Impact of microbial-assisted cultivation on the phytochemical and biological properties of Salvia rosmarinus Spenn.: a biotechnological approach to medicinal plants

Background. Salvia rosmarinus Spenn. is a medicinal and aromatic plant, known for its antimicrobial, antioxidant, and anti-inflammatory activities, largely attributed to its phenolics, flavonoids, and terpenes [1,2 ]. The levels of these compounds can be influenced by abiotic and biotic factors, including plant growth-promoting rhizobacteria, which are increasingly used to enhance bioactive compound production in medicinal plants [3 ]. This study investigates whether rhizobacterial treatment can stimulate polyphenol metabolism and improve the growth and bioactivity of S. rosmarinus. Methodologies. Plants either left untreated or treated biweekly for one year with the rhizobacterium S. rosmarinus were used. Aerial parts were collected across different seasons and ethanolic extracts were prepared and analysed for polyphenolic content using spectrophotometric and chromatographic methods. Bioactivity screening included radical scavenging (ABTS and DPPH), metal chelation, reducing power, and antiglycative assays [4 ]. Additionally, cytoprotective and antioxidant effects against tert-butyl hydroperoxide (tBOOH)-induced oxidative damage were assessed in Caco-2 colorectal adenocarcinoma cells [4]. Results. Results showed that, despite some changes in the phytochemical composition, rhizobacterial treatment did not enhance the radical scavenging, reducing, or antiglycative activities of the extracts, which were generally comparable to or lower than those of the corresponding seasonal controls. In Caco-2 cells, all extracts exhibited cytotoxicity at concentrations above 50 µg/mL. At non-toxic levels, however, all extracts significantly mitigated tBOOH-induced oxidative damage, with no significant differences observed between treated and untreated plants. Conclusion. Although some variations in phytochemical composition were observed, rhizobacterial inoculation appeared to have a limited effect on the antioxidant properties of S. rosmarinus. Nevertheless, its potential to enhance other biological activities, such as anti-inflammatory effects, warrants further investigation. References [1]Borges et al. J Ethnopharmacol 2019,229,29-45 [2]García-Villaraco et al. Plants (Basel), 2021, 10, 331. [3] Vaghela et al. J Basic Microbiol 2023, 63, 308–325. [4] Di Sotto et al. Molecules (Basel) 2019, 24, 3103.