Comprehensive Characterisation of n ‐Alkylresorcinols and Other Lipid Constituents of Mercurialis tomentosa L. from Alicante, Spain

Mercurialis tomentosa L. has been used in Spanish ethnomedicine. In the present study the first phytochemical characterisation of a lipid fraction from M .  tomentosa was performed. The CHC l 3 extraction of aerial parts from M .  tomentosa and GC / MS investigations revealed the occurrence of cuticular lipid and wax constituents, like long chain n ‐alcohols and n ‐aldehydes (C 22  – C 30 ), besides several aromatic constituents, i.e ., phenylpropanoids and n ‐alkylresorcinols. The latter were further purified by CC and analysed by LC / MS n . In contrast to other Mercurialis species, i.e ., M .  annua , M .  perennis , which exclusively contain 5‐ n ‐alkylresorcinols ( 1a  –  j , C n ), mainly 5‐ n ‐alkyl‐2‐methylresorcinols ( 2a  –  j , C n *) with side chain lengths of C 15  – C 25 were found in M .  tomentosa , in addition to 1a  –  j . Thus, the latter compounds may be utilised for analytical characterisation and authentication of M .  tomentosa based on fingerprinting methods. For structure elucidation a novel facile total synthesis of one representative 5‐ n ‐alkyl‐2‐methylresorcinol homologue ( 2d , C 19 *) was developed, starting with a Grignard reaction from a substituted benzoic acid chloride ( 19 ). The compound obtained by synthesis was identical to the natural product 2d in terms of its chromatographic and spectroscopic features. Futhermore, 2d exhibited satisfactory DPPH free radical scavenging activity ( IC 50  = 37.8 μ m ) when compared to trolox ( IC 50  = 21.0 μ m ), corroborating the antioxidant features of these amphipathic molecules.