A very weakly basic minor constituent, C₁₆H₁₃NO₂, isolated from the alkaloidal fraction from leaves of Lunasia quercifolia (Warb.) Lauterb. & K. Schum., has been identified by spectroscopic examination as 5-hydroxy-1-methyl-2-phenyl-4-quinolone (I). The structure of (I) follows from its spectroscopic similarities to eduleine (II), n.m.r. evidence for a strongly hydrogen-bonded C5 hydroxyl group (sharp one-proton singlet at δ 14.0, exchangeable with deuterium oxide), dark colour with ferric chloride (similar to 5-hydroxyflavones), and weak basicity (slight solubility in aqueous acid). Although (I) may be an artefact due to possible demethylation, its isolation is of interest as its oxygen substitution pattern differs from other Lunasia alkaloids. A laevorotatory angular isomer (V) of (-)-lunine (III) was prepared by converting (-)-lunine methiodide to (+)-lunidine (IV) in alkaline solution and then heating (+)-lunidine in aqueous hydrochloric acid. The structure of (V) was deduced by comparison of its n.m.r. spectrum with that of (-)-lunine, and it predominates in the reaction products.