Rindera graeca (A. DC.) Boiss. & Heldr. (Boraginaceae) In Vitro Cultures Targeting Lithospermic Acid B and Rosmarinic Acid Production

The in vitro cultures of Rindera graeca, a rare endemic plant, were developed as a sustainable source of phenolic acids. Various shoot and root cultures were established and scaled up in a sprinkle bioreactor. A multiplication rate of 7.2 shoots per explant was achieved. HPLC-PDA-ESI-HRMS analysis revealed the presence of rosmarinic acid (RA) and lithospermic acid B (LAB) as the main secondary metabolites in both the shoot and root cultures. The maximum RA (30.0 & PLUSMN; 3.2 mg/g DW) and LAB (49.3 & PLUSMN; 15.5 mg/g DW) yields were determined in root-regenerated shoots. The strongest free radical scavenging activity (87.4 & PLUSMN; 1.1%), according to 2,2-diphenyl-1-picrylhydrazyl-hydrate assay, was noted for roots cultivated in a DCR medium. The highest reducing power (2.3 & mu;M & PLUSMN; 0.4 TE/g DW), determined by the ferric-reducing antioxidant power assay, was noted for shoots cultivated on an SH medium containing 0.5 mg/L 6-benzylaminopurine. A genetic analysis performed using random amplified polymorphic DNA and start codon targeted markers revealed genetic variation of 62.8% to 96.5% among the investigated shoots and roots. This variability reflects the capacity of cultivated shoots and roots to produce phenolic compounds.

Automated summary

The in vitro cultures of Rindera graeca were developed to provide a sustainable source of phenolic acids. Both shoot and root cultures were established and yielded high levels of rosmarinic acid and lithospermic acid B. The highest antioxidant activity was observed in roots cultivated in DCR medium, while the highest reducing power was observed in shoots cultured on an SH medium with 0.5 mg/L 6-benzylaminopurine. Genetic analysis showed significant variation among the investigated shoots and roots, indicating the ability of cultivated tissues to produce phenolic compounds.