Biodynamic Substrate for the Optimization of Biomass and Constitution of Metabolites of Plectranthus Ornatus

Abstract

The Plectranthus ornatus Codd. (also known as acetaminofem and boldo) has been found to have various pharmaceutical uses, including insecticidal properties. The metabolite composition of P. ornatus varies depending on soil and climatic conditions. The objective of this study was to optimize the growth and metabolite composition of P. ornatus (N = 72) through biodynamic substrate cultivation in Machetá-Cundinamarca, Colombia, located at 1850 masl, over a period of 60 days. Four different substrates were tested: sandy, vermicompost, horse manure, and biodynamic substrate, with the aim of identifying significant differences that would indicate optimization.The study evaluated root growth, plant material growth, and relative metabolite amounts (%) present in an ethanolic extract obtained under the same conditions. Additionally, the volatile fraction was identified using HS-SPME/GC-MS, and soil analysis was performed. The results showed that the plants grown in the biodynamic substrate had the highest growth in plant material and root (p < 0.05), while the plants grown in the sandy substrate had the highest concentration of volatile fraction in the extract. Furthermore, the plants grown in the biodynamic substrate exhibited greater vitality, and the physicochemical/microbiological composition of this substrate at the end of the trial showed a higher concentration of nutrients required for aromatics cultivation and a higher concentration of nitrogen-fixing bacteria.In conclusion, this study suggests that in the long term, the biodynamic substrate may be more efficient in obtaining metabolites of pharmaceutical interest, and a combination with sandy substrate should be considered for optimal results.