Arbuscular mycorrhizal fungi as tool in pharmaceutical and cosmeceutical industry for the enhanced production of secondary metabolites of Anchusa officinalis

Arbuscular mycorrhizal fungi (AMF) are biotrophe microorganisms that establish a symbiotic association with host-plants. These plant-dependent microorganisms have already shown their strong effects concerning plant growth promotion and were reported to stimulate the secondary metabolites (SM) production of their host-plant. In this study, Anchusa officinalis plants, well-known for their therapeutic properties, were analyzed to assess the AMF effects on SM production. Two different experiments were developed on a semi-hydroponic system to compare treated A. officinalis plants with different AMF. In the first investigation, plants were inoculated with Rhizophagus irregularis, cultivated for 30 days and harvested two times. Concerning the second experiment, four different strains of AMF (R. clarus, R. intraradices, R. irregularis and Glomus aggretum) were tested separately on plants and one sampling was performed after one week. Roots and shoots were separated, lyophilized, ground and extracted using ultrasounds with EtOAc and MeOH (35:65 v/v) at 25°C. After centrifugation, the supernatants were removed and evaporated to dryness. Samples were analyzed with UHPLC-HRMS as well as HPTLC and HPLC-DAD-ELSD. Preliminary results of a targeted metabolomic analysis, showed that the concentration of main compound, rosmarinic acid, present in all the treated plants had no statistically difference from the controls. However, a discernable up-regulation and down-regulation of specific minor SMs in colonized plants was observed, suggesting that the aforementioned AMF affect specific biosynthetic pathways. Further experiments and analyses is needed but the cultivation of medicinal plants with AMF looks a promising way to enhance bioactive metabolites with applications in pharmaceutical and cosmeceutical industry.