Chemical Constituents and Biological Studies of the Leaves of Grevillea robusta

Abstract

Three new compounds: Graviquinone ( 1), cis-3-hydroxy-5-pentadecylcyclohexanone ( 2), and methyl 5-ethoxy-2-hydroxycinnamate ( 3), and thirty-eight known compounds were isolated and identified from the leaves of Grevillea robusta. The structures of these compounds were determined by spectroscopic and chemical transformation methods. Graviquinone ( 1) showed the strongest cytotoxicity against MCF-7, NCI-H460, and SF-268 cell lines. Methyl 2,5-dihydroxycinnamate ( 4), graviphane ( 13), and dehydrograviphane ( 14) exhibited very potent DPPH scavenging activity compared with α-tocopherol. Methyl 2,5-dihydroxycinnamate ( 4) and bis-norstriatol ( 17) demonstrated strong inhibition of L-DOPA oxidation by mushroom tyrosinase compared with kojic acid.