydrophobicity: its structure is highly lipophilic and it is particularly persistent in soil. Its lipophilicity has an estimated XlogP value of approximately 6, indicating a marked affinity for nonpolar solvents.
Topological polar surface area (TPSA): approximately 63.6 Ć
Ā², indicating its moderate surface polarity.
The compound also exists in the dissociated form (conjugated base) at neutral pH, but remains essentially neutral and hydrophobic.
– Biosynthesis and natural production
Sorgoleone is produced exclusively from the root hairs of Sorghum bicolor.
The biosynthetic pathway involves:
– a 16:3 acyl-CoA starter unit from a fatty desaturase;
– polyketide synthase to form a pentadecatrienyl intermediate;
– methylation (SAM-dependent O-methyltransferase);
– dioxygenation by cytochrome P450 to yield sorgoleone.
– Main properties of sorgoleone
1. Origin and chemical nature.
Sorghum is a lipid benzoquinone (2-hydroxy-5-methoxy-3-[(Z,Z)-ā¦]-p-benzoquinone) secreted as droplets from the root hairs of Sorghum bicolor.
It represents up to 85% of the metabolites exuded in the roots of some varieties.
2. Phytotoxic activity.
It is a potent inhibitor of photosynthesis, blocking photosystem II with remarkable efficacy even at low concentrations (IC50 < 10 ĀµM). Doses as low as 10 ĀµM significantly reduce the growth of various weed species (e.g., Abutilon theophrasti, Datura stramonium, Echinochloa crus-galli).
3. Soil persistence and degradation.
Although persistent in the soil, sorgoleone is gradually mineralized by microorganisms, which use the compound as an energy source; The methoxy group is the first to be degraded. Production is highest in young plants, decreasing with age.
4. Other allelopathic metabolites of sorghum.
In addition to sorgoleone, phenols and phenolic acids (gallic, protocatechuic, vanillic, p-hydroxyisobenzoic, p-coumaroic, ferulic, etc.) are present in root residues or exudates. In particular, sweet sorghum also contains dhurrin, a cyanogenic glycoside that decomposes to release HCN.
5. Agronomic implications
Sorggoleone can be used as a natural herbicide, thanks to its ability to inhibit seeds and weeds directly in the soil. Using sorghum (or its varieties) in rotation or as a catch crop offers an option for controlling weeds without the use of synthetic herbicides.
Disclaimer: The information provided is not medical advice and may not be accurate. The content is for illustrative purposes only and does not replace medical advice.