Alkylresorcinols, also known as resorcinolic lipids, are phenolic lipidscomposed of long aliphatic chains and resorcinol-type phenolic rings.
Natural sources of alkylresorcinols
Alkylresorcinols are relatively rare in nature, with the main known sources being wheat, rye, barley, triticale, the fruit of Ginkgo bilobaBilobol, a mollusc and some species of bacteria.
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.
Alkylresorcinols are present in high amounts in the bran layer of wheat and rye. 5-Alkylresorcinols can also be found in rice, though not in the edible parts of the rice plant. They are only present in very low amounts in the endosperm, which means that alkylresorcinols can be used as 'biomarkers' for people who eat foods containing wholegrain wheat and rye, rather than cerealproducts based on white flour. Alkylresorcinols were thought to have anti-nutritive properties, but this theory has been discredited, and a number of animal studies have demonstrated that they have no obvious negative effect on animals or humans.
Increasing evidence from human intervention trials suggests that they are the most promising biomarker of whole grain wheat and rye intake. Alkylresorcinol metabolites, 3,5-dihydroxybenzoic acid and 3,5-dihydroxyphenylpropionoic acid were first identified in urine and can be quantified in urine and plasma, and may be an alternative, equivalent biomarker of whole grain wheat intake. The average intake of alkylresorcinols in the UK is around 11 mg/person/day, and in Sweden is around 20 mg/person/day. This varies widely depending on whether people normally consume wholegrain/wholemeal/brown bread, which is high in alkylresorcinols, or white wheat bread, which has very low concentrations of alkylresorcinols.
Possible biological activities
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.
