Oxyprenylated secondary metabolites: a survey of their innovative extraction methodologies

Oxyprenylated secondary metabolites of plant, fungal, and microbial origin have emerged as biologically active natural compounds with a great potential for the next future. While originally obtained from the respective sources merely by conventional techniques of the phytochemical practice like maceration, percolation, and Soxhlet extractions, during the last five years novel and alternative experimental protocols to get such chemicals in higher yields and purity degree and/or in form of enriched phytopreparations have been developed. Such new processes include ultrasounds and microwaves assisted extractions, use of auxiliary agents like deep eutectic solvents and QuEChERS, employment of novel extractive solvents like supercritical CO2 and subcritical butane, accelerated solvent extractions, and finally extractions in the heterogeneous phase using solid supports. All these new methodologies proved to be very powerful and efficient in terms of yields and selectivity in concentrating classes of secondary metabolites from the respective matrices, comparing favorably to the already and widespread “classic” extraction techniques. All the developed processes can be framed in a green chemical context stating the employment of nontoxic, non-pollutant, environmentally friend, recyclable, easy to handle and to store solvents and reagents. The aim of this review article is to make a detailed survey of these alternative extraction processes for oxyprenylated secondary metabolites providing not only the most relevant examples of the recent literature, but also concrete suggestions and addresses to accomplish future research activities in the same field.