Extraction Optimization and Qualitative/Quantitative Determination of Bioactive Abietane-Type Diterpenes from Three Salvia Species (Common Sage, Greek Sage and Rosemary) by 1 H-qNMR.

The objective of this study was the optimization of the extraction process and the qualitative and quantitative determination of the bioactive metabolites: 12- O -methylcarnosic acid (12MCA), carnosic acid (CA), carnosol (CS), 7- O -methyl- epi -rosmanol (7MER) and rosmanol (RO) in infusions, decoctions, turbulent flow extracts, tinctures and oleolites from three Salvia species: Salvia officinalis L. (common sage, SO ), Salvia fruticosa Mill. (Greek sage, SF ) and Salvia rosmarinus Spenn (syn Rosmarinus officinalis L.) (rosemary, SR ), using Quantitative Proton Nuclear Magnetic Resonance Spectroscopy (1 H-qNMR). Regarding the aqueous extracts, decoctions appeared to be richer sources of the studied metabolites than infusions among the three plants. For SR , the turbulent flow extraction under heating was the most efficient one. The optimum time for the preparation of decoctions was found to be 5 min for SF and SO and 15 min for SR . It is noteworthy that SR tinctures were not stable in time due to decomposition of the abietane-type diterpenes CA and CS because of the polar solvent used for their preparation. Contrary to this finding, the oleolites of SR appeared to be very stable. Olive oil as a solvent for extraction was very protective for the contained abietane-type diterpenes. A preliminary stability study on the effect of the storage time of the SF on the abietane-type diterpenes content showed that the total quantity of abietanes decreased by 16.51% and 40.79% after 12 and 36 months, respectively. The results of this investigation also demonstrated that 1 H-qNMR is very useful for the analysis of sensitive metabolites, like abietane-type diterpenes, that can be influenced by solvents used in chromatographic analysis.