Antibacterial Prenylated p-Hydroxybenzoic Acid Derivatives from Oberonia myosurusand Identification of Putative Prenyltransferases

Twelve hitherto unknown tandem prenylated p-hydroxybenzoic acid derivatives, namely, oberoniamyosurusins A–L, together with five known derivatives, were isolated from an EtOH extract of the whole parts of the plant Oberonia myosurus. Compounds 10, 13, and 17exhibited moderate inhibitory activity against Staphylococcus aureussubsp. aureusATCC29213 with MIC50values ranging from 7.6 to 23 μg/mL. To determine the biosynthetic pathway of this class of tandem prenyl-substituted compounds, the full-length transcriptome of O. myosuruswas sequenced, yielding 19.09 Gb of clean data and 10 949 nonredundant sequences. Two isoforms of p-hydroxybenzoic acid prenyltransferases were annotated and functionally characterized as the enzymes that might be involved in the biosynthesis of nervogenic acid (13) in Pichia pastoris.