Phloroglucinols from Myrtaceae: attractive targets for structural characterization, biological properties and synthetic procedures

Myrtaceae Juss. is a very large family of flowering plants, that are a valuable source of bioactive compounds. From the phytochemical point of view, apart from ubiquitous tannins, flavonoid derivatives and volatile oils, Myrtaceae plants are very rich in phloroglucinol derivatives, divided in two principal subclasses: oligomeric acylphloroglucinols and phloroglucinol-terpene adducts. Despite this large structural variability, many studies on phloroglucinols from the Myrtaceae have focused on unique bioactive acylphloroglucinol compounds, named myrtucommulones. Nevertheless, many studies also reported other interesting phloroglucinol derivatives. Therefore, in this review, a comprehensive description of the chemical features of acylphloroglucinols and meroterpenoid-acylphloroglucinols from the Myrtaceae family is presented along with their biological activities. Moreover, since myrtucommulones and their derivatives have become attractive targets for organic chemists, thanks to their structural features and biological activities, relevant approaches and synthetic procedures are herewith discussed.