Flavonoids of Lavoisiera, Microlicia and Trembleya (Melastomataceae) and their taxonomic meaning

Leaves of species of three closely related genera of Melastomataceae, Lavoisiera, Microlicia and Trembleya were analyzed for their flavonoid composition. A total of 116 compounds were obtained, comprising 69 flavonol and 47 flavone glycosides. The common occurrence of flavones, including 6-oxygenated derivatives, characterize Lavoisiera (which often yielded methoxylated flavonols and flavones). Flavonols predominate in species of Microlicia. The flavonoid patterns of Trembleya are rather confusing, some species being akin to Lavoisiera, others to Microlicia. UPGMA analysis using the flavonoid aglycones as characters and the samples analyzed as OTUs gives no complete resolution for the three genera, but provides clusters combining exclusively or preferentially species of either Lavoisiera and Microlicia. Species of Trembleya emerge from the phenogram interspersed among species of the other genera. The data suggest the recognition of Lavoisiera and Microlicia and the lumping of species of Trembleya with either of these genera. If greater flavone diversity is viewed as indicative of further evolutionary advancement, shrubby habits in Microliceae (Lavoisiera and Trembleya) should be regarded as derived from herbaceous ones (Microlicia).