Distribution of flavonoids, alkaloids, acetophenones and phloroglucinols in the genus Bosistoa (Rutaceae)

Abstract

The leaves of six of the seven species currently assigned to the Australian genus Bosistoa (Rutacea) have been examined. Major groups of metabolites isolated were flavones and flavanones, 1,3,5-oxygenated acridone alkaloids phloroglucinols and acetophenones, all of which are further modified by the addition of 5-carbon prenyl substituents. In a recent revision Bosistoa was divided into two groups and the distribution of flavonoid aglycones is found to coincide with Group II while species in Group 1 yield acridones, phloroglucinols and acetophenones. It is suggested that secondary metabolite production in Bosistoa is best rationalized by considering a central triketide or tetraketide which through either internal cyclization (phloroglucinols, acetophenones) or condensation with anthranilic acid (acridone alkaloids) or cinnamic acids (flavonoids) can give rise to all major groups of metabolites.