Two new bicyclic phloroglucinols were isolated from the diethyl ether extract of an Argentine collection of the fern Elaphoglossum piloselloides. Structures were established by analysis of their spectroscopic data ((1)H NMR, HRMS, IR) and chemical derivatization. Both compounds show an acute molluscicidal activity against the schistosomiasis vector snail Biomphalaria peregrina.

A short total synthesis of (±)-garcinol and (±)-isogarcinol, two endo-type B PPAPs with reported activity against methiciline resistant Staphylococcus aureus (MRSA), is presented. The separation of framework-constructing from framework-decorating steps and the application of two highly regio- and stereoselective Pd-catalysed allylations, that is, the Pd-catalysed decarboxylative Tsuji-Trost allylation and the diastereoselective Pd-catalysed allyl-allyl cross-coupling, are key elements that allowed the total synthesis to be accomplished within 13 steps starting from acetylacetone. After separation of the enantiomers the absolute configurations of the four natural products (i.e., (-)-garcinol, (+)-guttiferone E (i.e., ent-garcinol), (-)-isogarcinol, and (+)-isoxanthochymol (i.e., ent-isogarcinol)) were assigned based on ECD spectroscopy.

Seven new prenylated acylphloroglucinols, yungensins A-G, were isolated from the diethyl ether extract of the scaly rhizomes and roots of an Argentine collection of the fern Elaphoglossum yungense. All the compounds contained a geranyl group attached to the filicinic acid-type residue. The diethyl ether extract and yungensins A-F displayed antibacterial effects against Staphylococcus aureus and Pseudomonas aeruginosa with MICs ranging from 10 to 200 μg/mL. All tested acylphloroglucinols, except for yungensin D, caused bacteriolysis of S. aureus at MBC or higher doses (50-200 μg/mL). At 10 μg/mL, the ether extract as well as yungensins A, B, and D-F altered the biofilm production in both microoganisms.