Alkylresorcinol

Natural sources of alkylresorcinols

Alkylresorcinols are relatively rare in nature and are reported to be found in fungi, bacteria, and some lower and higher plants. DB-2073 is an antibiotic isolated from the broth culture of Pseudomonas sp. They are also the main constituents of the outer shell of the cyst of Azotobacter.

Among the plant sources, the shell oil of cashew nut (Anacardium occidentale L.) has the highest amount of ARs, which consists of 20% phenolic lipids. Moreover, ARs were found in the peels and pulp of peas (Pisum sativum L.), pulp and leaves of ginkgo (Ginkgo biloba L.), pulp and peels of mango (Mangifera indica L.), and in some cereals. In the case of cereals, the hyaline layer, inner pericarp, and testa showed the highest amounts of AR.

Occurrence in cereals

The alkylresorcinols alkyl chain, present in cereals, ranges from 15 to 25 carbon atoms. ARs have been reported to be present in high amounts in rye, wheat, and triticale, and in low concentrations in barley, maize, oat, and millet, while no information is at present available for Khorasan wheat. They are most abundant in the bran fractions (2600-4100 μg/g; 0.1-0.3% of dry weight), whereas they are in trace amounts in strachy endosperm and germ. They can also be found in rice, though not in the edible parts of the rice plant.

Their presence in the endosperm (the part of cereal grain that is used to make white flour), means that alkylresorcinols can be used as 'biomarkers' for people who eat foods containing wholegrain wheat and rye, rather than cereal products based on white flour.{{Cite journal | doi-access = free

Biomarkers of a whole grain diet

Increasing evidence from human intervention trials suggests that they are the most promising biomarker of whole grain wheat and rye intake.{{Cite journal | doi-access = free | doi-access = free | doi-access = free | doi-access =

The average intake of alkylresorcinols in the UK is around 11 mg/person/day, and in Sweden is around 20 mg/person/day.{{Cite journal | doi-access = free

Biomarkers of cereal presence in archaeological pottery

Recently, alkylresorcinols have been widely recognised as a biomarker for the presence of cereals in archaeological pottery. They were previously found in a well-preserved Bronze Age wooden container from Switzerland, and coarse ware vessels from a Roman cavalry barrack at Vindolanda. A study demonstrated that the survival of ARs is highly dependent on the cooking procedures and burial conditions. However, if recoverable, analysis of these phenolic lipids in archaeological contexts is valuable as it can help explain the uptake and spread of cereal processing of past communities in particular regions.

Possible biological activities

In vitro studies have shown that alkylresorcinols may prevent cells turning cancerous, but that they do not have any effect on cells that are already cancerous. Alkylresorcinols also increase gamma-tocopherol levels in rats when fed in high amounts (0.2% of total diet and above).

The alkylresorcinols in Grevillea banksii and Grevillea 'Robyn Gordon' are responsible for contact dermatitis.{{Cite journal

Trivial names of some resorcinolic lipids

• olivetol
• persoonol
• grevillol
• ardisinol I
• ardisinol II
• adipostatin A
• adipostatin B
• bilobol
• hexylresorcinol
• hydrobilobol
• cardol
• rucinol
• irisresorcinol
• panosialin
• stemphol
• R-leprosol
• α-leprosol
• merulinic acid
• xenognosin

Derivatives

Sorgoleone is a hydrophobic root exudate of Sorghum bicolor.

References

References

1. (2010). "Alkylresorcinol biosynthesis in plants: New insights from an ancient enzyme family?". Plant Signaling & Behavior.
2. (1999-01-13). "Resorcinolic Lipids, the Natural Non-isoprenoid Phenolic Amphiphiles and Their Biological Activity". Chemical Reviews.
3. (2003-07-01). "Alkylresorcinols in Cereals and Cereal Products". Journal of Agricultural and Food Chemistry.
4. (1975). "DB-2073, a new alkylresorcinol antibiotic. I. Taxonomy, isolation and characterization". The Journal of Antibiotics.
5. (2006). "Phenolic lipid synthesis by type III polyketide synthases is essential for cyst formation in Azotobacter vinelandii". [[Proceedings of the National Academy of Sciences]].
6. (1999-02-01). "Alkylresorcinol Homologs in Pisum sativum L. Varieties". Zeitschrift für Naturforschung C.
7. (2000-12-01). "Alkylresorcinols in Fruit Pulp and Leaves of ''Ginkgo biloba'' L.". [[Zeitschrift für Naturforschung C]].
8. (2009-05-13). "Quantitative Determination of Allergenic 5-Alk(en)ylresorcinols in Mango (Mangifera indica L.) Peel, Pulp, and Fruit Products by High-Performance Liquid Chromatography". Journal of Agricultural and Food Chemistry.
9. (September 2008). "Localization of alkylresorcinols in wheat, rye and barley kernels". [[Journal of Cereal Science]].
10. (September 2015). "Alkylresorcinol composition allows the differentiation of ''Triticum'' spp. having different degrees of ploidy". [[Journal of Cereal Science]].
11. (2004-12-01). "Alkylresorcinols as Markers of Whole Grain Wheat and Rye in Cereal Products". [[Journal of Agricultural and Food Chemistry]].
12. (2008-11-12). "Phytochemical and Dietary Fiber Components in Barley Varieties in the HEALTHGRAIN Diversity Screen". Journal of Agricultural and Food Chemistry.
13. (1999). "Structures of 5-alkylresorcinol-related analogues in rye". [[Phytochemistry (journal).
14. (2003). "Biosynthesis of 5-alkylresorcinol in rice: Incorporation of a putative fatty acid unit in the 5-alkylresorcinol carbon chain". Bioorganic Chemistry.
15. Hao Y, Yang Z, Li Q, Wang Z, Liu J, Wang J. 5-Heptadecylresorcinol Protects against Atherosclerosis in Apolipoprotein E-Deficient Mice by Modulating SIRT3 Signaling: The Possible Beneficial Effects of Whole Grain Consumption. ''Mol Nutr Food Res''. 2022 May;66(9):e2101114. {{doi. 10.1002/mnfr.202101114 {{pmid. 35297565
16. (2017-07-26). "New criteria for the molecular identification of cereal grains associated with archaeological artefacts". Scientific Reports.
17. (May 2018). "Towards the detection of dietary cereal processing through absorbed lipid biomarkers in archaeological pottery". Journal of Archaeological Science.
18. (December 2017). "From the inside out: Upscaling organic residue analyses of archaeological ceramics". Journal of Archaeological Science: Reports.
19. (2010). "Sorgoleone". Phytochemistry.